Mateon announces positive topline data in ovarian cancer

Dive Brief:

  • Interim results from Mateon Therapeutics' Phase 2/3 study in patients with platinum resistant ovarian cancer (prOC) show cautious optimism for both the safety and efficacy of its vascular disrupting agent, CA4P (fosbretabulin), albeit in the small group of patients treated so far.
  • The interim analysis, carried out after the first 20 patients had been enrolled and treated for at least two months or discontinued, showed partial responses in two of the nine people group treated with chemotherapy plus Avastin (bevacizumab) plus CA4P, compared with one of the eleven people treated with just chemotherapy plus Avastin.
  • There were no significant safety issues. However, nearly all (89%) of people treated with CA4P showed a spike in blood pressure, resolving over a few hours, compared with 20% in the control arm.

Dive Insight:

Patients with platinum-resistant recurrent ovarian cancer have an overall response rate of only around 10% to 20% when treated with chemotherapy, with a median progression-free survival rate of three to four months and overall survival of nine to 12 months.

Mateon Therapeutics' CA4P is a vascular disrupting agent that acts by targeting tumor blood vessels and shutting the blood supply off to the tumor. It has a different mode of action to anti-angiogenic agents that target vascular endothelial growth factor (VEGF), preventing the growth of new blood vessels. The two drug types have potential for use in combination.

Mateon's study, dubbed FOCUS, combines CA4P with the VEGF targeting drug Avastin (bevacizumab) in platinum resistant ovarian cancer. While acknowledging the small number of patients treated so far, Mateon is cautiously optimistic about the interim results. 

"I am encouraged that the safety data is better than we expected and that the efficacy data is in line with our expectations," said William Schwieterman, president and CEO. "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."

CA4P is also being assessed in a Phase 1b/2 study in combination with Novartis' Votrient (pazopanib) in recurrent ovarian cancer, and a Phase 2/3 study is being planned in glioblastoma multiforme, in combination with Avastin.

Maxin Group analyst Jason Kolbert called the results "so far, so good" in a note to clients. He expects the dug to launch in ovarian cancer in the U.S. in 2021 and in Europe in 2022, with additional indications to follow. 

"While it's still very early, two of nine patients in the CA4P + Avastin + Chemotherapy arm experienced partial responses with reductions in tumor size of 76% and 64%. In the Avastin + Chemotherapy control arm, one patient experienced a partial response with tumor reduction of 46%. Given that it has only been two months and just a few patients, it is difficult to draw any conclusions, though the results are encouraging," he wrote. 

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Filed Under: Clinical Trials