Person:

Ott, Patrick

Blockade of the immunological checkpoint programmed death 1 (PD-1) using monoclonal antibodies has shown robust anti-tumor activity across a broad range of solid and hematological malignancies including melanoma and renal cell carcinoma (RCC). Characteristic markers such as the presence of tumor infiltrating lymphocytes, PD-L1 status, and mutational load may be equally or even more important in predicting clinical benefit from PD-1 pathway blockade than tumor histology. This case of a patient with concurrent metastatic melanoma and metastatic RCC, both of which were controlled for more than a year after a single dose of the anti-PD-1 antibody pembrolizumab, illustrates the potential to simultaneously treat distinct immunogenic tumors with anti-PD-1 agents.

Background: Monoclonal antibodies targeting the PD-1/PD-L1 axis have gained increasing attention across many solid tumors and hematologic malignancies due to their efficacy and favorable toxicity profile. With more than 1 agent now FDA-approved in a wide variety of tumor types, and with others in clinical trials, it is becoming more common that patients present to clinic for potential treatment with a second PD-1/PD-L1 inhibitor. Case presentation: In this report, we present two patients with renal cell carcinoma and one with melanoma who received PD-1/PD-L1 inhibitors. Upon progression on their first-line PD-1/PD-L1 inhibitors, these patients received a different PD-1 inhibitor (nivolumab in all cases) and all had progressive disease as their best response to the subsequent PD-1 inhibitor. The reported clinical information focuses on the course of the disease and the responses to all treatment regimens. Conclusions: Clinicians should refrain from using multiple PD-1/PD-L1 inhibitors sequentially outside of clinical trials until there is sufficient data to support this practice routinely. Prospective studies that allow prior treatment with PD-1/PD-L1 are needed to validate the efficacy and safety of these drugs in the second line or later setting. Furthermore, ongoing efforts that aim to identify mechanisms of resistance to immunotherapy will be informative and may ultimately assist physicians in select the optimal treatment following progression on PD-1/PD-L1 inhibitor.