Mesothelioma Cancer Vaccine Steps Closer to Reality

A masked doctor wearing green gloves uses a small syringe to withdraw an experimental cancer vaccine from a glass vial. The vaccine will be part of a mesothelioma treatment regimen.

The results of a small trial suggest another cancer treatment success for immunotherapy. Trial doctors treated mesothelioma patients with a cancer vaccine called galinpepimut-S (GPS). Most patients also received a checkpoint inhibitor drug (immunotherapy). Study patients lived longer and enjoyed nearly three months with no growth in their cancer.

Cancer vaccines are a type of immunotherapy. They teach a patient’s immune system to fight cancer. The GPS vaccine teaches the immune system to attack cells carrying a protein called WT1. Cancer cells like those in mesothelioma tumors carry a lot of WT1. So the GPS vaccine teaches the immune system to attack mesothelioma cells.

Cancer Vaccine Helped Patients With Tough Mesothelioma Cases

For this trial, doctors researched a new treatment for pleural mesothelioma patients whose tumors grew after standard chemotherapy. Because patients had already received therapy, the trial treatment was a second-line therapy.

Mesothelioma Cancer Vaccine Study Results
  • Median survival: 11 months
  • Time to cancer progression: 3 months

Many past attempts at second-line therapy have failed to improve mesothelioma survival. This fact may explain why there are currently no approved second-line therapies for mesothelioma. Unfortunately, this leaves patients with few options if standard treatments don’t work. But this study of a cancer vaccine and checkpoint inhibitor combination may change that.

Patients who received GPS and the checkpoint inhibitor Opdivo® (nivolumab) lived about 11 months. This is about 35% longer than the survival reported for other second-line therapies. Study patients also lived about three months without seeing tumor growth. This may mean they experienced a better quality of life during that time period.

Immunotherapies are well on their way to becoming mainstays of mesothelioma treatment. Opdivo® (nivolumab) and Yervoy® (ipilimumab) recently earned approval for first-line treatment of pleural mesothelioma. In a clinical trial, these drugs extended survival and improved quality of life better than chemotherapy. A similar drug combination was recently studied as a second-line treatment. Patients lived about 26 months in that study, which is more than double the survival of earlier second-line treatments.

What Does This Mean for Mesothelioma Patients?

Though these results are encouraging, they are also preliminary. Only eight patients so far have tried this treatment through the study. The organizers expect it to run through July 2023, and final results are unlikely to come out before that date.

If the completed study shows GPS and Opdivo safely improve survival, the combo will still require additional testing. It may be years before we know the fate of this treatment. In the meantime, these results can provide some helpful insights.

First, researchers are building on the recent success of Opdivo and Yervoy. Combining one or both with other treatments may prove beneficial. Second, there are many potential ways to combine immunotherapies. So there are just as many potential new treatments that may serve as tomorrow’s good news.