Clarus Lifesciences III SC 13D/A AVROBIO, Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 3)*

AVROBIO, Inc.

(Name of Issuer)

Common Stock, $.0001 par value per share

(Title of Class of Securities)

05455M100

(CUSIP Number)

Robert Liptak

Clarus Ventures, LLC

101 Main Street, Suite 1210

Cambridge, MA 02142

(617)949-2200

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

July 24, 2019

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of§§240.13d-1(e),240.13d-1(f) or240.13d-1(g), check the following box.  ☐

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See§240.13d-7 for other parties to whom copies are to be sent.

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 05455M100 13D Page 2 of 16 Pages

1	NAMES OF REPORTING PERSONS Clarus Lifesciences III, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS) WC
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e) ☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF   SHARES   BENEFICIALLY   OWNED BY   EACH   REPORTING   PERSON   WITH	7	SOLE VOTING POWER 0
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) ☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.0%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) PN

CUSIP No. 05455M100 13D Page 3 of 16 Pages

1	NAMES OF REPORTING PERSONS Clarus Ventures III GP, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS) AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e) ☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF   SHARES   BENEFICIALLY   OWNED BY   EACH   REPORTING   PERSON   WITH	7	SOLE VOTING POWER 0
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) ☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.0%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) PN

CUSIP No. 05455M100 13D Page 4 of 16 Pages

1	NAMES OF REPORTING PERSONS Blackstone Clarus III L.L.C.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS) AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e) ☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF   SHARES   BENEFICIALLY   OWNED BY   EACH   REPORTING   PERSON   WITH	7	SOLE VOTING POWER 0
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) ☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.0%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) OO

CUSIP No. 05455M100 13D Page 5 of 16 Pages

1	NAMES OF REPORTING PERSONS Blackstone Holdings II L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS) AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e) ☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF   SHARES   BENEFICIALLY   OWNED BY   EACH   REPORTING   PERSON   WITH	7	SOLE VOTING POWER 0
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) ☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.0%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) PN

CUSIP No. 05455M100 13D Page 6 of 16 Pages

1	NAMES OF REPORTING PERSONS Blackstone Holdings I/II GP L.L.C.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS) AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e) ☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF   SHARES   BENEFICIALLY   OWNED BY   EACH   REPORTING   PERSON   WITH	7	SOLE VOTING POWER 0
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) ☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.0%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) OO

CUSIP No. 05455M100 13D Page 7 of 16 Pages

1	NAMES OF REPORTING PERSONS The Blackstone Group Inc.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS) AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e) ☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF   SHARES   BENEFICIALLY   OWNED BY   EACH   REPORTING   PERSON   WITH	7	SOLE VOTING POWER 0
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) ☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.0%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) CO

CUSIP No. 05455M100 13D Page 8 of 16 Pages

1	NAMES OF REPORTING PERSONS Blackstone Group Management L.L.C.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS) AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e) ☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF   SHARES   BENEFICIALLY   OWNED BY   EACH   REPORTING   PERSON   WITH	7	SOLE VOTING POWER 0
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) ☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.0%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) OO

CUSIP No. 05455M100 13D Page 9 of 16 Pages

1	NAMES OF REPORTING PERSONS Stephen A. Schwarzman
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS) AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e) ☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF   SHARES   BENEFICIALLY   OWNED BY   EACH   REPORTING   PERSON   WITH	7	SOLE VOTING POWER 0
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) ☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.0%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) IN

Item 1.Security and Issuer.

This Amendment No. 3 (“Amendment No. 3”) to the statement on Schedule 13D amends and supplements the initial statement on Schedule 13D originally filed by Clarus Lifesciences III, L.P. and certain other reporting persons on July 5, 2018, as amended by Amendment No. 1 thereto filed on January 15, 2019, as amended by Amendment No. 2 thereto filed on May 23, 2019 (as amended, the “Schedule 13D”), relating to the Common Stock, par value $0.0001 per share (the “Common Stock”), of AVROBIO, Inc. (the “Issuer”). The address of the principal executive offices of the Issuer is One Kendall Square, Building 300, Suite 201, Cambridge, MA 02139.

This Amendment reflects, among other things, the conversion of The Blackstone Group L.P., a Delaware limited partnership, into a Delaware corporation named The Blackstone Group Inc., and the conversion of Blackstone Holdings I/II GP Inc., a Delaware corporation, into a Delaware limited liability company named Blackstone Holdings I/II GP L.L.C., each of which became effective on July 1, 2019. Certain terms used but not defined in this Amendment No. 3 have the meanings assigned thereto in the Schedule 13D. Except as specifically provided herein, this Amendment No. 3 does not modify any of the information previously reported in the Schedule 13D.

Item 2.Identity and Background.

Item 2 of the Schedule 13D is hereby amended and restated as follows:

This statement is being filed by:

(a) Clarus Lifesciences III, L.P. (the “Fund”);

(b) Clarus Ventures III GP, L.P. (“Clarus GP”), which is the sole general partner of the Fund;

(c) Blackstone Clarus III L.L.C., which is the sole general partner of Clarus GP, Blackstone Holdings II L.P., which is the sole member of Blackstone Clarus III L.L.C., Blackstone Holdings I/II GP L.L.C., which is the sole general partner of Blackstone Holdings II L.P., The Blackstone Group Inc., which is the sole member of Blackstone Holdings I/II GP L.L.C., and Blackstone Group Management L.L.C. (collectively, with Blackstone Clarus III L.L.C., Blackstone Holdings II L.P., Blackstone Holdings I/II GP L.L.C. and The Blackstone Group Inc., the “Control Entities”), which is the sole holder of the Class C common stock of The Blackstone Group Inc. and which is wholly-owned by Blackstone’s senior managing directors and controlled by its founder, Stephen A. Schwarzman.

The address of the principal business office of the Fund and Clarus GP is Clarus Ventures, 101 Main Street, Suite 1210, Cambridge, MA 02142. The address of the principal business office of each of the Control Entities and Mr. Schwarzman is c/o The Blackstone Group Inc., 345 Park Avenue, New York, NY 10154.

Information regarding each director and executive officer of The Blackstone Group Inc. is set forth onSchedule I attached hereto.

The principal business of the Fund is to invest in and assist early-stage and/or growth-oriented businesses in healthcare and life sciences. The principal business of Clarus GP is to act as the sole general partner of the Fund.

The principal business of Blackstone Clarus III L.L.C. is performing the functions of, and serving as, the general partner of Clarus GP. The principal business of Blackstone Holdings II L.P. is performing the functions of, and serving as, a managing member (or similar position) of and member or equity holder in Blackstone Clarus III L.L.C. and other affiliated Blackstone entities. The principal business of Blackstone Holdings I/II GP L.L.C. is performing the functions of, and serving as, the general partner (or similar position) of Blackstone Holdings II L.P. and other affiliated Blackstone entities. The principal business of The Blackstone Group Inc. is performing the functions of, and serving as, the sole member of Blackstone Holdings I/II GP L.L.C., and in a similar capacity for other affiliated Blackstone entities. The principal business of Blackstone Group Management L.L.C. is performing the functions of, and serving as, the sole holder of the Class C common stock of The Blackstone Group Inc. The principal occupation of Mr. Schwarzman is serving as an executive of The Blackstone Group Inc. and Blackstone Group Management L.L.C.

During the five years prior to the date hereof, none of the Reporting Persons or, to the best knowledge of the Reporting Persons, any of the other persons set forth onSchedule I attached hereto, has been convicted in a criminal proceeding or has been a party to a civil proceeding ending in a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

The Fund, Clarus GP and Blackstone Holdings II L.P. are limited partnerships organized under the laws of the State of Delaware. Blackstone Clarus III L.L.C., Blackstone Holdings I/II GP L.L.C. and Blackstone Group Management L.L.C. are limited liability companies organized under the laws of the State of Delaware. The Blackstone Group Inc. is a corporation organized under the laws of the State of Delaware. Mr. Schwarzman is a United States citizen.

Item 5.Interest in Securities of the Issuer.

Item 5 of the Schedule 13D is hereby amended and restated as follows:

(a) None of the Reporting Persons beneficially owns any shares of Common Stock.

(b) Regarding the number of shares as to which such person has:

(i) sole power to vote or to direct the vote: See line 7 of cover sheets

(ii) shared power to vote or to direct the vote: See line 8 of cover sheets

(iii) sole power to dispose or to direct the disposition: See line 9 of cover sheets

(iv) shared power to dispose or to direct the disposition: See line 10 of cover sheets

(c) On July 30, 2019, the Fund distributed 901,162 shares of Common Stock to its limited partners, including Clarus GP (the “Fund Distribution”). Clarus GP then distributed the 123,505 shares it received in the Fund Distribution to its limited partners. Except as set forth in this Amendment No. 3 or as set forth inSchedule II attached hereto, none of the Reporting Persons has effected any transaction in the Common Stock during the last 60 days.

(d) Not applicable.

(e) As of July 19, 2019, the Reporting Persons ceased to be the beneficial owners of more than five percent of the outstanding Common Stock.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: August 5, 2019

CLARUS LIFESCIENCES III, L.P.
By:	Clarus Ventures III GP, L.P., its general partner
By:	Blackstone Clarus III L.L.C., its general partner
By:	Blackstone Holdings II L.P., its managing member
By:	Blackstone Holdings I/II GP Inc., its general partner
By:	/s/ John G. Finley
Name:	John G. Finley
Title:	Chief Legal Officer

CLARUS VENTURES III GP, L.P.
By:	Blackstone Clarus III L.L.C., its general partner
By:	Blackstone Holdings II L.P., its managing member
By:	Blackstone Holdings I/II GP Inc., its general partner
By:	/s/ John G. Finley
Name:	John G. Finley
Title:	Chief Legal Officer

BLACKSTONE CLARUS III L.L.C.
By:	Blackstone Holdings II L.P., its managing member
By:	Blackstone Holdings I/II GP Inc., its general partner
By:	/s/ John G. Finley
Name:	John G. Finley
Title:	Chief Legal Officer

BLACKSTONE HOLDINGS II L.P.
By:	Blackstone Holdings I/II GP Inc., its general partner
By:	/s/ John G. Finley
Name:	John G. Finley
Title:	Chief Legal Officer

BLACKSTONE HOLDINGS I/II GP L.L.C.
By:	The Blackstone Group Inc., its sole member
By:	/s/ John G. Finley
Name:	John G. Finley
Title:	Chief Legal Officer

THE BLACKSTONE GROUP INC.
By:	/s/ John G. Finley
Name:	John G. Finley
Title:	Chief Legal Officer

BLACKSTONE GROUP MANAGEMENT L.L.C.
By:	/s/ John G. Finley
Name:	John G. Finley
Title:	Chief Legal Officer

/s/ Stephen A. Schwarzman

Stephen A. Schwarzman

[AVROBIO, Inc. – Schedule 13D/A]

SCHEDULE I

Executive Officers and Directors of The Blackstone Group Inc.

The name and principal occupation of each director and executive officer of The Blackstone Group Inc. are set forth below. The address for each person listed below is c/o The Blackstone Group Inc., 345 Park Avenue, New York, New York 10154. All executive officers and directors listed are United States citizens other than The Honorable Brian Mulroney, who is a citizen of Canada, and Sir John Antony Hood, who is a citizen of New Zealand.

OFFICERS:

Name	Present Principal Occupation or Employment
Stephen A. Schwarzman	Founder, Chairman and Chief Executive Officer of The Blackstone Group Inc.
Jonathan D. Gray	President, Chief Operating Officer of The Blackstone Group Inc.
Hamilton E. James	Executive Vice Chairman of The Blackstone Group Inc.
Bennett J. Goodman	Senior Managing Director andCo-Founder of GSO Capital Partners
Michael S. Chae	Chief Financial Officer of The Blackstone Group Inc.
John G. Finley	Chief Legal Officer of The Blackstone Group Inc.
Joan Solotar	Senior Managing Director — Head of Private Wealth Solutions and External Relations of The Blackstone Group Inc.

DIRECTORS:

Name	Present Principal Occupation or Employment
Stephen A. Schwarzman	Founder, Chairman and Chief Executive Officer of The Blackstone Group Inc.
Jonathan D. Gray	President, Chief Operating Officer of The Blackstone Group Inc.
Hamilton E. James	Executive Vice Chairman of The Blackstone Group Inc.
Bennett J. Goodman	Senior Managing Director andCo-Founder of GSO Capital Partners of The Blackstone Group Inc.
Kelly A. Ayotte	Former United States Senator from New Hampshire
James W. Breyer	Founder and Chief Executive Officer of Breyer Capital
Sir John Antony Hood	President and Chief Executive Officer of the Robertson Foundation and Chair of the Rhodes Trust

Rochelle B. Lazarus	Chairman Emeritus & Former Chief Executive Officer, Ogilvy & Mather Worldwide
Jay O. Light	Dean Emeritus, Harvard Business School
The Right Honorable Brian Mulroney	Senior Partner and International Business Consultant for the Montreal law firm, Norton Rose Canada LLP
William G. Parrett	Retired CEO and Senior Partner, Deloitte (Deloitte Touche Tohmatsu)

Except as set forth in this Schedule 13D, to the best knowledge of the Reporting Persons, none of the individuals listed above beneficially owns any shares of Class A Common Stock.

SCHEDULE II

60-Day Trading History

The below reflects the transactions effected by Clarus Lifesciences III, L.P. during the past 60 days.

Date	Common Stock Sold	Weighted Average Sales Price per Share
7/19/2019	7,004	$23.106336
7/19/2019	53,192	$23.000265
7/22/2019	66,329	$23.015349
7/22/2019	48,974	$22.964158
7/23/2019	17,687	$22.970506
7/23/2019	29,731	$22.941305
7/24/2019	95,509	$22.957081
7/25/2019	60,709	$23.070524
7/26/2019	162,442	$23.042708
7/30/2019	30,000	$22.900699
7/30/2019	8,423	$21.999973

The above transactions were effected on the open market.