Merck KGaA and Pfizer ($PFE) are pushing ahead with two new Phase III studies for avelumab, a PD-L1 checkpoint inhibitor which is playing catch-up among the second-tier companies looking for their first approvals. The companies say that these two Phase III studies bring the late-stage program up to 6 studies, meeting their goal for 2015. And they say they're the first to get into a Phase III for platinum-resistant/refractory ovarian cancer. The second study is in a first-line setting among patients with locally advanced or metastatic urothelial cancer. Both companies have a lot riding on their success here, with Pfizer looking to prove it can make another big splash in the cancer field as Merck KGaA tries to overcome a series of major setbacks that have prevented it from gaining any major new drug approvals in well over a decade. Roche ($RHHBY), meanwhile, is following Merck and Bristol-Myers Squibb ($BMY) with its own Phase III program while AstraZeneca ($AZN) has been falling behind. Release