Onconova Therapeutics Announces Initial Dosing of First Patient in US Phase 1 Clinical Trial 

Onconova Therapeutics, Inc. recently announced the first patient has been dosed in the US Phase 1 clinical trial of ON 123300, the company’s proprietary, novel multi-kinase inhibitor. The trial is expected to include three US sites that will enroll patients with advanced cancer including, but not limited to, HR+ HER 2- metastatic breast cancer patients who are refractory to, or progressing on, currently approved CDK 4/6 inhibitors.

The Phase 1 trial is designed to assess the safety, tolerability, and pharmacokinetics of ON 123300 administered orally as monotherapy at increasing doses starting at 40 mg daily for consecutive 28-day cycles. Following completion of the dose-escalation phase of the trial and once the recommended Phase 2 dose (RP2D) is established, additional patients with HR+ HER 2- metastatic breast cancer with at least one prior line of therapy, which are expected to include approved CDK 4/6 inhibitors, will be enrolled into the trial with the intent to identify signals of efficacy. Additional cancer indications are also under consideration for study, and will be chosen based on preclinical and developing data.

“We are excited to begin dosing patients in this Phase 1 study and are pleased to be advancing ON 123300’s clinical development in the US,” said Steven M. Fruchtman, MD, President and Chief Executive Officer of Onconova Therapeutics. “Our goal is to provide an innovative treatment option for patients with advanced breast cancer who have become resistant to the commercial CDK 4/6 inhibitors, and other refractory solid tumors driven by the overexpression of tyrosine kinases targeted by ON 123300. Notably, ON 123300’s ability to target multiple kinase pathways that are overexpressed in cancer may allow for single-agent efficacy and better tolerability compared to existing treatment regimens.”

Dr. Fruchtman added, “We are also pleased by the progress our partner HanX Biopharmaceuticals is making with their ongoing Phase 1 trial with ON 123300 in China. While the administration schedule differs between these two Phase 1 trials, the maximum tolerated dose has not yet been reached in the first two dose-escalation cohorts of this trial, which is a promising sign for ON 123300’s safety profile. Collectively, we expect these two complementary Phase 1 studies to provide important insights that will inform the design of subsequent trials.”

For more information on the U.S. Phase 1 clinical trial of ON 123300 see ClinicalTrials.gov identifier: NCT04739293.

Onconova Therapeutics is a clinical-stage biopharmaceutical company focused on discovering and developing novel products for patients with cancer. The company has proprietary targeted anti-cancer agents designed to disrupt specific cellular pathways that are important for cancer cell proliferation.

Onconova’s novel, proprietary multi-kinase inhibitor ON 123300 is being evaluated in two separate and complementary Phase 1 dose-escalation and expansion studies. These trials are currently underway in the US and China.

Onconova’s product candidate rigosertib is being studied in an investigator-initiated study program, including in a dose-escalation and expansion Phase 1 investigator-initiated study targeting patients with KRAS+ non-small cell lung cancer with oral rigosertib in combination with nivolumab. In addition, Onconova continues to conduct preclinical work investigating rigosertib in COVID-19. For more information, visit www.onconova.com.