Pfizer and Germany's Merck have kicked off a large-scale, late-stage study assessing their immunotherapy avelumab in ovarian cancer.

The companies will test the safety and efficacy of the drug in combination with, and/or as maintenance treatment to, platinum-based chemotherapy in patients with locally advanced or metastatic disease with previously untreated epithelial ovarian cancer.

The 950-patient study, dubbed JAVELIN Ovarian 100, is the first late-stage trial assessing the addition of an immune checkpoint inhibitor to standard-of-care in first-line treatment for this aggressive disease, the firms noted.

Patients will receive concurrent avelumab and chemotherapy, avelumab following chemotherapy, or chemotherapy alone, to test the effect on progression-free survival in treatment naive women.

"In an early ongoing study, avelumab showed encouraging tumor response rates in patients with recurrent or refractory ovarian cancer," said Alise Reicin, head of Global Clinical Development in the biopharma business of Merck.

"Historically, ovarian cancer presents as an advanced disease with poor survival rates. The hope is that avelumab can change the natural history of the disease and potentially take the survival rate beyond the current five year estimate."

"Patients with ovarian cancer need additional treatment options. We believe there could be synergistic activity in the combination of avelumab and established treatments such as platinum-based chemotherapy," said Chris Boshoff, head of Early Development, Translational and Immuno-Oncology, Oncology in Pfizer Global Product Development.

"With two studies now underway of avelumab in ovarian cancer, we look forward to receiving the results from these trials and continuing to break ground in this hard-to-treat cancer."