MedicalResearch.com Interview with: Dr. Kelly Garneski Paulson, MD, PHD Fred Hutchinson Cancer Research Center Seattle, WA   MedicalResearch.com: What is the background for this study? What are the main findings? Response: Merkel cell carcinoma (MCC) is an aggressive skin cancer with increasing impact. Currently, there are more than 2000 new cases of MCC diagnosed each year in the US. Over one third of patients will develop metastatic disease. Most cases of Merkel cell carcinoma are caused by a virus (Merkel cell polyomavirus). In these cancers, the viral oncoproteins (cancer causing proteins) are highly expressed (exclusively on tumor tissue), immunogenic and are necessary for cancer growth.  These oncoproteins are thus ideal targets for cancer immunotherapy, making MCC a great cancer in which to study and develop immunotherapy.  Indeed, immunotherapies are effective in MCC, with observed response to checkpoint inhibitor mono therapy on the order of 35-55%, although complete responses remain rare. In our first trial, we treated four patients with metastatic Merkel cell carcinoma with endogenous T cell therapy (ex vivo expanded polyclonal T cells recognizing Merkel cell polyomavirus). One patient developed a complete response, but three patients rapidly progressed. Interestingly, we observed that the patient with the complete response had low levels of PD-1 expression on the virus specific transferred T cells. We thus hypothesized adding adding an immune checkpoint inhibitor (avelumab, anti-PD-L1) to the transferred T cells would be acceptably safe and potentially improve clinical effectiveness. (more…)