<SEC-DOCUMENT>0001628280-25-045708-index.html : 20251021
<SEC-HEADER>0001628280-25-045708.hdr.sgml : 20251021
<ACCEPTANCE-DATETIME>20251021162214
ACCESSION NUMBER:		0001628280-25-045708
CONFORMED SUBMISSION TYPE:	144
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20251021
DATE AS OF CHANGE:		20251021

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Sionna Therapeutics, Inc.
		CENTRAL INDEX KEY:			0002036042
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		EIN:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		144
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	001-42504
		FILM NUMBER:		251407330

	BUSINESS ADDRESS:	
		STREET 1:		21 HICKORY DRIVE, SUITE 500
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451
		BUSINESS PHONE:		617-819-2020

	MAIL ADDRESS:	
		STREET 1:		21 HICKORY DRIVE, SUITE 500
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451

REPORTING-OWNER:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Atlas Venture Opportunity Fund II, L.P.
		CENTRAL INDEX KEY:			0001885327
		ORGANIZATION NAME:           	
		EIN:				872809161
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		144

	BUSINESS ADDRESS:	
		STREET 1:		300 TECHNOLOGY SQUARE
		STREET 2:		8TH FLOOR
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139
		BUSINESS PHONE:		857-201-2700

	MAIL ADDRESS:	
		STREET 1:		300 TECHNOLOGY SQUARE
		STREET 2:		8TH FLOOR
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139
</SEC-HEADER>
<DOCUMENT>
<TYPE>144
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
Document 1 - file: primary_doc.html

Document 1 - RAW XML: primary_doc.xml

</DOCUMENT>
</SEC-DOCUMENT>