[Form 4] Summit Therapeutics Inc. Insider Trading Activity

Rhea-AI Filing Summary

Robert W. Duggan, Co-Chief Executive Officer and Director of Summit Therapeutics Inc. (SMMT), reported purchases of the company's common stock on September 10 and 11, 2025. On 09/10/2025 he purchased 333,394 shares at a weighted-average price of $17.68 per share, and on 09/11/2025 he purchased 5,000 shares at $18.07 per share. Following the reported transactions, the filing lists 556,093,090 shares as beneficially owned directly by the reporting person. The filing also discloses several indirect holdings associated with the reporting person, including 31,000 shares held by a spouse and multi-million share interests held through trusts with the spouse as trustee (10,199,776 and 25,457,666 shares).

Positive

• Insider purchases disclosed: 333,394 shares on 09/10/2025 at a weighted-average $17.68 and 5,000 shares on 09/11/2025 at $18.07
• Large direct beneficial ownership reported: 556,093,090 shares reported as directly owned following transactions
• Clear footnote on price range: Purchases on 09/10/2025 occurred at prices ranging $17.49–$17.89, with the filer offering to provide a breakdown on request
• No derivative transactions reported: Table II shows no derivative securities acquired or disposed

Negative

• None.

Insights

Financial Analyst

TL;DR: Significant insider buys were disclosed—large direct holdings and incremental purchases at ~$17.68–$18.07.

The Form 4 shows the CEO and director acquiring 338,394 shares over two days at a weighted-average price of $17.68 on 09/10/2025 and $18.07 on 09/11/2025. The report lists a very large direct beneficial ownership total of 556,093,090 shares after these transactions and identifies indirect ownership through family trusts and a spouse. No derivative transactions were reported. For investors, insider purchases are a direct disclosure of the executive's transactions but this filing contains no discussion of rationale, timing beyond trade dates, or changes to compensation or options.

Corporate Governance Expert

TL;DR: Disclosure is clear on transaction sizes, prices, and related-party indirect holdings; no amendments or derivative activity noted.

The Form 4 is complete with transaction dates, codes and footnotes clarifying the weighted-average price range and a disclaimer of beneficial ownership for certain reported indirect holdings. The report is signed and dated 09/11/2025. The presence of significant indirect holdings via trusts and spouse relationships is properly disclosed, and the filer offers to provide breakdowns of purchase prices per the footnote. There are no indicated Section 16 exemptions or 10b5-1 plan checkboxes marked in the provided text.

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^*

DUGGAN ROBERT W

(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	D
Common Stock	09/11/2025		P		5,000	A	$18.07	556,093,090	D
Common Stock								31,000(2)	I	By Spouse
Common Stock								10,199,776(2)	I	By the Shaun Zanganeh Irrevocable Trust, with the Spouse of Reporting Person as Trustee
Common Stock								25,457,666(2)	I	By the Mahkam Zanganeh Revocable Trust, with the Spouse of Reporting Person as Trustee
Common Stock								50,000(2)	I	Immediate family member of Spouse

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 his 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/ Robert W. Duggan	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 shares did Robert W. Duggan buy and at what prices in the Form 4 for SMMT?

The filing shows purchases of 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.

How many shares does the reporting person beneficially own after the reported transactions (SMMT)?

Following the reported transactions the Form 4 lists 556,093,090 shares as beneficially owned directly by the reporting person.

Are there any indirect holdings disclosed in the SMMT Form 4?

Yes. The filing discloses indirect holdings including 31,000 shares by a spouse, 10,199,776 shares via the Shaun Zanganeh Irrevocable Trust, and 25,457,666 shares via the Mahkam Zanganeh Revocable Trust, among others.

Did the Form 4 report any derivative transactions for SMMT?

No. Table II in the filing shows no derivative securities acquired or disposed of.

Does the filing explain the weighted-average price for the September 10 purchase?

Yes. A footnote states the 09/10/2025 price is a weighted average for purchases made at prices ranging from $17.49 to $17.89, and the reporting person will provide a breakdown on request.