# EDGAR Filing Document

**Accession Number:** 0000882095
**File Stem:** 0001104659-26-049902
**Filing Date:** 2026-4
**Character Count:** 10058
**Document Hash:** ee8428e75c0cce5f364ed5e2462057e1
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-26-049902.hdr.sgml**: 20260428

**ACCESSION NUMBER**: 0001104659-26-049902

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13D/A

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20260428

**DATE AS OF CHANGE**: 20260428

**SUBJECT COMPANY**: 

**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

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-93375
- **FILM NUMBER:** 26903452

**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
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** GILEAD SCIENCES, INC.
- **CENTRAL INDEX KEY:** 0000882095
- **STANDARD INDUSTRIAL CLASSIFICATION:** BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 943047598
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A

**BUSINESS ADDRESS:**
- **STREET 1:** 333 LAKESIDE DR
- **CITY:** FOSTER CITY
- **STATE:** CA
- **ZIP:** 94404
- **BUSINESS PHONE:** 6505743000

**MAIL ADDRESS:**
- **STREET 1:** 333 LAKESIDE DR
- **CITY:** FOSTER CITY
- **STATE:** CA
- **ZIP:** 94404

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** GILEAD SCIENCES INC
- **DATE OF NAME CHANGE:** 19930328

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

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**(Amendment No. 1)**

**Arcellx, Inc.**

*(Name of Issuer)*

**Common Stock, par value $0.001**

*(Title of Class of Securities)*

**—**

*(CUSIP Number)*

**Gilead Sciences, Inc.**<br>333 Lakeside Drive,<br>Foster City CA 94404<br>650-574-3000

*(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)*

**04/28/2026**

*(Date of Event Which Requires Filing of this Statement)*

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**GILEAD SCIENCES, INC.** | Name of reporting person<br>**GILEAD SCIENCES, INC.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**100.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**100.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**0.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**100.00** | Aggregate amount beneficially owned by each reporting person<br>**100.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**100%** | Percent of class represented by amount in Row (11)<br>**100%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**CO** | Type of Reporting Person (See Instructions)<br>**CO** | |

---

**Comment for Reporting Person:** * See Item 4.

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
Common Stock, par value $0.001

**(b) Name of Issuer:**
Arcellx, Inc.

**(c) Address of Issuer's Principal Executive Offices:**
800 BRIDGE PARKWAY, REDWOOD CITY, CA, 94065

Explanatory Note

This Amendment No. 1 amends the Schedule 13D filed on February 23, 2026, by Gilead Sciences, Inc. ("Gilead") relating to shares of common stock, par value $0.001 per share ("Shares" or "Common Stock") of Arcellx, Inc. (the "Original Schedule 13D").  Except as set forth herein, the Original Schedule 13D is unmodified. Capitalized terms used by not otherwise defined in this Amendment No. 1 have the meanings set forth in the Original Schedule 13D.

**Item 4. Purpose of Transaction**

Item 4 of the Original Schedule 13D is amended to include the following at the end thereof:

"As previously disclosed, Gilead, Purchaser and Arcellx entered into the Merger Agreement pursuant to which Purchaser commenced the Offer on March 6, 2026. The Offer expired at 5:00 p.m., Eastern Time, on April 27, 2026.  Computershare Trust Company N.A., the depositary and paying agent for the Offer, advised Gilead that, as of the expiration of the Offer, 38,795,604 Shares had been validly tendered and not validly withdrawn pursuant to the Offer, representing, together with Shares already owned by Gilead, approximately 77.2% of the Shares outstanding as of the expiration of the Offer.

Following consummation of the Offer, on April 28, 2026, Gilead completed its acquisition of Arcellx through the merger of Purchaser with and into Arcellx, and without a meeting of the stockholders of Arcellx in accordance with Section 251(h) of the DGCL, with Arcellx surviving such Merger as a wholly owned subsidiary of Gilead. In connection with the Merger, each Share issued and outstanding immediately prior to the effective time of the Merger (other than (i) Shares owned immediately prior to the effective time of the Merger by Arcellx (including those held in Arcellx's treasury), (ii) Shares owned both as of the commencement of the Offer and immediately prior to the effective time of the Merger by Gilead, Purchaser or any other direct or indirect wholly owned subsidiary of Gilead, (iii) Shares irrevocably accepted for purchase pursuant to the Offer and (iv) Shares held by stockholders who are entitled to appraisal rights under Section 262 of the DGCL and have properly exercised and perfected their respective demands for appraisal of such Shares in the time and manner provided in Section 262 of the DGCL and, as of the effective time of the Merger, have neither effectively withdrawn nor lost their rights to such appraisal and payment under the DGCL) was cancelled and converted into the right to receive on a per Share basis, (x) the Closing Amount in cash, without any interest thereon, subject to any withholding tax, plus (y) one CVR per Share (the Closing Amount plus one CVR, together, the "Offer Price").

As a result of the Merger, the 100 issued and outstanding shares of common stock, par value $0.001 per share, of Purchaser held by Gilead were converted into 100 issued and outstanding shares of common stock, par value $0.001 per share (the "New Shares"), of Arcellx. Consequently, Gilead became the beneficial owner of such 100 New Shares, which represent all of Arcellx's issued and outstanding shares of capital stock.

Following the Merger, all Shares ceased trading prior to the opening of trading on the Nasdaq Global Select Market on April 28, 2026, and will be delisted from Nasdaq and deregistered under the Exchange Act."

**Item 5. Interest in Securities of the Issuer**

**(a)**
Item 5 of the Original Schedule 13D is hereby amended and restated in its entirety as follows:

"(a)-(b) The information relating to the beneficial ownership of the Shares by Gilead set forth in Rows 7 through 13 on each of the cover pages hereto is incorporated by reference herein and is as of the date hereof. This Schedule 13D shall not be construed as an admission by Gilead that Gilead is, for the purposes of Section 13(d) of the Act, the beneficial owner of any Shares covered by this statement.

**(b)**
"(a)-(b) The information relating to the beneficial ownership of the Shares by Gilead set forth in Rows 7 through 13 on each of the cover pages hereto is incorporated by reference herein and is as of the date hereof. This Schedule 13D shall not be construed as an admission by Gilead that Gilead is, for the purposes of Section 13(d) of the Act, the beneficial owner of any Shares covered by this statement.

**(c)**
Except as otherwise described herein and in the Original Schedule 13D, neither Gilead nor, to the best knowledge of Gilead, any of the individuals listed on Schedule I have effected any transactions in Common Stock during the past sixty (60) days. On April 28, 2026, Purchaser accepted for payment pursuant to the Offer in exchange for the Offer Price all Shares validly tendered and not validly withdrawn pursuant to the Offer prior to the expiration of the Offer.

**Item 6. Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer.**

Item 6 of the Original Schedule 13D is hereby amended and supplemented by adding the following at the end thereof:

"At the effective time of the Merger, the Tender and Support Agreements terminated in accordance with their express terms."

### SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** GILEAD SCIENCES, INC.

**Signature:** /s/ Andrew D. Dickinson

**Name/Title:** Andrew D. Dickinson / Chief Financial Officer

**Date:** 04/28/2026