4D pharma PLC's (LON:DDDD) chief executive Duncan Peyton talks to Proactive London's Katie Pilbeam about the clinical trial collaboration and supply agreement with Merck KGaA, and Pfizer Inc. Peyton says 'it's another step forward in how we work and expand our oncology franchise' which will begin with a clinical trial this year with BAVENCIO. This is a drug for advanced or metastatic urothelial carcinoma (a form of bladder cancer) developed by Merck and Pfizer, in combination with UK group’s MRx0518.