The latest doctors to join the discussion on this possible mesothelioma treatment are medical oncologists from Princess Margaret Cancer Center in Toronto.
Dr. Safiya Karim and Dr. Natasha Leighl examine the “current landscape and future directions” for Keytruda as a treatment for mesothelioma in an article in the British medical journal Future Oncology.
Unprecedented Results in Mesothelioma Trial
Keytruda began to get national attention as a potential mesothelioma treatment after the results of a mesothelioma clinical trial were released earlier this year.
In that trial, 76 percent of mesothelioma patients responded to treatment with Keytruda – a figure that the researchers called “unprecedented.” Mesothelioma tumors temporarily stopped growing in about half of the patients and about a quarter of the patients actually saw their mesothelioma tumors begin to shrink.
Keytruda also produced fewer serious side effects than conventional chemotherapy for mesothelioma.
Mesothelioma Treatment with Keytruda
As a monoclonal antibody, Keytruda is designed to block a cell surface protein called PD-1 (programmed cell death 1). An estimated 20 to 40 percent of mesothelioma tumors express this protein.
PD-1 is believed to suppress the immune system in some people with mesothelioma, allowing the asbestos cancer to grow out of control.
By blocking the expression of PD-1, Keytruda may help turn the body’s immune response against cancers like malignant pleural mesothelioma.
FDA Approval of Keytruda
Despite the promise of early mesothelioma clinical trials, Keytruda has not yet been approved specifically as a mesothelioma treatment.
However, it has recently been approved as a second-line treatment for relapsed non-small cell lung cancer and was already approved to treat melanoma skin cancer.
Like mesothelioma patients, people with non-small cell lung cancer have few viable treatment options. Keytruda was granted breakthrough therapy designation because it appears to offer “substantial improvement over available therapies”, according to an FDA press release.
Karim, s and Leighl, N, “Pembrolizumab for the treatment of thoracic malignancies: current landscape and future directions”, December 3, 2015, Epub ahead of print
“FDA approves Keytruda for advanced non-small cell lung cancer”, October 2, 2015, FDA website