The American Society of Clinical Oncology meeting was held from May 30 – June 3, 2014 in Chicago. This is the largest oncology meeting each year with around 30,000 attendees from all over the globe who congregate to discuss the latest research in all cancer types. I will provide you with my annual summary of the most prominent studies in mesothelioma.
Randomized trial of arginine deprivation with ADI-PEG20: This abstract was presented by Dr. Szlosarek from the United Kingdom. Arginine is an amino acid that normal cells make using an enzyme called A*S (time to make the joke here!). However, many cancer cells lack the A*S enzyme so they cannot make arginine and they need to get it from outside the cell. ADI-PEG20 starves the cancer cells of arginine. In this trial, patients with mesothelioma were randomized to receive treatment with ADI-PEG20 or just supportive care. In order to qualify, the tumor samples were tested to make sure they had low levels of A*S. Side effects were very mild with this treatment. About half of the patients had stabilization of their disease. The time for cancer growth to occur was longer in the ADI-PEG20 arm, but only by a small margin (1.9 versus 3.2 months). A future study will combine ADI-PEG20 with chemotherapy, and that trial should open later this year.
Phase 2 study with tremelimumab: Probably the hottest drugs in oncology right now are the antibodies that boost the immune system. These types of treatment have shown great benefit in melanoma, lung cancer, and many others. Tremelimumab is one of these drugs, and this trial, conducted in Italy by Dr. Calabro and colleagues, showed that mesothelioma also responds to these therapies. Of the 29 patients, 14% of patients had shrinkage of their mesothelioma and 38% had stabilization. These data support the international, randomized trial with tremelimumab that is currently ongoing that will include 542 patients. If this large trial shows that tremelimumab improves survival, this drug will get FDA approval for mesothelioma.
Anti-mesothelin vaccine CRS-207 plus chemotherapy: Dr. Hassan from the National Cancer Institute reported these results. Mesothelin is a protein on the surface of mesothelioma tumors, and seems to be an excellent target for treatment. CRS-207 is a vaccine that increases the immune response against mesothelin. In this study, CRS-207 was given with pemetrexed and cisplatin. Nearly 70% of patients had shrinkage of their cancer, much more than usual with chemotherapy alone, and the responses seemed to last longer. These results should encourage a larger future randomized study.
Next-generation sequencing in mesothelioma: The report from Dr. Scagliotti at the University of Turin, Italy, described his findings from an analysis of gene mutations in a group of mesothelioma tumor samples. This type of testing has become critical for identifying potential targets in all cancers, and customizing treatment for each patient.
Lee M. Krug, MD, is an Associate Attending Physician in the Division of Thoracic Oncology, Department of Medicine at Memorial Sloan-Kettering Cancer Center in New York, New York, where he completed a fellowship and chief fellowship in medical oncology. Dr. Krug is the Director of the Mesothelioma Program at Memorial Sloan-Kettering Cancer Center. He is also the chair of the board of directors of the Meso Foundation.