Pembrolizumab versus ipilimumab in advanced melanoma

The authors aimed to evaluate survival benefits of pembrolizumab (Keytruda) compared to ipilimumab (Yervoy) in advanced melanoma.

In the advanced stage of melanoma (stage III/IV), cancer spreads from the skin to other parts of the body. One of the standard treatments for advanced melanoma is immunotherapy that uses body’s own immune system to fight cancer. Ipilimumab is an immunotherapy, which has been associated with considerable survival benefit in advanced melanoma. However, adverse events such as skin rash, liver toxicity, and diarrhea are associated with this treatment. Pembrolizumab is another immunotherapy which works by blocking / inhibiting PD-1, an important protein in the immune system. This inhibition triggers the immune system to attack tumor cells and kill them.

The authors aimed to compare overall survival and progression-free survival (time following treatment before the disease progressed) with pembrolizumab compared to ipilimumab. Overall, 834 patients were randomly assigned to receive pembrolizumab every 2 weeks or every 3 weeks, or ipilimumab every 3 weeks.

Patients in both of the pembrolizumab groups had 42% reduced risk of disease progression after treatment over a 6-month period.  Survival over a 12-month period was 74.1% for pembrolizumab every 2 weeks, 68.4% for pembrolizumab every 3 weeks and 58.2% for ipilimumab. The response rate (percentage of patients whose cancer shrank or disappeared after treatment) was greater with pembrolizumab every 2 weeks (33.7%) and 3 weeks (32.9%) compared to ipilimumab (11.9%).  The occurrence of adverse events was lower in pembrolizumab groups compared to ipilimumab group.

The authors concluded that pembrolizumab was associated with increased survival benefit and fewer adverse effects compared to ipilimumab in advanced melanoma.