Aprea Therapeutics, Inc. announced that the first patient was dosed in its Phase 1/2a monotherapy clinical trial of ATRN-119, the Company's lead ATR inhibitor for the treatment of cancers with DDR mutations. The Phase 1/2a clinical trial is a multi-center, open-label, dose-escalation and expansion study designed to test ATRN-119 monotherapy in patients with advanced solid tumors harboring defined mutations in DDR pathways. The Phase 1 part of the study will assess tolerability, pharmacokinetics, recommended Phase 2 dose and analysis of patient biomarkers.

The Phase 2a expansion portion of the trial is designed to further evaluate tolerability and efficacy of ATRN-119 monotherapy. ATRN-119 is structurally differentiated from other ATR inhibitors. In preclinical studies, ATRN-119 has demonstrated potent anti-proliferative activity against a variety of cancer cell lines, inhibited tumor growth in genetically defined ovarian, colon, pancreatic and prostate cancer xenograft models and has shown potential to have lower hematological toxicity than other ATR inhibitors.