AACR: Immune Checkpoint Inhibitors Promising in Melanoma
Pembrolizumab, ipilimumab, and other medications harness immune cells to target cancers
MONDAY, April 20, 2015 (HealthDay News) -- Immune checkpoint inhibitors show promise in treating advanced melanoma, according to a pair of clinical trials published online April 19 and 20 in the New England Journal of Medicine. The research was published to coincide with the annual meeting of the American Association for Cancer Research, held from April 18 to 22 in Philadelphia.
One trial involved 834 patients with advanced melanoma in 16 countries. Two-thirds received pembrolizumab (Keytruda), while the rest received the current front-line treatment, ipilimumab (Yervoy). At 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 stood at 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 for ipilimumab. Only 12 percent of patients taking pembrolizumab suffered from side effects, compared with 20 percent in those who received ipilimumab.
The second trial showed that 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 received the combo therapy, which included the anti-CTLA-4 drug ipilimumab and the anti-PD1 drug nivolumab (Opdivo). Another third of patients received ipilimumab alone.
The researchers found that among patients with BRAF wild-type tumors, 61 percent responded to the combination treatment, compared to 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 patients with BRAF mutation-positive tumors. However, about half of the patients receiving the combination therapy did suffer from moderate to serious side effects, compared with just a quarter of patients treated with ipilimumab alone, the team found.
The pembrolizumab trial was funded by the drug company Merck, while the combination therapy trial was funded by Bristol-Myers Squibb.