Attendees at the this year’s Annual Meeting of the American Association of Cancer Researchers were greeted with news that a new approach to treating advanced-stage solid tumors such as mesothelioma showed tremendous success in a phase I clinical trial. The research was conducted by Memial researchers at the renowned Memorial Sloan Kettering Cancer Center, who announced that a chimeric antigen receptor (CAR) T-cell therapy successfully killed the tumors without showing any evidence of major toxicity.
Scientists Describe Novel Approach to CAR T Therapy
CAR T cells are T-cells that have been engineered to target a specific protein, and in this case the protein is mesothelin, which is commonly expressed in mesothelioma tumor cells. Though this therapy has previously delivered good results in patients with blood cancers, the same has not been true of those with solid tumors. Prasad S. Adusumilli, MD, deputy chief of thoracic surgery at Memorial Sloan Kettering Cancer Center (MSK) said, “Patients with advanced-stage solid tumors, such as mesothelioma, and lung and breast cancers, that are metastatic to the chest cavity have poor outcomes despite treatment. Treatment with CAR T cells results in dramatic successes in blood cancers; however, results have been disappointing to date for solid tumors.” Along with Michel Sadelain, MD, PhD, and other colleagues, Adusumilli created a new form of the CAR T cells using completely human components. One of the more novel aspects of their approach was to include a way for the cells to be turned off if the patient had a toxic response to the treatment. Another was the fact that it was engineered to attack mesothelin directly.
Researchers Indicate Tremendous Potential for Millions of Cancer Sufferers
Mesothelin is found on the surface of malignant mesothelioma cells, as well as of other solid tumors including lung cancers and breast cancers. While mesothelioma is rare, there are many other solid tumors where this approach can be incredibly helpful. According to Adusumilli, “If this approach is successful, 2 million patients with mesothelin-expressing solid tumors per year in the United States will be eligible for this treatment.”
Though this was just a phase one study, the results were remarkable, particularly for the 19 participants diagnosed with malignant pleural mesothelioma. The CAR T cells were injected directly into the area where the tumors existed, and remained in their blood through 9 months of testing The result was more than 50 percent decrease in the mesothelin peptide and tumor regression. A patient who had the treatment after radiation therapy to shrink tumors showed no tumor growth after 20 months, without further treatment, while two patients had complete metabolic response that continues. Five patients had partial response and four had stable disease without disease progression.
Patients diagnosed with malignant mesothelioma are desperately in need of a cure, and these test results offer tremendous hope. For more information on therapies that may be available to you, contact the Patient Advocates at Mesothelioma.net at 1-800-692-8608.