Acrivon Therapeutics Inc (NASDAQ:ACRV) shares tumbled 29.2% on Thursday after the clinical-stage biotechnology company disclosed a mixed set of results from its ongoing cancer studies, which appeared to fall short of investor expectations.
The company reported an overall response rate of 39% in its Phase 2b study evaluating ACR-368 as a monotherapy in OncoSignature-positive patients with endometrial cancer. Among patients who had received two or fewer prior lines of treatment, the response rate improved modestly to 44%. While Acrivon pointed to stronger outcomes in a narrower subgroup of serous endometrial cancer patients—where confirmed response rates reached 52% in the overall population and 67% in OncoSignature-positive patients—the broader efficacy data failed to impress the market.
As a result, Acrivon said it will narrow the focus of its Arm 3 study to serous endometrial cancer patients who have undergone no more than two prior therapies, removing the requirement for a tumor biopsy. Enrollment for this revised trial arm is expected to be completed by the fourth quarter of 2026.
The company also released early findings from its Phase 1 dose-escalation study of ACR-2316, a potential first-in-class WEE1/PKMYT1 inhibitor. Two once-weekly oral dosing regimens were established, both of which demonstrated what the company described as acceptable tolerability. Tumor reduction was observed in 9 of 20 evaluable patients receiving doses of 120 mg or higher, including confirmed and unconfirmed partial responses across several tumor types such as endometrial cancer, small cell lung cancer, and squamous non-small cell lung cancer.
In addition, Acrivon unveiled ACR-6840 as its next preclinical development candidate, positioning it as a potential first-in-class oral CDK11 inhibitor. The company plans to submit an investigational new drug (IND) application for this program in the fourth quarter of 2026.
From a financial standpoint, Acrivon reported preliminary, unaudited cash, cash equivalents, and investments totaling approximately $119 million as of December 31, 2025. Management said this funding is expected to support operations into the second quarter of 2027.