AT WCLC 2016
VIENNA (FRONTLINE MEDICAL NEWS) – The combination of nivolumab and ipilimumab as first-line therapy in patients with advanced non–small cell lung cancer (NSCLC) doubled median progression-free survival time compared with nivolumab monotherapy in updated results from the CheckMate 012 trial, Scott N. Gettinger, MD , reported at the World Congress on Lung Cancer.
This doubling of progression-free survival (PFS) applied to all comers regardless of whether or not their tumor expressed programmed death-ligand 1 (PD-L1). In those patients with any degree of PD-L1 expression – even if just 1% of tumor cells stained positive – combination therapy didn’t just double median PFS, it tripled it, compared with nivolumab alone, added Dr. Gettinger of the Yale Cancer Center in New Haven, Conn.
“Response rates seemed to go up as PD-L1 expression went up,” he said at the meeting sponsored by the International Association for the Study of Lung Cancer.
CheckMate 012 is a phase I study of nivolumab as first-line therapy for advanced NSCLC with numerous treatment arms. Dr. Gettinger presented updated results for 52 patients who received intravenous nivolumab monotherapy at a dose of 3 mg/kg every 2 weeks, 36 patients on nivolumab plus intravenous ipilimumab at 1 mg/kg every 12 weeks, and 39 who received nivolumab plus ipilimumab every 6 weeks. None of the participants had prior chemotherapy for their advanced stage IIIb or IV NSCLC.
Median PFS in the overall study population was 3.6 months with nivolumab monotherapy and 8.0 months with combination therapy. In the roughly 70% of participants who had any degree of tumor PD-L1 expression, median PFS was 3.5 months with monotherapy, compared with 12.7 months in the combined dual therapy arms. And, in the roughly one-quarter of patients whose tumor showed at least 50% PD-L1 expression, median PFS rose to 8.3 months with nivolumab monotherapy and hasn’t yet been reached in patients on combination therapy.
The 1-year overall survival rate in patients on nivolumab monotherapy was 73% in all treated patients, 69% in those with any detectable tumor PD-L1 expression, and 83% in patients with at least 50% PD-L1 expression. In patients on combination therapy, the corresponding figures were higher at 76%, 87%, and 100%.
The clearly enhanced efficacy achieved with the combination of nivolumab plus ipilimumab was accomplished with only a modest increase in toxicity compared with nivolumab alone. At a median follow-up of 22 months in the nivolumab monotherapy group and 16 months for combination therapy, the rate of any treatment-related adverse event leading to study withdrawal was 12% with monotherapy and 18% with combination therapy.
The combination of nivolumab (Opdivo), a PD-L1 immune checkpoint inhibitor, and ipilimumab (Yervoy), a cytotoxic T-lymphocyte–associated protein 4 immune checkpoint inhibitor, is biologically attractive: “The ipilimumab primes the immune system by inducing tumor infiltration of effector T cells while depleting the number of myeloid-derived suppressor cells and suppressive regulatory T cells within the tumor microenvironment,” Dr. Gettinger explained.
Nivolumab is approved for treatment of advanced NSCLC that has progressed despite platinum-based chemotherapy. Of the various toxicities associated with the drug, only dermatologic and GI adverse events occurred more frequently with combination therapy than nivolumab alone.
There were five complete responses in the nivolumab monotherapy group and six with combination therapy. Of note, four of these complete responses occurred in patients without any measurable tumor PD-L1 expression.
Based upon these encouraging results from CheckMate 012, a phase III randomized clinical trial of nivolumab as first-line therapy in patients with advanced NSCLC is underway. In the CheckMate 227 trial , patients with any detectable PD-L1 expression are randomized to nivolumab at 3mg/kg every 2 weeks plus ipilimumab at 1 mg/kg every 6 weeks, nivolumab monotherapy at 240 mg every 2 weeks, or standard platinum-based chemotherapy. Patients with no PD-L1 expression in their tumor are assigned to the nivolumab/ipilimumab combination, or nivolumab at 360 mg every 3 weeks plus chemotherapy, or chemotherapy alone.
Discussant Edward B. Garon, MD , said that most observers believe the two-drug nivolumab/ipilimumab immunotherapy combination will sail through phase III studies. They think it will become the new standard approach to first-line therapy of advanced NSCLC, pushing aside pembrolizumab (Keytruda), a PD-1 receptor inhibitor that has been approved as first-line therapy in patients with advanced NSCLC, albeit with the restriction that they must have at least 50% tumor PD-L1 expression. But he is less certain of this scenario than are many of his colleagues.
“I think we should be cautious despite the excitement about the combination,” argued Dr. Garon, director of thoracic oncology at the University of California, Los Angeles.
He noted that various iterations of the large CheckMate 012 phase I program have been presented repeatedly at major meetings, and the shifting data have raised concerns in his mind about possible patient selection bias stemming from the study design.
“From my perspective, until we see randomized data that can control for these biases, I will remain hopeful but not yet extremely confident that this combination will be the new frontline therapy for metastatic non–small cell lung cancer,” Dr. Garon said.
Dr. Gettinger reported serving as a consultant to Bristol-Myers Squibb, which markets nivolumab.
Dr. Garon reported that his institution receives funding from Bristol-Myers Squibb as well as AstraZeneca, Boehringer Ingelheim, Eli Lilly, Genentech, Mirati, Merck, Pfizer, and Novartis.