We’ve been interested in patients who have metastatic Merkel cell carcinoma which is a rare and aggressive form of skin cancer. In studies that were done a number of years ago we discovered that PD-L1 was expressed in many if not all of these tumours. So we’ve been studying a molecule called avelumab which is a monoclonal antibody that targets the PD-L1 receptor and we enrolled 88 patients who had metastatic Merkel cell carcinoma who had failed previous chemotherapy. Our initial results reported at six months’ follow-up and we had a 31% response rate. We’re now reporting one year of follow-up and it appears that we have a 33% response rate now with two additional complete responders. 74% of our responders still are in response at one year of follow-up so this really represents a significant advance for patients with this disease as there has been previously no therapy approved.
We also found that the side effect profile was quite tolerable so the major side effects were fatigue and infusion related reactions. Although immune mediated adverse events could occur, as have been reported with other T-cell checkpoint inhibitors, these were quite rare and there were only three grade 3 events, mostly isolated lab abnormalities.
Based on this data the United States FDA actually approved avelumab for the treatment of metastatic Merkel cell carcinoma, both in the first and second line setting. So this represents a significant advance for patients with this disease.
Is there potential for this drug to be used with other cancer types?
Yes, anywhere there’s PD-L1 expression this drug might be useful. In fact, there’s a large phase I with many expansion cohorts in different cancers so we’re particularly interested in non-small cell lung cancer, bladder cancer and actually gastric cancer where there seems to be a signal of activity. I also think that it’s going to be a useful drug for combination studies given the rather tolerable safety profile that we’ve seen so far.