A new study showing that the PD-1 inhibitor pembrolizumab, a cancer immunotherapy drug, decreased the growth of tumors in 76% of individuals with pleural mesothelioma, a rare and fatal type of cancer that affects the outer lining of the lungs and internal chest wall, was presented in the American Association for Cancer Research (AACR) Annual Meeting held in Philadelphia April 18-22, Pennsylvania, USA.
The study entitled “Clinical safety and efficacy of pembrolizumab (MK-3475) in patients with malignant pleural mesothelioma: Preliminary results from KEYNOTE-028” was led by Evan W. Alley, MD, PhD, co-director of the Penn Mesothelioma and Pleural Program, together with an international research team from United States, Europe and the United Kingdom.
In 2014, Pembrolizumab was approved by the FDA for the treatment of metastatic melanoma. The drug belongs to the novel group of medications designated PD-1 inhibitors, a highly selective humanized monoclonal antibody that inhibits programmed cell death protein-1 (PD-1), blocking the interaction with its ligands, PD-L1 and PD-L2. This blockage activates the immune system to fight cancer. PD-1 regulates the immune responses by inhibiting the activation of T-cells, which are white blood cells that protect the organism from infection. This type of regulation is important to prevent autoimmune diseases where the body produces antibodies that target its own tissues.
The research team evaluated the safety and efficacy of pembrolizumab in patients with malignant pleural mesothelioma (MPM) positive for PD-L1, which has a poor prognosis. Patients diagnosed with this disease associated with exposure to asbestos and have a median survival rate of about one year. Dr. Alley said in the news release that 76% of the patients previously treated for MPM had the disease controlled, suggesting that Pembrolizumab is a very promising treatment for this type of cancer. There were no patients dropping treatment due to side effects. All patients in the study had MPM that progressed regardless of having been treated previously with standard or first-line therapy, or were unable to receive such therapy. Unfortunately, for these groups of patients there are no FDA-approved successful alternative therapies.
“More research and trials will be occurring, which we hope will provide further grounds for optimism,” concluded Dr. Alley.
The present trial was financially supported by Merck, which manufactures pembrolizumab.