Washington, D.C. 20549


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 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).
1. Name and Address of Reporting Person*
Lee Gary K.

(Last) (First) (Middle)


(City) (State) (Zip)
2. Issuer Name and Ticker or Trading Symbol
Lyell Immunopharma, Inc. [ LYEL ]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
Director 10% Owner
X Officer (give title below) Other (specify below)
Chief Scientific Officer
3. Date of Earliest Transaction (Month/Day/Year)
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
Rule 10b5-1(c) Transaction Indication

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.
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 12,700(1) 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
Stock Option (right to buy) $1.87 11/16/2023 A 800,000 (2) 02/10/2032 Common Stock 800,000 (3)(4) 800,000 D
Stock Option (right to buy) $6.04 11/16/2023 D 800,000 (5) 02/10/2032 Common Stock 800,000 (3)(4) 0 D
Explanation of Responses:
1. Includes 4,702 shares acquired on November 18, 2022, 6,205 shares acquired on May 18, 2023 and 1,793 shares acquired on November 17, 2023 under the Issuer's 2021 Employee Stock Purchase Plan.
2. 350,000 shares were vested as of November 16, 2023 and the remaining unvested shares will vest in equal monthly installments over the following thirty-nine months based on the original vesting commencement date.
3. The transactions reported herein reflect a one-time stock option repricing (the "Option Repricing") effective on November 16, 2023 (the "Repricing Date"). The Option Repricing applies to options with exercise prices greater than $2.37 per share held by all continuing employees of the Issuer as of the Repricing Date.
4. Pursuant to the Option Repricing, the exercise price of the repriced options, including the Option, has been amended to reduce the exercise price to $1.87 per share, the closing price of the Issuer's common stock on the Repricing Date. However, if an employee exercises a repriced option before the end of a retention period of one year (subject to earlier termination in certain circumstances), such employee will be required to pay the original exercise price per share of such repriced option. In addition, the vesting schedule for the unvested shares underlying repriced options held by executive officers, including the reporting person, was extended for an additional year. There is no change to the expiration dates of or number of shares underlying the repriced options.
5. 1/4 of the option shares vested on January 31, 2023, with the remaining option shares vesting in equal monthly installments over the following thirty-six months.
/s/ Hector Casab, as Attorney-in-Fact 11/20/2023
** 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.