Avenzo Therapeutics Announces First Patient Dosed in Combination Cohort Evaluating CDK4 Selective Inhibitor (AVZO-023) with CDK2 Selective Inhibitor (AVZO-021) In Ongoing Phase 1/2 ORION-1 Study

On May 28, 2026 Avenzo Therapeutics, Inc. ("Avenzo"), a clinical-stage biotechnology company developing next-generation oncology therapies, reported that the first patient has been dosed in the combination cohort evaluating AVZO-023, its potentially differentiated cyclin-dependent kinase 4 (CDK4) selective inhibitor, in combination with AVZO-021, its potentially differentiated cyclin-dependent kinase 2 (CDK2) selective inhibitor, with fulvestrant in patients with advanced or metastatic hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) breast cancer in the ongoing Phase 1 portion of the ORION-1 Phase 1/2 clinical study.

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The Phase 1/2 first-in-human, open-label ORION-1 clinical study is designed to assess the safety, tolerability, and preliminary clinical activity of AVZO-023 with endocrine therapy as well as the combination of AVZO-023 and AVZO-021 with endocrine therapy. The combination cohort will evaluate AVZO-023 and AVZO-021 with fulvestrant in patients with HR+/HER2- advanced or metastatic breast cancer. AVZO-021 is currently being studied in a separate Phase 1/2 clinical study in HR+/HER2- advanced or metastatic breast cancer and other advanced solid tumors, and the company plans to present updated safety and efficacy results from the Phase 1 portion of the ongoing study at the 2026 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting.

"We are proud to have dosed the first patient in this combination cohort," said Mohammad Hirmand, M.D., Co-founder and Chief Medical Officer of Avenzo Therapeutics. "We believe this novel combination of AVZO-023 and AVZO-021 with fulvestrant may provide a differentiated treatment approach, and we look forward to continuing to evaluate its potential to meaningfully improve outcomes for patients with HR+/HER2- breast cancer."

(Press release, Avenzo Therapeutics, MAY 28, 2026, View Source [SID1234666141])