Trovagene announced the successful completion of its Phase 1b trial of onvansertib in combination with standard-of-care chemotherapy in acute myeloid leukemia (AML) and initiation of patient enrollment in Phase 2.
The Phase 1b dose-escalation trial confirmed that onvansertib in combination with standard-of-care chemotherapy is safe and well tolerated. Additionally, the primary efficacy endpoint of objective response (CR + CRi) was achieved in 5 of 21 patients treated with onvansertib + decitabine, indicating anti-leukemic activity in this difficult-to-treat relapsed/refractory AML population. Importantly, 30% of patients treated were biomarker positive, which was associated with an increase in response to treatment as measured by decreases in bone marrow blasts and the rate of complete response.
"Initiation of our Phase 2 trial in AML is a significant step forward in the development of onvansertib for the treatment of AML," said Thomas Adams, PhD, Chief Executive Officer and Chairman of Trovagene. "We are very pleased by the safety and clinical activity observed with onvansertib in combination with standard-of-care chemotherapy in patients with relapsed or refractory AML, where there remains a significant need for new effective treatment options. Our Phase 2 trial will focus on patients who are showing resistance to first-line treatment, including venetoclax. Our preclinical data showed anti-tumor activity of onvansertib in a venetoclax-resistant AML xenograft model, suggesting its potential to provide a new and effective treatment option for these patients."
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The Phase 2 AML trial will enroll 32 patients who are either treatment naïve and not candidates for induction therapy or who have relapsed following up to one prior regimen. Patients will receive onvansertib on days 1 through 5 in combination with decitabine in a 21-28 day cycle. The primary efficacy endpoint of objective response (CR + CRi) will be assessed in patients who complete at least 1 cycle of treatment.
Onvansertib is a first-in-class, third-generation, oral and highly-selective adenosine triphosphate (ATP) competitive inhibitor of the serine/threonine polo-like-kinase 1 (PLK1) enzyme, which is over-expressed in multiple cancers including leukemias, lymphomas and solid tumors. Onvansertib targets the PLK1 isoform only (not PLK2 or PLK3), is orally administered and has a 24-hour half-life with only mild-to-moderate side effects reported. Trovagene believes that targeting only PLK1 and having a favorable safety and tolerability profile, along with an improved dose/scheduling regimen will significantly improve on the outcome observed in previous studies with a former panPLK inhibitor in AML.
Onvansertib has demonstrated synergy in preclinical studies with numerous chemotherapies and targeted therapeutics used to treat leukemias, lymphomas and solid tumor cancers, including irinotecan, FLT3 and HDAC inhibitors, taxanes and cytotoxins. Trovagene believes the combination of onvansertib with other compounds has the potential to improve clinical efficacy in acute myeloid leukemia (AML), metastatic castration-resistant prostate cancer (mCRPC), colorectal cancer and triple-negative breast cancer (TNBC), as well as other types of cancer.