Adding the novel immune checkpoint inhibitor relatlimab to the more established nivolumab (Opdivo) significantly extended the progression-free survival (PFS) of patients with previously untreated advanced melanoma in comparison with nivolumab alone in the phase 3 RELATIVITY-047 trial.
Both drugs are from Bristol-Myers Squibb, which funded the study.
“Our findings demonstrate that relatlimab plus nivolumab is a potential novel treatment option for this patient population,” said lead researcher Evan J. Lipson, MD, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore.
Relatlimab has a different mechanism of action from currently available immune checkpoint inhibitors, such as nivolumab and similar agents, which act as inhibitors of the programmed cell death protein–1 (PD-1) or programmed cell death–ligand-1 (PD-L1). In contrast, relatlimab acts as an antibody that targets lymphocyte-activation gene 3 (LAG-3), which inhibits T cells and thus helps cancer cells evade immune attack.
“This is the first phase 3 study to validate inhibition of the LAG-3 immune checkpoint as a therapeutic strategy for patients with cancer, and it establishes the LAG-3 pathway as the third immune checkpoint pathway in history, after CLTA-4 and PD-1, for which blockade appears to have clinical benefit,” Dr. Lipson said at a press briefing ahead of the annual meeting of the American Society of Clinical Oncology (ASCO), where this study will be presented (abstract 9503).
Commenting for ASCO, Julie R. Gralow, MD, chief medical officer and executive vice president, agreed that “these results provide validation of the LAG-3 immune checkpoint as a therapeutic target ... and they also support combination treatment with immunotherapies that act on different parts of the immune system.”
When Dr. Lipson was asked whether he would recommend the combination of relatlimab plus nivolumab as a first-line treatment for this patient population, he said that “for many patients,” the first-line treatment choice is made on a “case-by-case” basis.
“We are fortunate in melanoma that we have an ever-expanding list of seemingly effective options, and I think we’ll find at some point this will be added to that list,” he said. “Whether this is the first-line choice for any given patient really depends on a lot of factors,” he added.
Dr. Gralow added a note of caution. “The combination was clearly more toxic, and so I think there will be a lot of discussion” as to when it would be used and for which patients, she said.
In the absence of head-to-head comparisons, “I’m not sure that we have one answer” as to which treatment to choose, she added. With the ever-increasing number of options available in melanoma, the individual treatment choice is “getting more complicated,” she said.
Study details
The global RELATIVITY-047 study was conducted in 714 patients with previously untreated unresectable or metastatic melanoma. The participants were randomly assigned to receive either relatlimab plus nivolumab or nivolumab alone.
Dr. Lipson explained that the treatments were given as a fixed-dosed combination, meaning the preparation of relatlimab and nivolumab was given in the “same medication phial and administered as a single intravenous infusion in order to reduce preparation and infusion times and minimize the risk of administration errors.”
PFS, as determined on blinded independent central review, was significantly longer with the combination therapy than with nivolumab alone, at a median of 10.12 months vs. 4.63 months (hazard ratio, 0.75; P = .0055).
At 12 months, the PFS rate among patients given relatlimab plus nivolumab was 47.7%, versus 36.0% among those given nivolumab alone.
“This significant improvement meant that the study met its primary endpoint,” Dr. Lipson said, adding that the PFS benefit “appeared relatively early in the course of therapy.” The curves separated at 12 weeks, and benefit was “sustained” over the course of follow-up.
He added that the performance of nivolumab alone was “in the range” of that seen in previous studies, although he underlined that cross-trial comparison is difficult, given the differences in study design.
“In general, treatment-related adverse events” associated with the combination therapy were “manageable and reflected the safety profile that we typically see with immune checkpoint inhibitors,” he noted.
The results showed that 40.3% of patients who received the combination therapy experienced a grade 3-4 adverse event, compared with 33.4% of those given nivolumab alone. Grade 3-4 treatment-related adverse events leading to discontinuation occurred in 8.5% and 3.1% of patients, respectively.
Three treatment-related deaths occurred in the relatlimab and nivolumab arm. Two such deaths occurred in the nivolumab-alone group.
The study was funded by Bristol Myers Squibb. Dr. Lipson has relationships with Array BioPharma, Bristol Myers Squibb, EMD Serono, Genentech, Macrogenics, Merck, Millennium, Novartis, Sanofi/Regeneron, and Sysmex (inst). Dr. Gralow has relationships with AstraZeneca, Genentech, Sandoz, and Immunomedics.
A version of this article first appeared on Medscape.com.