Aprea Therapeutics is accelerating development of its oral cancer drug APR-1051 after seeing early signs it can shrink tumors in some hard-to-treat cancers.
APR-1051 is a selective WEE1 kinase inhibitor. WEE1 enforces a cell-cycle checkpoint that gives cancer cells time to repair their DNA before dividing; blocking it can push DNA-damaged tumor cells to divide prematurely and die. Aprea’s version is designed to be selective for WEE1, avoiding some toxicity seen with dual WEE1/PLK inhibitors.
The early signals
In the Phase 1 ACESOT-1051 trial, 8 of 28 patients (29%) showed preliminary signs of activity — 2 partial responses and 6 with stable disease. Two standouts: a patient with PPP2R1A-mutated endometrial cancer had a 50% reduction in target lesions and an 87% drop in the CA-125 tumor marker; a patient with uterine serous carcinoma saw a 50% lesion reduction and a >90% CA-125 decline.
Why it matters — and the caveat
Aprea is expanding the trial from 3 to 10 sites to enroll faster and identify which patients respond best. “Our goal is to see who is responding the strongest…to de-risk the next phase,” said CEO Oren Gilad. These are early Phase 1 results in small numbers — encouraging signals, not proof of benefit — targeting cancers (uterine serous, platinum-resistant ovarian, some head-and-neck and colorectal) with real unmet need.