Aprea Therapeutics Shows Two Partial Responses, 54% Tolerability in Phase 1 WEE1 Trial
APRE•Aprea’s Phase 1 trial of WEE1 inhibitor APR-1051 showed two endometrial cancer partial responses and stable disease in six patients across colorectal, HPV+ head and neck or endometrial tumors. Treatment-related events occurred in 54% of patients—mainly Grade 1/2 nausea (36%) and fatigue (14%)—with APR-1051 well tolerated across dose levels.
1. ASCO Presentation
Aprea Therapeutics presented updated results from its first-in-human Phase 1 study ACESOT-1051 evaluating once-daily APR-1051 in advanced solid tumors at the ASCO 2026 meeting, with data cutoff May 6, 2026. The study enrolled 28 patients across dose levels from 10 mg to 300 mg once daily.
2. Efficacy and Safety Findings
The trial reported two partial responses in endometrial cancer patients and six additional cases of stable disease in colorectal, HPV+ head and neck or endometrial cancer cohorts. Treatment-related adverse events occurred in 54% of patients—primarily Grade 1/2 nausea (36%) and fatigue (14%)—with APR-1051 well tolerated across dose levels.
3. Expansion and Next Steps
Enrollment is expanding to include patients with uterine serous carcinoma and platinum-resistant ovarian cancer, with ongoing dose escalation in the 300 mg cohort. Dose escalation and backfill expansion are projected to complete in Q2 2027, paving the way for defining a recommended Phase 2 dose.
