Clinical Applications of Immunotherapy in Cancer Treatment
By Bao Dao, MD;
Advances in oncology are steadily progressing due to a better understanding of cancer biology, genetics, and immunology. Traditional oncologic therapies kill cancer cells via surgery, radiation, and cytotoxic chemotherapy given at various stages of disease. Besides inhibiting cell division of rapidly growing tumors, chemotherapy indiscriminately interferes with normal tissue growth leading to significant toxicities that can dramatically impact a patient’s quality of life. Cancer cells can become chemo-resistant hindering continued response. There is a clear need for novel therapies which can specifically target malignant cells without added side effects.
Recently, immunotherapy has arrived in our arsenal of oncologic treatments. Shifting the focus from poisoning cancer cells at the expense of surrounding normal cells, immunotherapy harnesses the power of the immune system to destroy disease. Tumors can evade detection by our immune system through increased activity of checkpoint inhibitors which prevent immunologic surveillance. New immunotherapeutic medications work by blocking this inhibition of the immune system effectively turning the body’s surveillance system back on and directing its activity against cancer cells.
Based on improved response rates and prolonged survival, the FDA has approved immunotherapeutic agents for the treatment of melanoma, lung cancer, and renal cell carcinoma. In metastatic melanoma, ipilimumab (Yervoy), nivolumab (Opdivo), and pembrolizumab (Keytruda) can be used in both untreated and relapsed disease. Recently, the FDA expanded the indication for Yervoy to include adjuvant therapy after resection of localized melanoma. In relapsed non-small cell lung cancer, both Opdivo and Keytruda demonstrate improvement in overall survival compared to traditional second line chemotherapy. A recent study published in The New England Journal of Medicine described a 5 month improvement in overall survival in pre-treated metastatic renal cell carcinoma patients given Opdivo compared to a standard second line agent.
In general, immunotherapy is well tolerated, but immune mediated toxicities can develop as a byproduct of unleashing the immune system against cancer cells. Development of an autoimmune colitis, inflammation of the pituitary gland, rash, and inflammation of the liver are side effects specific to this class of medications. Administration of steroids ameliorates many of these symptoms, but it is imperative that both physicians and patients remain aware of these unique toxicities.
New indications for immunotherapy agents are on the horizon. Several on-going small clinical trials have demonstrated substantial therapeutic activity in patients with relapsed Hodgkin’s lymphoma. Additional studies of immunotherapy agents are being done in leukemia, lymphoma, and other solid tumors. When appropriate, continued enrollment in clinical trials will help with expansion of immunotherapy to other cancer types.
The advent of immunotherapy marks a true oncologic breakthrough and underscores the importance of on-going clinical research efforts. Immunotherapy significantly prolongs survival for a number of solid tumor malignancies and offers a well-tolerated therapy for many patients in the relapsed or refractory setting. An exciting addition to our clinical armamentarium, immunotherapy introduces a new standard in oncologic care.
Dr. Dao is a board certified Medical Oncologist and Hematologist with Epic Care, a group of experts in the diagnosis and comprehensive treatment of cancer and blood disorders. www.epic-care.com