AnaptysBio (ANAB) SC 13D Anaptysbio Inc

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C.  20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. ___)*

AnaptysBio, Inc.

(Name of Issuer)

Common Stock, $0.001 par value per share

(Title of Class of Securities)

032724106

 (CUSIP Number)

Steve R. Bailey

c/o Frazier Healthcare Partners

601 Union Street, Suite 3200

Seattle, WA 98101

(206) 621-7200

(Name, Address and Telephone Number of Person Authorized to

Receive Notices and Communications)

January 31, 2017

(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) or 240.13d-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.   032724106 13D Page 2 of 21 Pages

1	NAMES OF REPORTING PERSONS
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
	Frazier Healthcare V, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☒
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 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 shares
		8	SHARED VOTING POWER
			3,688,447 shares
		9	SOLE DISPOSITIVE POWER
			0 shares
		10	SHARED DISPOSITIVE POWER
			3,688,447 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	3,688,447 shares
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	18.5%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	PN

CUSIP No.   032724106 13D Page 3 of 21 Pages

1	NAMES OF REPORTING PERSONS
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
	Frazier Healthcare VII, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☒
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 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 shares
		8	SHARED VOTING POWER
			3,688,447 shares
		9	SOLE DISPOSITIVE POWER
			0 shares
		10	SHARED DISPOSITIVE POWER
			3,688,447 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	3,688,447 shares
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	18.5%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	PN

CUSIP No.   032724106 13D Page 4 of 21 Pages

1	NAMES OF REPORTING PERSONS
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
	Frazier Healthcare VII-A, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☒
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 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 shares
		8	SHARED VOTING POWER
			3,688,447 shares
		9	SOLE DISPOSITIVE POWER
			0 shares
		10	SHARED DISPOSITIVE POWER
			3,688,447 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	3,688,447 shares
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	18.5%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	PN

CUSIP No.   032724106 13D Page 5 of 21 Pages

1	NAMES OF REPORTING PERSONS
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
	FHM V, LP
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☒
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 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 shares
		8	SHARED VOTING POWER
			3,688,447 shares
		9	SOLE DISPOSITIVE POWER
			0 shares
		10	SHARED DISPOSITIVE POWER
			3,688,447 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	3,688,447 shares
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	18.5%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	PN

CUSIP No.   032724106 13D Page 6 of 21 Pages

1	NAMES OF REPORTING PERSONS
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
	FHM V, LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☒
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 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 shares
		8	SHARED VOTING POWER
			3,688,447 shares
		9	SOLE DISPOSITIVE POWER
			0 shares
		10	SHARED DISPOSITIVE POWER
			3,688,447 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	3,688,447 shares
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	18.5%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	OO

CUSIP No.   032724106 13D Page 7 of 21 Pages

1	NAMES OF REPORTING PERSONS
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
	FHM VII, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☒
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 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 shares
		8	SHARED VOTING POWER
			3,688,447 shares
		9	SOLE DISPOSITIVE POWER
			0 shares
		10	SHARED DISPOSITIVE POWER
			3,688,447 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	3,688,447 shares
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	18.5%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	PN

CUSIP No.   032724106 13D Page 8 of 21 Pages

1	NAMES OF REPORTING PERSONS
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
	FHM VII, L.L.C.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☒
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 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 shares
		8	SHARED VOTING POWER
			3,688,447 shares
		9	SOLE DISPOSITIVE POWER
			0 shares
		10	SHARED DISPOSITIVE POWER
			3,688,447 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	3,688,447 shares
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	18.5%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	OO

CUSIP No.   032724106 13D Page 9 of 21 Pages

1	NAMES OF REPORTING PERSONS
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
	Alan Frazier
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☒
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(D) OR 2(E)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	United States Citizen
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			0 shares
		8	SHARED VOTING POWER
			3,688,447 shares
		9	SOLE DISPOSITIVE POWER
			0 shares
		10	SHARED DISPOSITIVE POWER
			3,688,447 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	3,688,447 shares
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	18.5%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	IN

CUSIP No.   032724106 13D Page 10 of 21 Pages

1	NAMES OF REPORTING PERSONS
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
	Nader Naini
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☒
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(D) OR 2(E)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	United States Citizen
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			0 shares
		8	SHARED VOTING POWER
			3,688,447 shares
		9	SOLE DISPOSITIVE POWER
			0 shares
		10	SHARED DISPOSITIVE POWER
			3,688,447 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	3,688,447 shares
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	18.5%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	IN

CUSIP No.   032724106 13D Page 11 of 21 Pages

1	NAMES OF REPORTING PERSONS
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
	Patrick Heron
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☒
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(D) OR 2(E)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	United States Citizen
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			0 shares
		8	SHARED VOTING POWER
			3,688,447 shares
		9	SOLE DISPOSITIVE POWER
			0 shares
		10	SHARED DISPOSITIVE POWER
			3,688,447 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	3,688,447 shares
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	18.5%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	IN

CUSIP No.   032724106 13D Page 12 of 21 Pages

1	NAMES OF REPORTING PERSONS
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
	James Topper
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☒
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(D) OR 2(E)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	United States Citizen
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			0 shares
		8	SHARED VOTING POWER
			3,688,447 shares
		9	SOLE DISPOSITIVE POWER
			0 shares
		10	SHARED DISPOSITIVE POWER
			3,688,447 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	3,688,447 shares
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	18.5%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	IN

CUSIP No.   032724106 13D Page 13 of 21 Pages

1	NAMES OF REPORTING PERSONS
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
	Nathan Every
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a)	☒
				(b)	☐
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(D) OR 2(E)				☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	United States Citizen
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER
			0 shares
		8	SHARED VOTING POWER
			3,688,447 shares
		9	SOLE DISPOSITIVE POWER
			0 shares
		10	SHARED DISPOSITIVE POWER
			3,688,447 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	3,688,447 shares
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)				☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	18.5%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	IN

CUSIP No.   032724106 13D Page 14 of 21 Pages

Item 1.   Security and Issuer

This statement relates to the common stock, $0.001 par value (the "Common Stock") of AnaptysBio, Inc. (the "Issuer") having its principal executive office at 10421 Pacific Center Court, Suite 200, San Diego, CA 92121.

Item 2.   Identity and Background

This statement is being filed by:

(a) Frazier Healthcare V, L.P. ("FH V"), Frazier Healthcare VII, L.P. ("FH VII"), Frazier Healthcare VII-A, L.P. ("FH VII-A");

(b) FHM V, L.P. ("FM V L.P."), which is the sole general partner of FH V; FHM V, LLC ("FM V LLC"), which is the sole general partner of FM V L.P.; FHM VII, L.P. ("FM VII L.P."), which is the sole general partner of FH VII and FH VII-A; and FHM VII, L.L.C. ("FM VII L.L.C."), which is the sole general partner of FM VII L.P.; and

(c) Alan Frazier ("Frazier"), Nader Naini ("Naini"), Patrick Heron ("Heron"), James Topper ("Topper") and Nathan Every ("Every") (collectively, the "Members").  The Members are the members of FM V LLC and FM VII L.L.C.

The persons named in this Item 2 are referred to individually herein as a "Reporting Person" and collectively as the "Reporting Persons."

The address of the principal business office of each Reporting Person is:

c/o Frazier Healthcare Partners

601 Union Street, Suite 3200

Seattle, WA 98101

FH V, FH VII and FH VII-A are affiliated venture capital funds concentrating in healthcare and related fields.  The sole business of FM V L.P. and FM V LLC is to serve as general partner entities for FH V.  The sole business of FM VII L.P. and FM VII L.L.C. is to serve as general partner entities for FH VII and FH VII-A.  The principal business of each of the Members is to manage FH V, FM V L.P., FM V LLC, FH VII, FH VII-A, FM VII L.P., FM VII L.L.C. and a number of affiliated partnerships with similar businesses.

During the five years prior to the date hereof, none of the Reporting Persons 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.

Each of FH V, FM V L.P., FH VII, FH VII-A, and FM VII L.P. are limited partnerships organized under the laws of the State of Delaware.  FM V LLC and FM VII L.L.C. are limited liability companies organized under the laws of the State of Delaware.  Each of the Members is a United States citizen.

Item 3.   Source and Amount of Funds or Other Consideration

On January 25, 2017, the Registration Statement on Form S-1 filed with the Securities and Exchange Commission by the Issuer (File No. 333-206849) in connection with its initial public offering of 5,000,000 shares of Common Stock of the Issuer (the "IPO") was declared effective.  The closing of the IPO took place on January 31, 2017, and at such closing FH VII purchased 311,291 shares of Common Stock at the IPO price of $15.00 per share and FHVII-A purchased 88,709 shares of Common Stock at the IPO price of $15.00 per share.  In addition, immediately prior to the closing of the IPO, (i) all Series B Preferred Stock held by FH V converted into 1,428,571 shares of Common Stock, (ii) all Series C Preferred Stock held by FH V converted into 604,055 shares of Common Stock, (iii) all Series C-1 Preferred Stock held by FH V converted into 195,751 shares of Common Stock, (iv) all Series D Preferred Stock held by FH VII converted into 733,740 shares of Common Stock and (v) all Series D Preferred Stock held by FH VII-A converted into 209,095 shares of Common Stock.  On February 2, 2017, FH V exercised a warrant to purchase 117,235 shares of Common Stock at an exercise price of $4.55 per share.  FH V now holds a total of 2,345,612 shares of the Issuer's Common Stock (the "FH V Shares"); FH VII now holds a total of 1,045,031 shares of the Issuer's Common Stock (the "FH VII Shares") and FH VII-A now holds a total of 297,804 shares of the Issuer's Common Stock (the "FH VII Shares" and, together with the FH V Shares and the FH VII Shares, the "FH Shares").

The working capital of FH V, FH VII and FH VII-A was the source of the funds for the purchase of the FH Shares.  No part of the purchase price of the FH Shares was represented by funds or other consideration borrowed or otherwise obtained for the purpose of acquiring, holding, trading or voting the FH Shares.

CUSIP No.   032724106 13D Page 15 of 21 Pages

Item 4.   Purpose of Transaction

FH V, FH VII and FH VII-A acquired the FH Shares for investment purposes.  Depending on market conditions, its continuing evaluation of the business and prospects of the Issuer and other factors, FH V, FH VII, FH VII-A and other Reporting Persons may dispose of or acquire additional shares of the Issuer.  Except as set forth above, none of the Reporting Persons has any present plans which relate to or would result in:

(a) The acquisition by any person of additional securities of the Issuer, or the disposition of securities of the Issuer;

(b) An extraordinary corporate transaction, such as a merger, reorganization or liquidation, involving the Issuer or any of its subsidiaries;

(c) A sale or transfer of a material amount of assets of the Issuer or any of its subsidiaries;

(d) Any change in the present board of directors or management of the Issuer, including any plans or proposals to change the number or term of directors or to fill any existing vacancies on the board;

(e) Any material change in the present capitalization or dividend policy of the Issuer;

(f) Any other material change in the Issuer's business or corporate structure;

(g) Changes in the Issuer's charter, bylaws or instruments corresponding thereto or other actions which may impede the acquisition of control of the Issuer by any person;

(h) Causing a class of securities of the Issuer to be delisted from a national securities exchange or to cease to be authorized to be quoted in an inter-dealer quotation system of a registered national securities association;

(i) A class of equity securities of the Issuer becoming eligible for termination of registration pursuant to Section 12(g)(4) of the Securities Exchange Act of 1934, as amended; or

(j) Any action similar to any of those enumerated above.

Item 5.   Interest in Securities of the Issuer

(a) FH V is the record owners of the FH V Shares.  As the sole general partner of FH V, FM V L.P. may be deemed to own beneficially the FH V Shares.  As the sole general partner of FM V L.P., FM V LLC may be deemed to own beneficially the FH V Shares.  As members of FM V LLC, each of the Members may be deemed to own beneficially the FH V Shares.

FH VII and FH VII-A are the record owners of the FH VII Shares and FH VII-A Shares.  As the sole general partner of FH VII and of FH VII-A, FM VII L.P. may be deemed to own beneficially the FH VII Shares and FH VII-A Shares.  As the sole general partner of FM VII L.P., FM VII L.L.C. may be deemed to own beneficially the FH VII Shares and FH VII-A Shares.  As members of FM VII L.L.C., each of the Members may be deemed to own beneficially the FH VII Shares and FH VII-A Shares.

The percentage of outstanding Common Stock of the Issuer which may be deemed to be beneficially owned by each Reporting Person is set forth on Line 13 of such Reporting Person's cover sheet.  Such percentage was calculated based on the 19,159,333 shares of Common Stock outstanding immediately after the IPO on the Issuer's prospectus filed under Rule 424(b)(4), filed with the Securities Exchange Commission on January 25, 2017.

CUSIP No.   032724106 13D Page 16 of 21 Pages

(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) Not applicable.

(d) No other person is known to have the right to receive or the power to direct the receipt of dividends from, or any proceeds from the sale of, FH Shares beneficially owned by any of the Reporting Persons.

(e) Not applicable.

Item 6.   Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer

In connection with the IPO, FH V, FH VII, FH VII-A, and Mr. Topper, along with all of the Issuer's other directors, executive officers and substantially all other stockholders agreed with the underwriters for the offering, subject to certain exceptions, not to offer or sell any shares of Common Stock for a period of 180 days from January 25, 2017, except with the prior written consent of Credit Suisse Securities (USA) LLC and Stifel, Nicolaus & Company, Incorporated.

Item 7.   Material to Be Filed as Exhibits

Exhibit 99.1 – Agreement regarding filing of joint Schedule 13D.

Exhibit 99.2 – Power of Attorney regarding Schedule 13D filings.

CUSIP No.   032724106 13D Page 17 of 21 Pages

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:      February 10, 2017

FRAZIER HEALTHCARE V, L.P.

By: FHM V, L.P., its General Partner

By: FHM V, LLC, its General Partner

By:  /s/ Steve R. Bailey                                       

Steve R. Bailey, Chief Financial Officer

FHM V, L.P.

By: FHM V, LLC, its General Partner

By:  /s/ Steve R. Bailey                                        

Steve R. Bailey, Chief Financial Officer

FHM V, LLC, its General Partner

By:  /s/ Steve R. Bailey                                       

Steve R. Bailey, Chief Financial Officer

FRAZIER HEALTHCARE VII, L.P.

By: FHM VII, L.P., its General Partner

By: FHM VII, L.L.C., its General Partner

By:  /s/ Steve R. Bailey                                       

Steve R. Bailey, Chief Financial Officer

FRAZIER HEALTHCARE VII-A, L.P.

By: FHM VII, L.P., its General Partner

By: FHM VII, L.L.C., its General Partner

By:  /s/ Steve R. Bailey                                       

        Steve R. Bailey, Chief Financial Officer

FHM VII, L.P.

By: FHM VII, L.L.C., its General Partner

By:  /s/ Steve R. Bailey                                        

Steve R. Bailey, Chief Financial Officer

FHM VII, L.L.C.

By:  /s/ Steve R. Bailey                                        

        Steve R. Bailey, Chief Financial Officer

CUSIP No.   032724106 13D Page 18 of 21 Pages

                      *                                       

Alan Frazier

                      *                                       Nader Naini

                      *                                       Patrick Heron

                      *                                       James Topper

                      *                                       Nathan Every

     *By:  /s/ Steve R. Bailey                                

Steve R. Bailey, as Attorney-in-Fact

This Schedule 13D was executed by Steve R. Bailey on behalf of the individuals listed above pursuant to a Power of Attorney a copy of which is attached as Exhibit 99.2.

CUSIP No.   032724106 13D Page 19 of 21 Pages

EXHIBIT 99.1

AGREEMENT

Pursuant to Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, the undersigned hereby agree that only one statement containing the information required by Schedule 13D need to be filed with respect to the ownership by each of the undersigned of shares of Common Stock of AnaptysBio, Inc.

Dated:   February 10, 2017

FRAZIER HEALTHCARE V, L.P.

By: FHM V, L.P., its General Partner

By: FHM V, LLC, its General Partner

By:  /s/ Steve R. Bailey                                        

Steve R. Bailey, Chief Financial Officer

FHM V, L.P.

By: FHM V, LLC, its General Partner

By:  /s/ Steve R. Bailey                                       

Steve R. Bailey, Chief Financial Officer

FHM V, LLC, its General Partner

By:  /s/ Steve R. Bailey                                       

Steve R. Bailey, Chief Financial Officer

FRAZIER HEALTHCARE VII, L.P.

By: FHM VII, L.P., its General Partner

By: FHM VII, L.L.C., its General Partner

By:  /s/ Steve R. Bailey                                       

Steve R. Bailey, Chief Financial Officer

FRAZIER HEALTHCARE VII-A, L.P.

By: FHM VII, L.P., its General Partner

By: FHM VII, L.L.C., its General Partner

By:  /s/ Steve R. Bailey

        Steve R. Bailey, Chief Financial Officer

FHM VII, L.P.

By: FHM VII, L.L.C., its General Partner

By:  /s/ Steve R. Bailey

        Steve R. Bailey, Chief Financial Officer

FHM VII, L.L.C.

By:  /s/ Steve R. Bailey                                        

        Steve R. Bailey, Chief Financial Officer

CUSIP No.   032724106 13D Page 20 of 21 Pages

                      *                                       

Alan Frazier

                      *                                       Nader Naini

                      *                                       Patrick Heron

                      *                                       James Topper

                      *                                       Nathan Every

     *By:  /s/ Steve R. Bailey                                    

Steve R. Bailey, as Attorney-in-Fact

This Schedule 13D was executed by Steve R. Bailey on behalf of the individuals listed above pursuant to a Power of Attorney a copy of which is attached as Exhibit 99.2.

CUSIP No.   032724106 13D Page 21 of 21 Pages

EXHIBIT 99.2

POWER OF ATTORNEY

KNOW ALL BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoints Steve R. Bailey with full power to act singly, his true and lawful attorney-in-fact, with full power of substitution, to: (i) sign any and all instruments, certificates and documents that may be necessary, desirable or appropriate to be executed on behalf of himself as an individual or in his capacity as a general partner of any partnership or limited liability company, pursuant to Section 13 or 16 of the Securities Exchange Act of 1934, as amended, and any and all regulations promulgated thereunder, (ii) file the same (including any amendments thereto), with all exhibits thereto, and any other documents in connection therewith, with the Securities and Exchange Commission, and any stock exchange or similar authority and (iii) take any other action of any type whatsoever in connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this power of attorney shall be in such form and shall contain such terms and conditions as such attorney‑in‑fact may approve in such attorney‑in‑fact's discretion, granting unto said attorney-in-fact full power and authority to do and perform each and every act and thing necessary, desirable or appropriate.

Each of the undersigned hereby grant to the attorney-in-fact full power and authority to do and perform any and every act and thing whatsoever requisite, necessary or proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as the undersigned might or could do if personally present with full power of substitution or revocation, hereby ratifying and confirming all that such attorney-in-fact or such attorney-in-fact's substitute or substitutes, shall lawfully do or cause to be done by virtue of this power of attorney and the rights and powers herein granted.

This power of attorney shall remain in full force and effect until revoked by the undersigned in a signed writing delivered to the attorney-in-fact.

IN WITNESS WHEREOF, this Power of Attorney has been signed as of the 16th day of February, 2016.

/s/ Alan Frazier                                

    Alan Frazier

/s/ Nader Naini                                 

    Nader Naini

/s/ Patrick Heron                              

    Patrick Heron

/s/ James Topper                              

    James Topper

/s/ Nathan Every                              

    Nathan Every