“In addition, the dramatically increased risk of cutaneous squamous-cell carcinoma among people with immunosuppression pointed to an important role for immune surveillance with this cancer,” the authors wrote.
In the phase 2 study, 29% of patients experienced a serious adverse event – including two cases of pneumonitis – and three patients (5%) discontinued treatment. There were three deaths due to adverse events: One patient died from pneumonia complications, one died in his sleep, and one patient died following hypercalcemia and deep vein thrombosis.
Aside from these, most adverse events were grade 1 or 2. Around one-quarter of patients experienced diarrhea (27%) or fatigue (24%), while the other most common adverse events were nausea (17%), constipation (15%) and rash (15%). The authors noted that these adverse events were similar to those seen in other PD-1 inhibitors.
“Our results are consistent with an emerging theme regarding the high efficacy of immune checkpoint blockade for the treatment of hypermutated cancers, since the mutation burden of cutaneous squamous-cell carcinoma is similar to that reported for advanced solid tumors with microsatellite instability,” the authors wrote.