No survival improvement with pembrolizumab in malignant pleural mesothelioma
medwireNews: Pembrolizumab does not confer a progression free survival (PFS) or overall survival (OS) advantage in previously treated patients with advanced malignant pleural mesothelioma, suggest findings from the PROMISE-meso trial.
These phase III results were reported at the ESMO Congress 2019 in Barcelona, Spain.
Presenting author Sanjay Popat (The Royal Marsden NHS Foundation Trust, London, UK) and colleagues found that median PFS was 2.5 months for the 73 patients who were randomly assigned to receive 200 mg pembrolizumab every 3 weeks, after progressing on previous platinum-based chemotherapy. This did not differ significantly from the median PFS of 3.4 months observed among the 71 patients given single-agent chemotherapy, either gemcitabine or vinorelbine.
Subgroup analyses did not identify specific groups of patients that derived a potential benefit from pembrolizumab therapy in terms of PFS. By contrast, “when we look at the non-epithelioid subgroup of patients, this small group gave a signal of potentially having superior PFS with chemotherapy,” Popat highlighted.
Median OS was also comparable across the pembrolizumab and chemotherapy groups, at 10.7 and 11.7 months, respectively, and again no subgroup benefited from treatment with the PD-1 inhibitor.
Of note, 63% of the participants initially allocated to receive chemotherapy crossed over to the pembrolizumab group at time of progression. But there was no OS benefit with pembrolizumab even after accounting for this “significant crossover rate,” the presenter commented.
He also pointed out that although most endpoints investigated in this trial were not met, pembrolizumab was associated with a significantly improved objective response rate, at 22%, nearly four times higher than the rate observed with chemotherapy, at 6%.
Additionally, pembrolizumab-treated patients had a lower rate of treatment-related adverse events of grade 3–5, at 19.4%, compared with 24.3% among the chemotherapy-treated group, with a total of two treatment-related deaths, one per treatment group.
In light of the negative findings of this study, Popat concluded: “Further exploratory translational work is ongoing to identify subgroups that could benefit from pembrolizumab.”
By Hannah Kitt
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