Sierra Oncology (SRRA) SC 13G/A Sierra Oncology / New Leaf Biopharma Opportunities I ownership change

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO

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

PURSUANT TO RULE 13d-2

(Amendment No. 3)

Sierra Oncology, Inc.

(Name of Issuer)

Common Stock, $0.001 par value per share

(Title of Class of Securities)

82640U404

(CUSIP Number)

December 31, 2021

(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 the disclosures provided in a prior cover page.

The information required in 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).

13G

CUSIP No. 82640U404

1	NAMES OF REPORTING PERSONS   I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)   New Leaf Biopharma Opportunities I, L.P. (“Biopharma I”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)   (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION   Delaware

NUMBER OF SHARES  BENEFICIALLY  OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 125,511 shares; except that (i) New Leaf BPO Associates I, L.P. (“BPO Associates”), the sole general partner of Biopharma I, may be deemed to have sole power to vote such shares; (ii) New Leaf Venture Management III, L.L.C. (“NLV Management III”), the sole general partner of BPO Associates and ultimate general partner of Biopharma I, may be deemed to have sole power to vote such shares; and (iii) each of Ronald Hunt (“Hunt”) and Vijay Lathi (“Lathi”), the managers of NLV Management III, may be deemed to have shared power to vote such shares.
	6	SHARED VOTING POWER   See response to row 5.
	7	SOLE DISPOSITIVE POWER 125,511 shares; except that (i) BPO Associates, the sole general partner of Biopharma I, may be deemed to have sole power to dispose of such shares; (ii) NLV Management III, the sole general partner of BPO Associates and ultimate general partner of Biopharma I, may be deemed to have sole power to dispose of such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management III, may be deemed to have shared power to dispose of such shares.
	8	SHARED DISPOSITIVE POWER   See response to row 7.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON   125,511
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)   ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)   0.6% (1)
12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)   PN

(1) Based on 19,323,028 shares of the Issuer’s Common Stock outstanding as of January 26, 2022, as reported by the Issuer in its prospectus supplement filed under Rule 424(b)(5), assuming full exercise of the underwriter’s option to exercise additional shares, filed with the United States Securities and Exchange Commission on January 27, 2022 (the “Prospectus Supplement”).

13G

CUSIP No. 82640U404

1	NAMES OF REPORTING PERSONS   I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)   New Leaf BPO Associates I, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)   (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION   Delaware

NUMBER OF SHARES  BENEFICIALLY  OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 125,511 shares, all of which are owned by BioPharma I; except that (i) BPO Associates, the sole general partner of Biopharma I, may be deemed to have sole power to vote such shares; (ii) NLV Management III, the sole general partner of BPO Associates and ultimate general partner of Biopharma I, may be deemed to have sole power to vote such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management III, may be deemed to have shared power to vote such shares.
	6	SHARED VOTING POWER   See response to row 5.
	7	SOLE DISPOSITIVE POWER 125,511 shares, all of which are owned by BioPharma I; except that (i) BPO Associates, the sole general partner of Biopharma I, may be deemed to have sole power to dispose of such shares; (ii) NLV Management III, the sole general partner of BPO Associates and ultimate general partner of Biopharma I, may be deemed to have sole power to dispose of such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management III, may be deemed to have shared power to dispose of such shares.
	8	SHARED DISPOSITIVE POWER   See response to row 7.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON   125,511
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)   ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)   0.6% (1)
12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)   PN

(1) Based on 19,323,028 of the Issuer’s Common Stock outstanding as of January 26, 2022, as reported in the Prospectus Supplement.

13G

CUSIP No. 82640U404

1	NAMES OF REPORTING PERSONS   I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)   New Leaf Venture Management III, L.L.C.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)   (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION   Delaware

NUMBER OF SHARES  BENEFICIALLY  OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 125,511 shares, all of which are owned by BioPharma I; except that (i) BPO Associates, the sole general partner of Biopharma I, may be deemed to have sole power to vote such shares; (ii) NLV Management III, the sole general partner of BPO Associates and ultimate general partner of Biopharma I, may be deemed to have sole power to vote such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management III, may be deemed to have shared power to vote such shares.
	6	SHARED VOTING POWER   See response to row 5.
	7	SOLE DISPOSITIVE POWER 125,511 shares, all of which are owned by BioPharma I; except that (i) BPO Associates, the sole general partner of Biopharma I, may be deemed to have sole power to dispose of such shares; (ii) NLV Management III, the sole general partner of BPO Associates and ultimate general partner of Biopharma I, may be deemed to have sole power to dispose of such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management III, may be deemed to have shared power to dispose of such shares.
	8	SHARED DISPOSITIVE POWER   See response to row 7.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON   125,511
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)   ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)   0.6% (1)
12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)   OO

(1) Based on 19,323,028 of the Issuer’s Common Stock outstanding as of January 26, 2022, as reported in the Prospectus Supplement.

13G

CUSIP No. 82640U404

1	NAMES OF REPORTING PERSONS   I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)   New Leaf Ventures IV, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)   (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION   Delaware

NUMBER OF SHARES  BENEFICIALLY  OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 661,903 shares, of which 284,100 shares are Common Stock, 284,062 shares represent Common Stock issuable upon the exercise of Series A Warrants, exercisable within 60 days of the date hereof and 93,741 shares represent Common Stock issuable upon the exercise of Series B Warrants, exercisable within 60 days of the date hereof, all of such securities are owned by New Leaf Ventures IV, L.P. (“NLV IV”); except that (i) New Leaf Venture Associates IV, L.P. (“NLV Associates IV”), as the sole general partner of NLV IV, may be deemed to have sole power to vote such shares; (ii) New Leaf Venture Management IV, L.L.C (“NLV Management IV”), the sole general partner of NLV Associates IV and ultimate general partner of NLV IV, may be deemed to have sole power to vote such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management IV, may be deemed to have shared power to vote such shares.
	6	SHARED VOTING POWER   See response to row 5.
	7	SOLE DISPOSITIVE POWER 661,903 shares, of which 284,100 shares are Common Stock, 284,062 shares represent Common Stock issuable upon the exercise of Series A Warrants, exercisable within 60 days of the date hereof and 93,741 shares represent Common Stock issuable upon the exercise of Series B Warrants, exercisable within 60 days of the date hereof, all of such securities are owned by NLV IV; except that (i) NLV Associates IV, as the sole general partner of NLV IV, may be deemed to have sole power to dispose of such shares; (ii) NLV Management IV, the sole general partner of NLV Associates IV and ultimate general partner of NLV IV, may be deemed to have sole power to dispose of such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management IV, may be deemed to have shared power to dispose of such shares.
	8	SHARED DISPOSITIVE POWER   See response to row 7.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON   661,903
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)   ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)   3.4% (1)
12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)   PN

(1) Based on 19,323,028 of the Issuer’s Common Stock outstanding as of January 26, 2022, as reported in the Prospectus Supplement.

13G

CUSIP No. 82640U404

1	NAMES OF REPORTING PERSONS   I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)   New Leaf Venture Associates IV, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)   (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION   Delaware

NUMBER OF SHARES  BENEFICIALLY  OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 661,903 shares, of which 284,100 shares are Common Stock, 284,062 shares represent Common Stock issuable upon the exercise of Series A Warrants, exercisable within 60 days of the date hereof and 93,741 shares represent Common Stock issuable upon the exercise of Series B Warrants, exercisable within 60 days of the date hereof, all of such securities are owned by NLV IV; except that (i) NLV Associates IV, as the sole general partner of NLV IV, may be deemed to have sole power to vote such shares; (ii) NLV Management IV, the sole general partner of NLV Associates IV and ultimate general partner of NLV IV, may be deemed to have sole power to vote such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management IV, may be deemed to have shared power to vote such shares.
	6	SHARED VOTING POWER   See response to row 5.
	7	SOLE DISPOSITIVE POWER 661,903 shares, of which 284,100 shares are Common Stock, 284,062 shares represent Common Stock issuable upon the exercise of Series A Warrants, exercisable within 60 days of the date hereof and 93,741 shares represent Common Stock issuable upon the exercise of Series B Warrants, exercisable within 60 days of the date hereof, all of such securities are owned by NLV IV; except that (i) NLV Associates IV, as the sole general partner of NLV IV, may be deemed to have sole power to dispose of such shares; (ii) NLV Management IV, the sole general partner of NLV Associates IV and ultimate general partner of NLV IV, may be deemed to have sole power to dispose of such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management IV, may be deemed to have shared power to dispose of such shares.
	8	SHARED DISPOSITIVE POWER   See response to row 7.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON   661,903
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)   ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)   3.4% (1)
12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)   PN

(1) Based on 19,323,028 of the Issuer’s Common Stock outstanding as of January 26, 2022, as reported in the Prospectus Supplement.

13G

CUSIP No. 82640U404

1	NAMES OF REPORTING PERSONS   I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)   New Leaf Venture Management IV, L.L.C
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)   (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION   Delaware

NUMBER OF SHARES  BENEFICIALLY  OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 661,903 shares, of which 284,100 shares are Common Stock, 284,062 shares represent Common Stock issuable upon the exercise of Series A Warrants, exercisable within 60 days of the date hereof and 93,741 shares represent Common Stock issuable upon the exercise of Series B Warrants, exercisable within 60 days of the date hereof, all of such securities are owned by NLV IV; except that (i) NLV Associates IV, as the sole general partner of NLV IV, may be deemed to have sole power to vote such shares; (ii) NLV Management IV, the sole general partner of NLV Associates IV and ultimate general partner of NLV IV, may be deemed to have sole power to vote such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management IV, may be deemed to have shared power to vote such shares.
	6	SHARED VOTING POWER   See response to row 5.
	7	SOLE DISPOSITIVE POWER 661,903 shares, of which 284,100 shares are Common Stock, 284,062 shares represent Common Stock issuable upon the exercise of Series A Warrants, exercisable within 60 days of the date hereof and 93,741 shares represent Common Stock issuable upon the exercise of Series B Warrants, exercisable within 60 days of the date hereof, all of such securities are owned by NLV IV; except that (i) NLV Associates IV, as the sole general partner of NLV IV, may be deemed to have sole power to dispose of such shares; (ii) NLV Management IV, the sole general partner of NLV Associates IV and ultimate general partner of NLV IV, may be deemed to have sole power to dispose of such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management IV, may be deemed to have shared power to dispose of such shares.
	8	SHARED DISPOSITIVE POWER   See response to row 7.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON   661,903
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)   ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)   3.4%
12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)   OO

(1) Based on 19,323,028 of the Issuer’s Common Stock outstanding as of January 26, 2022, as reported in the Prospectus Supplement.

13G

CUSIP No. 82640U404

1	NAMES OF REPORTING PERSONS   I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)   Vijay Lathi
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)   (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION   United States

NUMBER OF SHARES  BENEFICIALLY  OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER   See response to row 6.
	6	SHARED VOTING POWER 787,414 shares, consisting of (A) 125,511 shares of Common Stock which are owned by BioPharma I; except that (i) BPO Associates, the sole general partner of Biopharma I, may be deemed to have sole power to vote such shares; (ii) NLV Management III, the sole general partner of BPO Associates and ultimate general partner of Biopharma I, may be deemed to have sole power to vote such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management III, may be deemed to have shared power to vote such shares and (B) 661,941 shares owned by NLV IV, of which 284,100 shares are Common Stock, 284,062 shares represent Common Stock issuable upon the exercise of Series A Warrants, exercisable within 60 days of the date hereof and 93,741 shares represent Common Stock issuable upon the exercise of Series B Warrants, exercisable within 60 days of the date hereof, all of such securities are owned by NLV IV; except that (i) NLV Associates IV, as the sole general partner of NLV IV, may be deemed to have sole power to vote such shares; (ii) NLV Management IV, the sole general partner of NLV Associates IV and ultimate general partner of NLV IV, may be deemed to have sole power to vote such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management IV, may be deemed to have shared power to vote such shares.
	7	SOLE DISPOSITIVE POWER   See response to row 8.
	8	SHARED DISPOSITIVE POWER 787,414 shares, consisting of (A) 125,511 shares of Common Stock which are owned by BioPharma I; except that (i) BPO Associates, the sole general partner of Biopharma I, may be deemed to have sole power to vote such shares; (ii) NLV Management III, the sole general partner of BPO Associates and ultimate general partner of Biopharma I, may be deemed to have sole power to vote such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management III, may be deemed to have shared power to vote such shares and (B) 661,941 shares owned by NLV IV, of which 284,100 shares are Common Stock, 284,062 shares represent Common Stock issuable upon the exercise of Series A Warrants, exercisable within 60 days of the date hereof and 93,741 shares represent Common Stock issuable upon the exercise of Series B Warrants, exercisable within 60 days of the date hereof, all of such securities are owned by NLV IV; except that (i) NLV Associates IV, as the sole general partner of NLV IV, may be deemed to have sole power to vote such shares; (ii) NLV Management IV, the sole general partner of NLV Associates IV and ultimate general partner of NLV IV, may be deemed to have sole power to vote such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management IV, may be deemed to have shared power to vote such shares.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON   787,414
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)   ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)   4.1%
12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)   IN

(1) Based on 19,323,028 of the Issuer’s Common Stock outstanding as of January 26, 2022, as reported in the Prospectus Supplement.

13G

CUSIP No. 82640U404

1	NAMES OF REPORTING PERSONS   I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)   Ronald Hunt
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)   (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION   United States citizen

NUMBER OF SHARES  BENEFICIALLY  OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER   See response to row 6.
	6	SHARED VOTING POWER 787,414 shares, consisting of (A) 125,511 shares of Common Stock which are owned by BioPharma I; except that (i) BPO Associates, the sole general partner of Biopharma I, may be deemed to have sole power to vote such shares; (ii) NLV Management III, the sole general partner of BPO Associates and ultimate general partner of Biopharma I, may be deemed to have sole power to vote such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management III, may be deemed to have shared power to vote such shares and (B) 661,941 shares owned by NLV IV, of which 284,100 shares are Common Stock, 284,062 shares represent Common Stock issuable upon the exercise of Series A Warrants, exercisable within 60 days of the date hereof and 93,741 shares represent Common Stock issuable upon the exercise of Series B Warrants, exercisable within 60 days of the date hereof, all of such securities are owned by NLV IV; except that (i) NLV Associates IV, as the sole general partner of NLV IV, may be deemed to have sole power to vote such shares; (ii) NLV Management IV, the sole general partner of NLV Associates IV and ultimate general partner of NLV IV, may be deemed to have sole power to vote such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management IV, may be deemed to have shared power to vote such shares.
	7	SOLE DISPOSITIVE POWER   See response to row 8.
	8	SHARED DISPOSITIVE POWER 787,414 shares, consisting of (A) 125,511 shares of Common Stock which are owned by BioPharma I; except that (i) BPO Associates, the sole general partner of Biopharma I, may be deemed to have sole power to dispose of such shares; (ii) NLV Management III, the sole general partner of BPO Associates and ultimate general partner of Biopharma I, may be deemed to have sole power to dispose of such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management III, may be deemed to have shared power to dispose of such shares and (B) 661,941 shares owned by NLV IV, of which 284,100 shares are Common Stock, 284,062 shares represent Common Stock issuable upon the exercise of Series A Warrants, exercisable within 60 days of the date hereof and 93,741 shares represent Common Stock issuable upon the exercise of Series B Warrants, exercisable within 60 days of the date hereof, all of such securities are owned by NLV IV; except that (i) NLV Associates IV, as the sole general partner of NLV IV, may be deemed to have sole power to dispose of such shares; (ii) NLV Management IV, the sole general partner of NLV Associates IV and ultimate general partner of NLV IV, may be deemed to have sole power to dispose of such shares; and (iii) each of Hunt and Lathi, the managers of NLV Management IV, may be deemed to have shared power to dispose of such shares.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON   787,414
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)   ☐
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)   4.1%
12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)   IN

(1) Based on 19,323,028 of the Issuer’s Common Stock outstanding as of January 26, 2022, as reported in the Prospectus Supplement.

13G

CUSIP No. 82640U404

Schedule 13G

This Amendment No. 3 (“Amendment No. 3”) amends and supplements the Schedule 13G originally filed with the Securities and Exchange Commission (the “SEC”) on February 14, 2018 and amended on February 13, 2019 and February 13, 2020 (collectively, the “Original Schedule 13G”) by the Reporting Persons. The “Reporting Persons” are, collectively, New Leaf Biopharma Opportunities I, L.P. (“Biopharma I”), New Leaf BPO Associates I, L.P. (“BPO Associates”), New Leaf Venture Management III, L.L.C. (“NLV Management III”), New Leaf Ventures IV, L.P. (“NLV IV”), New Leaf Venture Associates IV, L.P. (“NLV Associates IV”), New Leaf Venture Management IV, L.L.C (“NLV Management IV”), Ronald Hunt (“Hunt”) and Vijay Lathi (“Lathi”). Only those items that are hereby reported are amended; all other items reported in the Original Schedule 13G remain unchanged. Information given in response to each item shall be deemed incorporated by reference in all other items, as applicable. Capitalized terms not defined in this Amendment No. 3 have the meanings ascribed to them in the Original Schedule 13G.

Item 4. Ownership.

(a) Amount beneficially owned:

See line 9 of each cover sheet.

(b) Percent of class:

See line 11 and the corresponding footnotes of each cover sheet.

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

(i) Sole power to vote or to direct the vote: see line 5 of cover sheets.*

(ii) Shared power to vote or to direct the vote: see line 6 of cover sheets.*

(iii) Sole power to dispose or to direct the disposition of: see line 7 of cover sheets.*

(iv) Shared power to dispose or to direct the disposition of: see line 8 of cover sheets.*

*Each Reporting Person disclaims beneficial ownership of such shares of Common Stock, except for the shares, if any, such Reporting Person holds of record and to the extent of their pecuniary interest therein, if any.

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

The Reporting Persons ceased to be the beneficial owner of more than five percent (5%) of the Issuer’s Shares due to dilution caused by the Issuer’s issuance of additional shares of its Shares from time to time since the date of the filing of the Original Schedule 13G.

13G

CUSIP No. 82640U404

SIGNATURES

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 11, 2022

NEW LEAF VENTURES IV, L.P.
By:	NLV ASSOCIATES IV, L.P.
	Its General Partner
	By:	NEW LEAF VENTURE MANAGEMENT IV, L.L.C.
		Its General Partner
		By:	/s/ Craig L. Slutzkin
			Craig L. Slutzkin
			Chief Financial Officer
NLV ASSOCIATES IV, L.P.
By:	NEW LEAF VENTURE MANAGEMENT IV, L.L.C.
	Its General Partner
	By:	/s/ Craig L. Slutzkin
		Craig L. Slutzkin
		Chief Financial Officer
NEW LEAF VENTURE MANAGEMENT IV, L.L.C.
By:	/s/ Craig L. Slutzkin
	Craig L. Slutzkin
	Chief Financial Officer
NEW LEAF BIOPHARMA OPPORTUNITIES I, L.P.
By:	NEW LEAF BPO ASSOCIATES I, L.P.
	Its General Partner
	By:	NEW LEAF VENTURE MANAGEMENT III, L.L.C.
		Its General Partner
		By:	/s/ Craig L. Slutzkin
			Craig L. Slutzkin
			Chief Financial Officer

NEW LEAF BPO ASSOCIATES I, L.P.
By:	NEW LEAF VENTURE MANAGEMENT III, L.L.C.
	Its General Partner
	By:	/s/ Craig L. Slutzkin
		Craig L. Slutzkin
		Chief Financial Officer

NEW LEAF VENTURE MANAGEMENT III, L.L.C.
By:	/s/ Craig L. Slutzkin
	Craig L. Slutzkin
	Chief Financial Officer
*
Vijay Lathi
*
Ronald Hunt

/s/ Craig L. Slutzkin

* Craig L. Slutzkin

As attorney-in-fact

* This Schedule 13G was executed by Craig L. Slutzkin on behalf of the individuals listed above pursuant to Powers of Attorney. Note that copies of the applicable Powers of Attorney are already on file with the appropriate agencies.