<SEC-DOCUMENT>0000899243-17-025510.txt : 20171107
<SEC-HEADER>0000899243-17-025510.hdr.sgml : 20171107
<ACCEPTANCE-DATETIME>20171107160853
ACCESSION NUMBER:		0000899243-17-025510
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20171106
FILED AS OF DATE:		20171107
DATE AS OF CHANGE:		20171107

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			FORMELA JEAN FRANCOIS
		CENTRAL INDEX KEY:			0001030575
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38266
		FILM NUMBER:		171183455

	MAIL ADDRESS:	
		STREET 1:		C/O ATLAS VENTURE
		STREET 2:		890 WINTER STREET
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Spero Therapeutics, Inc.
		CENTRAL INDEX KEY:			0001701108
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		675 MASSACHUSETTS AVENUE
		STREET 2:		14TH FLOOR
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139
		BUSINESS PHONE:		857-242-1600

	MAIL ADDRESS:	
		STREET 1:		675 MASSACHUSETTS AVENUE
		STREET 2:		14TH FLOOR
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Spero Therapeutics, LLC
		DATE OF NAME CHANGE:	20170316
</SEC-HEADER>
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    <footnotes>
        <footnote id="F1">Reflects shares of the Issuer's common stock that were purchased in connection with the Issuer's initial public offering.</footnote>
        <footnote id="F2">Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017).  Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.</footnote>
        <footnote id="F3">Shares held by Atlas Venture Fund IX, L.P. (&quot;Atlas Venture Fund IX&quot;).  The general partner of Atlas Venture Fund IX is Atlas Venture Associates IX, L.P. (&quot;AVA IX LP&quot;). Atlas Venture Associates IX, LLC (&quot;AVA IX LLC&quot;) is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.</footnote>
        <footnote id="F4">Shares held by Atlas Venture Fund X, L.P. (&quot;Atlas Venture Fund X&quot;).  The general partner of Atlas Venture Fund X is Atlas Venture Associates X, L.P. (&quot;AVA X LP&quot;).   Atlas Venture Associates X, LLC (&quot;AVA X LLC&quot;) is the general partner of AVA X LP. Dr. Formela is a member of AVA X LLC and disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Frank Castellucci, Attorney-in-Fact for Jean-Francois Formela</signatureName>
        <signatureDate>2017-11-07</signatureDate>
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