Initial Registration Statement for Employee Benefit Plan (Form S-8)

As filed with the Securities and Exchange Commission on March 4, 2026

Registration No. 333-   

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM S-8

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

TSCAN THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

Delaware		82-5282075
(State or other jurisdiction of incorporation or organization)		(I.R.S. Employer Identification No.)
830 Winter Street Waltham, Massachusetts		02451
(Address of Principal Executive Offices)		(Zip Code)

TSCAN THERAPEUTICS, INC. AMENDED AND RESTATED 2021 EQUITY INCENTIVE PLAN

TSCAN THERAPEUTICS, INC. 2021 EMPLOYEE STOCK PURCHASE PLAN

(Full title of the plan)

Gavin MacBeath

Chief Executive Officer

TScan Therapeutics, Inc.

830 Winter Street

Waltham, Massachusetts 02451

(Name and address of agent for service)

(857) 399-9500

(Telephone number, including area code, of agent for service)

Copies to:

Mitchell S. Bloom, Esq.

William D. Collins, Esq.

Finnbarr Murphy, Esq.

Goodwin Procter LLP

100 Northern Avenue

Boston, Massachusetts 02210

(617) 570-1000

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule 12b-2 of the Exchange Act.

Large accelerated filer		☐		Accelerated filer		☐
Non-accelerated filer		☒		Smaller reporting company		☒
				Emerging growth company		☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

EXPLANATORY NOTE

This Registration Statement on Form S-8 registers (i) 5,196,535 additional shares of common stock, $0.0001 par value per share ("Common Stock"), of TScan Therapeutics, Inc. (the "Registrant"), under the TScan Therapeutics, Inc. Amended and Restated 2021 Equity Incentive Plan (the "2021 Plan") and (ii) 569,016 additional shares of Common Stock under the TScan Therapeutics, Inc. 2021 Employee Stock Purchase Plan (the "2021 ESPP"). The number of shares of Common Stock reserved and available for issuance under the 2021 Plan is subject to an automatic annual increase on each January 1, beginning in 2022, by an amount equal to the lower of (i) four percent of the number of shares of Common Stock outstanding (including the shares of Common Stock underlying outstanding pre-funded warrants) on the immediately preceding December 31 and (ii) an amount of shares determined by our Board of Directors. Accordingly, on January 1, 2026, the number of shares of Common Stock reserved and available for issuance under the 2021 Plan increased by 5,196,535. The additional shares are of the same class as other securities relating to the 2021 Plan for which the Registrant's registration statements filed on Form S-8 with the Securities and Exchange Commission on July 16, 2021 (Registration No. 333-257941), March 9, 2022 (Registration No. 333-263380), March 8, 2023 (Registration No. 333-270343), June 16, 2023 (Registration No. 333-272733), March 6, 2024 (Registration No. 333-277695), June 14, 2024 (Registration No. 333-280212) and March 5, 2025 (Registration No. 333-285571) are effective. The number of shares of Common Stock reserved and available for issuance under the 2021 ESPP is subject to an automatic annual increase on each January 1, beginning in 2022, by an amount equal to the least of (i) one percent of the number of shares of Common Stock issued and outstanding on the immediately preceding December 31 or (ii) such number of shares of Common Stock as determined by our Board of Directors. Accordingly, on January 1, 2026, the number of shares of Common Stock reserved and available for issuance under the 2021 ESPP increased by 569,016. The additional shares are of the same class as other securities relating to the 2021 ESPP for which the Registrant's registration statements filed on Form S-8 with the Securities and Exchange Commission on July 16, 2021 (Registration No. 333-257941), March 9, 2022 (Registration No. 333-263380), March 8, 2023 (Registration No. 333-270343), March 6, 2024 (Registration No. 333-277695) and March 5, 2025 (Registration No. 333-285571) are effective. The information contained in the Registrant's registration statements on Form S-8 (Registration No. 333-257941, No. 333-263380, No. 333-270343, No. 333-272733, No. 333-277695, No. 333-280212 and No. 333-285571) is hereby incorporated by reference pursuant to General Instruction E.

Part II

INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 8.

Exhibits.

Exhibit No.		Description
4.1		Amended and Restated Certificate of Incorporation of the Registrant (Incorporated by reference to Exhibit 3.1 to the Registrant's Current Report on Form 8-K (File No. 001-40603) filed with the Securities and Exchange Commission on July 20, 2021).
4.2		Amended and Restated By-laws of the Registrant (Incorporated by reference to Exhibit 3.2 to the Registrant's Current Report on Form 8-K (File No. 001-40603) filed with the Securities and Exchange Commission on July 20, 2021).
5.1*		Opinion of Goodwin Procter LLP.
23.1*		Consent of Deloitte & Touche LLP, independent registered public accounting firm.
23.2*		Consent of Goodwin Procter LLP (included in Exhibit 5.1).
24.1*		Power of Attorney (included on signature page).
99.1		TScan Therapeutics, Inc. 2021 Amended and Restated Equity Incentive Plan and form of agreements thereunder (incorporated by reference to Exhibit 10.1 to the Registrant's Current Report on Form 8-K, filed with the Securities and Exchange Commission on June 14, 2024).
99.2		2021 Employee Stock Purchase Plan (Incorporated by reference to Exhibit 10.4 to the Registrant's Registration Statement on Form S-1 (File No. 333-255491) filed with the Securities and Exchange Commission on April 23, 2021).
107.1*		Filing Fee Table.

*	Filed herewith.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Waltham, Commonwealth of Massachusetts, on March 4, 2026.

TScan Therapeutics, Inc.
By:		/s/ Gavin MacBeath, Ph.D.
		Gavin MacBeath, Ph.D.
		Chief Executive Officer (Principal Executive Officer)

POWER OF ATTORNEY AND SIGNATURES

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints Gavin MacBeath and Jason A. Amello, and each of them, as such person's true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution in each of them, for such person in such person's place and stead, in any and all capacities, to sign for us and in our names in the capacities indicated below the Registration Statement on Form S-8 of TScan Therapeutics, Inc., and any or all amendments (including post-effective amendments), and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite or necessary to be done in connection therewith and about the premises, as fully to all intents and purposes as he might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents or any of them, or substitutes of any of them, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, as amended, this Registration Statement on Form S-8 has been signed by the following persons in the capacities and on the dates indicated.

Signature		Title		Date
/s/ Gavin MacBeath, Ph.D. Gavin MacBeath, Ph.D.		Chief Executive Officer and Director (Principal Executive Officer)		March 4, 2026
/s/ Jason A. Amello Jason A. Amello		Chief Financial Officer (Principal Financial Officer)		March 4, 2026
/s/ Leiden Dworak Leiden Dworak		Vice President, Finance (Principal Accounting Officer)		March 4, 2026
/s/ Stephen Biggar Stephen Biggar, M.D., Ph.D.		Director		March 4, 2026
/s/ Barbara Klencke, M.D. Barbara Klencke, M.D.		Director		March 4, 2026
/s/ Garry Nicholson Garry Nicholson		Director		March 4, 2026
/s/ Gabriela Gruia Gabriela Gruia, M.D.		Director		March 4, 2026
/s/ Katina Dorton Katina Dorton, J.D., M.B.A.		Director		March 4, 2026
/s/ R. Keith Woods R. Keith Woods		Director		March 4, 2026