February 3, 2014
TapImmune Inc. is pleased to report that analysis of the interim data from the first set of patients in a Phase I clinical trial show that each of the patients have raised specific T-cell immune responses against a set of naturally processed HER2/neu Class II antigenic epitopes. The Phase I trial is being carried at the Mayo Clinic, Rochester, MN.
Importantly, this immune response data supports our contention that immune responses to our proprietary Class II antigens should be found in up to 84% of the patient population, making this potentially applicable to a much wider spectrum of patients when compared to other HER2/neu therapies; for example, Roche’s Herceptin®. Herceptin, a $6+B per year drug (2013) and the current standard of care for this patient population treats less than 20% of the HER2/neu+ breast cancer patient population, leaving a very large market opportunity for a TapImmune vaccine approach.
Dr. Keith Knutson, Director Cancer Vaccines and Immune Therapies Program, Vaccine & Gene Therapy Institute of Florida, this trial’s Principal Investigator, further commented that “The finding of specific immune responses in all patients has confirmed expectations that our approach is well reasoned, capable of reaching a broad population of breast cancer patients and is amenable to other HER2/neu indications such as colorectal and ovarian cancers. We are extremely pleased with the results thus far and expect to advance these studies to a Phase II Clinical Study in the near future.”
Earlier the company had reported that the first endpoint to demonstrate safety on these patients was met.
In the current analysis of the first six patients, immune responses were stimulated against the HER2/neu antigens corresponding to T-cell epitopes mapping directly to both external and internal domains of the HER2/neu protein. Five patients showed immune responses against all four epitopes while one patient had immune responses to 3 epitopes. The use of these epitopes, discovered by Dr. Keith Knutson as naturally processed subdominant epitopes from breast cancer patient samples, illustrates an important focus of our vaccine development strategy, namely, to identify and amplify naturally occurring patient immune responses to cancer antigens.
Ultimately, TapImmune’s therapeutic approach is designed to stimulate a long-lived Killer T-cell (CD8+, Class 1 HLA) mediated immune response resulting from the concomitant stimulation of one or more Helper T-Cell (CD4+ Class 2 HLA) responses. In contrast, Herceptin®, a monoclonal antibody directed to an external domain only of the HER2/neu protein, is not designed or intended to stimulate a Killer T-cell response. Furthermore, we believe that the use of TapImmune’s candidate HER2/neu vaccine composition(s) could be expanded to include indications where there is a large market opportunity and unmet need, such as ovarian and colorectal cancers.