The interim analysis was conducted after the first 20 patients enrolled into the trial had been treated for at least two months or had discontinued from the trial. The analysis was conducted primarily to evaluate the safety of the triplet drug combination as well as to evaluate early signs of efficacy.
William D. Schwieterman, M.D., President and Chief Executive Officer said: "I am encouraged that the safety data is better than we expected and that the efficacy data is in line with our expectations.
"After executing on the strategy we developed in late 2015, it is gratifying to be able to report new data for CA4P supporting its use in combination with bevacizumab and chemotherapy as a new treatment for platinum-resistant ovarian cancer. I am eager to see results from the additional interim analyses planned for later this year."
Safety Results
No significant safety issues were identified in the interim analysis, and the overall safety profile of CA4P was similar to or better than results seen in previous randomized trials of CA4P. Most adverse events that occurred more frequently in the CA4P-treated arm were mild to moderate in severity.
As expected, the most common adverse event observed was an acute increase in blood pressure, which peaked within an hour of infusion and then dissipated over the next two to three hours.
Nearly all patients (89%) receiving CA4P experienced some blood pressure increase, compared to 20% of patients in the control arm. Rates of grade 3 hypertension were similar between the treatment and control groups, and there were no cases of grade 4 hypertension.
Other adverse events that occurred more frequently in the treatment arm included anemia, abdominal pain, constipation, nausea, vomiting, fatigue, cough, mucosal inflammation and dyspnoea (breathing difficulty).
There was a lower than expected rate of hematological adverse events, and no patients receiving CA4P experienced neutropenia or leukopenia (low blood counts of neutrophils or white blood cells).
There were no cardiovascular adverse events reported.
Efficacy Results
Progression free survival, the primary endpoint of the study, currently favors the CA4P arm of the study, although Mateon believes that it is too early in the clinical trial to draw any conclusions.
Two of nine (22%) patients treated with CA4P had partial responses (PR) compared to one of eleven (9%) in the control arm.
The magnitude of the responses was larger in the active treatment arm, with reductions in lesion size of approximately 76% and 64% for the patients receiving CA4P compared to a reduction of 46% for the patient receiving control.