<SEC-DOCUMENT>0000950123-24-006208-index.html : 20240918
<SEC-HEADER>0000950123-24-006208.hdr.sgml : 20240918
<ACCEPTANCE-DATETIME>20240612155457
<PRIVATE-TO-PUBLIC>
ACCESSION NUMBER:		0000950123-24-006208
CONFORMED SUBMISSION TYPE:	DRS
PUBLIC DOCUMENT COUNT:		29
FILED AS OF DATE:		20240612
<PUBLIC-REL-DATE>20240918
DATE AS OF CHANGE:		20240612

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Upstream Bio, Inc.
		CENTRAL INDEX KEY:			0002022626
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		DRS
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	377-07271
		FILM NUMBER:		241038317

	BUSINESS ADDRESS:	
		STREET 1:		460 TOTTEN POND ROAD, SUITE 420
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451
		BUSINESS PHONE:		781-208-2466

	MAIL ADDRESS:	
		STREET 1:		460 TOTTEN POND ROAD, SUITE 420
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451
</SEC-HEADER>
<DOCUMENT>
<TYPE>DRS
<SEQUENCE>1
<FILENAME>filename1.htm
<TEXT>
Document 1 - file: filename1.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-3.1
<SEQUENCE>2
<FILENAME>filename2.htm
<TEXT>
Document 2 - file: filename2.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-3.3
<SEQUENCE>3
<FILENAME>filename3.htm
<TEXT>
Document 3 - file: filename3.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-10.1
<SEQUENCE>4
<FILENAME>filename4.htm
<TEXT>
Document 4 - file: filename4.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-10.13
<SEQUENCE>5
<FILENAME>filename5.htm
<TEXT>
Document 5 - file: filename5.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-10.15
<SEQUENCE>6
<FILENAME>filename6.htm
<TEXT>
Document 6 - file: filename6.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-10.16
<SEQUENCE>7
<FILENAME>filename7.htm
<TEXT>
Document 7 - file: filename7.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-21.1
<SEQUENCE>8
<FILENAME>filename8.htm
<TEXT>
Document 8 - file: filename8.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>9
<FILENAME>g843142g00u68.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 9 - file: g843142g00u68.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>10
<FILENAME>g843142g03n03.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 10 - file: g843142g03n03.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>11
<FILENAME>g843142g04f18.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 11 - file: g843142g04f18.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>12
<FILENAME>g843142g09d27.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 12 - file: g843142g09d27.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>13
<FILENAME>g843142g17j14.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 13 - file: g843142g17j14.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>14
<FILENAME>g843142g21m48.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 14 - file: g843142g21m48.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>15
<FILENAME>g843142g22q66.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 15 - file: g843142g22q66.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>16
<FILENAME>g843142g25s47.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 16 - file: g843142g25s47.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>17
<FILENAME>g843142g28n28.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 17 - file: g843142g28n28.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>18
<FILENAME>g843142g31l12.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 18 - file: g843142g31l12.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>19
<FILENAME>g843142g33n33.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 19 - file: g843142g33n33.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>20
<FILENAME>g843142g35n35.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 20 - file: g843142g35n35.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>21
<FILENAME>g843142g42a01.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 21 - file: g843142g42a01.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>22
<FILENAME>g843142g42b02.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 22 - file: g843142g42b02.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>23
<FILENAME>g843142g45n45.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 23 - file: g843142g45n45.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>24
<FILENAME>g843142g47a01.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 24 - file: g843142g47a01.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>25
<FILENAME>g843142g47b02.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 25 - file: g843142g47b02.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>26
<FILENAME>g843142g49n49.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 26 - file: g843142g49n49.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>27
<FILENAME>g843142g70c41.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 27 - file: g843142g70c41.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>28
<FILENAME>g843142g76t53.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 28 - file: g843142g76t53.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>29
<FILENAME>g843142g79l54.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 29 - file: g843142g79l54.jpg

</DOCUMENT>
</SEC-DOCUMENT>