[Form 4] Summit Therapeutics Inc. Insider Trading Activity

Rhea-AI Filing Summary

Summit Therapeutics Inc. (SMMT) Form 4 filing shows insider transactions by Mahkam Zanganeh, who is identified as Co-Chief Executive Officer, a Director and a 10% owner. On 09/10/2025 the reporting person purchased 333,394 shares of common stock at a weighted average price of $17.68 per share. On 09/11/2025 an additional 5,000 shares were purchased at $18.07 per share. The filing also reports a disposition of 31,000 shares and lists significant indirect holdings through trusts and a spouse, while the reporting person disclaims beneficial ownership of certain reported securities except for any pecuniary interest.

Positive

• Insider purchases: Reporting person acquired 333,394 shares on 09/10/2025 at a weighted average price of $17.68 and 5,000 shares on 09/11/2025 at $18.07, indicating insider accumulation.
• Transparent disclosure: Transaction prices are disclosed with a footnote explaining the weighted average and price range for the 09/10/2025 purchases.

Negative

• Disposition reported: A sale of 31,000 shares is recorded, reducing direct holdings.
• Beneficial ownership disclaimer: The reporting person disclaims beneficial ownership of certain reported securities except to extent of any pecuniary interest, which limits clarity on actual control of reported holdings.

Insights

Securities Analyst

TL;DR: Co-CEO and director reported net purchases of 338,394 shares across two days, with a separate 31,000-share disposition and multiple indirect holdings disclosed.

The filing documents open-market purchases totaling 333,394 shares on 09/10/2025 at a weighted average price of $17.68 and 5,000 shares on 09/11/2025 at $18.07, indicating recent insider accumulation. The report separately shows a 31,000-share sale. The reporting person lists extensive indirect positions via trusts and a spouse, but explicitly disclaims beneficial ownership of certain securities except for any pecuniary interest. For investors, the key facts are the size and timing of the purchases and the presence of indirect holdings; the filing contains no information about the source of funds, purpose of trades, or any 10b5-1 plan.

Corporate Governance Expert

TL;DR: Insider filings properly disclose status and multiple transactions; the disclaimer of beneficial ownership and trust structures are notable governance details.

The report clearly states the reporting person’s roles and provides transaction-level detail: purchase on 09/10/2025 (weighted average $17.68) and on 09/11/2025 ($18.07), plus a 31,000-share disposition. The form includes explanatory footnotes about price ranges and a disclaimer regarding beneficial ownership of certain reported securities. From a governance perspective, the use of trusts and spouse holdings is documented, and the filing is signed, meeting Form 4 disclosure requirements. The filing does not state whether trades were pursuant to a Rule 10b5-1 plan.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Zanganeh Mahkam

(Last) (First) (Middle)

C/O SUMMIT THERAPEUTICS INC.

601 BRICKELL KEY DRIVE, SUITE 1000

(Street)

MIAMI FL 33131

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Summit Therapeutics Inc. [ SMMT ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	X	10% Owner
X	Officer (give title below)		Other (specify below)
	Co-Chief Executive Officer

3. Date of Earliest Transaction (Month/Day/Year)
09/10/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	09/10/2025		P		333,394	A	$17.68(1)	556,088,090(2)	I	By Spouse
Common Stock	09/11/2025		P		5,000	A	$18.07	556,093,090(2)	I	By Spouse
Common Stock								10,199,776(2)	I	By the Shaun Zanganeh Irrevocable Trust, with the Reporting Person as Trustee
Common Stock								25,457,666(2)	I	By the Mahkam Zanganeh Revocable Trust, with the Reporting Person as Trustee
Common Stock								50,000(2)	I	Immediate family member
Common Stock								31,000	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. The reported price in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $17.49 to $17.89 per share, inclusive. The Reporting Person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote.

2. The Reporting Person disclaims beneficial ownership of these securities, except to the extent of her pecuniary interest therein, if any, and the inclusion of these securities in this report shall not be deemed an admission of beneficial ownership of all of the reported securities for purposes of Section 16 or for any other purpose

Remarks:

	/s/ Mahkam Zanganeh	09/11/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What transactions did Mahkam Zanganeh report on the Form 4 for SMMT?

The filing reports purchases of 333,394 shares on 09/10/2025 at a weighted average price of $17.68, purchases of 5,000 shares on 09/11/2025 at $18.07, and a disposition of 31,000 shares.

What roles does the reporting person hold at Summit Therapeutics (SMMT)?

The reporting person is disclosed as Co-Chief Executive Officer, a Director, and a 10% owner of the issuer.

Does the Form 4 indicate whether the purchases were part of a 10b5-1 plan?

The filing does not state that the transactions were made pursuant to a Rule 10b5-1 plan; no 10b5-1 box or instruction is checked to indicate such a plan.

Are there indirect holdings disclosed in the Form 4?

Yes; the filing lists indirect holdings through the Shaun Zanganeh Irrevocable Trust, the Mahkam Zanganeh Revocable Trust, and holdings attributed to a spouse and an immediate family member, with a disclaimer about beneficial ownership.

What price range was disclosed for the 09/10/2025 purchases?

The footnote states the 09/10/2025 purchases were made in multiple transactions at prices ranging from $17.49 to $17.89 per share.