# EDGAR Filing Document

**Accession Number:** 0001789632
**File Stem:** 0001789632-26-000010
**Filing Date:** 2026-4
**Character Count:** 9905
**Document Hash:** a64fef01c1e935d2e4b21165c012a620
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001789632-26-000010.hdr.sgml**: 20260428

**ACCESSION NUMBER**: 0001789632-26-000010

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260428

**FILED AS OF DATE**: 20260428

**DATE AS OF CHANGE**: 20260428

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Heery Christopher
- **CENTRAL INDEX KEY:** 0001789632

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-41259
- **FILM NUMBER:** 26908273

**MAIL ADDRESS:**
- **STREET 1:** 407 WATTS STREET
- **CITY:** DURHAM
- **STATE:** NC
- **ZIP:** 27701
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Arcellx, Inc.
- **CENTRAL INDEX KEY:** 0001786205
- **STANDARD INDUSTRIAL CLASSIFICATION:** BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 472855917
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 800 BRIDGE PARKWAY
- **CITY:** REDWOOD CITY
- **STATE:** CA
- **ZIP:** 94065
- **BUSINESS PHONE:** 240-327-0603

**MAIL ADDRESS:**
- **STREET 1:** 800 BRIDGE PARKWAY
- **CITY:** REDWOOD CITY
- **STATE:** CA
- **ZIP:** 94065

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

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

[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**<sup>*</sup><br>Heery Christopher<br><sub>(Last) (First) (Middle)</sub><br>C/O ARCELLX, INC.<br>800 BRIDGE PARKWAY<br><sub>(Street)</sub><br>REDWOOD CITY, CA 94065<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-04-28 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [ ] 10% Owner<br>[X] Officer (give title below) [ ] Other (specify below)<br>_CHIEF MEDICAL OFFICER_ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>Arcellx, Inc. [ ACLX ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Common Stock | 2026-04-28 |  | U |  | 23749 | D | <sup>(1)</sup> | 0 | D |  |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| Stock Option (right to buy) | $6.28 | 2026-04-28 |  | D |  |  | 10901 | <sup>(2)</sup> | 2031-06-09 | Common Stock | 10901 | <sup>(2)</sup> | 0 | D |  |
| Stock Option (right to buy) | $6.28 | 2026-04-28 |  | D |  |  | 43604 | <sup>(2)</sup> | 2031-06-09 | Common Stock | 43604 | <sup>(2)</sup> | 0 | D |  |
| Stock Option (right to buy) | $15 | 2026-04-28 |  | D |  |  | 132416 | <sup>(2)</sup> | 2032-02-03 | Common Stock | 132416 | <sup>(2)</sup> | 0 | D |  |
| Stock Option (right to buy) | $19.97 | 2026-04-28 |  | D |  |  | 40000 | <sup>(2)</sup> | 2032-09-28 | Common Stock | 40000 | <sup>(2)</sup> | 0 | D |  |
| Stock Option (right to buy) | $31.03 | 2026-04-28 |  | D |  |  | 76242 | <sup>(2)</sup> | 2033-01-03 | Common Stock | 76242 | <sup>(2)</sup> | 0 | D |  |
| Stock Option (right to buy) | $56.15 | 2026-04-28 |  | D |  |  | 60096 | <sup>(2)</sup> | 2034-01-02 | Common Stock | 60096 | <sup>(2)</sup> | 0 | D |  |
| Restricted Stock Unit | <sup>(3)</sup> | 2026-04-28 |  | D |  |  | 13021 | <sup>(4)</sup> | <sup>(4)</sup> | Common Stock | 13021 | <sup>(4)</sup> | 0 | D |  |
| Restricted Stock Unit | <sup>(3)</sup> | 2026-04-28 |  | D |  |  | 39194 | <sup>(4)</sup> | <sup>(4)</sup> | Common Stock | 39194 | <sup>(4)</sup> | 0 | D |  |
| Restricted Stock Unit | <sup>(3)</sup> | 2026-04-28 |  | D |  |  | 67708 | <sup>(4)</sup> | <sup>(4)</sup> | Common Stock | 67708 | <sup>(4)</sup> | 0 | D |  |
| Performance-based Restricted Stock Unit | <sup>(3)</sup> | 2026-04-28 |  | A |  | 45138 |  | <sup>(4)</sup> | <sup>(4)</sup> | Common Stock | 45138 | <sup>(4)</sup> | 45138 | D |  |
| Performance-based Restricted Stock Unit | <sup>(3)</sup> | 2026-04-28 |  | D |  |  | 45138 | <sup>(4)</sup> | <sup>(4)</sup> | Common Stock | 45138 | <sup>(4)</sup> | 0 | D |  |

---

### Footnotes:

(1) Pursuant to the Agreement and Plan of Merger, dated February 22, 2026 (the "Merger Agreement"), by and among Arcellx, Inc. ("Company"), Gilead Sciences, Inc. ("Parent"), and Ravens Sub, Inc., a wholly owned subsidiary of Parent ("Purchaser"), the shares of common stock of Company that were tendered to Purchaser prior to the expiration time of the offer were exchanged for (x) $115.00 per share ("Closing Amount"), net to the seller in cash, without interest, subject to withholding tax, plus (y) one contractual contingent value right (a "CVR"), which represents the right to receive one contingent payment of $5.00 per CVR in cash, without interest, and subject to any withholding tax, pursuant to the terms and subject to the conditions of a contingent value rights agreement. After completion of the tender offer, pursuant to the terms of the Merger Agreement, Purchaser merged with and into Company (the "Merger"), with Company surviving the Merger as a wholly owned subsidiary of Parent.

(2) Pursuant to the Merger Agreement, each outstanding option to purchase shares of Common Stock (a "Company Option"), whether or not vested, and which had a per share exercise price that was less than the Closing Amount, was canceled and converted into the right of the holder to receive (i) (subject to any applicable withholding taxes) a lump-sum cash payment equal to (x) the excess (if any) 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 (1) CVR for each share subject to such Company Option immediately prior to the effective time of the Merger.

(3) Each restricted stock unit represents a contingent right to receive one share of Company Common Stock.

(4) Pursuant to the Merger Agreement, each outstanding restricted stock unit (a "Company RSU"), whether or not vested, was canceled and converted into the right of the holder to receive (i) (subject to any applicable withholding taxes) a lump-sum cash payment equal to (x) the Closing Amount, multiplied by (y) the total number of shares subject to such Company RSU immediately prior to the effective time of the Merger (with the number of shares underlying any Company RSUs that were subject to performance-based vesting conditions determined based on achievement of actual performance in connection with the Merger, as determined by the Company's board of directors or a committee thereof), and (ii) one (1) CVR for each share subject to such Company RSU immediately prior to the effective time of the Merger.

**Signature:** /s/ Michelle Gilson, as Attorney-in-Fact  
**Date:** 2026-04-28

### Remarks:

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.**