[Form 4] Arcellx, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Arcellx, Inc. director Kavita Patel reported the cancellation of multiple stock option awards in connection with Arcellx’s merger with Gilead Sciences. On April 28, 2026, five blocks of stock options covering Arcellx common stock were disposed of in transactions classified as dispositions to the issuer.

The options covered 9,174 shares at an exercise price of $63.68 per share, 8,011 shares at $51.30, 11,459 shares at $37.94, 20,513 shares at $15.00, and 27,077 shares at $6.66. Each block shows zero derivative shares remaining after the transactions.

According to the merger agreement among Arcellx, Gilead Sciences, and a Gilead subsidiary, each outstanding company stock option with a per share exercise price below a Closing Amount of $115 per share was canceled and converted into the right to receive a lump-sum cash payment and one contractual contingent value right for each share subject to the option.

Insider Trade Summary

5 transactions reported

Mixed 5 txns

Insider Patel Kavita

Role null

Type	Security	Shares	Price	Value
Disposition	Stock Option (right to buy)	27,077	$0.00	--
Disposition	Stock Option (right to buy)	20,513	$0.00	--
Disposition	Stock Option (right to buy)	11,459	$0.00	--
Disposition	Stock Option (right to buy)	8,011	$0.00	--
Disposition	Stock Option (right to buy)	9,174	$0.00	--

Holdings After Transaction: Stock Option (right to buy) — 0 shares (Direct, null)

Footnotes (1)

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Key Figures

Option block 1: 9,174 options at $63.68 Option block 2: 8,011 options at $51.30 Option block 3: 11,459 options at $37.94 +4 more

7 metrics

Option block 1 9,174 options at $63.68 Disposed on April 28, 2026; derivative balance after transaction: 0

Option block 2 8,011 options at $51.30 Disposed on April 28, 2026; derivative balance after transaction: 0

Option block 3 11,459 options at $37.94 Disposed on April 28, 2026; derivative balance after transaction: 0

Option block 4 20,513 options at $15.00 Disposed on April 28, 2026; derivative balance after transaction: 0

Option block 5 27,077 options at $6.66 Disposed on April 28, 2026; derivative balance after transaction: 0

Closing Amount $115 per share Reference price used in merger agreement to calculate cash payments

Derivative transactions 5 derivative dispositions All coded as D (Disposition to issuer) in Form 4

Key Terms

Agreement and Plan of Merger, contingent value right, per share exercise price, lump sum cash payment, +1 more

5 terms

Agreement and Plan of Merger regulatory

"Pursuant to the Agreement and Plan of Merger, dated February 22, 2026, by and among Arcellx, Inc."

An Agreement and Plan of Merger is a formal document where two companies agree to combine into one, outlining how the process will happen. It’s like a step-by-step plan for merging, and it matters because it shows both sides have agreed on the details before the official transition takes place.

contingent value right financial

"and (ii) one contractual contingent value right for each share subject to such Company Option"

A contingent value right is a special security that gives its holder the right to receive one or more future payments only if specified events happen, such as a product reaching a sales target or getting regulatory approval. It matters to investors because it offers potential extra payout tied to uncertain outcomes—like a bet that a project will succeed—so it can add upside to a deal while also carrying extra risk and valuation uncertainty.

per share exercise price financial

"and which had a per share exercise price less than $115 per share (the "Closing Amount")"

lump sum cash payment financial

"was canceled and converted into the right to receive (i) a lump sum cash payment equal to (x) the excess"

Company stock option financial

"Each outstanding Company stock option ("Company Option"), whether or not vested"

Form 4 Insider Transactions: What Each Field Means →

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

X

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^*

Patel Kavita

(Last) (First) (Middle)

C/O ARCELLX, INC.

800 BRIDGE PARKWAY

(Street)

REDWOOD CITY CALIFORNIA 94065

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Arcellx, Inc. [ ACLX ]

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

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/28/2026

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

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

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

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

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)	$6.66	04/28/2026		D			27,077	(1)	12/07/2031	Common Stock	27,077	(1)	0	D
Stock Option (right to buy)	$15	04/28/2026		D			20,513	(1)	02/03/2032	Common Stock	20,513	(1)	0	D
Stock Option (right to buy)	$37.94	04/28/2026		D			11,459	(1)	06/14/2033	Common Stock	11,459	(1)	0	D
Stock Option (right to buy)	$51.3	04/28/2026		D			8,011	(1)	05/28/2034	Common Stock	8,011	(1)	0	D
Stock Option (right to buy)	$63.68	04/28/2026		D			9,174	(1)	05/29/2035	Common Stock	9,174	(1)	0	D

Explanation of Responses:

1. Pursuant to the Agreement and Plan of Merger, dated February 22, 2026, by and among Arcellx, Inc. ("Company"), Gilead Sciences, Inc. ("Parent"), and Ravens Sub, Inc., a wholly owned subsidiary of Parent ("Purchaser"), Purchaser merged with and into Company (the "Merger"), with Company surviving the Merger as a wholly owned subsidiary of Parent. Each outstanding Company stock option ("Company Option"), whether or not vested, and which had a per share exercise price less than $115 per share (the "Closing Amount"), was canceled and converted into the right to receive (i) a lump sum cash payment equal to (x) the excess of (a) the Closing Amount over (b) the per share exercise price subject to such Company Option, multiplied by (y) the total number of shares subject to such Company Option immediately prior to the effective time of the Merger, and (ii) one contractual contingent value right for each share subject to such Company Option immediately prior to the effective time of the Merger.

	/s/ Michelle Gilson, as Attorney-in-Fact	04/28/2026
	** 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.
* Form 4: SEC 1474 (03-26)