Cancer vaccines have gained increasing popularity since the US FDA approved the first cancer vaccine, sipuleucel-T, in 2010 and then approved the active specific immunotherapeutic agent, ipilimumab, in 2011.
Several other recently reported positive randomised trials have started reversing the seemingly endless flow of failed cancer vaccine trials [1–4]. This has not been a complete reversal, however, with the recent report at ASCO that the Stimuvax trial failed to meet its primary end point in lung cancer; however, there was a significant improvement in overall survival in a large subset of over 800 patients. Since the majority of cancer vaccine trials have been performed in melanoma, this disease entity has endured more than its share of cancer vaccine failures. However, melanoma has taught us more than any other disease about the endogenous immune response to cancer. Specifically, multiple immunogenic peptides have been described from melanoma-specific antigens such as p-mel and MART-1 that efficiently induce and expand T cells with the capacity to recognise and destroy melanoma cells expressing these antigens. It is understandable then why these peptides have been the focus of many early and ongoing clinical trials. As with most vaccines, the antigenic focus of the vaccine must be joined with an immunoadjuvant to enhance its effectiveness.
Development of cancer vaccines has been greatly stimulated by two recent advances in immune-oncology, namely the emergence success of checkpoint (CTL-4; PD1; PDL-1) inhibitors and the understanding of the importance of stimulating T-helper cells (CD4) cells to achieve a broad and long-acting immune response. In the past, the production of checkpoint molecules by tumour cells reduced the ability of the immune system to fight cancer. Thus, there is now the potential to use checkpoint inhibitors and vaccines in combination (for a “one-two” punch) to take the brakes off the immune system with the vaccine stimulating the immune system to attack specific targets. TapImmune’s phase II clinical trial in ovarian cancer at Memorial Sloan Kettering Cancer Center, New York, in combination with Astra-Zeneca’s durvalumab is such an example.
About the author:
Dr Glynn Wilson is the Chairman and CEO of TapImmune Inc., a clinical-stage immuno-oncology company specializing in the development of T-cell vaccines for breast and ovarian cancer. Dr. Wilson brings an extensive background of success in corporate management and product development with tenures in both major multinational pharmaceutical companies and start-up pharmaceutical/biotech organizations. Dr Wilson’s former positions include Head of Drug Delivery at SmithKline Beecham Pharmaceuticals, Research Area Head in Advanced Drug Delivery at Ciba-Geigy Pharmaceuticals and President and co-founder of Auriga Pharmaceuticals. As Executive Vice President of R&D at Tacora Corporation, he was responsible for merging the company with Access Pharmaceuticals. He is a recognised leader in the development of drug delivery systems.Dr. Wilson has a Ph.D. in Biochemistry and conducted medical research at The Rockefeller University, New York. He has been on the Board of TapImmune for five years.