CytomX Therapeutics, Inc. 8-K

What Happened
CytomX Therapeutics announced it entered into Amendment No. 4 to its Collaboration and License Agreement with Regeneron Pharmaceuticals, originally effective November 16, 2022. Amendment No. 4 was entered on May 29, 2026 and is effective May 31, 2026. The amendment extends the program selection period and allows for up to eight additional collaboration programs; Regeneron has nominated the first two under the expanded scope.

Key Details

• Amendment No. 4 (entered May 29, 2026; effective May 31, 2026) extends the period for Regeneron to nominate additional programs under the agreement.
• Up to eight additional collaboration programs may be added; Regeneron has nominated two so far, triggering aggregate target nomination payments to CytomX of $37.0 million.
• Total potential target nomination payments and preclinical, clinical, regulatory and commercial milestones under the agreement are up to approximately $4 billion.
• Royalty obligations (including previously disclosed tiered royalty rates on global net sales) are not changed by Amendment No. 4. CytomX will file the amendment as an exhibit to its Form 10‑Q for the quarter ending June 30, 2026, with confidential portions omitted.

Why It Matters
This amendment expands the collaboration pipeline with Regeneron, providing CytomX with near-term cash from nomination payments (at least $37.0 million for the two nominated programs) and a pathway to significant future milestone and royalty revenue (up to ~$4 billion in milestones). The unchanged royalty terms mean potential future product sales remain monetizable under the previously disclosed tiered structure. The filing and upcoming 10‑Q exhibit give investors fuller disclosure of the amended terms when posted.