Merck, Sharp & Dohme Inc., (MSD; NYSE: MRK), a leading US pharmaceutical company, has announced that the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) has issued a positive opinion recommending the approval of its PD-1 inhibitor, Keytruda (pembrolizumab), in combination with pemetrexed plus platinum for the first-line treatment of adult patients with unresectable non-epithelioid malignant pleural mesothelioma (MPM).
Positive Opinion Based on Clinical Trial Results
The endorsement from the CHMP is based on the results from the pivotal Phase II/III IND.227/KEYNOTE-483 trial. This trial demonstrated that the combination of KEYTRUDA plus chemotherapy showed a statistically significant improvement in overall survival (OS) compared to chemotherapy alone for patients with MPM.
Clinical Trial Outcomes and Analysis
In the IND.227/KEYNOTE-483 trial, patients with epithelioid disease (n=345) treated with the pembrolizumab/chemo combo had a median OS of 19.8 months, compared to 18.2 months for those on chemotherapy alone (HR=0.89). The median progression-free survival (PFS) for the pembrolizumab treatment group was 7.13 months, and for the chemotherapy group, it was 7.39 months (HR=0.93). For patients with non-epithelioid disease (n=95), the median OS with pembrolizumab combined with chemotherapy was 12.3 months, while the median OS for chemotherapy alone was 8.2 months (HR=0.57). The 3-year OS rates were 23% and 7% for the pembrolizumab and chemotherapy groups, respectively. The median PFS for the pembrolizumab treatment group was 6.9 months, compared to 4.5 months for the chemotherapy group (HR=0.48). Non-epithelial MPM patients experienced a more significant benefit from the combination therapy.
CHMP’s Conservative Stance and FDA Approval
The CHMP’s recommendation is more conservative for epithelial MPM patients, only recommending approval of pembrolizumab combined with chemotherapy for non-epithelial MPM patients. This stance contrasts with the indication approved by the US FDA, which does not have such limitations, reflecting the different regulatory approaches to the use of immunotherapy in this patient population.-Fineline Info & Tech
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