Confirmation that pembrolizumab (Keytruda) is a more effective medication for advanced melanoma than ipilimumab (Yervoy) comes from a five-year follow-up of a clinical trial.

The original study (KEYNOTE-006) randomised patients to one of two regimens of the programmed cell-death-1 (PD-1) antibody, pembrolizumab or to ipilimumab (a cytotoxic T-lymphocyte-associated antigen-4 antibody).

It found that after two years of treatment, the 556 patients who received either two or three-weekly pembrolizumab 10mg/kg for two years had better outcomes than the 278 patients given four doses of ipilimumab 3mg/kg every three weeks.

According to the new study, funded by Merck Sharpe & Dohme, the superiority of being treated with pembrolizumab continued five years after randomisation, said the international team of researchers, led by Professor Georgina Long, of the University of Sydney.