UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 15

CERTIFICATION AND NOTICE OF TERMINATION OF REGISTRATION

UNDER SECTION 12(g) OF THE SECURITIES EXCHANGE ACT OF 1934

OR SUSPENSION OF DUTY TO FILE REPORTS UNDER SECTIONS 13 AND 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

Commission File Number 001-37368

Adaptimmune Therapeutics plc

(Exact name of registrant as specified in its charter)

60 Jubilee Avenue,
Milton Park Abingdon, Oxfordshire OX14 4RX
United Kingdom
(44) 1235 430000

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

American Depositary Shares, each representing six ordinary shares, par value £0.001 per share

(Title of each class of securities covered by this Form)

None

(Titles of all other classes of securities for which a duty to file reports under Section 13(a) or 15(d) remains)

Please place an X in the box(es) to designate the appropriate rule provision(s) relied upon to terminate or suspend the duty to file reports:

Rule 12g-4(a)(1)	x
Rule 12g-4(a)(2)	¨
Rule 12h-3(b)(1)(i)	x
Rule 12h-3(b)(1)(ii)	¨
Rule 15d-6	¨
Rule 15d-22(b)	¨

Approximate number of holders of record as of the certification or notice date: 25.

Pursuant to the requirements of the Securities Exchange Act of 1934, Adaptimmune Therapeutics plc has caused this certification/notice to be signed on its behalf by the undersigned duly authorized person.

By:	/s/ Adrian Rawcliffe
	Name:	Adrian Rawcliffe
	Title:	Chief Executive Officer

Date: November 13, 2025