DOYLESTOWN, PA — Aprea Therapeutics Inc. (Nasdaq: APRE) is expanding enrollment and broadening the clinical development strategy for its investigational WEE1 inhibitor APR-1051 as the company advances a Phase 1 trial and targets a new data presentation in the fourth quarter of 2026.
The company reported that enrollment in the ACESOT-1051 study is accelerating, with active trial sites increasing from three to 10. Aprea expects enrollment to reach six to 10 patients per month by the fourth quarter, supporting continued dose escalation and data collection ahead of a planned clinical update at a medical meeting later this year.
The expansion reflects Aprea’s strategy to evaluate APR-1051 across biomarker-defined cancers where WEE1 inhibition may provide a therapeutic benefit. In addition to advancing the drug in uterine serous carcinoma and cyclin E-overexpressing platinum-resistant ovarian cancer, the company plans to add combination treatment arms in HPV-positive head and neck squamous cell carcinoma and colorectal cancer.
Gene Kennedy, the company’s chief medical advisor, indicated the expanded enrollment and planned combination studies are intended to broaden the clinical dataset as development progresses, adding that Aprea expects to present updated trial data during the fourth quarter.
The company previously disclosed plans to enroll at least 50 patients with uterine serous carcinoma or cyclin E-overexpressing platinum-resistant ovarian cancer. Dose-escalation and backfill enrollment are expected to conclude during the second quarter of 2027.
According to Aprea, planned combination studies will pair APR-1051 with immune checkpoint therapy in HPV-positive head and neck cancer and with standard chemotherapy in colorectal cancer. The company expects to use dose levels that have already completed safety review and demonstrated single-agent activity in the ongoing study.
ACESOT-1051 is a multicenter, open-label Phase 1 trial evaluating once-daily oral APR-1051 in adults with advanced solid tumors carrying specified genetic alterations. The study’s first stage includes dose escalation and expansion involving up to 100 patients, followed by a second stage designed to identify the recommended Phase 2 dose in up to 80 additional participants.
Dose escalation is currently evaluating the 300-milligram cohort. Eligible patients include those with uterine serous carcinoma, cyclin E-overexpressing platinum-resistant ovarian cancer, tumors harboring CCNE1, CCNE2, FBXW7 or PPP2R1A alterations, HPV-positive gynecologic and oropharyngeal cancers, and colorectal cancers with KRAS and TP53 mutations.
Primary endpoints include safety, dose-limiting toxicities, maximum tolerated or administered dose, and selection of a recommended Phase 2 dose. Secondary objectives include pharmacokinetics and antitumor activity.
The company noted that the most recent clinical findings from ACESOT-1051 were presented at the 2026 American Society of Clinical Oncology annual meeting. Additional information about the trial is available at ClinicalTrials.gov under identifier NCT06260514.
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