[S-8] CytomX Therapeutics, Inc. Employee Benefit Plan Registration

Rhea-AI Filing Summary

CytomX Therapeutics (CTMX) filed a Form S-8 on 7 Aug 2025 to register 4,381,320 additional common shares for issuance under its Amended & Restated 2015 Equity Incentive Plan. The statement incorporates eleven prior S-8 filings and updates only the exhibit section (legal opinion, auditor consent, revised plan documents).

The company is classified as an accelerated filer and a smaller reporting company. Shares will be issued as option grants, RSUs or other awards vest and are exercised; no immediate cash proceeds are expected. Although the filing does not include financial results, the newly registered shares expand the equity pool, enabling continued employee compensation but creating potential dilution for existing shareholders. All required signatures, powers of attorney and fee calculations are provided.

Insights

Equity Analyst

TL;DR: Routine S-8 registers 4.38 M shares; minimal immediate financial impact, modest dilution risk.

This Form S-8 is administrative, enlarging CytomX’s employee equity pool by roughly 4.4 million shares. Because issuance occurs over time as awards vest, near-term cash flow and earnings are unaffected. The filing signals management’s continued reliance on stock-based compensation to attract and retain talent—typical for a clinical-stage biotech. Current shareholders face incremental dilution; at a recent 96 M basic shares outstanding (not disclosed here but in last 10-Q), the pool equates to ~4.5% potential dilution, which is within sector norms. No change to strategic outlook or capitalization structure beyond this.

Corporate Governance Specialist

TL;DR: Governance neutral; plan already approved, filing merely adds shares.

The Amended & Restated 2015 Plan was previously adopted by shareholders, so this filing only implements that authorization. Exhibits include standard attorney and auditor consents, maintaining compliance. Power-of-attorney language is routine. No red flags around board oversight or compensation policy emerge from the document.

As filed with the Securities and Exchange Commission on August 7, 2025

Registration No. 333-   

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

CytomX Therapeutics, Inc.

(Exact name of Registrant as specified in its charter)

Delaware		27-3521219
(State or other jurisdiction of incorporation or organization)		(I.R.S. Employer Identification No.)

151 Oyster Point Blvd., Suite 400

South San Francisco, CA 94080

(Address of Principal Executive Offices) (Zip Code)

CytomX Therapeutics, Inc. Amended and Restated 2015 Equity Incentive Plan

(Full Title of the Plan)

Sean A. McCarthy, D.Phil.

President and Chief Executive Officer

CytomX Therapeutics, Inc.

151 Oyster Point Blvd., Suite 400

South San Francisco, CA 94080

(650) 515-3185

(Name and address of agent for service)

(Telephone number, including area code, of agent for service)

Copies to:

Mark V. Roeder, Esq.

John C. Williams, Esq.

Latham & Watkins LLP

140 Scott Drive

Menlo Park, California 94025

(650) 328-4600

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		☐		Accelerated filer		☒
Non-accelerated filer		☐		Smaller reporting company		☒
				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. ☐

Proposed sale to take place as soon after the effective date of the

registration statement as awards under the plans are exercised and/or vest.

EXPLANATORY NOTE

This Registration Statement on Form S-8 is being filed for the purpose of registering an additional 4,381,320 shares of the Registrant’s common stock issuable under the following employee benefit plan for which Registration Statements of the Registrant on Form S-8 (File Nos. 333-207694, 333-209992, 333-215795, 333-223491, 333-229916, 333-236711, 333-253452, 333-263321, 333-270869, 333-277819 and 333-285594) are effective: the CytomX Therapeutics, Inc. Amended and Restated 2015 Equity Incentive Plan, as a result of the amendment and restatement of such plan, which added 4,381,320 shares of common stock.

INCORPORATION BY REFERENCE OF CONTENTS OF

REGISTRATION STATEMENT ON FORM S-8

Pursuant to Instruction E of Form S-8, the contents of the Registration Statements on Form S-8 filed with the Securities and Exchange Commission on October 30, 2015 (File No. 333-207694), March 7, 2016 (File No. 333-209992), January 27, 2017 (File No. 333-215795), March 7, 2018 (File No. 333-223491), February 27, 2019 (File No. 333-229916), February 27, 2020 (File No. 333-236711), February 24, 2021 (File No. 333-253452), March 4, 2022 (File No. 333-263321), March 27, 2023 (333-270869), March  11, 2024 (333-277819) and March 6, 2025 (File No. 333-285594) are incorporated by reference herein; except for Item 8 which is being updated by this Registration Statement.

Item 8. Exhibits

Incorporated by Reference

Exhibit Number

Exhibit Description

Form

Date

Number

Filed Herewith

4.1

Amended and Restated Certificate of Incorporation.

8-K

5/17/2024

3.1

4.2

Amended and Restated Bylaws.

8-K

3/22/2024

3.1

4.3

Form of Common Stock Certificate.

S-1/A

9/28/2015

4.1

4.4

Registration Rights Agreement dated as of September 29, 2017 by and between CytomX Therapeutics, Inc. and Amgen, Inc.

10-Q

11/7/2017

4.4

5.1

Opinion of Latham & Watkins LLP.

X

23.1

Consent of Independent Registered Public Accounting Firm.

X

23.2

Consent of Latham & Watkins LLP (included in Exhibit 5.1).

X

24.1

Power of Attorney. Reference is made to the signature page to the Registration Statement.

X

99.1(a)#

CytomX Therapeutics, Inc. Amended and Restated 2015 Equity Incentive Plan.

8-K

6/13/2025

10.1

99.1(b)#

Form of Option Award Notice under the CytomX Therapeutics, Inc. Amended and Restated 2015 Equity Incentive Plan.

10-Q

11/23/2015

10.4

99.1(c)#

Form of Early Exercise Option Award Notice under the CytomX Therapeutics, Inc. Amended and Restated 2015 Equity Incentive Plan.

10-Q

11/23/2015

10.5

99.1(d)#

Form of Restricted Share Unit Award Grant Notice and Agreement under the CytomX Therapeutics, Inc. Amended and Restated 2015 Equity Incentive Plan.

10-K

3/1/2022

10.3

(d)

107

Filing Fee Table.

X

# Indicates management contract or compensatory plan.

SIGNATURES

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-8 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in South San Francisco, State of California, on August 7, 2025.

CytomX Therapeutics, Inc.
By:		/s/ Sean A. McCarthy
		Sean A. McCarthy, D.Phil.
		President and Chief Executive Officer

POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below does hereby constitute and appoint Sean A. McCarthy and Christopher W. Ogden, and each of them, with full power of substitution and full power to act without the other, his or her true and lawful attorney-in-fact and agent to act for him or her in his or her name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this registration statement, and to file this registration statement, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in order to effectuate the same as fully, to all intents and purposes, as they or he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or any of them, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, as amended, this registration statement has been signed by the following persons in the capacities and on the date indicated.

Signature		Title		Date
/s/ Sean A. McCarthy Sean A. McCarthy, D.Phil.		President, Chief Executive Officer and Chairman (Principal Executive Officer)		August 7, 2025
/s/ Christopher W. Ogden Christopher W. Ogden		Chief Financial Officer (Principal Financial Officer and Principal Accounting Officer)		August 7, 2025
/s/ Matthew P. Young Matthew P. Young		Director		August 7, 2025
/s/ Alan Ashworth Alan Ashworth, Ph.D. FRS		Director		August 7, 2025
/s/ James R. Meyers James R. Meyers		Director		August 7, 2025
/s/ Elaine V. Jones Elaine V. Jones, Ph.D.		Director		August 7, 2025
/s/ Halley E. Gilbert Halley E. Gilbert		Director		August 7, 2025
/s/ Mani Mohindru Mani Mohindru, Ph.D.		Director		August 7, 2025
/s/ Zhen Su Zhen Su, M.D.		Director		August 7, 2025