BioVaxys MRI Study Validates Immune Response Mechanism of MVP-S Combination Therapy in Ovarian Cancer
Key Insights
A new MRI study published in Nature/NPJ Imaging demonstrates how BioVaxys' MVP-S vaccine combined with checkpoint inhibitors and cyclophosphamide significantly reduces tumor volume in ovarian cancer (search) models.
The preclinical research led by Dalhousie University researchers used magnetic resonance imaging to track immune cell infiltration, showing increased myeloid and CD8+ T cells in tumors treated with the combination therapy.
The findings validate the immune response mechanism of MVP-S, which targets survivin (search)-expressing tumor cells and is currently in phase II development for platinum-resistant ovarian cancer (search).
BioVaxys Technology Corp (search). announced the publication of a preclinical study that validates the immune response mechanism of its maveropepimut-S (MVP-S) immunotherapeutic vaccine when combined with checkpoint inhibitors and low-dose cyclophosphamide in ovarian cancer (search). The research, published in the April 2026 edition of Nature/NPJ Imaging, provides new insights into how this combination therapy exerts its antitumor effects through advanced magnetic resonance imaging techniques.
Novel MRI Approach Reveals Treatment Mechanism
Led by Dr. Kimberly Brewer of the IWK Health Center (search) and Associate Professor at Dalhousie University's Faculty of Medicine, the study titled "MRI of Combination Immunotherapy in an Epithelial Ovarian Cancer (search) Preclinical Model" utilized magnetic resonance imaging to track tumor growth and immune cell infiltration in a murine ovarian cancer (search) model. Co-authored with BioVaxys Scientific Advisor Dr. Marianne Stanford of Dalhousie University, the research employed a clinically relevant treatment combination of MVP-S, anti-PD-1, and low-dose cyclophosphamide.
The study design involved implanting mice with mouse ovarian surface epithelial (MOSE) cancer cells. Researchers isolated myeloid and CD8+ cells from matched donor mice, labeled them with superparamagnetic iron oxide (SPIO), and tracked their movement using MRI scanning. This innovative approach allowed real-time visualization of immune cell behavior within the tumor microenvironment.
Significant Tumor Reduction and Immune Cell Infiltration
The combination therapy demonstrated substantial efficacy in the preclinical model. Tumor volumes in the treatment group, as measured by MRI, were significantly lower than in the control group. Additionally, the density of SPIO-labeled myeloid and CD8+ T cells in tumors was higher in the treatment group compared to controls, indicating enhanced immune cell infiltration and activation.
The study provides new insight into how MRI can be used in concert with biological assays to study how immunotherapy and chemotherapy combinations exert their antitumor effects, offering a valuable tool for future research and clinical monitoring.
MVP-S Targets Survivin in Multiple Cancer Types
Maveropepimut-S represents BioVaxys' investigational immunotherapeutic vaccine that utilizes the company's lipid-based DPX™ delivery platform to stimulate T cell immune responses to survivin (search) epitopes restricted by five HLA class I haplotypes. Survivin, a tumor-associated antigen, is highly expressed in ovarian and other cancers but nearly undetectable in normal tissues, making it a promising target for cancer immunotherapy.
The DPX platform presents antigens to the immune system using a novel non-systemic mechanism that forces active uptake of immune cells and delivery into lymphatic nodes. This "no release" mechanism allows for sustained activation of the immune system, with T cell flow maintained over a longer duration than traditional vaccines.
MVP-S is currently in clinical development for multiple cancer indications, including ovarian, bladder, and breast cancer (search), as well as relapsed/refractory diffuse large B-cell lymphoma (search). The vaccine is in phase II clinical development for advanced relapsed-refractory diffuse large B-cell lymphoma and platinum-resistant ovarian cancer (search).
Clinical Translation Through PESCO Trial
The preclinical findings support the ongoing PESCO trial, an investigator-initiated, open-label, non-randomized phase 1B/2 trial evaluating the safety and efficacy of MVP-S combined with pembrolizumab (Keytruda™) and cyclophosphamide in patients with recurrent epithelial ovarian cancer (search). Results from this clinical study are scheduled for presentation at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting in early June.
Addressing Critical Unmet Need in Ovarian Cancer
Epithelial ovarian cancer (search) represents one of the most challenging malignancies, characterized by a pattern of relapse and progression through successive recurrences. The disease has overall poor survival rates due to late detection, high heterogeneity, and development of resistance to standard treatments. Epithelial ovarian cancer accounts for 90% of all ovarian cancer (search) cases, with high-grade serous ovarian cancer being the most aggressive and recurrent subtype.
Current treatment typically involves tumor-reducing surgery and cytotoxic chemotherapy; however, many patients cannot tolerate the side effects or experience recurrence due to significant drug resistance. Recent studies have shown that checkpoint inhibitor monotherapy has demonstrated limited efficacy in treating ovarian cancer (search), highlighting the need for combination approaches.
The global epithelial ovarian cancer (search) market is projected to reach over $7.0 billion by 2033, reflecting robust growth fueled by innovation and expanding treatment options. The combination of checkpoint inhibitors with immunotherapeutic cancer vaccines demonstrates potential to expand antigen-specific T-cells and inhibit regulatory T-cells, thereby enhancing the overall tumor immune response.