CytomX (NASDAQ: CTMX) adds programs, gains $37M from Regeneron

Rhea-AI Filing Summary

CytomX Therapeutics updated its cancer drug collaboration with Regeneron through Amendment No. 4 to their 2022 Collaboration and License Agreement. The amendment, effective May 31, 2026, extends the period in which Regeneron can select additional drug programs and allows for up to eight more collaboration programs.

Regeneron has already nominated the first two of these additional programs, which entitle CytomX to receive $37.0 million in aggregate target nomination payments. Across all potential programs, the Agreement provides for up to approximately $4 billion in target nomination, preclinical, clinical, regulatory and commercial milestone payments, while previously disclosed tiered royalty terms remain unchanged.

Positive

• Regeneron expands collaboration and commits cash: Amendment No. 4 adds capacity for up to eight additional collaboration programs, with the first two already nominated and triggering $37.0 million in target nomination payments plus up to approximately $4 billion in potential milestone payments under the Agreement.

Negative

• None.

Insights

Biopharma partnerships analyst

CytomX expands its Regeneron collaboration, adding near-term cash and large milestone potential.

The amendment deepens the alliance between CytomX and Regeneron around conditionally activated bispecific cancer therapies. It extends Regeneron’s window to select collaboration programs and raises the ceiling to eight additional programs, broadening the scope of potential co-developed assets.

Regeneron’s nomination of the first two extra programs triggers $37.0 million in target nomination payments to CytomX, providing non-dilutive funding. The Agreement also includes up to approximately $4 billion in cumulative nomination and milestone payments, while existing tiered royalty terms on global net sales are preserved.

The overall impact will depend on how many of the remaining six optional programs Regeneron ultimately nominates and on the clinical and commercial progress of partnered products over time, but this amendment confirms ongoing commitment from a large biopharma partner.

8-K Event Classification

Item 1.01 — Entry into a Material Definitive Agreement

1 item

Item 1.01 Entry into a Material Definitive Agreement Business

The company signed a significant contract such as a merger agreement, credit facility, or major partnership.

Key Figures

Target nomination payments: $37.0 million Total potential milestones: up to approximately $4 billion Additional collaboration programs allowed: up to eight programs +3 more

6 metrics

Target nomination payments $37.0 million Aggregate payments for first two additional collaboration programs nominated by Regeneron

Total potential milestones up to approximately $4 billion Target nomination, preclinical, clinical, regulatory and commercial milestones under the Agreement

Additional collaboration programs allowed up to eight programs Maximum number of additional collaboration programs under Amendment No. 4

Additional programs already nominated two programs First two additional collaboration programs nominated by Regeneron in connection with Amendment No. 4

Amendment effective date May 31, 2026 Effective date of Amendment No. 4 to the Collaboration and License Agreement

Amendment execution date May 29, 2026 Date CytomX and Regeneron entered into Amendment No. 4

Key Terms

Collaboration and License Agreement, Probody® therapeutic platform, Veloci-Bi® bispecific antibody development platform, milestones, +1 more

5 terms

Collaboration and License Agreement financial

"previously entered into that certain Collaboration and License Agreement, effective November 16, 2022"

Probody® therapeutic platform technical

"conditionally-activated investigational bispecific cancer therapies utilizing the Company’s Probody® therapeutic platform"

Veloci-Bi® bispecific antibody development platform technical

"Regeneron’s Veloci-Bi® bispecific antibody development platform"

milestones financial

"preclinical, clinical, regulatory and commercial milestones covered under the scope of the Agreement"

Milestones are specific, measurable progress points a company aims to reach during a project—like completing a clinical trial step, securing a regulatory approval, or hitting a sales target. They matter to investors because each checkpoint reduces uncertainty about the business plan, can trigger payments or changes in valuation, and often signals whether future revenue or growth is likely, similar to passing checkpoints on a racecourse that show how close you are to the finish line.

royalty obligations financial

"The royalty obligations under the Agreement, including the tiered royalty rates on global net sales of licensed products"

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Understanding 8-K Material Events →

false 0001501989 0001501989 2026-05-29 2026-05-29

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): May 29, 2026

CytomX Therapeutics, Inc.

(Exact name of Registrant as Specified in Its Charter)

Delaware		001-37587		27-3521219
(State or Other Jurisdiction of Incorporation)		(Commission File Number)		(IRS Employer Identification No.)

151 Oyster Point Blvd
Suite 400
South San Francisco, California		94080
(Address of Principal Executive Offices)		(Zip Code)

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

Not Applicable

(Former Name or Former Address, if Changed Since Last Report)

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:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

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

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Common Stock, $0.00001 par value per share		CTMX		Nasdaq Global Select Market

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. ☐

Item 1.01 Entry into a Material Definitive Agreement.

CytomX Therapeutics, Inc. (the “Company”) previously entered into that certain Collaboration and License Agreement, effective November 16, 2022 (as amended, the “Agreement”), with Regeneron Pharmaceuticals, Inc. (“Regeneron”), providing for the collaboration on the creation of conditionally-activated investigational bispecific cancer therapies utilizing the Company’s Probody^® therapeutic platform and Regeneron’s Veloci-Bi^® bispecific antibody development platform. On May 29, 2026, the Company and Regeneron entered into Amendment No. 4 to the Agreement (“Amendment No. 4”), effective May 31, 2026, pursuant to which the parties agreed to (i) extend the program selection period within which Regeneron may nominate additional collaboration programs and (ii) provide for the addition of up to eight additional collaboration programs to the Agreement, of which Regeneron has nominated the first two as described below, and the remaining six of which are subject to Regeneron’s exercise of its nomination option and payment of certain per-program nomination fees. Total potential target nomination payments and preclinical, clinical, regulatory and commercial milestones covered under the scope of the Agreement are up to approximately $4 billion. The royalty obligations under the Agreement, including the tiered royalty rates on global net sales of licensed products previously disclosed by the Company, are not modified by Amendment No. 4.

Additionally, in connection with Amendment No. 4, Regeneron nominated the first two additional collaboration programs under the Agreement, entitling the Company to receive aggregate target nomination payments of $37.0 million.

The foregoing summary of the material terms of Amendment No. 4 is qualified in its entirety by the full text thereof, a copy of which will be filed as an exhibit to the Company’s Quarterly Report on Form 10-Q for the quarterly period ending June 30, 2026. The Company intends to omit certain confidential portions of Amendment No. 4.

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.

				CYTOMX THERAPEUTICS, INC.
Date: June 3, 2026				By:		/s/ Leslie J.B. Robbins
						Leslie J.B. Robbins Senior Vice President, Intellectual Property

FAQ

What did CytomX Therapeutics (CTMX) announce in its latest 8-K?

CytomX Therapeutics announced Amendment No. 4 to its collaboration and license agreement with Regeneron. The change extends program selection timelines, allows up to eight additional collaboration programs, and confirms that existing tiered royalty terms on licensed product sales remain unchanged.

How much cash will CytomX (CTMX) receive immediately from the Regeneron amendment?

Regeneron’s nomination of the first two additional collaboration programs entitles CytomX to receive aggregate target nomination payments of $37.0 million. These payments are tied specifically to the nomination of those programs under the expanded collaboration structure described in Amendment No. 4.

What is the total potential milestone value of CytomX’s agreement with Regeneron?

The agreement between CytomX and Regeneron covers up to approximately $4 billion in total potential payments. This figure includes target nomination payments and preclinical, clinical, regulatory, and commercial milestone payments across the collaboration’s scope, subject to program advancement and achievement of milestones.

How many additional collaboration programs can be added under the amended CytomX–Regeneron deal?

Amendment No. 4 provides for the addition of up to eight further collaboration programs to the existing agreement. Regeneron has already nominated the first two of these programs, while the remaining six depend on Regeneron exercising its nomination option and paying per-program nomination fees.

Did Amendment No. 4 change CytomX’s royalty terms with Regeneron?

The amendment did not modify CytomX’s royalty structure. The company states that the royalty obligations, including previously disclosed tiered royalty rates on global net sales of licensed products, remain unchanged under Amendment No. 4 to the Regeneron collaboration agreement.

When does Amendment No. 4 to CytomX’s Regeneron collaboration become effective?

Amendment No. 4 was entered into on May 29, 2026 and becomes effective on May 31, 2026. CytomX also notes that the full text of the amendment will be filed as an exhibit to its Form 10-Q for the quarter ending June 30, 2026.

Filing Exhibits & Attachments

3 documents

Other Documents

• EX-101 XBRL TAXONOMY EXTENSION SCHEMA 3.1 KB
• EX-101 XBRL TAXONOMY EXTENSION LABEL LINKBASE 17.6 KB
• EX-101 XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE 11.0 KB