Details of the results in earlier stage disease
The KEYNOTE-716 trial enrolled patients with newly diagnosed, resected, high-risk stage 2 melanoma aged ≥ 12 years and a good performance status. The majority (~64%) had stage 2B melanoma, and the rest had stage 2C. T3b disease was present in 41% of patients, 23% had T4a disease, and 35% had T4b disease.
Patients were randomized to receive pembrolizumab or placebo.
In a subsequent part of the study, patients with recurrence will be unblended, with either crossover from the placebo to active treatment group or rechallenge with pembrolizumab for up to 2 years.
Presenting the first part, Dr. Luke said that, of 487 patients assigned to pembrolizumab, 483 started treatment, of whom 206 have completed treatment, 133 are still on therapy, and 144 have discontinued.
In the placebo group, 489 patients were assigned and 486 began treatment. Of those, 229 completed treatment, 152 are still ongoing, and 105 discontinued.
The two groups were well balanced in terms of baseline characteristics. The median age was approximately 60 years, with only one patient enrolled who was aged 12-17 years.
At 12 months, the study met its primary endpoint.
Relapse-fee survival was 90.5% in patients treated with pembrolizumab versus 83.1% in the placebo group, at a hazard ratio for recurrence of 0.65 (P = .00658).
“Despite this trial hitting this primary endpoint very early, there are a number of patients who are censored later in the curves,” Dr. Luke said, adding that “we will continue to see these data mature.”
“In fact, it’s our full expectation that curves will continue to separate over time.”
When looking at key subgroups, Dr. Luke showed that the results favored pembrolizumab when stratifying patients by age, gender, race, and performance status.
Interestingly, patients with T3b disease did a lot better on pembrolizumab compared with those who had T4b disease, at a hazard ratio for recurrence of 0.44 versus 0.94.
Data on recurrence patterns revealed that 11.1% of patients taking pembrolizumab had an event, with 6.4% experiencing skin and/or lymph node regional recurrence and 4.7% distant recurrence.
In the placebo group, 16.8% of patients had a recurrence event, with 8.4% having a loco-regional recurrence and 7.8% a distant recurrence.
Dr. Luke explained that this equates to an approximate 40% reduction in distant recurrence with pembrolizumab over placebo.
Finally, the researchers examined change in global health status on the EORTC QLQ-C30 quality of life score. Examining mean change over time, they found that there were no clinically meaningful changes, and the scores in the pembrolizumab and placebo groups tracked each other during the course of follow-up.
Quality of life was, therefore, “only minimally changed,” Dr. Luke said.
The study was funded by MSD. Dr. Luke and Dr. Hamid have declared relationships with multiple companies.
A version of this article first appeared on Medscape.com.