SC 13G

 UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

(Rule 13d-102)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT

TO RULES 13d-1(b), (c), AND (d) AND AMENDMENTS THERETO FILED

PURSUANT TO RULE 13d-2(b)

(Amendment No.   )¹

AnaptysBio, Inc.

 (Name of Issuer)

Common Stock, $0.001 par value

 (Title of Class of Securities)

032724106

 (CUSIP Number)

January 23, 2020

 (Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

☐  Rule 13d-1(b)

☒  Rule 13d-1(c)

☐  Rule 13d-1(d)

1              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

	1	NAME OF REPORTING PERSON
			Biotechnology Value Fund, L.P.
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	CITIZENSHIP OR PLACE OF ORGANIZATION
			Delaware
NUMBER OF			5	SOLE VOTING POWER
SHARES
BENEFICIALLY					0 shares
OWNED BY			6	SHARED VOTING POWER
EACH
REPORTING					733,882
PERSON WITH			7	SOLE DISPOSITIVE POWER
					0 shares
			8	SHARED DISPOSITIVE POWER
					733,882
	9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			733,882
	10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES				☐
	11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
			2.7%
	12	TYPE OF REPORTING PERSON
			PN

2

CUSIP No. 032724106

	1	NAME OF REPORTING PERSON
			BVF I GP LLC
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	CITIZENSHIP OR PLACE OF ORGANIZATION
			Delaware
NUMBER OF			5	SOLE VOTING POWER
SHARES
BENEFICIALLY					0 shares
OWNED BY			6	SHARED VOTING POWER
EACH
REPORTING					733,882
PERSON WITH			7	SOLE DISPOSITIVE POWER
					0 shares
			8	SHARED DISPOSITIVE POWER
					733,882
	9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			733,882
	10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES				☐
	11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
			2.7%
	12	TYPE OF REPORTING PERSON
			OO

3

CUSIP No. 032724106

	1	NAME OF REPORTING PERSON
			Biotechnology Value Fund II, L.P.
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	CITIZENSHIP OR PLACE OF ORGANIZATION
			Delaware
NUMBER OF			5	SOLE VOTING POWER
SHARES
BENEFICIALLY					0 shares
OWNED BY			6	SHARED VOTING POWER
EACH
REPORTING					564,092
PERSON WITH			7	SOLE DISPOSITIVE POWER
					0 shares
			8	SHARED DISPOSITIVE POWER
					564,092
	9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			564,092
	10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES				☐
	11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
			2.1%
	12	TYPE OF REPORTING PERSON
			PN

4

CUSIP No. 032724106

	1	NAME OF REPORTING PERSON
			BVF II GP LLC.
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	CITIZENSHIP OR PLACE OF ORGANIZATION
			Delaware
NUMBER OF			5	SOLE VOTING POWER
SHARES
BENEFICIALLY					0 shares
OWNED BY			6	SHARED VOTING POWER
EACH
REPORTING					564,092
PERSON WITH			7	SOLE DISPOSITIVE POWER
					0 shares
			8	SHARED DISPOSITIVE POWER
					564,092
	9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			564,092
	10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES				☐
	11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
			2.1%
	12	TYPE OF REPORTING PERSON
			OO

5

CUSIP No. 032724106

	1	NAME OF REPORTING PERSON
			Biotechnology Value Trading Fund OS LP
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	CITIZENSHIP OR PLACE OF ORGANIZATION
			Cayman Islands
NUMBER OF			5	SOLE VOTING POWER
SHARES
BENEFICIALLY					0 shares
OWNED BY			6	SHARED VOTING POWER
EACH
REPORTING					99,383
PERSON WITH			7	SOLE DISPOSITIVE POWER
					0 shares
			8	SHARED DISPOSITIVE POWER
					99,383
	9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			99,383
	10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES				☐
	11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
			Less than 1%
	12	TYPE OF REPORTING PERSON
			PN

6

CUSIP No. 032724106

	1	NAME OF REPORTING PERSON
			BVF Partners OS Ltd.
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	CITIZENSHIP OR PLACE OF ORGANIZATION
			Cayman Islands
NUMBER OF			5	SOLE VOTING POWER
SHARES
BENEFICIALLY					0 shares
OWNED BY			6	SHARED VOTING POWER
EACH
REPORTING					99,383
PERSON WITH			7	SOLE DISPOSITIVE POWER
					0 shares
			8	SHARED DISPOSITIVE POWER
					99,383
	9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			99,383
	10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES				☐
	11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
			Less than 1%
	12	TYPE OF REPORTING PERSON
			CO

7

CUSIP No. 032724106

	1	NAME OF REPORTING PERSON
			BVF GP HOLDINGS LLC
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	CITIZENSHIP OR PLACE OF ORGANIZATION
			Delaware
NUMBER OF			5	SOLE VOTING POWER
SHARES
BENEFICIALLY					0 shares
OWNED BY			6	SHARED VOTING POWER
EACH
REPORTING					1,297,974
PERSON WITH			7	SOLE DISPOSITIVE POWER
					0 shares
			8	SHARED DISPOSITIVE POWER
					1,297,974
	9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			1,297,974
	10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES				☐
	11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
			4.8%
	12	TYPE OF REPORTING PERSON
			OO

8

CUSIP No. 032724106

	1	NAME OF REPORTING PERSON
			BVF Partners L.P.
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	CITIZENSHIP OR PLACE OF ORGANIZATION
			Delaware
NUMBER OF			5	SOLE VOTING POWER
SHARES
BENEFICIALLY					0 shares
OWNED BY			6	SHARED VOTING POWER
EACH
REPORTING					1,441,565
PERSON WITH			7	SOLE DISPOSITIVE POWER
					0 shares
			8	SHARED DISPOSITIVE POWER
					1,441,565
	9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			1,441,565
	10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES				☐
	11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
			5.3%
	12	TYPE OF REPORTING PERSON
			PN, IA

9

CUSIP No. 032724106

	1	NAME OF REPORTING PERSON
			BVF Inc.
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	CITIZENSHIP OR PLACE OF ORGANIZATION
			Delaware
NUMBER OF			5	SOLE VOTING POWER
SHARES
BENEFICIALLY					0 shares
OWNED BY			6	SHARED VOTING POWER
EACH
REPORTING					1,441,565
PERSON WITH			7	SOLE DISPOSITIVE POWER
					0 shares
			8	SHARED DISPOSITIVE POWER
					1,441,565
	9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			1,441,565
	10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES				☐
	11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
			5.3%
	12	TYPE OF REPORTING PERSON
			CO

10

CUSIP No. 032724106

	1	NAME OF REPORTING PERSON
			Mark N. Lampert
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	CITIZENSHIP OR PLACE OF ORGANIZATION
			United States
NUMBER OF			5	SOLE VOTING POWER
SHARES
BENEFICIALLY					0 shares
OWNED BY			6	SHARED VOTING POWER
EACH
REPORTING					1,441,565
PERSON WITH			7	SOLE DISPOSITIVE POWER
					0 shares
			8	SHARED DISPOSITIVE POWER
					1,441,565
	9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			1,441,565
	10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES				☐
	11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
			5.3%
	12	TYPE OF REPORTING PERSON
			IN

11

CUSIP No. 032724106

Item 1(a). Name of Issuer:

AnaptysBio, Inc., a Delaware corporation (the “Issuer”).

Item 1(b). Address of Issuer's Principal Executive Offices:

10421 Pacific Center Court, Suite 200

San Diego, California 92121

Item 2(a). Name of Person Filing

Item 2(b). Address of Principal Business Office or, if None, Residence

Item 2(c). Citizenship

Biotechnology Value Fund, L.P. (“BVF”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

BVF I GP LLC (“BVF GP”),

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

Biotechnology Value Fund II, L.P. (“BVF2”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

BVF II GP LLC (“BVF2 GP”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

Biotechnology Value Trading Fund OS LP (“Trading Fund OS”)

PO Box 309 Ugland House

Grand Cayman, KY1-1104

Cayman Islands

Citizenship: Cayman Islands

BVF Partners OS Ltd. (“Partners OS”)

PO Box 309 Ugland House

Grand Cayman, KY1-1104

Cayman Islands

Citizenship: Cayman Islands

BVF GP Holdings LLC (“BVF GPH”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

BVF Partners L.P. (“Partners”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

BVF Inc.

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

Mark N. Lampert (“Mr. Lampert”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: United States

Each of the foregoing is referred to as a “Reporting Person” and collectively as the “Reporting Persons.”

12

CUSIP No. 032724106

Item 2(d). Title of Class of Securities:

Common Stock, $0.001 par value per share (the “Shares”)

Item 2(e). CUSIP Number:

032724106

Item 3. If This Statement is Filed Pursuant to Rule 13d-1(b), or 13d-2(b) or (c), Check Whether the Person Filing is a:

	/x/	Not applicable.
(a)	/ /	Broker or dealer registered under Section 15 of the Exchange Act.
(b)	/ /	Bank as defined in Section 3(a)(6) of the Exchange Act.
(c)	/ /	Insurance company as defined in Section 3(a)(19) of the Exchange Act.
(d)	/ /	Investment company registered under Section 8 of the Investment Company Act.
(e)	/ /	An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E).
(f)	/ /	An employee benefit plan or endowment fund in accordance with Rule 13d-1(b)(1)(ii)(F).
(g)	/ /	A parent holding company or control person in accordance with Rule 13d-1(b)(1)(ii)(G).
(h)	/ /	A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act.
(i)	/ /	A church plan that is excluded from the definition of an investment company under Section 3(c)(14) of the Investment Company Act.
(j)	/ /	Group, in accordance with Rule 13d-1(b)(1)(ii)(J).
(k)	/ /	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K). If filing as a non-U.S. institution in accordance with Rule 240.13d-1(b)(1)(ii)(J), please specify the type of institution: ____

Item 4. Ownership

(a) Amount beneficially owned:

As of the close of business on February 3, 2020 (i) BVF beneficially owned 733,882 Shares, (ii) BVF2 beneficially owned 564,092 Shares, and (iii) Trading Fund OS beneficially owned 99,383 Shares.

BVF GP, as the general partner of BVF, may be deemed to beneficially own the 733,882 Shares beneficially owned by BVF.

BVF2 GP, as the general partner of BVF2, may be deemed to beneficially own the 564,092 Shares beneficially owned by BVF2.

Partners OS, as the general partner of Trading Fund OS, may be deemed to beneficially own the 99,383 Shares beneficially owned by Trading Fund OS.

13

CUSIP No. 032724106

BVF GPH, as the sole member of each of BVF GP and BVF2 GP, may be deemed to beneficially own the 1,297,974 Shares beneficially owned in the aggregate by BVF and BVF2.

Partners, as the investment manager of BVF, BVF2 and Trading Fund OS, and the sole member of Partners OS, may be deemed to beneficially own the 1,441,565 Shares beneficially owned in the aggregate by BVF, BVF2, Trading Fund OS, and a certain Partners Managed account (the “Partners Managed Account”), including 44,208 Shares held in the Partners Managed Account.

BVF Inc., as the general partner of Partners, may be deemed to beneficially own the 1,441,565 Shares beneficially owned by Partners.

Mr. Lampert, as a director and officer of BVF Inc., may be deemed to beneficially own the 1,441,565 Shares beneficially owned by BVF Inc.

The foregoing should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership of any Shares owned by another Reporting Person. BVF GP disclaims beneficial ownership of the Shares beneficially owned by BVF. BVF2 GP disclaims beneficial ownership of the Shares beneficially owned by BVF2. Partners OS disclaims beneficial ownership of the Shares beneficially owned by Trading Fund OS. BVF GPH disclaims beneficial ownership of the Shares beneficially owned by BVF and BVF2. Each of Partners, BVF Inc. and Mr. Lampert disclaims beneficial ownership of the Shares beneficially owned by BVF, BVF2, Trading Fund OS, and the Partners Managed Account, and the filing of this statement shall not be construed as an admission that any such person or entity is the beneficial owner of any such securities.

(b) Percent of class:

The following percentages are based on 27,133,459 Shares outstanding, as of November 5, 2019, as disclosed in the Issuer’s Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on November 8, 2019.

As of the close of business on February 3, 2020 (i) BVF beneficially owned approximately 2.7% of the outstanding Shares, (ii) BVF2 beneficially owned approximately 2.1% of the outstanding Shares, (iii) Trading Fund OS beneficially owned less than 1% of the outstanding Shares, (iv) BVF GP may be deemed to beneficially own approximately 2.7% of the outstanding Shares, (v) BVF2 GP may be deemed to beneficially own approximately 2.1% of the outstanding Shares, (vi) Partners OS may be deemed to beneficially own less than 1% of the outstanding Shares, (vii) BVF GPH may be deemed to beneficially own approximately 4.8% of the outstanding Shares, and (viii) each of Partners, BVF Inc. and Mr. Lampert may be deemed to beneficially own approximately 5.3% of the outstanding Shares (less than 1% of the outstanding Shares are held in the Partners Managed Account).

(c) Number of shares as to which such person has:

(i) Sole power to vote or to direct the vote

See Cover Pages Items 5-9.

(ii) Shared power to vote or to direct the vote

See Cover Pages Items 5-9.

(iii) Sole power to dispose or to direct the disposition of

See Cover Pages Items 5-9.

(iv) Shared power to dispose or to direct the disposition of

See Cover Pages Items 5-9.

Item 5. Ownership of Five Percent or Less of a Class.

Not Applicable.

14

CUSIP No. 032724106

Item 6. Ownership of More than Five Percent on Behalf of Another Person.

Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the Shares beneficially owned by BVF, BVF2, Trading Fund OS, and the Partners Managed Account.

Item 7. Identification and Classification of the Subsidiary That Acquired the Security Being Reported on by the Parent Holding Company or Control Person.

Not Applicable.

Item 8. Identification and Classification of Members of the Group.

See Exhibit 99.1.

Item 9. Notice of Dissolution of Group.

Not Applicable.

Item 10. Certifications.

By signing below each of the undersigned certifies that, to the best of its knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

15

CUSIP No. 032724106

SIGNATURE

After reasonable inquiry and to the best of his knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.

Dated: February 3, 2020

BIOTECHNOLOGY VALUE FUND, L.P.		Biotechnology Value Trading Fund OS LP
By:	BVF I GP LLC., its general partner
		By:	BVF Partners L.P., its investment manager
By:	/s/ Mark N. Lampert	By:	BVF Inc., its general partner
	Mark N. Lampert
	Chief Executive Officer	By:	/s/ Mark N. Lampert
			Mark N. Lampert
			President
BVF I GP LLC
By:	/s/ Mark N. Lampert	BVF GP HOLDINGS LLC
	Mark N. Lampert
	Chief Executive Officer	By:	/s/ Mark N. Lampert
			Mark N. Lampert
			Chief Executive Officer
BIOTECHNOLOGY VALUE FUND II, L.P.
By:	BVF II GP LLC its general partner	BVF PARTNERS L.P.
By:	/s/ Mark N. Lampert	By:	BVF Inc., its general partner
	Mark N. Lampert
	Chief Executive Officer	By:	/s/ Mark N. Lampert
			Mark N. Lampert
			President
BVF II GP LLC
By:	/s/ Mark N. Lampert	BVF INC.
	Mark N. Lampert
	Chief Executive Officer	By:	/s/ Mark N. Lampert
			Mark N. Lampert
			President
BVF PARTNERS OS LTD.
By:	BVF Partners L.P., its sole member	Mark N. Lampert
By:	BVF Inc., its general partner	MARK N. LAMPERT
By:	/s/ Mark N. Lampert
	Mark N. Lampert
	President

16

EX-99.1

Exhibit 99.1

Joint Filing Agreement

The undersigned hereby agree that the Statement on Schedule 13G dated February 3, 2020 with respect to the shares of Common Stock of AnaptysBio, Inc., and any further amendments thereto executed by each and any of the undersigned shall be filed on behalf of each of the undersigned pursuant to and in accordance with the provisions of Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended.

Dated: February 3, 2020

BIOTECHNOLOGY VALUE FUND, L.P.		Biotechnology Value Trading Fund OS LP
By:	BVF I GP LLC., its general partner
		By:	BVF Partners L.P., its investment manager
By:	/s/ Mark N. Lampert	By:	BVF Inc., its general partner
	Mark N. Lampert
	Chief Executive Officer	By:	/s/ Mark N. Lampert
			Mark N. Lampert
			President
BVF I GP LLC
By:	/s/ Mark N. Lampert	BVF GP HOLDINGS LLC
	Mark N. Lampert
	Chief Executive Officer	By:	/s/ Mark N. Lampert
			Mark N. Lampert
			Chief Executive Officer
BIOTECHNOLOGY VALUE FUND II, L.P.
By:	BVF II GP LLC its general partner	BVF PARTNERS L.P.
By:	/s/ Mark N. Lampert	By:	BVF Inc., its general partner
	Mark N. Lampert
	Chief Executive Officer	By:	/s/ Mark N. Lampert
			Mark N. Lampert
			President
BVF II GP LLC
By:	/s/ Mark N. Lampert	BVF INC.
	Mark N. Lampert
	Chief Executive Officer	By:	/s/ Mark N. Lampert
			Mark N. Lampert
			President
BVF PARTNERS OS LTD.
By:	BVF Partners L.P., its sole member	Mark N. Lampert
By:	BVF Inc., its general partner	MARK N. LAMPERT
By:	/s/ Mark N. Lampert
	Mark N. Lampert
	President