Even after the best multimodal treatment approach, a combination of two or more therapies (chemotherapy, surgery and radiation), the probability of mesothelioma cancer recurrence remains high because of the diffuse nature of the disease.
Researchers are moving closer to fixing that dilemma.
Doctors currently are testing a Wilms’ tumor 1 (WT1) peptide vaccine for its ability to halt mesothelioma recurrence in a Phase II clinical trial conducted at the MD Anderson Cancer Center in Houston.
MD Anderson still is accepting new participants for this randomized study that began in 2013. The expected completion date is 2017.
“To this point, it looks very promising,” Anne Tsao, M.D., director of the Mesothelioma Program at MD Anderson, told Asbestos.com. “We’ve been encouraged with what we’ve seen.”
The vaccine is a form of immunotherapy designed to trigger the body’s own immune system into preventing any new growth of the tumor. Tsao said the vaccine has been well tolerated by patients and shown no serious side effects.
It is one of several immunotherapy agents researchers are exploring in the fight against mesothelioma, an aggressive cancer which has no definitive cure and is caused by exposure to asbestos fibers.
Mesothelioma tumors typically have high levels of WT1, a protein that causes cell growth and regulates gene expression. When it becomes abnormal, it can lead to the development of cancer. The vaccine is given in combination with drugs GM-CSF and Montanide, which together are designed to cause white blood cells to grow and encourage an immune response.
The addition of the analog peptide vaccine helps direct the response to any mesothelioma cells that remain.
“After treatment [surgical resection and radiation], the premise here is that the immune system can then prevent recurrence from any microscopic disease that was left behind,” Tsao said. “So far, that’s our hope.”
To qualify for the trial, patients must have finished a multimodal therapy that included a complete surgical resection through either a pleurectomy/decortication (P/D) or an extrapleural pneumonectomy (EPP).
They must test positive for high levels of the WT1 protein and have received either chemotherapy or radiation within the previous 4-12 weeks.
As part of the trial, patients will be given six injections over a 12-week period. All will receive GM-CSF and Montanide. As a random trial, though, only half of patients actually will be receiving the WT1 peptide.
Researchers will be looking for one-year progression-free survival calculated from the date of randomization to date of progression, death or the last follow-up.
Tsao said centers involved in the study are actively recruiting new patients for the trial. She also talked about how much patients can be helped at a specialty center like MD Anderson, along with the importance of enrolling in a clinical trial to advance the goal of eventually finding a cure.
“It’s absolutely essential to have patients enrolled in clinical trials to move forward with this disease,” she said. “It’s important to identify which of these immunotherapy agents work the best.”
Most mesothelioma experts agree that immunotherapy may offer the best hope for the future, moving away from the toxicity of traditional chemotherapy and radiation, which can scare off many patients.
“I think there are several promising treatments out there now,” she said. “Advancements are being made, both for patients and for research.”