Physicians Urge Change to Mesothelioma Treatment Regimen

Mesothelioma experts are urging their community to adopt a new standard of care in the treatment of malignant pleural mesothelioma. The change would represent the first major adjustment in over ten years.

According to data provided by lead author Gerard Zalcman M.D. at the American Society of Clinical Oncology 2015 meeting held in Chicago, researchers have determined that by adding the drug bevacizumab (Avastin) to the current treatment protocol of pemetrexed and cisplatin, patients have significantly longer overall survival. The data was a result of the MAPS study, a phase 2/3 study that involved multiple treatment centers and which compared results between patients who were dosed with the existing pemetrexed and cisplatin standard of care and the proposed triplet therapy of bevacizumab, pemetrexed and cisplatin. Natasha Leighi, M.D>, a member of the research group from Princess Margaret Cancer Centre in Toronto, Canada referred to their results as “practice changing.”

The existing global standard of care of using pemetrexed and cisplatin has been in place since 2003. The study was a continuation of a previous Phase 2 study that had been presented at the 2012 ASCO meeting; in the Phase 3 trial researchers provided patients with this combination at standard dosage every three weeks for six cycles, and the same dosing schedule for the triplet therapy, though after six weeks patients that received the triplet therapy continued receiving the bevacizumab alone until it was determined that their cancer had begun to spread again. All of the patients selected for the trial were chosen because they were not eligible for curative therapy. They were reportedly a representative group for mesothelioma patients, consisting of 75 percent male patients with a median age of 65. Eighty percent of those studied were diagnosed with the epithelioid type of malignant pleural mesothelioma. The group was followed up at a median of 39.4 months, and researchers found that those receiving the triplet therapy had a median survival of 18.8 months as compared to 16.1 for those who received the current standard of care. Similar improvements were shown in the period during which the illness was progression free.

The researchers were encouraged to report that there were no new toxicities found during the phase 3 trials, and felt that their study was well designed. They do caution that despite the clinical significance of their findings there are concerns about putting it in place, including high costs. Dr. Leighl said, “It is expensive an will cause financial toxicity.” The group also expressed concern about whether the extension of life corresponded with improvements in qualify of life, and whether their study results would be replicated in different demographics, specifically stating concern about health economics.