[SCHEDULE 13G/A] Adaptimmune Therapeutics plc American SEC Filing

Rhea-AI Filing Summary

EcoR1 Capital, Oleg Nodelman and an EcoR1 fund report joint beneficial ownership of Adaptimmune Therapeutics plc ordinary shares. The filing shows EcoR1 Capital and Mr. Nodelman each have shared voting and dispositive power over 66,000,000 ordinary shares (representing 4.2% of the class), while EcoR1 Capital Fund Qualified, L.P. holds shared power over 63,184,650 ordinary shares (representing 4.0% of the class). The shares are held through American Depositary Shares (11,000,000 ADS for EcoR1/ Nodelman; 10,530,775 ADS for the Qualified Fund), with each ADS representing six ordinary shares. Percentages are calculated using 1,590,309,546 ordinary shares outstanding as of August 11, 2025. The filing states the positions were acquired in the ordinary course of business and not to influence control.

Insights

Financial Analyst

TL;DR: EcoR1 and affiliates report a meaningful but sub-5% stake in ADAP, indicating increased ownership without an explicit control intent.

The filing documents shared voting and dispositive power over 66,000,000 ordinary shares by EcoR1 Capital and Oleg Nodelman and 63,184,650 shares by the Qualified Fund, equal to about 4.2% and 4.0% of outstanding shares respectively. Holdings are via ADSs, each representing six ordinary shares, and percentages use 1,590,309,546 shares outstanding. The certification language expressly states the positions were acquired in the ordinary course and not for control purposes. For investors, this is informative about concentrated ownership by an activist/private investment manager but remains below regulatory 5% thresholds that often trigger additional reporting or presumptions of influence.

Corporate Governance Expert

TL;DR: Joint filing clarifies beneficial ownership and disclaims group control; no change-of-control intent asserted.

The Schedule 13G/A shows coordinated reporting by EcoR1 Capital, its Qualified Fund, and Oleg Nodelman with an exhibit for a joint-filing agreement. The filing includes explicit disclaimers that the Qualified Fund does not admit beneficial ownership beyond pecuniary interests and that holdings were not acquired to influence control. Shared voting/dispositive powers are reported rather than sole powers, and signatures by the manager and reporting person are provided. From a governance standpoint, this disclosure increases transparency about insiders of the investment manager but does not assert governance actions or control initiatives.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 2)

Adaptimmune Therapeutics PLC

(Name of Issuer)

Ordinary Shares

(Title of Class of Securities)

00653A107

(CUSIP Number)

08/15/2025

(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)

SCHEDULE 13G

CUSIP No. 00653A107

1

Names of Reporting Persons

EcoR1 Capital, LLC

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 0.00
6	Shared Voting Power 66,000,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 66,000,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

66,000,000.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

4.2 %

12

Type of Reporting Person (See Instructions)

IA, OO

Comment for Type of Reporting Person: These Ordinary Shares are held through 11,000,000 American Depositary Shares of the Issuer, each representing 6 Ordinary Shares. Percentage calculated based on 1,590,309,546 Ordinary Shares outstanding on August 11, 2025, as reported in the Form 10-Q filed by the Issuer for the quarter ended June 30, 2025.

SCHEDULE 13G

CUSIP No. 00653A107

1

Names of Reporting Persons

Oleg Nodelman

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 0.00
6	Shared Voting Power 66,000,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 66,000,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

66,000,000.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

4.2 %

12

Type of Reporting Person (See Instructions)

HC, IN

Comment for Type of Reporting Person: These Ordinary Shares are held through 11,000,000 American Depositary Shares of the Issuer, each representing 6 Ordinary Shares. Percentage calculated based on 1,590,309,546 Ordinary Shares outstanding on August 11, 2025, as reported in the Form 10-Q filed by the Issuer for the quarter ended June 30, 2025.

SCHEDULE 13G

CUSIP No. 00653A107

1

Names of Reporting Persons

EcoR1 Capital Fund Qualified, 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 0.00
6	Shared Voting Power 63,184,650.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 63,184,650.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

63,184,650.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

4.0 %

12

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person: These Ordinary Shares are held through 10,530,775 American Depositary Shares of the Issuer, each representing 6 Ordinary Shares. Percentage calculated based on 1,590,309,546 Ordinary Shares outstanding on August 11, 2025, as reported in the Form 10-Q filed by the Issuer for the quarter ended June 30, 2025.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Adaptimmune Therapeutics PLC
(b)	Address of issuer's principal executive offices: 60 Jubilee Avenue, Milton Park, Abingdon, Oxfordshire OX14 4RX, United Kingdom
Item 2.
(a)	Name of person filing: EcoR1 Capital, LLC, a Delaware limited liability company ("EcoR1") EcoR1 Capital Fund Qualified, L.P., a Delaware limited partnership ("Qualified Fund") Oleg Nodelman Qualified Fund is filing this statement jointly with the other reporting persons, but not as a member of a group, and it expressly disclaims membership in a group. In addition, the filing of this Schedule 13G on behalf of Qualified Fund should not be construed as an admission that it is, and it disclaims that it is, a beneficial owner, as defined in Rule 13d-3 under the Act, of any securities covered by this Schedule 13G. Each reporting person also disclaims beneficial ownership of the securities reported herein except to the extent of that person's pecuniary interest therein.
(b)	Address or principal business office or, if none, residence: 357 Tehama Street #3 San Francisco, CA 94103
(c)	Citizenship: See Item 4 of the cover sheet for each reporting person.
(d)	Title of class of securities: Ordinary Shares
(e)	CUSIP No.: 00653A107
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: EcoR1: 66,000,000 Oleg Nodelman: 66,000,000 Qualified Fund: 63,184,650
(b)	Percent of class: EcoR1: 4.2% Oleg Nodelman: 4.2% Qualified Fund: 4.0%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: EcoR1: 0 Oleg Nodelman: 0 Qualified Fund: 0
	(ii) Shared power to vote or to direct the vote: EcoR1: 66,000,000 Oleg Nodelman: 66,000,000 Qualified Fund: 63,184,650
	(iii) Sole power to dispose or to direct the disposition of: EcoR1: 0 Oleg Nodelman: 0 Qualified Fund: 0
	(iv) Shared power to dispose or to direct the disposition of: EcoR1: 66,000,000 Oleg Nodelman: 66,000,000 Qualified Fund: 63,184,650
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which 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.
	If a group has filed this schedule pursuant to §240.13d-1(b)(1)(ii)(J), so indicate under Item 3(j) and attach an exhibit stating the identity and Item 3 classification of each member of the group. If a group has filed this schedule pursuant to §240.13d-1(c) or §240.13d-1(d), attach an exhibit stating the identity of each member of the group. EcoR1 is the general partner and investment adviser of investment funds, including Qualified Fund. Mr. Nodelman is the control person of EcoR1.
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and 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, other than activities solely in connection with a nomination under ?? 240.14a-11. By signing below I certify that, to the best of my 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, other than activities solely in connection with a nomination under ?? 240.14a-11.

SIGNATURE

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.

EcoR1 Capital, LLC

Signature:	/s/ Oleg Nodelman
Name/Title:	Manager
Date:	08/19/2025

Oleg Nodelman

Signature:	/s/ Oleg Nodelman
Name/Title:	Reporting person
Date:	08/19/2025

EcoR1 Capital Fund Qualified, L.P.

Signature:	/s/ Oleg Nodelman
Name/Title:	Manager of the General Partner, EcoR1 Capital, LLC
Date:	08/19/2025

Comments accompanying signature: Exhibit 99 -- Agreement Regarding Joint Filing of Statement on Schedule 13D or 13G

Exhibit Information

EXHIBIT 99 - AGREEMENT REGARDING JOINT FILING OF STATEMENT ON SCHEDULE 13D OR 13G

FAQ

How many Adaptimmune (ADAP) ordinary shares does EcoR1 Capital report owning?

EcoR1 Capital and Oleg Nodelman each report beneficially owning 66,000,000 ordinary shares with shared voting and dispositive power.

What percentage of ADAP does EcoR1's reported stake represent?

The filing reports the stake as 4.2% of ordinary shares for EcoR1 and Oleg Nodelman and 4.0% for the Qualified Fund, based on 1,590,309,546 shares outstanding.

Are the shares held directly or through ADSs in the Schedule 13G/A?

The shares are held through American Depositary Shares: 11,000,000 ADSs for EcoR1/Nodelman and 10,530,775 ADSs for the Qualified Fund, with each ADS representing six ordinary shares.

Does the filing indicate EcoR1 is seeking to influence control of Adaptimmune?

No. The filing includes certifications stating the securities were not acquired to change or influence control and were acquired in the ordinary course of business.

Who signed the Schedule 13G/A for EcoR1 and the reporting persons?

The filing is signed by /s/ Oleg Nodelman as Manager of EcoR1 Capital, LLC and as the reporting person, dated August 19, 2025.