Benzinga | Nov 23, 2020 08:02AM EST

Onconova Therapeutics Files Investigational New Drug Application for Multi-kinase CDK4/6 Inhibitor ON 123300

* U.S. Phase 1 trial patient enrollment to begin in the first half of 2021

* China Phase 1 trial enrollment ongoing

* Key regulatory milestone achieved to enable further study of product candidate for patients with HR+ HER 2- metastatic breast cancer and other tumors

NEWTOWN, Pa., Nov. 23, 2020 (GLOBE NEWSWIRE) -- Onconova Therapeutics, Inc. (NASDAQ:ONTX), a biopharmaceutical company focused on discovering and developing novel products to treat cancer, today announced the filing of an Investigational New Drug application (IND) with the U.S. Food and Drug Administration (FDA) for ON 123300, the Company's proprietary, differentiated, first-in-class multi-kinase inhibitor. The IND seeks permission to begin a Phase 1 trial with ON 123300 in relapsed/refractory advanced cancer including patients with HR+ HER 2- metastatic breast cancer with resistance to approved second-generation CDK4/6 inhibitors.

"We believe that ON 123300, based on its novel mechanism of action, presents an innovative approach to study advanced cancers including in HR+ HER 2- metastatic breast cancer that is or has become resistant to commercial CDK4/6 inhibitors. We are delighted to have filed our IND on schedule, and look forward to enrolling patients in the U.S. to complement the ongoing Phase 1 dose-escalation study underway in China by our partner HanX Biopharmaceuticals," said Steven M. Fruchtman, M.D., President and Chief Executive Officer of Onconova. "The HanX Phase 1 ON 123300 study, which began in September 2020, has enrolled three patients to date and is expected to continue to enroll patients with advanced relapsed/refractory cancer at two sites until the recommended Phase 2 dose is identified. We believe that data from these two studies will generate important information to inform anticipated later-stage studies."

As currently envisioned, the Phase 1 trial in the U.S. will assess the safety, tolerability, and pharmacokinetics of ON 123300 administered orally as monotherapy at increasing doses starting at 40 mg daily or higher for consecutive 28-day cycles. The Phase 1 trial is planned for patients with relapsed/refractory advanced cancer, including but not limited to patients with HR+ HER 2- metastatic breast cancer with clinical resistance to the approved second-generation CDK4/6 inhibitors. Once the recommended Phase 2 dose is established, the Company's plan is to enroll additional HR+ HER 2- postmenopausal metastatic breast cancer patients refractory to approved second-generation CDK4/6 inhibitors, as well as patients diagnosed with advanced non-Hodgkin's lymphoma with a special interest in mantle cell lymphoma.

This trial design in the U.S. differs from the study in China because HanX is dosing patients daily for 21 days. Notably, of the three currently approved CDK4/6 inhibitors, two are approved for dosing in 21-day cycles and one is approved for dosing in a 28-day cycle. All three are blockbuster drugs marketed by well-known pharmaceutical companies, and all of these approved therapies require concomitant treatment with an aromatase inhibitor.

"Beyond metastatic breast cancer, we believe that ON 123300 may present an innovative approach to treating other cancers including mantle cell lymphoma, multiple myeloma, advanced colorectal cancer, advanced hepatocellular carcinoma, and inoperable glioblastoma based on preclinical studies suggesting ON 123300 crosses the blood-brain barrier," added Richard Woodman, M.D, Chief Medical Officer.

Commenting on the expected timetable and next steps with this program, Dr. Fruchtman added: "Once the FDA approves our IND, we will seek Institutional Review Board approval at the site where this Phase 1 trial will be conducted. We anticipate the first patient to be enrolled during the first half of 2021. With the ON 123300 program advancing, investigator-sponsored trials underway with our pipeline product rigosertib, and an active business development campaign to evaluate additional compounds, we look forward to an expanding portfolio of novel therapeutics for large, underserved oncology indications."