    <SEC-DOCUMENT>0001193125-18-217909-index.html : 20180713
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    <ACCEPTANCE-DATETIME>20180713165114
    ACCESSION NUMBER:		0001193125-18-217909
    CONFORMED SUBMISSION TYPE:	424B4
    PUBLIC DOCUMENT COUNT:		13
    FILED AS OF DATE:		20180713
    DATE AS OF CHANGE:		20180713

    FILER:

    	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

    	FILING VALUES:
    		FORM TYPE:		424B4
    		SEC ACT:		1933 Act
    		SEC FILE NUMBER:	333-226093
    		FILM NUMBER:		18952996

    	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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    <SEQUENCE>1
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