Immune Checkpoint Inhibitors Promising in Melanoma

In two recent studies, researchers found that immune checkpoint inhibitors show promise in treating advanced melanoma. In one study of 834 patients with advanced melanoma in 16 countries, patients received one of two types of immune checkpoints inhibitors: Two-thirds received pembrolizumab (Keytruda), and the rest received the current first-line treatment, ipilimumab (Yervoy). Six months after treatment, progression-free survival was 46.4 percent for pembrolizumab and 26.5 percent for ipilimumab. Overall survival rates after one year were 74.1 percent and 68.4 percent for pembrolizumab, depending on the dose patients received, compared with 58.2 percent for ipilimumab. About 33 percent of patients responded to treatment with pembrolizumab, compared with 12 percent with ipilimumab. Only 12 percent of patients taking pembrolizumab suffered from side effects, whereas 20 percent of those who received ipilimumab did.

In another study, patients responded better to a combination of two different types of immune checkpoint inhibitors than to ipilimumab used on its own. The trial involved 142 patients with advanced melanoma, two-thirds of whom received the combination therapy, which included the anti-CTLA drug ipilimumab and the anti-PD1 drug nivolumab (Opdivo). The other third of patients received ipilimumab alone. Among patients with BRAF wild-type tumors, 61 percent responded to the combination treatment, compared with just 11 percent who responded to treatment with ipilimumab alone. Complete responses were reported in 16 patients (22 percent) in the combination group and no patients in the ipilimumab group. Similar results for response rate and progression-free survival were seen in 33 percent with BRAF mutationpositive tumors. However, about half of the patients receiving combination therapy did suffer from moderate to serious side effects, compared with just a quarter of patients treated with ipilimumab alone.

The pembrolizumab trial was funded by Merck, and the combination therapy trial was funded by Bristol-Myers Squibb. The study was published online April 19 and 20 in the New England Journal of Medicine.