This SBIR grant application for the clinical development of a novel vaccine to treat patients with sarcoma is based on a foundation of 30 years of studies at Memorial Sloan Kettering Cancer Center (MSKCC). During these 30 years, the antigens expressed by various cancers (neuroblastoma, sarcoma, breast, ovarian, melanoma, etc.) were defined using Immunohistology, SCLC and sarcomas were identified as having the most intense expression of immunogenic antigens, and sarcomas selected as the most suitable setting for the initial proof of concept randomized trial. Three cell surface antigens most relevant for a sarcoma vaccine and uniquely over-expressed in all types of sarcomas were identified as the gangliosides GM2, GD2 and GD3. The benefit of immunization with ganglioside-KLH conjugate vaccines or treatment with monoclonal antibodies against these gangliosides was demonstrated in preclinical studies, with the most striking benefit resulting when the targets were micrometastases or circulating tumor cells;a setting comparable to the adjuvant setting in the clinic. Responses to treatment with murine mAbs against each of these antigens have been seen in both preclinical studies and clinical trials. Conjugate vaccines against all three gangliosides have also been used in clinical trials. Vaccination with either the monovalent (GM2) or bivalent (GM2/GD2 or GD2/GD3) gangliosides has demonstrated very mild toxicity profiles and consistent high titer antibodies in the clinical trials conducted to date. The objective of this combined Phase I and II SBIR grant application is to evaluate for the first time the clinical efficacy of a trivalent ganglioside vaccine plus immunological adjuvant in sarcoma patients. Over the initial 6 month Phase I portion of this STTR proposal, scale-up of production of the final component (GD2-KLH) will be performed, and the trivalent vaccine will be vialed and released. This will involve a significant scale up in the complex preparation of GD2 and trivalent vaccine compared to what we have previously undertaken. Also, protocols in at least 5 of the 11 medical centers will be IRB approved and investigator training will be started in preparation for initiation of the Phase 2 trial. The Phase II portion of this proposal will support conduct of the randomized, multi-center Phase 2 trial. It is hoped that this double-blind trial will prove pivotal for this sarcoma population of patients and that it will facilitate subsequent trials with this same vaccine in patients with neuroblastoma and pediatric sarcomas. The translational research objectives proposed here will add depth to our understanding of the role of antibodies in this setting while they validate the use of a PCR based circulating tumor cell (CTC) assay for prognostic and possibly staging purposes, and as a surrogate marker for vaccine efficacy.
Antibodies induced by the proposed trivalent vaccine against sarcoma gangliosides GM2, GD2 and GD3 are ideally suited for eradication of free tumor cells and micrometastases. If antibodies of sufficient titer can be induced against these antigens to eliminate these sarcoma cells from the blood and to eradicate micrometastases, this would dramatically change our approach to treating sarcoma patients. Establishment of new metastases would no longer be possible, so more aggressive local therapies (including surgery or radiation therapy) might result in long term control of metastatic sarcoma. The primary endpoint for this pivotal multicenter randomized trial is improvement in progression-free survival at one year.
|Wu, Xiaohong; Ragupathi, Govind; Panageas, Katherine et al. (2013) Accelerated tumor growth mediated by sublytic levels of antibody-induced complement activation is associated with activation of the PI3K/AKT survival pathway. Clin Cancer Res 19:4728-39|