SEC Filing | TScan Therapeutics, Inc.

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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

TScan Therapeutics, Inc.

(Name of Issuer)

Voting Common Stock, $0.0001 par value per share

(Title of Class of Securities)

89854M101

(CUSIP Number)

May 26, 2023

(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. 89854M101


	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
OWNED BY			6	SHARED VOTING POWER
EACH
REPORTING					3,023,416 (1)
PERSON WITH			7	SOLE DISPOSITIVE POWER

					0
			8	SHARED DISPOSITIVE POWER

					3,023,416 (1)
	9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

			3,023,416 (1)
	10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES				☐


	11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

			6.8% (1)
	12	TYPE OF REPORTING PERSON

			PN

(1) Includes 1,425,436 Shares (as defined below) underlying certain Pre-Funded Warrants (as defined below). The Pre-Funded Warrants are subject to the Pre-Funded Warrants Blocker (as defined below).

CUSIP No. 89854M101


	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
OWNED BY			6	SHARED VOTING POWER
EACH
REPORTING					3,023,416 (1)
PERSON WITH			7	SOLE DISPOSITIVE POWER

					0
			8	SHARED DISPOSITIVE POWER

					3,023,416 (1)
	9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

			3,023,416 (1)
	10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES				☐


	11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

			6.8% (1)
	12	TYPE OF REPORTING PERSON

			OO

(1) Includes 1,425,436 Shares underlying certain Pre-Funded Warrants. The Pre-Funded Warrants are subject to the Pre-Funded Warrants Blocker.

CUSIP No. 89854M101


	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
OWNED BY			6	SHARED VOTING POWER
EACH
REPORTING					1,210,605
PERSON WITH			7	SOLE DISPOSITIVE POWER

					0
			8	SHARED DISPOSITIVE POWER

					1,210,605
	9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

			1,210,605
	10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES				☐


	11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

			2.8%
	12	TYPE OF REPORTING PERSON

			PN

CUSIP No. 89854M101


	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
OWNED BY			6	SHARED VOTING POWER
EACH
REPORTING					1,210,605
PERSON WITH			7	SOLE DISPOSITIVE POWER

					0
			8	SHARED DISPOSITIVE POWER

					1,210,605
	9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

			1,210,605
	10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES				☐


	11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

			2.8%
	12	TYPE OF REPORTING PERSON

			OO

CUSIP No. 89854M101

NAME OF REPORTING PERSON

Biotechnology Value Trading Fund OS LP

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

Cayman Islands

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

140,576

PERSON WITH

SOLE DISPOSITIVE POWER

SHARED DISPOSITIVE POWER

140,576

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

140,576

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

Less than 1%

TYPE OF REPORTING PERSON

CUSIP No. 89854M101

NAME OF REPORTING PERSON

BVF Partners OS Ltd.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

Cayman Islands

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

140,576

PERSON WITH

SOLE DISPOSITIVE POWER

SHARED DISPOSITIVE POWER

140,576

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

140,576

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

Less than 1%

TYPE OF REPORTING PERSON

CUSIP No. 89854M101


	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
OWNED BY			6	SHARED VOTING POWER
EACH
REPORTING					4,234,021 (1)
PERSON WITH			7	SOLE DISPOSITIVE POWER

					0
			8	SHARED DISPOSITIVE POWER

					4,234,021 (1)
	9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

			4,234,021 (1)
	10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES				☐


	11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

			9.6% (1)
	12	TYPE OF REPORTING PERSON

			OO

(1) Includes 1,425,436 Shares underlying certain Pre-Funded Warrants. The Pre-Funded Warrants are subject to the Pre-Funded Warrants Blocker.

CUSIP No. 89854M101


	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
OWNED BY			6	SHARED VOTING POWER
EACH
REPORTING					4,414,910 (1)
PERSON WITH			7	SOLE DISPOSITIVE POWER

					0
			8	SHARED DISPOSITIVE POWER

					4,414,910 (1)
	9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

			4,414,910 (1)
	10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES				☐


	11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

			9.99% (1)
	12	TYPE OF REPORTING PERSON

			PN, IA

(1) Includes 1,425,436 Shares underlying certain Pre-Funded Warrants. The Pre-Funded Warrants are subject to the Pre-Funded Warrants Blocker.

CUSIP No. 89854M101


	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
OWNED BY			6	SHARED VOTING POWER
EACH
REPORTING					4,414,910 (1)
PERSON WITH			7	SOLE DISPOSITIVE POWER

					0
			8	SHARED DISPOSITIVE POWER

					4,414,910 (1)
	9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

			4,414,910 (1)
	10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES				☐


	11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

			9.99% (1)
	12	TYPE OF REPORTING PERSON

			CO

(1) Includes 1,425,436 Shares underlying certain Pre-Funded Warrants. The Pre-Funded Warrants are subject to the Pre-Funded Warrants Blocker.

CUSIP No. 89854M101


	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
OWNED BY			6	SHARED VOTING POWER
EACH
REPORTING					4,414,910 (1)
PERSON WITH			7	SOLE DISPOSITIVE POWER

					0
			8	SHARED DISPOSITIVE POWER

					4,414,910 (1)
	9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

			4,414,910 (1)
	10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES				☐


	11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

			9.99% (1)
	12	TYPE OF REPORTING PERSON

			IN

(1) Includes 1,425,436 Shares underlying certain Pre-Funded Warrants. The Pre-Funded Warrants are subject to the Pre-Funded Warrants Blocker.

CUSIP No. 89854M101

Item 1(a).

Name of Issuer:

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

Item 1(b).

Address of Issuer’s Principal Executive Offices:

830 Winter Street

Waltham, Massachusetts 02451

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

CUSIP No. 89854M101

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.”

Item 2(d).

Title of Class of Securities:

Voting Common Stock, $0.0001 par value per share (the “Shares”)

Item 2(e).

CUSIP Number:

89854M101

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)	/ /	A non-U.S. institution, in accordance with Rule 13d-1(b)(1)(ii)(J).

(k)	/ /	Group, in accordance with Rule 13d-1(b)(1)(ii)(K). If filing as a non-U.S. institution in accordance with Rule 13d-1(b)(1)(ii)(J), please specify the type of institution: ____

CUSIP No. 89854M101

Item 4.

Ownership

(a)

Amount beneficially owned:

As of the close of business on June 5, 2023, the Reporting Persons held an aggregate of 9,510,526 pre-funded warrants (the “Pre-Funded Warrants”) exercisable for an aggregate of 9,510,526 Shares. Each Pre-Funded Warrant is exercisable for one Share at an exercise price of $0.0001 per Share. The Pre-Funded Warrants are immediately exercisable subject to the limitations of the Pre-Funded Warrants Blocker (as defined and described below).

A holder of a Pre-Funded Warrant will not be entitled to exercise any portion of any Pre-Funded Warrant which, upon giving effect to such exercise, would cause the aggregate number of Shares beneficially owned by the holder (together with its affiliates and other attribution parties (as defined in the Pre-Funded Warrant)) to exceed 4.99% of the number of Shares that would be outstanding immediately after giving effect to the exercise (the “Pre-Funded Warrants Blocker”). As a result, the Pre-Funded Warrants Blocker currently prohibits the exercise of all of the Pre-Funded Warrants held by the Reporting Persons. However, any holder may increase or decrease such percentage to any other percentage not in excess of 19.99% upon at least 61 days’ prior notice from the holder to the Issuer. The Reporting Persons have notified the Issuer of an increase in such percentage from 4.99% to 9.99%, which takes effect within 60 days of the date hereof. Accordingly, this report reflects beneficial ownership of the Shares based on the 9.99% ownership limitation, which, upon its effectiveness, will limit the exercise of the Pre-Funded Warrants held by the Reporting Persons into 1,425,436 Shares out of the 9,510,526 Shares underlying such Pre-Funded Warrants.

As of the close of business on the date hereof (i) BVF beneficially owned 3,023,416 Shares, including 1,425,436 Shares underlying certain Pre-Funded Warrants held by it and excluding 3,658,277 Shares underlying certain Pre-Funded Warrants held by it due to the Pre-Funded Warrants Blocker; (ii) BVF2 beneficially owned 1,210,605 Shares, excluding 3,851,344 Shares underlying certain Pre-Funded Warrants held by it due to the Pre-Funded Warrants Blocker; and (iii) Trading Fund OS beneficially owned 140,576 Shares, excluding 447,219 Shares underlying certain Pre-Funded Warrants held by it due to the Pre-Funded Warrants Blocker.

BVF GP, as the general partner of BVF, may be deemed to beneficially own the 3,023,416 Shares beneficially owned by BVF.

BVF2 GP, as the general partner of BVF2, may be deemed to beneficially own the 1,210,605 Shares beneficially owned by BVF2.

CUSIP No. 89854M101

Partners OS, as the general partner of Trading Fund OS, may be deemed to beneficially own the 140,576 Shares beneficially owned by Trading Fund OS.

BVF GPH, as the sole member of each of BVF GP and BVF2 GP, may be deemed to beneficially own the 4,234,021 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 4,414,910 Shares beneficially owned in the aggregate by BVF, BVF2 and Trading Fund OS and held in a certain Partners managed account (the “Partners Managed Account”), including 40,313 Shares held in the Partners Managed Account and excluding 128,250 Shares underlying certain Pre-Funded Warrants held in the Partners Managed Account due to the Pre-Funded Warrants Blocker.

BVF Inc., as the general partner of Partners, may be deemed to beneficially own the 4,414,910 Shares beneficially owned by Partners.

Mr. Lampert, as a director and officer of BVF Inc., may be deemed to beneficially own the 4,414,910 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 and Trading Fund OS and held in 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 a denominator that is the sum of (i) 42,470,203 Shares outstanding as of May 31, 2023, which is the total number of Shares outstanding following the close of the Issuer’s public offering as disclosed in the Issuer’s Prospectus filed with the Securities and Exchange Commission on May 30, 2023, (ii) 297,660 Shares issued in connection with the partial exercise of the underwriters overallotment option as disclosed in the Issuer’s Current Report on Form 8-K filed with the Securities and Exchange Commission on May 31, 2023, and (iii) 1,425,436 Shares issuable upon the exercise of certain Pre-Funded Warrants owned by the Reporting Persons, as applicable

As of the close of business on the date hereof, (i) BVF beneficially owned approximately 6.8% of the outstanding Shares, (ii) BVF2 beneficially owned approximately 2.8% 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 6.8% of the outstanding Shares, (v) BVF2 GP may be deemed to beneficially own approximately 2.8% 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 9.6% of the outstanding Shares, and (viii) each of Partners, BVF Inc. and Mr. Lampert may be deemed to beneficially own approximately 9.99% of the outstanding Shares (less than 1% of the outstanding Shares are held in the Partners Managed Account).

CUSIP No. 89854M101

(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.

Item 6.

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

BVF GP, BVF GPH, Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the Shares beneficially owned by BVF. BVF GPH, Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the Shares beneficially owned by BVF2. Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the Shares beneficially owned by Trading Fund OS and held in 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.

CUSIP No. 89854M101

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.

CUSIP No. 89854M101

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: June 5, 2023

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:	BVF Inc., its general partner
By:	/s/ Mark N. Lampert
	Mark N. Lampert	By:	/s/ Mark N. Lampert
	Chief Executive Officer		Mark N. Lampert
			President

BVF I GP LLC
		BVF GP HOLDINGS LLC
By:	/s/ Mark N. Lampert
	Mark N. Lampert	By:	/s/ Mark N. Lampert
	Chief Executive Officer		Mark N. Lampert
			Chief Executive Officer

BIOTECHNOLOGY VALUE FUND II, L.P.
		BVF PARTNERS L.P.
By:	BVF II GP LLC, its general partner
		By:	BVF Inc., its general partner
By:	/s/ Mark N. Lampert
	Mark N. Lampert	By:	/s/ Mark N. Lampert
	Chief Executive Officer		Mark N. Lampert
			President

BVF II GP LLC
		BVF INC.
By:	/s/ Mark N. Lampert
	Mark N. Lampert	By:	/s/ Mark N. Lampert
	Chief Executive Officer		Mark N. Lampert
			President

BVF PARTNERS OS LTD.
		/s/ Mark N. Lampert
By:	BVF Partners L.P., its sole member	MARK N. LAMPERT
By:	BVF Inc., its general partner

By:	/s/ Mark N. Lampert
	Mark N. Lampert
	President

Exhibit 99.1

Joint Filing Agreement

The undersigned hereby agree that the Statement on Schedule 13G dated June 5, 2023 with respect to the Voting Common Stock, $0.0001 par value per share, of TScan Therapeutics, Inc., a Delaware corporation, 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: June 5, 2023

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:	BVF Inc., its general partner
By:	/s/ Mark N. Lampert
	Mark N. Lampert	By:	/s/ Mark N. Lampert
	Chief Executive Officer		Mark N. Lampert
			President

BVF I GP LLC
		BVF GP HOLDINGS LLC
By:	/s/ Mark N. Lampert
	Mark N. Lampert	By:	/s/ Mark N. Lampert
	Chief Executive Officer		Mark N. Lampert
			Chief Executive Officer

BIOTECHNOLOGY VALUE FUND II, L.P.
		BVF PARTNERS L.P.
By:	BVF II GP LLC, its general partner
		By:	BVF Inc., its general partner
By:	/s/ Mark N. Lampert
	Mark N. Lampert	By:	/s/ Mark N. Lampert
	Chief Executive Officer		Mark N. Lampert
			President

BVF II GP LLC
		BVF INC.
By:	/s/ Mark N. Lampert
	Mark N. Lampert	By:	/s/ Mark N. Lampert
	Chief Executive Officer		Mark N. Lampert
			President

BVF PARTNERS OS LTD.
		/s/ Mark N. Lampert
By:	BVF Partners L.P., its sole member	MARK N. LAMPERT
By:	BVF Inc., its general partner

By:	/s/ Mark N. Lampert
	Mark N. Lampert
	President