# EDGAR Filing Document

**Accession Number:** 0001670683
**File Stem:** 0001670683-26-000002
**Filing Date:** 2026-4
**Character Count:** 7205
**Document Hash:** 8f97a1d6e59b4e3bfe09abc7abb69d16
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001670683-26-000002.hdr.sgml**: 20260428

**ACCESSION NUMBER**: 0001670683-26-000002

**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:** Patel Kavita
- **CENTRAL INDEX KEY:** 0001670683

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-41259
- **FILM NUMBER:** 26908359

**MAIL ADDRESS:**
- **STREET 1:** C/O TESARO, INC.
- **STREET 2:** 1000 WINTER STREET, SUITE 3300
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02451
**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>Patel Kavita<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>[X] Director [ ] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **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 |
|  |  |  |  |  |  |  |  |  |  |  |

---

## 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) | $6.66 | 2026-04-28 |  | D |  |  | 27077 | <sup>(1)</sup> | 2031-12-07 | Common Stock | 27077 | <sup>(1)</sup> | 0 | D |  |
| Stock Option (right to buy) | $15 | 2026-04-28 |  | D |  |  | 20513 | <sup>(1)</sup> | 2032-02-03 | Common Stock | 20513 | <sup>(1)</sup> | 0 | D |  |
| Stock Option (right to buy) | $37.94 | 2026-04-28 |  | D |  |  | 11459 | <sup>(1)</sup> | 2033-06-14 | Common Stock | 11459 | <sup>(1)</sup> | 0 | D |  |
| Stock Option (right to buy) | $51.30 | 2026-04-28 |  | D |  |  | 8011 | <sup>(1)</sup> | 2034-05-28 | Common Stock | 8011 | <sup>(1)</sup> | 0 | D |  |
| Stock Option (right to buy) | $63.68 | 2026-04-28 |  | D |  |  | 9174 | <sup>(1)</sup> | 2035-05-29 | Common Stock | 9174 | <sup>(1)</sup> | 0 | D |  |

---

### Footnotes:

(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.

**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.**