FDA Approves Keytruda Plus Chemo for Pleural Mesothelioma Subset

FDA approves Keytruda plus chemo for unresectable advandced or metastatic malignant pleural mesothelioma.

The Food and Drug Administration (FDA) approved Keytruda (pembrolizumab) plus pemetrexed and platinum chemotherapy for the first-line treatment of patients with unresectable advanced or metastatic malignant pleural mesothelioma.

This disease is a cancer that develops in the thin tissue that covers the lungs and lines the chest wall, known as the pleura.

This approval was based on findings from the KEYNOTE-483 trial, according to a release from the FDA. The trial included patients with unresectable (unable to be removed with surgery) advanced or metastatic malignant pleural mesothelioma who did not previously receive systemic therapy for advanced/metastatic disease. Patients were randomly assigned to receive either Keytruda for up to two years plus pemetrexed and platinum-based chemotherapy for up to six cycles (222 patients), or pemetrexed and platinum-based chemotherapy for up to six cycles.

The main focus of the study was to assess overall survival (the time when a patient with cancer is still alive). Other areas of interest included progression-free survival (the time during and after treatment when a patient with cancer is alive without the disease worsening), duration of response (the time that a patient’s tumor continues to remain stable or shrinks from treatment) and objective response rate (the percentage of patients with a complete or partial response to treatment).

Findings from the KEYNOTE-483 trial demonstrated a statistically significant improvement in overall survival for those in the Keytruda plus chemotherapy group compared with patients in the chemotherapy alone group. The median overall survival for the Keytruda group was 17.3 months compared with 16.1 months in the chemotherapy alone group.

The median progression-free survival was 7.1 months in both groups, according to the release. Patients assigned Keytruda plus chemotherapy had a confirmed overall response rate of 52% compared with 29% in those assigned chemotherapy alone. The median duration of response was 6.9 months in the Keytruda group versus 6.9 months in the chemotherapy alone group.

According to findings from the study published in The Lancet in 2023, side effects related to treatment considered grade 3 (severe) or grade 4 (life threatening) occurred in 27% of patients in the Keytruda group and 15% of those in the chemotherapy alone group. Serious side effects from one or more of the study drugs resulting in hospital admissions occurred in 18% of patients assigned Keytruda compared with 6% assigned chemotherapy alone. Grade 5 (causing death) side effects from one or more of the drugs used in this study occurred in two patients in the Keytruda group and one patient in the chemotherapy alone group.

In the background section of the published study, researchers noted that patients with pleural mesothelioma are typically diagnosed with the disease “at an advanced, incurable stage.” The standard treatment for these patients is chemotherapy with platinum-pemetrexed. With this study, researchers were aiming to see whether adding Keytruda to chemotherapy would improve overall survival in these patients.

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