Cytomx Therapeutics, Inc. (CTMX) SEC Filing 10-K Annual Report for the fiscal year ending Sunday, December 31, 2023

Exhibit 99.1

CytomX Therapeutics Reports 2023 Financial Results and Provides Business Update

- CX-904 (EGFRxCD3 T-cell engager) initial Phase 1a dose escalation data in solid tumors anticipated in the 2nd half of 2024 -

- CX-2051 (EpCAM ADC) Phase 1 clinical study initiation in solid tumors, including colorectal cancer (CRC) anticipated in the 1st half of 2024 -

- CX-801 (IFNα2b) Phase 1 clinical study initiation in solid tumors including melanoma, renal, and head and neck squamous cell carcinoma anticipated in 1st half of 2024 -

- Management to hold conference call today at 5 p.m. EDT / 2 p.m. PDT -

SOUTH SAN FRANCISCO, Calif., March 11, 2024 –

“2023 was a year of sustained execution across our pipeline, highlighted by the continued progress of CX-904 in Phase 1 dose escalation and the parallel advancement of CX-2051 and CX-801 through successful IND enabling activities towards clinical initiation in the first half of 2024,” said Sean McCarthy, D.Phil., chief executive officer and chairman of CytomX. “We entered 2024 with a robust therapeutic pipeline based upon more than a decade of innovation with the PROBODY® platform. Our lead programs leverage validated oncology targets, potent effector mechanisms and tailored masking approaches. Our strategy is to address large oncology markets and major unmet needs to make a meaningful difference for patients, building on the strong company foundation we have laid with our comprehensive progress to date.”

McCarthy added, “Importantly, while advancing key programs throughout 2023, we maintained a consistently strong financial position through disciplined capital allocation and financing that included a strategic equity investment from our largest shareholder, BVF Partners, and ongoing funding from major collaborations.”

Fourth Quarter Business Highlights and Recent Developments

Pipeline

CX-904, PROBODY® T-cell-engager (TCE) targeted to EGFRxCD3 progressing in Phase 1, with dose escalation data anticipated in second half of 2024.

CX-904 is a conditionally activated PROBODY T-cell engager designed to target the epidermal growth factor receptor (EGFR) on cancer cells and the CD3 receptor on T cells within the tumor microenvironment. CX-904 is partnered with Amgen in a global co-development alliance and is being evaluated in an ongoing Phase 1 study in unselected patients with advanced solid tumors that are considered to have EGFR expression. Backfilling of certain dose escalation cohorts has been initiated and dose ranging continues.