US regulators have agreed to undertake a priority review Merck and Pfizer's avelumab as a potential treatment for metastatic urothelial carcinoma (mUC).

The companies are targeting the treatment towards patients with locally advanced or mUC with disease progression on or after platinum-based therapy.

Bladder cancer accounts for around 90 percent of urothelial cancers and is the sixth most common cancer in the US. Despite available options, the prognosis for patients with mUC remains poor, particularly when the disease has metastasised.

"Advanced urothelial carcinoma remains a difficult-to-treat tumour, which is why we are developing a comprehensive clinical development programme that involves Phase I and III trials designed to address this challenge," noted Chris Boshoff, senior vice president and head of Immuno-oncology, Early Development and Translational Oncology, Pfizer Global Product Development.

Avelumab is an investigational, fully human anti-PD-L1 antibody, which has not yet been approved anywhere in the world. A decision by the FDA for the drug in the mUC indication should be made by the end of August.

The drug has already picked up a priority review, FDA Breakthrough Therapy and Fast Track Designations for metastatic Merkel cell carcinoma, as well as orphan status. It is also currently under review in Europe.

The clinical development programme for the drug, known as JAVELIN, is evaluating its potential across more than 15 different tumour types, including breast, gastric/gastro-esophageal junction, head and neck and Hodgkin's lymphoma.