After Disappointing Results, Mateon to End FOCUS Trial for CA4P in Ovarian Cancer Patients

After Disappointing Results, Mateon to End FOCUS Trial for CA4P in Ovarian Cancer Patients

Mateon Therapeutics announced that it is immediately ending the FOCUS trial of CA4P to treat platinum-resistant ovarian cancer, based on disappointing interim results. The results showed that CA4P (fosbretabulin) did not significantly improve progression-free survival in patients receiving CA4P plus standard of care with Avastin (bevacizumab) and chemotherapy.

FOCUS was a Phase 2/3 clinical trial (NCT02641639) that initially enrolled 91 patients. The first 70 patients either received CA4P plus Avastin and chemotherapy or a placebo plus Avastin and chemotherapy.

CA4P is a tubulin-binding vascular disrupting agent (VDA) designed to shut down blood flow to tumors.

The study’s interim results showed that progression-free survival was not significantly improved in the CA4P group, although a slight positive trend existed compared with the placebo group.

Of the first 70 participants, 24 either died or saw their disease progress. Half of those were in the CA4P group and the other half were in the placebo group.

No complete responses were seen either in the CA4P or the placebo group. And more partial responses were seen in the placebo group (13) than in the CA4P group (8). A comparable number of patients in each group showed stable disease. Progressive disease was actually higher in the CA4P group than in the placebo group.

Mateon decided that continuing the study would be inappropriate based on these results, and it will not further develop CA4P. However, it will support preclinical studies of CA4P in combination with immuno-oncology agents, and investigator-sponsored clinical studies.

CA4P’s safety profile was favorable, with transient increases in blood pressure occurring more often in the CA4P group than in the placebo group. Also, CA4P caused more hypertension, fatigue, nausea, vomiting, and abdominal pain than standard therapy alone. High blood pressure caused severe or life-threatening adverse events in 29.4% of patients in the CA4P group compared with 5.6% in the control group.

The company said it will cut staff by 60% and focus on OXi4503 for treating acute myeloid leukemia (AML).

“We are clearly disappointed that CA4P did not show a clinically meaningful benefit when it was added to the current standard of care in platinum-resistant ovarian cancer,” William D. Schwieterman, MD, Mateon’s president and chief executive officer, said in a press release. “I want to thank our investigators and advisors, as well as the patients that we treated, for their efforts to advance future cancer care. These external participants, along with our internal team, did a great job planning and executing the study, but the outcome is clear, and unfortunately negative.”