Pharma Focus Asia

Aprea Therapeutics' Safety Review Committee Approves 800 mg Dosing of ATRN-119 in ABOYA-119 Trial

Wednesday, May 29, 2024

Aprea Therapeutics, Inc. (Nasdaq: APRE) (“Aprea” or the “Company”), a clinical-stage biopharmaceutical company focused on precision oncology through synthetic lethality, announced that the Safety Review Committee (SRC) for the ABOYA-119 clinical trial has approved the start of dosing patients with ATRN-119 at 800 mg once daily (Cohort 6). This decision follows a review of safety and pharmacokinetic data from patients dosed at 550 mg once daily (Cohort 5). Cohort 6 is now open for enrollment.

“We are very pleased with the progress in the ABOYA-119 clinical trial and the SRC’s endorsement to commence dosing at 800 mg once daily, marking significant progress in ATRN-119 development,” said Nadeem Q. Mirza, M.D., M.P.H., Chief Medical Officer of Aprea. “Pharmacokinetic data indicate that systemic exposure duration increases substantially with each dose level of ATRN-119. Recent data presented at the AACR annual meeting reveal that plasma concentrations of the drug are reaching the expected therapeutic range at doses of 550 mg and above. We look forward to announcing additional safety and initial efficacy data in the second half of 2024 and completing dose escalation by the fourth quarter. We are highly optimistic about ATRN-119, which we believe stands out in selectivity and toxicity profile among ATR inhibitors.”

ABOYA-119 is a Phase 1/2a multi-center, open-label, dose-escalation and expansion clinical trial evaluating ATRN-119 monotherapy in patients with advanced solid tumors featuring specific mutations in DDR pathways. Part 1 (Phase 1) of the study focuses on assessing tolerability, pharmacokinetics, the recommended Phase 2 dose (RP2D), and patient biomarkers. Upon completion of Part 1, the company aims to identify an RP2D to be used in Phase 2a cohort expansion (Part 2) to further test the tolerability and potential efficacy of ATRN-119 monotherapy. More details are available at under NCT04905914.

Seventeen patients have been enrolled across the first five cohorts of the dose escalation phase (50 mg, 100 mg, 200 mg, 350 mg, and 550 mg once daily). Following a favorable safety profile, Aprea submitted an amendment to the FDA in March 2024 to include additional cohorts at 1100 mg and 1300 mg, planning to dose patients across up to eight cohorts.

Preliminary clinical benefits have been noted, with two patients achieving stable disease (SD) as of the March 12, 2024 data cutoff—one in the 50 mg cohort and another showing prolonged SD at 200 mg. The latter patient exhibited SD at Days 55, 112, and 168. These updates were highlighted in a poster at the AACR Annual Meeting in April. Further information, including the status of all patients enrolled to date, can be found in the AACR poster on the Aprea corporate website.

Initial efficacy data from Part 1 of the study are anticipated in the second half of 2024, with dose escalation expected to conclude in the fourth quarter of 2024. The RP2D is projected to be determined in the first quarter of 2025, with Phase 2a cohort enrollment beginning in the same quarter. Additional safety and efficacy data are expected by the third quarter of 2025.

ATRN-119 is a first-in-class, highly selective, and potent macrocyclic inhibitor of ATR, a clinically validated target. Designed for patients with mutations in DDR-related genes, ATRN-119 addresses a significant unmet medical need, as these patients typically have poor prognoses and currently lack approved effective therapies.

A copy of the AACR poster detailing the pharmacokinetic data on ATRN-119, showing near dose-proportional exposure from 50 mg to 550 mg once daily, is available on the Aprea corporate website.



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