A new cancer vaccine was found to be effective in mesothelioma patients alongside Opdivo in a new study. It was studied in people whose cancer no longer responded to standard chemotherapy. The phase I clinical trial took place at the Memorial Sloan Kettering Cancer Center and it involved the galinpepimut-S vaccine, or GPS. Data early on in the trial shows that it has a good anti-cancer synergism with Opdivo. The vaccine targets the WT1 protein, which can be expressed in people with many different types of cancer. The protein is not found in many people without cancer and is very resistant to chemotherapy. The vaccine works by creating a strong T-cell response to the WT1 antigen and luckily does not have a lot of side effects, but there is a temporary reaction at the site of injection in certain people. The vaccine has been given orphan drug and fast track status designations from the FDA. SELLAS Life Sciences Group created it.
There were only four patients whose data was reported early. All were men with three having epithelioid mesothelioma and one having sarcomatoid mesothelioma. Two of the patients were diagnosed with stage four disease and all had mesothelioma that either had disease progression or chemotherapy resistance. The median progression free survival was 8.8 weeks and the median overall survival was 35.4 weeks. Researchers expect the median overall survival to be longer with more patients being reported at the end of 2021. This data when compared to the estimated overall survival of 20 to 24 weeks shows that this treatment can help patients live longer lives. The patient with the hardest to treat type (sarcomatoid) had the most promising results since the typical survival time after diagnosis is five to six months and the patient lived past 25 months. A double blind, placebo-controlled study showed that the vaccine is effective because it created a 21.4-month median survival in mesothelioma patients compared to patients in the placebo group having a 16.6-month survival.
The GPS vaccine is most effective when it is combined with another treatment or it is used to prevent disease reoccurrence. It is also showing great results as a second line treatment to be used to delay the recurrence of cancer in people who have compete remission of disease or have a small amount of the disease left. The fast track designation allows drugs to be developed faster for rare and aggressive cancers like mesothelioma. New patients are still being accepted and the vaccine is going to be tested with other treatments in more studies. This vaccine won’t cure mesothelioma, but it could at least help extend the survival in patients with this hard to treat disease.
