Form 8-K CytomX Therapeutics, For: Jul 24

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): July 24, 2026

CytomX Therapeutics, Inc.

(Exact name of Registrant as Specified in Its Charter)

Registrant’s Telephone Number, Including Area Code: 650-515-3185

Former Name or Former Address, if Changed Since Last Report: N/A

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

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 13(a) of the Exchange Act. ☐

On July 24, 2026, Charles Fuchs, M.D., M.P.H., was appointed to the Board of Directors (the “Board”) of CytomX Therapeutics, Inc. (the “Company”), effective immediately, as a Class II director, with an initial term expiring at the Company’s 2029 annual meeting of stockholders.

Dr. Fuchs will receive the Company’s standard non-employee director compensation. Upon appointment to the Board, Dr. Fuchs received an option under the Company’s 2015 Equity Incentive Plan to purchase 118,000 shares of the Company’s common stock with an exercise price equal to the closing price of the Company’s common stock on July 24, 2026, the effective date of Dr. Fuchs’s appointment. The option will vest and become exercisable as to 1/36th of the shares subject to the option on each monthly anniversary of the date of appointment to the Board, subject to Dr. Fuchs’s continued service to the Company through each applicable vesting date.

In connection with Dr. Fuchs’s appointment to the Board, the Company will enter into an indemnification agreement with Dr. Fuchs in accordance with the Company’s standard practice and pursuant to the form previously approved by the Board, which form was filed as Exhibit 10.16 to the Company’s Registration Statement on Form S-1 filed with the Securities and Exchange Commission on August 28, 2015.

There have not been any transactions since the beginning of the Company’s last fiscal year, nor are there any proposed transactions, in which the Company was or is to be a participant involving amounts exceeding $120,000 and in which Dr. Fuchs had or will have a direct or indirect material interest. There are no arrangements or understandings between Dr. Fuchs and the Company or any other persons pursuant to which Dr. Fuchs was appointed as a director of the Company.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.