Pharma Company Stops Patient Enrollment in Ewing Sarcoma Trial to Prioritize Development of a Blood Cancer Drug

A San Diego-based pharmaceutical company announced that it has deprioritized the development of an Ewing sarcoma drug, ONCT-216, and instead will focus on zilovertamab (formerly known as cirmtuzumab), an investigational drug that is being studied for the treatment of patients with mantle cell lymphoma (MCL).

Moving forward, Oncternal Therapeutics will stop patient enrollment in the phase 1/2 study of ONCT-216 to reallocate resources to launching the phase 3 ZILO-301 trial of zilovertamab.

“This asset prioritization allows us to further sharpen our focus on hematological malignancies and prostate cancer, while deploying our capital towards meaningful catalysts as we navigate this historically challenging pandemic, geopolitical and capital markets macroenvironment,” Dr. James Breitmeyer, Oncternal’s president and CEO, said in a press release.

The company plans to kickoff ZILO-301 in the final months of 2022, and noted it will take geopolitical factors and COVID-19—related supply chain issues into account. Patients with relapsed/refractory MCL who have stable disease or a partial response after treatment with Imbruvica (ibrutinib) will be randomly assigned to receive either zilovertamab plus Imbruvica or placebo plus Imbruvica.

The combination of zilovertamab plus Imbruvica previously showed exciting results in a phase 1/2 clinical trial. The data, which were presented at a medical conference last year, showed that 83.3% of patients with MCL and 91.1% of patients with chronic lymphocytic leukemia (CLL) had their disease shrink as a result of treatment, and 39.9% of patients with MCL and 14.7% of patients with CLL experienced a complete response, meaning that clinicians could not detect any remaining disease after a patient received zilovertamab/Imbruvica treatment.

Now, the phase 3 ZILO-301 trial will be conducted in at least 50 cancer centers across the United States, and researchers hope that data will show positive progression-free survival (the time from treatment until disease worsens) outcomes that will support a Biologics License Application, which could lead to Food and Drug Administration (FDA) approval, according to a press release from Oncternal Therapeutics that was published in January 2022.

Zilovertamab is also being studied in a phase 1b trial in combination with paclitaxel for women with HER2-negative metastatic, locally advanced, unresectable breast cancer; and a phase 2 trial in combination with Venclexta (venetoclax) for patients with relapsed/refractory CLL. The drug has not yet been approved in any indication.

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