Aprea Therapeutics Highlights Positive Emerging Clinical Activity for WEE1 Inhibitor, APR-1051, with a Confirmed Partial Response in the Ongoing Phase 1 ACESOT-1051 Trial

Core Viewpoint - Aprea Therapeutics has confirmed a partial response in its ACESOT-1051 trial for APR-1051, a WEE1 kinase inhibitor, indicating potential anti-tumor activity in biomarker-defined cancers [1][7] Group 1: Clinical Trial Results - A confirmed partial response was observed in a patient with PPP2R1A-mutated endometrial cancer, showing a 50% reduction in target lesion size and a decrease in CA-125 levels from 362 U/mL to 40.2 U/mL [2][3] - The ACESOT-1051 trial has treated 24 patients with advanced solid tumors, with two patients achieving partial responses, both with endometrial cancers harboring PPP2R1A mutations [3][4] - Five additional patients in the trial have shown stable disease, including those with HPV+ head and neck squamous cell carcinoma and colorectal cancers [4] Group 2: Drug Development and Safety - APR-1051 has been generally safe and well-tolerated, with the most common adverse events being Grade 1 or 2, primarily nausea and fatigue [4][5] - The company plans to escalate the dose to 300 mg once daily in the second quarter of 2026 and will enroll additional patients with specific tumor types or mutations that may respond better to the treatment [5][6] Group 3: Company Overview - Aprea Therapeutics is focused on developing targeted therapies for biomarker-defined cancers, utilizing a precision medicine approach to exploit vulnerabilities in cancer cell mutations [6] - The company's lead programs include APR-1051 and ATRN-119, both in clinical development for solid tumor indications [6]