<SEC-DOCUMENT>0001193125-22-144344.txt : 20220509
<SEC-HEADER>0001193125-22-144344.hdr.sgml : 20220509
<ACCEPTANCE-DATETIME>20220509080629
ACCESSION NUMBER:		0001193125-22-144344
CONFORMED SUBMISSION TYPE:	6-K
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20220509
FILED AS OF DATE:		20220509
DATE AS OF CHANGE:		20220509

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Mereo Biopharma Group plc
		CENTRAL INDEX KEY:			0001719714
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			X0
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		6-K
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38452
		FILM NUMBER:		22903321

	BUSINESS ADDRESS:	
		STREET 1:		ONE CAVENDISH PLACE
		STREET 2:		FOURTH FLOOR
		CITY:			LONDON
		STATE:			X0
		ZIP:			W1G0QF
		BUSINESS PHONE:		4403330237300

	MAIL ADDRESS:	
		STREET 1:		ONE CAVENDISH PLACE
		STREET 2:		FOURTH FLOOR
		CITY:			LONDON
		STATE:			X0
		ZIP:			W1G0QF
</SEC-HEADER>
<DOCUMENT>
<TYPE>6-K
<SEQUENCE>1
<FILENAME>d272240d6k.htm
<DESCRIPTION>6-K
<TEXT>
<HTML><HEAD>
<TITLE>6-K</TITLE>
</HEAD>
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<Center><DIV STYLE="width:8.5in" align="left">
 <P STYLE="line-height:1.0pt;margin-top:0pt;margin-bottom:0pt;border-bottom:1px solid #000000">&nbsp;</P>
<P STYLE="line-height:3.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1px solid #000000">&nbsp;</P> <P STYLE="margin-top:4pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>UNITED STATES </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>SECURITIES AND EXCHANGE COMMISSION </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman" ALIGN="center"><B>WASHINGTON, D.C. 20549 </B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center>
<P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>FORM <FONT
STYLE="white-space:nowrap">6-K</FONT> </B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center>
<P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman" ALIGN="center"><B>REPORT OF
FOREIGN PRIVATE ISSUER </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman" ALIGN="center"><B>PURSUANT TO RULE <FONT STYLE="white-space:nowrap">13a-16</FONT> or
<FONT STYLE="white-space:nowrap">15d-16</FONT> </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman" ALIGN="center"><B>UNDER THE&nbsp;SECURITIES EXCHANGE ACT OF 1934 </B></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>For the month of May, 2022 </B></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Commission File Number: <FONT STYLE="white-space:nowrap">001-38452</FONT> </B></P>
<P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center> <P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:24pt; font-family:Times New Roman" ALIGN="center"><B>MEREO BIOPHARMA GROUP PLC </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>(Translation of registrant&#146;s name into English) </B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center>
<P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>4<SUP
STYLE="font-size:85%; vertical-align:top">th</SUP> Floor, One Cavendish Place,</B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>London, W1G 0QF, United Kingdom</B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(Address of principal executive office) </B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center>
<P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Indicate by
check mark whether the registrant files or will file annual reports under cover of Form <FONT STYLE="white-space:nowrap">20-F</FONT> or Form <FONT STYLE="white-space:nowrap">40-F.</FONT> </P>
<P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">Form
<FONT STYLE="white-space:nowrap">20-F&nbsp;&nbsp;&nbsp;&nbsp;&#9746;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Form</FONT> <FONT STYLE="white-space:nowrap">40-F&nbsp;&nbsp;&#9744;</FONT> </P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Indicate by check mark if the registrant is submitting the Form <FONT STYLE="white-space:nowrap">6-K</FONT> in paper as permitted by Regulation
<FONT STYLE="white-space:nowrap">S-T</FONT> Rule 101(b)(1):&nbsp;&nbsp;&#9744; </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Indicate by check mark if the registrant is submitting the
Form <FONT STYLE="white-space:nowrap">6-K</FONT> in paper as permitted by Regulation <FONT STYLE="white-space:nowrap">S-T</FONT> Rule 101(b)(7):&nbsp;&nbsp;&#9744; </P> <P STYLE="font-size:10pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<P STYLE="line-height:1.0pt;margin-top:0pt;margin-bottom:0pt;border-bottom:1px solid #000000">&nbsp;</P> <P STYLE="line-height:3.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1px solid #000000">&nbsp;</P>
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<Center><DIV STYLE="width:8.5in" align="left">
 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>Mereo BioPharma Group plc Announces Positive <FONT STYLE="white-space:nowrap">Top-Line</FONT> Efficacy
and Safety Data from &#147;ASTRAEUS&#148; Phase 2 Trial of Alvelestat in <FONT STYLE="white-space:nowrap">Alpha-1</FONT> Antitrypsin Deficiency-associated Emphysema </B></P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">On May&nbsp;9, 2022, Mereo BioPharma Group plc (the &#147;Company&#148;) announced positive
<FONT STYLE="white-space:nowrap">top-line</FONT> efficacy and safety results from &#147;ASTRAEUS&#148; a Phase 2 study of the investigational oral neutrophil elastase (NE) inhibitor, alvelestat <FONT STYLE="white-space:nowrap">(MPH-966),</FONT> in
patients with severe <FONT STYLE="white-space:nowrap">alpha-1</FONT> antitrypsin deficiency-related emphysema, or AATD. The double-blind placebo-controlled study evaluated two different doses of alvelestat (high or low dose) or placebo, over a <FONT
STYLE="white-space:nowrap">12-week</FONT> period (at weeks four, eight and 12) and the effect on three primary biomarker endpoints associated with AATD-related lung disease <FONT STYLE="white-space:nowrap">(AATD-LD),</FONT> blood neutrophil elastase
activity, A<FONT STYLE="FONT-FAMILY:SYMBOL">&#097;</FONT><FONT STYLE="white-space:nowrap">-val</FONT><SUP STYLE="font-size:85%; vertical-align:top">360</SUP> and the elastin breakdown product, desmosine. A total of 99 patients were enrolled and 98
patients were dosed in the study. At the high dose, alvelestat demonstrated statistically significant changes versus placebo in all three primary biomarker endpoints. </P>
<P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>ASTRAEUS Study Design Overview </B></P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">ASTRAEUS (ClinicalTrials.gov Identifier: NCT03636347) was a randomized double-blind placebo-controlled study in patients
na&iuml;ve to augmentation therapy or following a <FONT STYLE="white-space:nowrap">six-month</FONT> <FONT STYLE="white-space:nowrap">wash-out</FONT> period. The study enrolled 99 adults with severe AATD related emphysema across 26 sites in North
America, Europe and the U.K. of which 98 were dosed. To support the use of a biomarker development strategy interrogating the pathogenic pathway, an amendment elevated two secondary biomarkers (neutrophil elastase (NE) activity and A<FONT
STYLE="FONT-FAMILY:SYMBOL">&#097;</FONT><FONT STYLE="white-space:nowrap">-val</FONT><SUP STYLE="font-size:85%; vertical-align:top">360</SUP>) to primary endpoints in addition to desmosine resulting in three primary biomarker primary endpoints.
Patients were randomized to one of three different arms, high dose, low dose or placebo, following Independent Safety Data Monitoring Committee (IDMC) review of the initial cohorts. The protocol allowed prioritization of enrollment to the high dose
arm in the case of recruitment challenges and this change was implemented during the <FONT STYLE="white-space:nowrap">COVID-19</FONT> pandemic. The Company made the decision to close the study when it was determined an adequate number of subjects
had been recruited to the high dose arm to assess the primary endpoints. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Patients underwent a twelve-week dosing period
followed by a four-week <FONT STYLE="white-space:nowrap">follow-up.</FONT> The primary endpoints included within individual percentage change from baseline up to end of treatment within a treatment arm and in comparison to placebo at weeks, four,
eight and 12 in blood NE activity, blood A<FONT STYLE="FONT-FAMILY:SYMBOL">&#097;</FONT><FONT STYLE="white-space:nowrap">-Val</FONT><SUP STYLE="font-size:85%; vertical-align:top">360</SUP> levels and plasma desmosine levels. The secondary endpoints
were the proportion of subjects with NE below the limit of quantitation and Pharmacokinetic (PK), safety and tolerability. Exploratory endpoints included rate of acute exacerbations of COPD, pulmonary function tests, St. Georges Respiratory
questionnaire, inflammatory and lung damage biomarkers. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">The study was originally designed to enroll 165 patients,
however, the Company took the decision to close the study when it was determined an adequate number of subjects were recruited to the high dose arm to assess the primary endpoints, with a total of 99&nbsp;patients enrolled. </P>
<P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>Enrollment Overview </B></P> <P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">At
the close of the study the number of patients enrolled and completed in the arms were, 41 in the high dose arm, 22 in the low dose arm and 36 in the placebo arm. All patients were of the severe alpha
<FONT STYLE="white-space:nowrap">1-antitrypsin</FONT> (&#147;AAT&#148;) deficiency (PiZZ) genotype representing the more severe patient population which occurs in Z allele homozygotes and is associated with early-onset emphysema. All patients had
low AAT levels and only 11% of the patients had received prior augmentation therapy. The <FONT STYLE="white-space:nowrap">wash-out</FONT> period was greater than two years for those patients who had received prior augmentation therapy. </P>
<P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>ASTRAEUS Efficacy </B></P> <P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">The
study enrolled 99 patients with 98 patients being dosed. The full analysis set (FAS) includes subjects with at least one measurement of a primary endpoint post baseline, a total of 94 patients. Due to the known effect of acute respiratory
exacerbations increasing A<FONT STYLE="FONT-FAMILY:SYMBOL">&#097;</FONT><FONT STYLE="white-space:nowrap">-val</FONT><SUP STYLE="font-size:85%; vertical-align:top">360</SUP> and desmosine in AATD patients, a per protocol set (PPS) was defined in the
Statistical Analysis Plan and identified prior to unblinding excluding these subjects who had moderate/severe acute exacerbations. The per protocol set includes 84&nbsp;patients. Data from the three primary endpoints are presented below. </P>
</DIV></Center>


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<Center><DIV STYLE="width:8.5in" align="left">
 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>Neutrophil Elastase Activity </B></P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Statistically significant inhibition of NE was observed from first assessment at week four, and this was maintained over the
course of the study. The effect was greater in the high dose compared to the low dose. No significant changes from baseline were observed in the placebo arm. </P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="92%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" ALIGN="center">


<TR>

<TD WIDTH="62%"></TD>

<TD VALIGN="bottom" WIDTH="7%"></TD>
<TD></TD>
<TD></TD>
<TD></TD>

<TD VALIGN="bottom" WIDTH="6%"></TD>
<TD></TD>
<TD></TD>
<TD></TD>

<TD VALIGN="bottom" WIDTH="6%"></TD>
<TD></TD>
<TD></TD>
<TD></TD>

<TD VALIGN="bottom" WIDTH="6%"></TD>
<TD></TD>
<TD></TD>
<TD></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="bottom" NOWRAP> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; border-bottom:1.00pt solid #000000; display:table-cell; font-size:8pt; font-family:Times New Roman; ">Week</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="14" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000">Within Group % Change from Baseline LSM</TD>
<TD VALIGN="bottom">&nbsp;</TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>Low&nbsp;Dose&nbsp;(n=20)</I></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>P&nbsp;value</I></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>High&nbsp;dose&nbsp;(n=39)</I></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>P value</I></TD>
<TD VALIGN="bottom">&nbsp;</TD></TR>


<TR BGCOLOR="#cceeff" STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">4</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">-89.9</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">0.001</TD>
<TD NOWRAP VALIGN="bottom">**&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">-88.9</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">&lt;0.001</TD>
<TD NOWRAP VALIGN="bottom">***&nbsp;</TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">8</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">-83.5</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">0.006</TD>
<TD NOWRAP VALIGN="bottom">**&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">-93.9</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">&lt;0.001</TD>
<TD NOWRAP VALIGN="bottom">***&nbsp;</TD></TR>
<TR BGCOLOR="#cceeff" STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">12</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">-81.7</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">0.026</TD>
<TD NOWRAP VALIGN="bottom">*&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">-87.8</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">&lt;0.001</TD>
<TD NOWRAP VALIGN="bottom">***&nbsp;</TD></TR>
</TABLE> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Changes versus placebo *&lt; 0.02, ** &lt; 0.01, ***&lt;0.001 (LSM &#150; least squared means). </P>
<P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>A</B><FONT STYLE="FONT-FAMILY:SYMBOL">&#097;</FONT><B></B><B><FONT STYLE="white-space:nowrap">-val</FONT><SUP STYLE="font-size:85%; vertical-align:top">360</SUP>
</B></P> <P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">At the high dose of alvelestat,
A<FONT STYLE="FONT-FAMILY:SYMBOL">&#097;</FONT><FONT STYLE="white-space:nowrap">-val</FONT><SUP STYLE="font-size:85%; vertical-align:top">360</SUP><B> </B>decreased below baseline at week four with progressive decreases resulting in statistical
significance verses placebo at weeks eight and 12. The placebo showed an increase at all time points. </P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="76%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" ALIGN="center">


<TR>

<TD WIDTH="80%"></TD>

<TD VALIGN="bottom" WIDTH="6%"></TD>
<TD></TD>
<TD></TD>
<TD></TD>

<TD VALIGN="bottom" WIDTH="5%"></TD>
<TD></TD>
<TD></TD>
<TD></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="bottom" NOWRAP> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; border-bottom:1.00pt solid #000000; display:table-cell; font-size:8pt; font-family:Times New Roman; ">Week</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="6" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000">%&nbsp;Change&nbsp;Alvelestat&nbsp;vs<BR>Placebo LSM</TD>
<TD VALIGN="bottom">&nbsp;</TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>High&nbsp;Dose</I></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>P&nbsp;value</I></TD>
<TD VALIGN="bottom">&nbsp;</TD></TR>


<TR BGCOLOR="#cceeff" STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">4</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">&nbsp;</TD>
<TD VALIGN="top" ALIGN="right">-8.1</TD>
<TD NOWRAP VALIGN="top">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">&nbsp;</TD>
<TD VALIGN="top" ALIGN="right">0.146</TD>
<TD NOWRAP VALIGN="top">&nbsp;</TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">8</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">&nbsp;</TD>
<TD VALIGN="top" ALIGN="right">-27.1</TD>
<TD NOWRAP VALIGN="top">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">&nbsp;</TD>
<TD VALIGN="top" ALIGN="right">0.006</TD>
<TD NOWRAP VALIGN="top">&nbsp;</TD></TR>
<TR BGCOLOR="#cceeff" STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">12</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">&nbsp;</TD>
<TD VALIGN="top" ALIGN="right">-27.6</TD>
<TD NOWRAP VALIGN="top">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">&nbsp;</TD>
<TD VALIGN="top" ALIGN="right">0.002</TD>
<TD NOWRAP VALIGN="top">&nbsp;</TD></TR>
</TABLE> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Smaller effects were observed in the low dose arm, and these generally did not reach statistical significance
(LSM - least squared means). </P>
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<p style="margin-top:1em; margin-bottom:0em; page-break-before:always">
<HR SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">


<Center><DIV STYLE="width:8.5in" align="left">
 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>Desmosine </B></P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">At the high dose of alvelestat desmosine levels decreased with time whereas placebo increased over time. </P>
<P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="92%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" ALIGN="center">


<TR>

<TD WIDTH="70%"></TD>

<TD VALIGN="bottom" WIDTH="4%"></TD>
<TD></TD>
<TD></TD>
<TD></TD>

<TD VALIGN="bottom" WIDTH="3%"></TD>
<TD></TD>
<TD></TD>
<TD></TD>

<TD VALIGN="bottom" WIDTH="3%"></TD>
<TD></TD>
<TD></TD>
<TD></TD>

<TD VALIGN="bottom" WIDTH="3%"></TD>
<TD></TD>
<TD></TD>
<TD></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="bottom" NOWRAP> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; border-bottom:1.00pt solid #000000; display:table-cell; font-size:8pt; font-family:Times New Roman; ">Week</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="14" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000">Within Group % Change from Baseline LSM</TD>
<TD VALIGN="bottom">&nbsp;</TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>High&nbsp;Dose</I></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>P&nbsp;value</I></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>Placebo</I></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>P&nbsp;value</I></TD>
<TD VALIGN="bottom">&nbsp;</TD></TR>


<TR BGCOLOR="#cceeff" STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">4</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">-9.4</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">0.097</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">10.1</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">NS&nbsp;&gt;0.9</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">8</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">-13.7</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">0.035</TD>
<TD NOWRAP VALIGN="bottom">*&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">17.9</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">NS &gt;0.9</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD></TR>
<TR BGCOLOR="#cceeff" STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">12</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">-10.6</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">0.061</TD>
<TD NOWRAP VALIGN="bottom">#&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">18.1</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">NS &gt;0.9</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD></TR>
</TABLE> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">*p = 0.032 alvelestat versus placebo, #p =0.181 alvelestat versus placebo (LSM &#150; least squared means).
</P> <P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">No changes in the level of desmosine in the low dose could be detected at any time point. However, the number of patients
in the low dose arm were small due to the preferential enrollment to the high dose group, reducing the power to detect effects in this arm. </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">The percentage changes in desmosine and
A<FONT STYLE="FONT-FAMILY:SYMBOL">&#097;</FONT><FONT STYLE="white-space:nowrap">-val</FONT><SUP STYLE="font-size:85%; vertical-align:top">360</SUP> at the high dose were comparable to those reported with placebo-controlled augmentation studies
following three and six months of treatment. Desmosine and A<FONT STYLE="FONT-FAMILY:SYMBOL">&#097;</FONT><FONT STYLE="white-space:nowrap">-val</FONT><SUP STYLE="font-size:85%; vertical-align:top">360</SUP> have been demonstrated to correlate with
lung function and lung density in patients with AATD and respond to AAT replacement during weekly intravenous augmentation therapy. </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">The Company plans to complete additional analyses on the other secondary and exploratory endpoints in the second half of 2022.
</P> <P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>Safety and Tolerability </B></P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Consistent with the known safety profile of alvelestat, no safety signals were observed in adverse event (AE) monitoring. Most
AEs were mild to moderate, including within Adverse Events of Special Interest (AESI) which were observed in 23 subjects. AESIs of infection were recorded in 21 subjects and these were of similar frequency and severity in the alvelestat and placebo
arms and were events expected in the disease population. A single AESI of liver enzyme (Alanine Transaminase) elevation <U>&gt;</U>5 x Upper Limit of Normal (ULN), associated with raised Aspartate Transaminase (AST) <U>&gt;</U>2 x ULN, without
raised bilirubin occurred at week 8 in the high dose arm. The event met study drug stopping criteria and the raised transaminase levels dropped over the course of the next 10 days. One case of prolonged QTcF occurred in a subject who was on
medication known to prolong QTcF at entry to the study. This event occurred at the high dose during the week 4 study visit and the study drug was discontinued. There were no incidences of Hy&#146;s law nor deaths on study. </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Treatment emergent adverse events, including SAEs, were more frequent in the alvelestat groups predominantly due to headache.
Dose-escalation for the high dose arm was instigated to manage the headaches. </P> <P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>Updated Cash Balance Update and Guidance </B></P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">As of March&nbsp;31, 2022,&nbsp;the&nbsp;Company had cash and short-term deposits of &pound;84.9&nbsp;million ($111.4 million).
The Company expects its existing cash and short-term deposits will enable it to fund its currently committed clinical trials, operating expenses and capital expenditure requirements into 2024. </P>
<P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>Next Steps </B></P> <P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">The Company
plans to analyze the additional data on the secondary and exploratory endpoints in the second half of 2022 and to then engage with the regulators in the US and Europe for an End of Phase 2 meeting to determine the design of a pivotal registrational
trial for alvelestat for the treatment of <FONT STYLE="white-space:nowrap">AATD-LD.</FONT> </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">The investigator led ATALANta
trial studying alvelestat in a broader range of patient populations, including other genotypes and those on augmentation therapy, is expected to read out in the first half of 2023. </P>
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 <P STYLE="margin-top:0pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">The contents of this Report on Form
<FONT STYLE="white-space:nowrap">6-K</FONT> (excluding Exhibit 99.1 hereto) are incorporated by reference in the Company&#146;s registration statement on Form <FONT STYLE="white-space:nowrap">F-3</FONT> (File
<FONT STYLE="white-space:nowrap">No.&nbsp;333-258495).</FONT> </P> <P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>About <FONT STYLE="white-space:nowrap">AATD-LD</FONT> </B></P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><FONT STYLE="white-space:nowrap">Alpha-1</FONT> antitrypsin deficiency is a genetic condition that results in progressive
alveolar destruction leading to emphysema. People with <FONT STYLE="white-space:nowrap">alpha-1</FONT> antitrypsin deficiency have significantly reduced levels of AAT, a protective protein that inhibits the protease, neutrophil elastase. Unopposed
neutrophil elastase is believed to the key enzyme in the causal pathologic pathway of <FONT STYLE="white-space:nowrap">AATD-LD.</FONT> <FONT STYLE="white-space:nowrap">AATD-LD</FONT> presents at age 20 to 50 with symptoms including, shortness of
breath, cough, and reduced exercise tolerance. People with AATD may progress to chronic oxygen therapy, lung surgery, transplant, and death. </P> <P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>About
Alvelestat </B></P> <P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Alvelestat <FONT STYLE="white-space:nowrap">(MPH-966)</FONT> is a novel, oral small molecule designed to
inhibit neutrophil elastase, a key enzyme involved in the destruction of lung tissue. Prior to Mereo BioPharma licensing alvelestat from AstraZeneca (AZ), trials across COPD, bronchiectasis and cystic fibrosis (CF) had been performed. Over 1,000
subjects were exposed to alvelestat, with signals of efficacy in both bronchiectasis and CF. Statistically significant reduction in urine desmosine was seen in the CF trial and an improvement in Forced Expiratory Volume in 1 second (FEV<SUB
STYLE="font-size:85%; vertical-align:bottom">1</SUB>) of 100ml vs placebo in the bronchiectasis trial. Alvelestat is also under clinical investigation in an ongoing Phase 1b/2 investigator-sponsored study Bronchiolitis Obliterans Syndrome (BOS)
following allogeneic hematopoietic stem cell transplant. Interim data from the phase 1b portion of the study showed progressive reduction of plasma desmosine over 8 weeks in 6 of 7 treated patients, all of whom had improved or stable lung disease
(FEV<SUB STYLE="font-size:85%; vertical-align:bottom">1</SUB>) and reduction in stimulated neutrophil elastase activity and fibrosis biomarkers. Mereo reported a positive Phase 1b/2 trial in <FONT STYLE="white-space:nowrap">COVID-19</FONT> which was
completed in 2021 and showed alvelestat was safe and well tolerated. Alvelestat on top of standard of care resulted in a more rapid time to improvement in WHO Disease Severity score of &gt;=2 in the first <FONT STYLE="white-space:nowrap">5-7</FONT>
days compared to placebo plus standard of care. </P> <P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>About Mereo BioPharma Group plc </B></P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Mereo BioPharma Group plc is a biopharmaceutical company focused on the development of innovative therapeutics that aim to
improve outcomes for oncology and rare diseases and plans to commercialize selected rare disease programs. The Company has developed a portfolio of six clinical stage product candidates. Mereo&#146;s lead oncology product candidate, etigilimab
(anti-TIGIT), has advanced into an open label Phase 1b/2 basket study evaluating anti-TIGIT in combination with an <FONT STYLE="white-space:nowrap"><FONT STYLE="white-space:nowrap">anti-PD-1</FONT></FONT> in a range of tumor types including three
rare tumors and three gynecological carcinomas, cervical, ovarian, and endometrial carcinomas. The Company&#146;s second oncology product, navicixizumab, for the treatment of late line ovarian cancer, has completed a Phase 1 study and has been
partnered with OncXerna Therapeutics, Inc., formerly Oncologie, Inc. The Company has two rare disease product candidates, alvelestat for the treatment of severe <FONT STYLE="white-space:nowrap">Alpha-1</FONT> antitrypsin deficiency (AATD) and
Bronchiolitis Obliterans Syndrome (BOS), and setrusumab for the treatment of osteogenesis imperfecta (OI). Alvelestat has recently received U.S. Orphan Drug Designation for the treatment of AATD and positive
<FONT STYLE="white-space:nowrap">top-line</FONT> data were recently reported from a Phase 2 <FONT STYLE="white-space:nowrap"><FONT STYLE="white-space:nowrap">proof-of-concept</FONT></FONT> study in North America, Europe and the UK. The
Company&#146;s partner, Ultragenyx Pharmaceutical, Inc., has initiated a pivotal Phase 2/3 pediatric study in young adults <FONT STYLE="white-space:nowrap">(5-25</FONT> years old) for setrusumab in OI and expects to initiate a study in pediatric
patients <FONT STYLE="white-space:nowrap">(2-5</FONT> years old) in the second half of 2022. </P> <P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>Forward-Looking Statements </B></P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">This Report on <FONT STYLE="white-space:nowrap">Form&nbsp;6-K&nbsp;contains</FONT> &#147;forward-looking statements.&#148; All
statements other than statements of historical fact contained herein are forward-looking statements within the meaning of Section&nbsp;27A of the Securities Act of 1933, as amended (the &#147;Securities Act&#148;), and Section&nbsp;21E of the
Securities Exchange Act of 1934, as amended (the &#147;Exchange Act&#148;). Forward-looking statements usually relate to future events and anticipated revenues, earnings, cash flows or other aspects of our operations or operating results.
Forward-looking statements are often identified by the words &#147;believe,&#148; &#147;expect,&#148; &#147;anticipate,&#148; &#147;plan,&#148; &#147;intend,&#148; &#147;foresee,&#148; &#147;should,&#148; &#147;would,&#148; &#147;could,&#148;
&#147;may,&#148; &#147;estimate,&#148; &#147;outlook&#148; and similar expressions, including the negative thereof. The absence of these words, however, does not mean that the statements are not forward-looking. These forward-looking statements are
based on the Company&#146;s current expectations, beliefs and assumptions concerning future developments and business conditions and their potential effect on the Company. While management believes that these forward-looking statements are
reasonable as and when made, there can be no assurance that future developments affecting the Company will be those that it anticipates. </P>
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 <P STYLE="margin-top:0pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">All of the Company&#146;s forward-looking statements involve known and
unknown risks and uncertainties some of which are significant or beyond its control and assumptions that could cause actual results to differ materially from the Company&#146;s historical experience and its present expectations or projections. You
should carefully consider the foregoing factors and the other risks and uncertainties that affect the Company&#146;s business, including those described in the &#147;Risk Factors&#148; section of its latest Annual Report <FONT
STYLE="white-space:nowrap"><FONT STYLE="white-space:nowrap">on&nbsp;Form&nbsp;20-F,&nbsp;reports&nbsp;on&nbsp;Form&nbsp;6-K&nbsp;and&nbsp;other</FONT></FONT> documents furnished or filed from time to time by the Company with the Securities and
Exchange Commission. The Company wishes to caution you not to place undue reliance on any forward-looking statements, which speak only as of the date hereof. The Company undertakes no obligation to publicly update or revise any of our
forward-looking statements after the date they are made, whether as a result of new information, future events or otherwise, except to the extent required by law. </P>
<P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B><U>Exhibit Index </U></B></P> <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B><U>Exhibits </U></B></P>
<P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
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<TD VALIGN="top" NOWRAP>99.1</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top"><A HREF="d272240dex991.htm">Press release dated May&nbsp;
9, 2022 titled &#147;Mereo BioPharma Announces Positive <FONT STYLE="white-space:nowrap">Top-Line</FONT> Efficacy and Safety Data from &#147;ASTRAEUS&#148; Phase 2 Trial of Alvelestat in Alpha-1 Antitrypsin Deficiency-associated
Emphysema.&#148;</A></TD></TR>
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 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>SIGNATURES </B></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed
on its behalf by the undersigned, thereunto duly authorized. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Date: May&nbsp;9, 2022 </P>
<P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><DIV ALIGN="right">
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<TD VALIGN="top" COLSPAN="3"> <P ALIGN="justify" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt"><B>MEREO BIOPHARMA GROUP PLC</B></P></TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P ALIGN="justify" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt">By:</P></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:1pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman" ALIGN="justify">/s/ Christine Fox</P></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top"> <P ALIGN="justify" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt">Name:&nbsp;&nbsp;&nbsp;Christine Fox</P></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top"> <P ALIGN="justify" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt">Title:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Chief Financial Officer</P></TD></TR>
</TABLE></DIV>
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<Center><DIV STYLE="width:8.5in" align="left">
 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="right"><B>Exhibit 99.1 </B></P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Mereo BioPharma announces Positive <FONT STYLE="white-space:nowrap">Top-Line</FONT> Efficacy and Safety Data from &#147;ASTRAEUS&#148; Phase
2 Trial of Alvelestat in <FONT STYLE="white-space:nowrap">Alpha-1</FONT> Antitrypsin Deficiency-associated Emphysema </B></P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><I>Statistically
significant inhibition of blood neutrophil elastase activity of up to 90% in patients in both high and low dose alvelestat groups throughout the <FONT STYLE="white-space:nowrap">12-week</FONT> dosing period </I></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><I>Statistically significant reductions in the biomarkers A</I><FONT STYLE="FONT-FAMILY:SYMBOL">&#097;</FONT><I></I><I><FONT
STYLE="white-space:nowrap">-val</FONT><SUP STYLE="font-size:85%; vertical-align:top">360</SUP> and desmosine at the high dose demonstrating clear impact of alvelestat on the pathogenic pathway of AATD-lung disease </I></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><I>No safety signals were associated with alvelestat </I></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><I>Conference Call Today at 10:30 a.m. ET </I></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><B>London and Redwood City, Calif., May</B><B></B><B>&nbsp;9, 2022</B>&nbsp;&#150; Mereo BioPharma Group plc (NASDAQ: MREO),
(&#147;Mereo&#148; or &#147;the Company&#148;), a clinical-stage biopharmaceutical company focused on oncology and rare diseases, today announced positive <FONT STYLE="white-space:nowrap">top-line</FONT> efficacy and safety results from
&#147;ASTRAEUS&#148; a Phase 2 study of the investigational oral neutrophil elastase (NE) inhibitor, alvelestat <FONT STYLE="white-space:nowrap">(MPH-966),</FONT> in patients with severe <FONT STYLE="white-space:nowrap">alpha-1</FONT> antitrypsin
deficiency-associated emphysema. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">The double-blind placebo-controlled study evaluated two different doses of alvelestat (high or low dose)
or placebo, over a <FONT STYLE="white-space:nowrap">12-week</FONT> period (at weeks four, eight and 12) and the effect on three primary biomarker endpoints associated with AATD-related lung disease <FONT STYLE="white-space:nowrap">(AATD-LD),</FONT>
blood neutrophil elastase activity, A<FONT STYLE="FONT-FAMILY:SYMBOL">&#097;</FONT><FONT STYLE="white-space:nowrap">-val</FONT><SUP STYLE="font-size:85%; vertical-align:top">360</SUP> and the elastin breakdown product, desmosine. A total of 99
patients were enrolled and 98 patients were dosed in the study. At the high dose, alvelestat demonstrated statistically significant changes versus placebo in all three primary biomarker endpoints. </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">&#147;These positive <FONT STYLE="white-space:nowrap">top-line</FONT> results demonstrate the clear impact of alvelestat on key known
biomarkers along the pathogenic pathway of <FONT STYLE="white-space:nowrap">AATD-LD,&#148;</FONT> said Dr.&nbsp;Denise Scots-Knight, Chief Executive Officer of Mereo. &#147;Alvelestat has the potential to be the <FONT STYLE="white-space:nowrap"><FONT
STYLE="white-space:nowrap">first-in-class</FONT></FONT> oral neutrophil elastase inhibitor for the treatment of <FONT STYLE="white-space:nowrap">AATD-LD.</FONT> We look forward to analyzing the additional data on the secondary and exploratory
endpoints and to engaging with the regulators on the design of a pivotal study.&#148; </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Mereo is grateful for the commitment of individuals
with AATD who volunteered to take part in the study, to the investigators and their teams, especially as the study was conducted during height of the <FONT STYLE="white-space:nowrap">COVID-19</FONT> pandemic. The Company also thanks the <FONT
STYLE="white-space:nowrap">Alpha-1</FONT> Foundation for their funding in support of the study. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">&#147;We are exceptionally pleased with
these results, for the first time demonstrating the specific inhibition of neutrophil elastase on biomarkers relevant to the disease pathway in patients with severe AATD-related emphysema. As an oral therapy, alvelestat has the potential to
significantly improve the management of AATD, and we look forward to further development to increase the therapeutic options for patients,&#148; stated Prof. Robert Stockley, Lung Investigation Unit, University of Birmingham (United Kingdom) and
Chief Investigator of the ASTRAEUS trial. </P>
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 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Prof. Mark Dransfield, of the University of Alabama at Birmingham (United States) and
principal investigator of the ATALANTa study (a companion trial to ASTRAEUS), stated &#147;We are delighted to see these positive results from ASTRAEUS and will be building on the data with our ATALANTa study investigating alvelestat in a broader
group of patients, including those already on AAT augmentation. We look forward to the additional data readout adding to the learnings from ASTRAEUS presented today.&#148; </P>
<P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>Conference Call and Webcast </B></P> <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><B></B>Mereo
BioPharma will hold a conference call today, May&nbsp;9, at 10:30am EDT. To participate by telephone, please dial US (toll free): (866) <FONT STYLE="white-space:nowrap">374-5140</FONT> or international: (404)
<FONT STYLE="white-space:nowrap">400-0571.</FONT> The conference ID number is 50222760. To view the slideshow please use the live webcast at <U>https://wsw.com/webcast/cc/mph.l3/1480428</U> or through the Investors section of the Company&#146;s
website at www.mereobiopharma.com/investors. An archived replay of the webcast will be available on the Company&#146;s website for two weeks following the live presentation. </P>
<P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>ASTRAEUS Study Design Overview </B></P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><B></B>ASTRAEUS (ClinicalTrials.gov Identifier: NCT03636347) was a randomized double-blind placebo-controlled study in patients na&iuml;ve to
augmentation or following a <FONT STYLE="white-space:nowrap">6-month</FONT> <FONT STYLE="white-space:nowrap">wash-out</FONT> period. The study enrolled 99 adults with severe AATD related emphysema across 26 sites in North America, EU and U.K. of
which 98 were dosed. To support the use of a biomarker development strategy interrogating the pathogenic pathway, as previously announced, an amendment elevated two secondary biomarkers (NE activity and
A<FONT STYLE="FONT-FAMILY:SYMBOL">&#097;</FONT><FONT STYLE="white-space:nowrap">-val</FONT><SUP STYLE="font-size:85%; vertical-align:top">360</SUP>) to primary endpoints in addition to desmosine resulting in three biomarker primary endpoints.
Patients were randomized to one of three different arms, high dose, low dose or placebo, following Independent Safety Data Monitoring Committee (IDMC) review of the safety from the initial cohorts. As previously announced, the protocol allowed
prioritization of enrollment to the high dose arm in the case of recruitment challenges and this change was implemented during the <FONT STYLE="white-space:nowrap">COVID-19</FONT> pandemic. As previously announced, the Company took the decision to
close the study when it was determined an adequate number of patients had been recruited to the high dose arm to assess the primary endpoints. </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Patients underwent a twelve-week dosing period followed by a four-week <FONT STYLE="white-space:nowrap">follow-up.</FONT> The primary
endpoints included within individual % change from baseline up to end of treatment within a treatment arm and in comparison to placebo at weeks, four, eight and 12 in blood neutrophil elastase activity,
A<FONT STYLE="FONT-FAMILY:SYMBOL">&#097;</FONT><FONT STYLE="white-space:nowrap">-Val</FONT><SUP STYLE="font-size:85%; vertical-align:top">360 </SUP>levels and desmosine levels. The secondary endpoints were the proportion of patients with NE below
the limit of quantitation and PK, safety and tolerability. Exploratory endpoints included rate of acute exacerbations of COPD, pulmonary function tests, St George&#146;s Respiratory Questionnaire, inflammatory and lung damage biomarkers. </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">The study was originally designed to enroll 165 patients, however, the Company took the decision to close the study when it was determined an
adequate number of subjects were recruited to the high dose arm to assess the primary endpoints, with a total of 99 patients enrolled. </P>
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 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><B>Enrollment Overview</B> </P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><B></B>At the close of the study the number of patients enrolled and completed in the arms were, 41 in the high dose arm, 22 in the low dose
arm and 36 in the placebo arm. All patients were of the PiZZ genotype representing the more severe patient population which occurs in Z allele homozygotes and is associated with early-onset emphysema. All patients had low AAT levels and only 11% of
the patients had received prior augmentation therapy. The <FONT STYLE="white-space:nowrap">wash-out</FONT> period was greater than two years for those patients who had received prior augmentation therapy. </P>
<P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><B>ASTRAEUS Efficacy</B> </P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><B></B>The study enrolled 99 patients with 98 patients being dosed. The full analysis set (FAS) includes subjects with at least one measurement
of a primary endpoint post baseline, a total of 94 patients. Due to the known effect of acute respiratory exacerbations increasing A<FONT STYLE="FONT-FAMILY:SYMBOL">&#097;</FONT><FONT STYLE="white-space:nowrap">-val</FONT><SUP
STYLE="font-size:85%; vertical-align:top">360</SUP><B> </B>and desmosine in AATD patients, a per protocol set (PPS) was defined in the Statistical Analysis Plan and identified prior to unblinding excluding these subjects who had moderate/severe
acute exacerbations. The per protocol set includes 84 patients. Data from the three primary endpoints are presented below. </P> <P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><B>Neutrophil
Elastase Activity</B> </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><B></B>Statistically significant inhibition of NE was observed from first assessment at week four, and this was
maintained over the course of the study. The effect was greater in the high dose compared to the low dose. No significant changes from baseline were observed in the placebo arm. </P>
<P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="92%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" ALIGN="center">


<TR>

<TD WIDTH="62%"></TD>

<TD VALIGN="bottom" WIDTH="7%"></TD>
<TD></TD>
<TD></TD>
<TD></TD>

<TD VALIGN="bottom" WIDTH="6%"></TD>
<TD></TD>
<TD></TD>
<TD></TD>

<TD VALIGN="bottom" WIDTH="6%"></TD>
<TD></TD>
<TD></TD>
<TD></TD>

<TD VALIGN="bottom" WIDTH="6%"></TD>
<TD></TD>
<TD></TD>
<TD></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="bottom" NOWRAP> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; border-bottom:1.00pt solid #000000; display:table-cell; font-size:8pt; font-family:Times New Roman; ">Week</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="14" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000">Within&nbsp;Group&nbsp;%&nbsp;Change&nbsp;from&nbsp;Baseline&nbsp;LSM</TD>
<TD VALIGN="bottom">&nbsp;</TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>Low&nbsp;Dose&nbsp;(n=20)</I></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>P&nbsp;value</I></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>High&nbsp;dose&nbsp;(n=39)</I></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>P value</I></TD>
<TD VALIGN="bottom">&nbsp;</TD></TR>


<TR BGCOLOR="#cceeff" STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">4</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">-89.9</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">0.001</TD>
<TD NOWRAP VALIGN="bottom">**&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">-88.9</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">&lt;0.001</TD>
<TD NOWRAP VALIGN="bottom">***&nbsp;</TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">8</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">-83.5</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">0.006</TD>
<TD NOWRAP VALIGN="bottom">**&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">-93.9</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">&lt;0.001</TD>
<TD NOWRAP VALIGN="bottom">***&nbsp;</TD></TR>
<TR BGCOLOR="#cceeff" STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">12</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">-81.7</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">0.026</TD>
<TD NOWRAP VALIGN="bottom">*&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">-87.8</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">&lt;0.001</TD>
<TD NOWRAP VALIGN="bottom">***&nbsp;</TD></TR>
</TABLE> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Changes versus placebo *&lt; 0.02, ** &lt; 0.01, ***&lt;0.001 (LSM &#150; least squared means). </P>
<P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><B>A</B><FONT STYLE="FONT-FAMILY:SYMBOL">&#097;</FONT><B></B><B><FONT STYLE="white-space:nowrap">-val</FONT></B><B><SUP
STYLE="font-size:85%; vertical-align:top">360</SUP></B><B> </B></P> <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><B></B>At the high dose of alvelestat,
A<FONT STYLE="FONT-FAMILY:SYMBOL">&#097;</FONT><FONT STYLE="white-space:nowrap">-val</FONT><SUP STYLE="font-size:85%; vertical-align:top">360</SUP><B> </B>decreased below baseline at week four with progressive decreases resulting in statistical
significance versus placebo at weeks 8 and 12. The placebo showed an increase at all time points. </P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="76%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" ALIGN="center">


<TR>

<TD WIDTH="70%"></TD>

<TD VALIGN="bottom" WIDTH="11%"></TD>
<TD></TD>
<TD></TD>
<TD></TD>

<TD VALIGN="bottom" WIDTH="10%"></TD>
<TD></TD>
<TD></TD>
<TD></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="bottom" NOWRAP> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; border-bottom:1.00pt solid #000000; display:table-cell; font-size:8pt; font-family:Times New Roman; ">Week</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="6" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000">%&nbsp;Change&nbsp;Alvelestat&nbsp;vs&nbsp;Placebo&nbsp;LSM</TD>
<TD VALIGN="bottom">&nbsp;</TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>High&nbsp;Dose</I></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>P&nbsp;value</I></TD>
<TD VALIGN="bottom">&nbsp;</TD></TR>


<TR BGCOLOR="#cceeff" STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">4</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">&nbsp;</TD>
<TD VALIGN="top" ALIGN="right">-8.1</TD>
<TD NOWRAP VALIGN="top">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">&nbsp;</TD>
<TD VALIGN="top" ALIGN="right">0.146</TD>
<TD NOWRAP VALIGN="top">&nbsp;</TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">8</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">&nbsp;</TD>
<TD VALIGN="top" ALIGN="right">-27.1</TD>
<TD NOWRAP VALIGN="top">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">&nbsp;</TD>
<TD VALIGN="top" ALIGN="right">0.006</TD>
<TD NOWRAP VALIGN="top">&nbsp;</TD></TR>
<TR BGCOLOR="#cceeff" STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">12</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">&nbsp;</TD>
<TD VALIGN="top" ALIGN="right">-27.6</TD>
<TD NOWRAP VALIGN="top">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">&nbsp;</TD>
<TD VALIGN="top" ALIGN="right">0.002</TD>
<TD NOWRAP VALIGN="top">&nbsp;</TD></TR>
</TABLE> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Smaller effects were observed in the low dose arm, and these generally did not reach statistical significance.
(LSM&#151;least squared means). </P>
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<Center><DIV STYLE="width:8.5in" align="left">
 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><B>Desmosine</B> </P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><B></B>At the high dose of alvelestat desmosine levels decreased with time whereas placebo increased over time. </P>
<P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="92%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" ALIGN="center">


<TR>

<TD WIDTH="70%"></TD>

<TD VALIGN="bottom" WIDTH="4%"></TD>
<TD></TD>
<TD></TD>
<TD></TD>

<TD VALIGN="bottom" WIDTH="3%"></TD>
<TD></TD>
<TD></TD>
<TD></TD>

<TD VALIGN="bottom" WIDTH="3%"></TD>
<TD></TD>
<TD></TD>
<TD></TD>

<TD VALIGN="bottom" WIDTH="3%"></TD>
<TD></TD>
<TD></TD>
<TD></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="bottom" NOWRAP> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; border-bottom:1.00pt solid #000000; display:table-cell; font-size:8pt; font-family:Times New Roman; ">Week</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="14" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000">Within&nbsp;Group&nbsp;%&nbsp;Change&nbsp;from&nbsp;Baseline&nbsp;LSM</TD>
<TD VALIGN="bottom">&nbsp;</TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>High&nbsp;Dose</I></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>P&nbsp;value</I></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>Placebo</I></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom" COLSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><I>P&nbsp;value</I></TD>
<TD VALIGN="bottom">&nbsp;</TD></TR>


<TR BGCOLOR="#cceeff" STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">4</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">-9.4</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">0.097</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">10.1</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">NS&nbsp;&gt;0.9</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">8</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">-13.7</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">0.035</TD>
<TD NOWRAP VALIGN="bottom">*&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">17.9</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">NS &gt;0.9</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD></TR>
<TR BGCOLOR="#cceeff" STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">12</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">-10.6</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">0.061</TD>
<TD NOWRAP VALIGN="bottom">#&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">18.1</TD>
<TD NOWRAP VALIGN="bottom">%&nbsp;</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD>
<TD NOWRAP VALIGN="bottom" ALIGN="right">NS &gt;0.9</TD>
<TD NOWRAP VALIGN="bottom">&nbsp;</TD></TR>
</TABLE> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">*p = 0.032 alvelestat versus placebo, #p = 0.181 alvelestat versus placebo (LSM &#150; least squared means).
</P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">No changes in the level of desmosine in the low dose could be detected at any time point. However, the number of patients in the low dose
arm were small due to the preferential enrollment to the high dose group, reducing the power to detect effects in this arm. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">The
percentage changes in desmosine and A<FONT STYLE="FONT-FAMILY:SYMBOL">&#097;</FONT><FONT STYLE="white-space:nowrap">-val</FONT><SUP STYLE="font-size:85%; vertical-align:top">360</SUP> at the high dose were comparable to those reported with
placebo-controlled augmentation studies following 3 and 6 months of treatment. Desmosine and A<FONT STYLE="FONT-FAMILY:SYMBOL">&#097;</FONT><FONT STYLE="white-space:nowrap">-val</FONT><SUP STYLE="font-size:85%; vertical-align:top">360</SUP> have
been demonstrated to correlate with lung function and lung density in patients with AATD and respond to AAT replacement during weekly intravenous augmentation therapy. </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">The Company plans to complete additional analyses on the other secondary and exploratory endpoints in 2H 2022. </P>
<P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><B>Safety and Tolerability</B> </P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><B></B>Consistent with the known safety profile of alvelestat, no safety signals were observed in adverse event (AE) monitoring. Most AEs were
mild to moderate, including within Adverse Events of Special Interest (AESI) which were observed in 23 subjects. AESIs of infection were recorded in <FONT STYLE="white-space:nowrap">twenty-one</FONT> subjects and these were of similar frequency and
severity in the alvelestat and placebo arms and were events expected in the disease population. A single AESI of liver enzyme (Alanine Transaminase) elevation &gt;5 X Upper Limit of Normal (ULN), associated with raised Aspartate Transaminase (AST)
&gt;2 x ULN, without raised bilirubin occurred at week 8 in the high dose arm. The event met study drug stopping criteria and the raised transaminase levels dropped over the course of the next 10 days. One case of prolonged QTcF occurred in a
subject with a prior history and who was on medication known to prolong QTc at entry to the study. This event occurred at the high dose during the week 4 study visit and the study drug was discontinued. There were no incidences of Hy&#146;s law nor
deaths on study. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Treatment emergent adverse events, including SAEs, were more frequent in the alvelestat groups predominantly due to
headache. Dose-escalation for the high dose arm was instigated to manage the headaches. </P> <P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>Updated Cash Balance Update and Guidance </B></P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">As of March&nbsp;31, 2022,&nbsp;the&nbsp;Company had cash and short-term deposits of &pound;84.9&nbsp;million ($111.4 million). The Company
expects its existing cash and short-term deposits will enable it to fund its currently committed clinical trials, operating expenses and capital expenditure requirements into 2024. </P>
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 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>Next Steps </B></P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">The Company plans to analyze the additional data on the secondary and exploratory endpoints in 2H 2022 and to then engage with the regulators
in the US and Europe for an End of Phase 2 meeting to determine the design of a pivotal registrational trial for alvelestat for the treatment of <FONT STYLE="white-space:nowrap">AATD-LD.</FONT> </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">The investigator led ATALANta trial studying alvelestat in a broader range of patient populations, including other genotypes and those on
augmentation therapy, is expected to read out in 1H 2023. </P> <P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><B>About <FONT STYLE="white-space:nowrap">AATD-LD</FONT></B> </P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><B></B><FONT STYLE="white-space:nowrap">Alpha-1</FONT> antitrypsin deficiency is a genetic condition that results in progressive alveolar
destruction leading to emphysema. People with <FONT STYLE="white-space:nowrap">alpha-1</FONT> antitrypsin deficiency have significantly reduced levels of AAT, a protective protein that inhibits the protease neutrophil elastase. Unopposed neutrophil
elastase is believed to the key enzyme in the causal pathologic pathway of <FONT STYLE="white-space:nowrap">AATD-LD.</FONT> <FONT STYLE="white-space:nowrap">AATD-LD</FONT> presents at age 20 to 50 with symptoms including, shortness of breath, cough,
and reduced exercise tolerance. People with AATD may progress to chronic oxygen therapy, lung surgery, transplant, and death. </P> <P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>About Alvelestat
</B></P> <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Alvelestat <FONT STYLE="white-space:nowrap">(MPH-966)</FONT> is a novel, oral small molecule designed to inhibit neutrophil elastase,
a key enzyme involved in the destruction of lung tissue. Prior to Mereo BioPharma licensing alvelestat from AstraZeneca (AZ), trials across COPD, bronchiectasis and cystic fibrosis (CF) had been performed. Over 1,000 subjects were exposed to
alvelestat, with signals of efficacy in both bronchiectasis and CF. Statistically significant reduction in urine desmosine was seen in the CF trial and an improvement in Forced Expiratory Volume in 1 second (FEV<SUB
STYLE="font-size:85%; vertical-align:bottom">1</SUB>) of 100ml vs placebo in the bronchiectasis trial. Alvelestat is also under clinical investigation in an ongoing Phase 1b/2 investigator-sponsored study Bronchiolitis Obliterans Syndrome (BOS)
following allogeneic hematopoietic stem cell transplant. Interim data from the phase 1b portion of the study showed progressive reduction of plasma desmosine over 8 weeks in 6 of 7 treated patients, all of whom had improved or stable lung disease
(FEV<SUB STYLE="font-size:85%; vertical-align:bottom">1</SUB>) and reduction in stimulated neutrophil elastase activity and fibrosis biomarkers. Mereo reported a positive Phase 1b/2 trial in <FONT STYLE="white-space:nowrap">COVID-19</FONT> which was
completed in 2021 and showed alvelestat was safe and well tolerated. Alvelestat on top of standard of care resulted in a more rapid time to improvement in WHO Disease Severity score of &gt;=2 in the first <FONT STYLE="white-space:nowrap">5-7</FONT>
days compared to placebo plus standard of care. </P> <P STYLE="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>About Mereo BioPharma </B></P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">Mereo BioPharma is a biopharmaceutical company focused on the development of innovative therapeutics that aim to improve outcomes for oncology
and rare diseases and plans to commercialize selected rare disease programs. The Company has developed a portfolio of six clinical stage product candidates. Mereo&#146;s lead oncology product candidate, etigilimab (anti-TIGIT), has advanced into an
open label Phase 1b/2 basket study evaluating anti-TIGIT in combination with an <FONT STYLE="white-space:nowrap"><FONT STYLE="white-space:nowrap">anti-PD-1</FONT></FONT> in a range of tumor types including three rare tumors and three gynecological
carcinomas, cervical, ovarian, and endometrial carcinomas. The Company&#146;s second oncology product, navicixizumab, for the treatment of late line ovarian cancer, has completed a Phase 1 study and has been partnered with OncXerna Therapeutics,
Inc., formerly Oncologie, Inc. The Company has two rare disease product candidates, alvelestat for the treatment of severe <FONT STYLE="white-space:nowrap">Alpha-1</FONT> antitrypsin deficiency (AATD) and Bronchiolitis Obliterans Syndrome (BOS), and
setrusumab for the treatment of osteogenesis imperfecta (OI). Alvelestat has recently received U.S. Orphan Drug Designation for the treatment of AATD and positive <FONT STYLE="white-space:nowrap">top-line</FONT> data were recently reported from a
Phase 2 <FONT STYLE="white-space:nowrap"><FONT STYLE="white-space:nowrap">proof-of-concept</FONT></FONT> study in North America, Europe and the UK. The Company&#146;s partner, Ultragenyx Pharmaceutical, Inc., has initiated a pivotal Phase 2/3
pediatric study in young adults <FONT STYLE="white-space:nowrap">(5-25</FONT> years old) for setrusumab in OI and expects to initiate a study in pediatric patients <FONT STYLE="white-space:nowrap">(2-5</FONT> years old) in 2H 2022. </P>
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 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify"><B>Forward-Looking Statements </B>This press release contains &#147;forward-looking
statements.&#148; All statements other than statements of historical fact contained in this press release are forward-looking statements within the meaning of Section&nbsp;27A of the United States Securities Act of 1933, as amended (the
&#147;Securities Act&#148;), and Section&nbsp;21E of the United States Securities Exchange Act of 1934, as amended (the &#147;Exchange Act&#148;). Forward-looking statements usually relate to future events and anticipated revenues, earnings, cash
flows or other aspects of our operations or operating results. Forward-looking statements are often identified by the words &#147;believe,&#148; &#147;expect,&#148; &#147;anticipate,&#148; &#147;plan,&#148; &#147;intend,&#148; &#147;foresee,&#148;
&#147;should,&#148; &#147;would,&#148; &#147;could,&#148; &#147;may,&#148; &#147;estimate,&#148; &#147;outlook&#148; and similar expressions, including the negative thereof. The absence of these words, however, does not mean that the statements are
not forward-looking. These forward-looking statements are based on the Company&#146;s current expectations, beliefs and assumptions concerning future developments and business conditions and their potential effect on the Company. While management
believes that these forward-looking statements are reasonable as and when made, there can be no assurance that future developments affecting the Company will be those that it anticipates. </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="justify">All of the Company&#146;s forward-looking statements involve known and unknown risks and uncertainties some of which are significant or beyond
its control and assumptions that could cause actual results to differ materially from the Company&#146;s historical experience and its present expectations or projections. You should carefully consider the foregoing factors and the other risks and
uncertainties that affect the Company&#146;s business, including those described in the &#147;Risk Factors&#148; section of its latest Annual Report on Form <FONT STYLE="white-space:nowrap">20-F,</FONT> reports on Form
<FONT STYLE="white-space:nowrap">6-K</FONT> and other documents furnished or filed from time to time by the Company with the Securities and Exchange Commission. The Company wishes to caution you not to place undue reliance on any forward-looking
statements, which speak only as of the date hereof. The Company undertakes no obligation to publicly update or revise any of our forward-looking statements after the date they are made, whether as a result of new information, future events or
otherwise, except to the extent required by law. </P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
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<TD VALIGN="top"> <P ALIGN="justify" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt"><B>Mereo BioPharma Contacts:</B></P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top"></TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="8"></TD>
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<TD VALIGN="top"> <P ALIGN="justify" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt"><B>Mereo</B></P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top"> <P ALIGN="justify" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt"><B>+44 (0)333 023 7300</B></P></TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="8"></TD>
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<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P ALIGN="justify" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt">Denise Scots-Knight, Chief Executive Officer</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top"></TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
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<TD VALIGN="top"> <P ALIGN="justify" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt">Christine Fox, Chief Financial Officer</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top"></TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
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<TD VALIGN="top"> <P ALIGN="justify" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt"><B>Burns McClellan (Investor Relations Adviser to Mereo)</B></P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top"> <P ALIGN="justify" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt"><B>+01 212 213 0006</B></P></TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="8"></TD>
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<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P ALIGN="justify" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt">Lee Roth</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top"></TD></TR>
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<TD HEIGHT="16"></TD>
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<TD VALIGN="top"> <P ALIGN="justify" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt"><B>Investors</B></P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top"> <P ALIGN="justify" STYLE=" margin-top:0pt ; margin-bottom:0pt; font-family:Times New Roman; font-size:10pt"><U>investors@mereobiopharma.com</U></P></TD></TR>
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