Keytruda is now approved for certain mesothelioma patients. The immunotherapy drug has been tested for mesothelioma before, but has not been approved for the treatment of it. The approval is for adult and pediatric cancers with unresectable disease and high mutational burden that have been treated and have no other treatment options available. Unfortunately, there has only been a small amount of success when Keytruda has been combined with other therapies to treat mesothelioma. While it is effective for some, it is not the cure that many people are hoping for, so surgery is the best option available to reduce tumors.
Keytruda has been approved because of certain information that has been found in clinical trials studying the use of the drug for inhibiting tumor growth in patients that have the PD-1 protein. The study is not just looking at mesothelioma, it is also looking at small cell lung, thyroid, cervical, biliary, anal, salivary, and endometrial cancers. The study had 99 patients with high levels of the PD-1 protein and 652 patients without high levels of the protein. The low protein group had a majority of mesothelioma patients, with 12 percent of them being mesothelioma sufferers.
The response rate was low for both groups, but was much lower for the patients with the lower amount of the PD-1 protein. The high protein group had a 29 percent response rate while the low or no protein group only had a six percent response rate. The progression free survival for the high protein group was 26.1 percent while it was 14.1 for the low protein group. The two year survival rates ended up being 18.9 percent and 6.5 percent respectively. Thankfully, there were tolerable side effects including decreased appetite, musculoskeletal pain, fatigue, nausea, rash, abdominal pain, and cough. According to other studies, mesothelioma patients do not have high levels of PD-1, which means the treatment is not as effective for the disease, but 16 percent of the mesothelioma patients have high levels of the protein, so it can be helpful for some. Chemotherapy had a 3.4 months progression free survival while Keytruda had a 2.5 month progression free survival.
Other approved treatments for mesothelioma include tumor treating fields, which uses electrical fields to target cancer cells and is being used alongside chemotherapy. Tumor treating fields were the first treatment approved for mesothelioma since 2004. Keytruda has also been approved to treat metastatic non-small cell lung cancer as well as some head and neck cancers, bladder cancer, and colorectal cancer.