As filed with the Securities and Exchange Commission
on April 28, 2026
Registration No. 333-271731
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
POST- EFFECTIVE AMENDMENT NO. 1
TO
FORM S-3
REGISTRATION STATEMENT NO. 333-271731
UNDER
THE SECURITIES ACT OF 1933
Arcellx, Inc.
(Exact name of registrant as specified in its
charter)
| Delaware |
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47-2855917 |
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(State or other jurisdiction of
incorporation or organization) |
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(I.R.S. Employer
Identification Number) |
800 Bridge Parkway
Redwood City, CA 94065
(240) 327-0630
(Address, including zip code, and telephone
number, including area code, of registrant’s principal executive offices)
Andrew D. Dickinson
President and Treasurer
Arcellx, Inc.
333 Lakeside Drive
Foster City, CA 94404
(240) 327-0630
(Name, address, including zip code, and telephone
number, including area code, of agent for service)
Copy to:
Emily Oldshue
Nicholas Roper
Ropes & Gray LLP
Prudential Tower, 800 Boylston Street
Boston, Massachusetts 02199
(617) 951-7000
(Approximate date of commencement of proposed
sale to the public): Not applicable.
If the only securities being registered on this
Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box: ¨
If any of the securities being registered on this
Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities
offered only in connection with dividend or interest reinvestment plans, check the following box: ¨
If this Form is filed to register additional
securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities
Act registration statement number of the earlier effective registration statement for the same offering. ¨
If this Form is a post-effective amendment
filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement
number of the earlier effective registration statement for the same offering. ¨
If this Form is a registration statement
pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission
pursuant to Rule 462(e) under the Securities Act, check the following box. x
If this Form is a post-effective amendment
to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes
of securities pursuant to Rule 413(b) under the Securities Act, check the following box. ¨
Indicate by check mark whether the registrant
is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company.
See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,”
and “emerging growth company” in Rule 12b-2 of the Exchange Act.
| Large accelerated filer |
x |
Accelerated filer |
¨ |
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| Non-accelerated filer |
¨ |
Smaller reporting company |
¨ |
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Emerging growth company |
¨ |
If an emerging growth company, indicate by check
mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting
standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ¨
DEREGISTRATION OF SECURITIES
This Post-Effective Amendment (this “Post-Effective
Amendment”) is being filed by Arcellx, Inc. (the “Registrant”) to deregister any and all securities,
registered but unsold or otherwise unissued as of the date hereof under the following Registration Statement on Form S-3 (the “Registration
Statement”) previously filed by the Registrant with the U.S. Securities and Exchange Commission (the “SEC”):
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Registration Statement No. 333-271731, filed with the SEC on May 8, 2023, relating to the registration of (i) an unspecified number of the Company’s common stock, par value $0.001 per share (“Common Stock”), preferred stock, debt securities, warrants and/or units, with an unspecified aggregate offering price and (ii) up to $350 million of Common Stock that may be sold under that certain At-The-Market Equity Offering Sales Agreement, dated May 8, 2023, by and between the Company and Stifel, Nicolaus & Company, Incorporated. |
On April 28, 2026, pursuant to an Agreement
and Plan of Merger (the “Merger Agreement”), dated as of February 22, 2026, by and among the Registrant, Gilead
Sciences, Inc. (“Parent”) and Ravens Sub, Inc. (“Merger Sub”), Merger Sub merged with
and into the Registrant (the “Merger”), with the Registrant continuing as the surviving corporation and becoming a
wholly owned subsidiary of Parent. As a result of the transactions contemplated by the Merger Agreement, the Registrant has terminated
any and all offerings and sales of securities pursuant to the Registration Statement. In accordance with the undertakings made by the
Registrant in the Registration Statement to remove from registration, by means of a post-effective amendment, any of the securities of
the Registrant registered under the Registration Statement which remain unsold at the termination of the offering, the Registrant hereby
terminates the effectiveness of the Registration Statement and removes from registration all of the securities that remain unsold under
the Registration Statement as of the date hereof, if any. The Registration Statement is hereby amended, as appropriate, to reflect the
deregistration of such securities. After giving effect to this Post-Effective Amendment, there will be no remaining securities registered
by the Registrant pursuant to the Registration Statement.
The foregoing description of the Merger, the Merger
Agreement and the transactions contemplated thereby does not purport to be complete and is subject to, and qualified in its entirety by,
the Merger Agreement, which is attached as Exhibit 2.1 to the Registrant’s Current Report on Form 8-K filed with the SEC
on February 23, 2026.
SIGNATURE
Pursuant to the requirements of the Securities Act of 1933, as amended,
the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and
has duly caused this Post-Effective Amendment to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of
Redwood City, State of California, on April 28, 2026.
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ARCELLX, INC. |
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By: |
/s/ Andrew D. Dickinson |
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Name: |
Andrew D. Dickinson |
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Title: |
President and Treasurer |
No other person is required to sign this Post-Effective Amendment in
reliance upon Rule 478 under the Securities Act of 1933, as amended.
