Phase I study of allogeneic monocyte-derived inflammatory dendritic cells in combination with pembrolizumab.

PD-1 checkpoint inhibition has revolutionized the care of cancer. A small portion of patients with stage IV cancer achieve durable control. But, early progression is common and dramatic control is achieved for only a minority. We hypothesized that ilixadencel, an allogeneic monocyte-derived dendritic cell product could be injected into tumor to potentiate PD-1 response and thus conducted a phase I study of pembrolizumab plus ilixadencel. Twenty-one patients were accrued. The most common treatment emergent adverse events were fatigue, injection site pain, anemia, weight decreased and hyponatremia, mostly grade 1-2. No dose limiting toxicities were observed and the recommended phase II dose was established at 10 million cells administered twice. Two unconfirmed responses were observed, with no confirmed responses.