A 3-year follow-up of the Japanese MERIT trial – the basis for regulatory approval of nivolumab in pemetrexed-platinum-treated malignant pleural mesothelioma (MPM) in Japan – reported that nivolumab administered every 2 weeks provides sustained efficacy in pre-treated disease (Abstract 1895MO).
As discussed at ESMO Virtual Congress 2020, the trial involved 34 Japanese patients with advanced or metastatic MPM previously treated with up to two chemotherapy regimens. Patients with histologically confirmed measurable lesions and an Eastern Cooperative Oncology Group performance status (ECOG PS) 0–1 received nivolumab 240 mg every 2 weeks until disease progression or unacceptable toxicity. The vast majority of participants were male (85.3%), the median age was 68 years and nearly two-thirds of patients (61.8%) had an ECOG performance status of 1. Most patients had epithelioid disease (79.4%) and had received one prior regimen (70.6%). Enrolment was not restricted according to PD-L1 status; 58.8% of patients had PD-L1 ≥1% and 35.3% had PD-L1 <1%.
At a minimum follow-up of 36 months, 29.4% of patients (95% confidence interval [CI] 16.8–46.2) achieved the primary endpoint of objective response rate, assessed by an independent review committee. The disease control rate was 67.6% (95% CI 50.8–80.9). Among responders, the median duration of response was 11.1 months (95% CI 3.5–28.6+).
The data cut-off date was 12 November 2019, at which point seven patients were alive. At 2 years, the overall survival (OS) rate was 35.3% (95% CI 19.9–51.0) and the progression-free survival (PFS) rate was 17.0% (95% CI 6.3–32.0). At 3 years, the OS and PFS rates were 23.5% (95% CI 11.1–38.6) and 12.7% (95% CI 3.7–27.6), respectively.
Twenty-six (76.5%) patients reported treatment-related adverse events (TRAEs), most commonly skin disorders (n=6), elevated lipase levels (n=5), elevated amylase levels (n=4) and diarrhoea (n=4). Eleven (32.4%) of the TRAEs reported were grade 3-4.
These follow-up data from the MERIT trial provide important information about the long-term efficacy achievable with nivolumab as second- and third-line treatment in Japanese patients with MPM.