DPX-Survivac triggers a 43% reduction in a patient’s tumor and induces survivin-specific polyfunctional T cell responses; target immune and clinical responses achieved and maintained with modified treatment schedule
June 2, 2014
Immunovaccine Inc., a clinical stage vaccine company, presented positive results from a Phase I/Ib clinical study of the Company’s lead cancer vaccine candidate, DPX-Survivac, this weekend at the American Society of Clinical Oncology (ASCO) 2014 Annual Meeting. In a poster presentation at the conference, Immunovaccine highlighted promising early evidence of clinical activity for DPX-Survivac in ovarian cancer patients. One patient, who experienced a 43% reduction in tumor size, was classified as a partial response (PR) as measured by Response Evaluation Criteria In Solid Tumors (RECIST 1.1). The PR, which persisted following discontinuation of treatment, was accompanied by reduction in levels of a commonly used ovarian cancer biomarker (CA125) and a significant increase in vaccine-induced immune responses. The patient’s tumor and CA125 levels remain stable eight months following initiation of the DPX-Survivac therapy demonstrating a potentially durable effect of the therapy.
Additionally, patients across all vaccine doses exhibited evidence of desired polyfunctional T cell responses against survivin, a protein that is over-expressed in ovarian cancer and several other tumor types. Statistically significant increases in immune response were achieved with higher doses of DPX-Survivac (p=0.013) and when DPX-Survivac was combined with low dose oral cyclophosphamide (CPA) (p=0.015). A modified vaccination schedule, reducing the dose for the first two vaccinations then boosting with a lower dose every eight weeks, resulted in a lower frequency of local injection related adverse events. Importantly, robust immune responses were produced with the modified immunization schedule, demonstrating the potency and flexibility of DPX-Survivac. Finally, DPX-Survivac was well tolerated with no significant vaccine related systemic adverse events reported.
“With these latest results, we can for the first time point to the fact that the pronounced and persistent survivin-specific T cell immune responses we achieve with DPX-Survivac treatment may translate to a measurable clinical benefit,” stated Dr. Marc Mansour, chief operating officer of Immunovaccine. “This connection between immune response and clinical activity is exciting, particularly since we have demonstrated the ability to generate what we believe are some of the strongest antigen-specific polyfunctional T cell responses reported in a clinical trial.”
The multicenter Phase I/Ib study enrolled 30 stage IIc-IV first-line or recurrent ovarian cancer patients with no evidence of disease progression following chemotherapy. The patients were enrolled across five treatment cohorts to receive various doses of DPX-Survivac (0.1, 0.25 and 0.5 mL) alone or in combination with CPA. A modified vaccination schedule was used in two of the cohorts to evaluate the safety and immune response impact of varying the timing of treatment.
“With our ongoing clinical development efforts, we continue to grow our understanding of the potential role that DPX-Survivac may play in this new cancer immunotherapy environment. In addition to correlating immune response to clinical benefit, this study has offered insight into modulating immune response levels and mitigating adverse events, all through adjusting the vaccine dose and schedule,” said Dr. Mansour. “We are establishing the optimal dosing regimen for future trials including our planned randomized Phase II trial in ovarian cancer.”
In April, Immunovaccine presented positive data from clinical and preclinical vaccine studies, including DPX-Survivac, at the American Association for Cancer Research (AACR) 2014 Annual Meeting. Results demonstrated that metronomic cyclophosphamide (mCPA), an immune modulating agent, enhanced the immunogenicity of DepoVax™-based vaccines in preclinical cancer models consistent with previously reported Phase I data showing a similar enhancement of DPX-Survivac in patients. Importantly, the animal studies demonstrated the combination therapy’s ability to eliminate advanced tumors that could not be treated with vaccine or mCPA alone. The addition of anti-PD-1 checkpoint inhibitor to the DepoVax vaccine/mCPA combination resulted in further enhanced anti-tumor activity, which allowed the treatment of more advanced tumors. The effective tumor regressions that were observed could not be achieved without the use of vaccine or the use of anti-PD-1.
Immunovaccine expects a large randomized Phase II trial of DPX-Survivac to be initiated in 2014 in ovarian cancer. The 250 patient trial will be sponsored and conducted by Canada’s NCIC Clinical Trials Group (NCIC CTG). Additionally, researchers at the University of Rome are planning to initiate a Phase l/II trial of DPX-Survivac in glioblastoma (brain cancer).
DepoVax™ is a patented formulation that provides controlled and prolonged exposure of antigens plus adjuvant to the immune system, resulting in a strong, specific and sustained immune response with the capability for single-dose effectiveness. The DepoVax platform possesses impressive flexibility, allowing it to work with a broad range of target antigens in various therapeutic applications. The technology is also commercially scalable, with potential for years of stability and ease of use in the clinic.
DPX-Survivac consists of survivin-based peptide antigens formulated in the DepoVax™ adjuvanting platform. Survivin has been recognized by the National Cancer Institute (NCI) as a promising tumor-associated antigen (TAA) because of its therapeutic potential and its cancer specificity. Survivin is broadly over-expressed in solid tumors and blood cancers including ovarian, breast, colon and lung cancers, among others. Survivin plays an essential role in antagonizing apoptosis, supporting tumor-associated angiogenesis, and promoting resistance to various anti-cancer therapies. Survivin is also a prognostic factor for many cancers and it is found in high percentage of cancer patients.
The DPX-Survivac vaccine is thought to work by eliciting a cytotoxic T cell immune response against cells presenting survivin peptides on HLA class I molecules. This targeted therapy attempts to use the immune system to actively search for tumor cells expressing survivin and destroy them.
Immunovaccine Inc. develops cancer immunotherapies and infectious disease vaccines based on the Company’s DepoVax™ platform, a patented formulation that provides controlled and prolonged exposure of antigens and adjuvants to the immune system. Immunovaccine has advanced two T cell activation therapies for cancer through Phase I human clinical trials. Lead cancer vaccine therapy, DPX-Survivac, is expected to enter Phase II clinical studies in 2014, in ovarian cancer and glioblastoma (brain cancer). The Company is also advancing an infectious disease pipeline including innovative vaccines for respiratory syncytial virus (RSV) and anthrax.
Connect at www.imvaccine.com