OREANDA-NEWS. Merck and Pfizer today announced the opening of trial sites for an international Phase III study of avelumab*, an investigational fully human anti-PD-L1 IgG1 monoclonal antibody, in patients with platinum-resistant/refractory ovarian cancer. The JAVELIN Ovarian 200 trial is the first Phase III study of a PD-L1 inhibitor investigated as a treatment for platinum-resistant/refractory ovarian cancer.

The alliance also announced that the US Food and Drug Administration has provided approval to move forward with a Phase III study of avelumab as a maintenance treatment, in the first-line setting, in patients with locally advanced or metastatic urothelial cancer. The first trial sites are expected to open shortly.

"There are limited treatment options for women with ovarian cancer, and the prognosis for women with platinum-resistant ovarian cancer is especially poor," said Chris Boshoff, Vice President and Head of Early Development, Translational and Immuno-Oncology at Pfizer Oncology. "We have observed encouraging signs of early clinical activity of avelumab in patients with platinum-resistant or platinum-refractory ovarian cancer, and we hope to build on these results next year through a planned Phase III study of avelumab in combination with platinum therapy in patients with previously-untreated ovarian cancer."

This Phase III, randomized (1:1:1), open-label, parallel, multicenter, global study (JAVELIN Ovarian 200) is designed to evaluate the superiority of avelumab as a monotherapy or in combination with pegylated liposomal doxorubicin (PLD), compared with PLD alone, in treating patients with platinum-resistant/refractory ovarian cancer. The primary endpoint is overall survival (OS). Study investigators anticipate enrolling approximately 550 patients across more than 190 sites in Asia, Europe and North America.

Merck and Pfizer have also initiated a Phase III study (JAVELIN Bladder 100) investigating avelumab as a maintenance treatment, in the first-line setting, in patients with locally advanced or metastatic urothelial cancer. This is currently the only Phase III trial designed to evaluate an immunotherapy agent as a maintenance treatment, in the first-line setting, in patients with urothelial cancer.

"Locally advanced or metastatic urothelial cancer is another aggressive cancer, with the disease often progressing quickly following first-line treatment," said Dr. Alise Reicin, Head of Global Clinical Development at Merck's biopharma business. "It's an exciting time for the Merck-Pfizer Alliance as we continue to accelerate our clinical development program, and now into urothelial cancer. This disease has an exceptionally high unmet need and we believe there is potential for our anti-PD-L1 antibody to be part of future treatment strategies."

This open-label, multicenter, randomized, global, Phase III study is designed to evaluate the safety and efficacy of avelumab plus best supportive care (BSC), compared with BSC alone, in patients with unresectable locally advanced or metastatic urothelial cancer whose disease did not progress on (or following) completion of first-line treatment with a platinum-containing chemotherapy. The primary endpoint of the study is OS which will be assessed in two urothelial cancer patient populations: patients with PD-L1 positivity and all randomized patients.

JAVELIN Bladder 100 is expected to enroll 668 patients across more than 200 sites in 38 countries. PD-L1 expression status will be determined by retrospective analysis of mandatory tumor samples collected from patients enrolled in the trial. It is estimated that at least half of those patients randomized to treatment will be PD-L1-positive.

The clinical development program for avelumab now includes more than 1,500 patients who have been treated across more than 15 tumor types, including breast cancer, gastric/gastro-esophageal junction cancers, head and neck cancer, melanoma, Merkel cell carcinoma, non-small cell lung cancer, ovarian cancer, renal cell carcinoma and urothelial (e.g. bladder) cancer. The alliance has initiated six pivotal trials, reaching its goal for 2015, with additional trials expected to initiate in 2016.