Two trials presented at the 2016 annual meeting of the American Society of Clinical Oncology (ASCO) provide somewhat discouraging findings on checkpoint inhibitors for second-line treatment of mesothelioma.
In the largest checkpoint inhibitor study in mesothelioma to date, a Phase IB study conducted with the programmed death ligand-1 (PD-L1) inhibitor avelumab (Pfizer), the objective response rate (ORR) among the 53 patients in the study, who had unresectable pleural or peritoneal mesothelioma that had progressed after chemotherapy, was 9.4%, and 47.2% achieved stable disease (abstract 8503). The median progression-free survival was 17.1 weeks, but several responders remain on avelumab and are being followed for long-term benefit, reported Raffit Hassan, MD, the head of the thoracic and solid tumor immunotherapy section of the National Cancer Institute, in Bethesda, Md.
Although the ORR has been closer to 30% in smaller and previously reported studies with the programmed death-1 (PD-1) inhibitors pembrolizumab (Keytruda, Merck) and nivolumab (Opdivo, Bristol-Myers Squibb), the ASCO-invited discussant of the study, Tom John, MBBS, PhD, a senior investigator in thoracic oncology at the Olivia Newton-John Cancer Research Institute, in Melbourne, Australia, suggested the studies have been relatively consistent. “There is a signal for efficacy in mesothelioma, but these studies are also a reality check,” Dr. John reported. With a PD-1 inhibitor monotherapy, “most patients do not seem to benefit.”
Modest Results for Checkpoint Agents in Mesothelioma
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