A Viral Nanoparticle Cancer Vaccine Delays Tumor Progression and Prolongs Survival in a HER2+ Tumor Mouse Model

Human epidermal growth factor receptor 2 (HER2) overexpression is associated with aggressive tumors with increased incidence of metastasis and recurrence. Therapeutic antibodies such as Trastuzumab inhibit tumor growth through blockade of HER2 receptors. However, the short lifespan of such therapeutic antibodies necessitates repeat administrations with ensuing cardiac toxicity and development of resistance, while offering no protection against relapse. Cancer vaccines targeting HER2 can overcome these shortcomings of passive immunotherapy by instigating an endogenous and sustained immune response and memory against the cancer antigen. The efficacy of a viral nanoparticle (VNP)‐based cancer vaccine is demonstrated here in activating a potent anti‐HER2 immune response that delays progression of primary tumors as well as metastases and prolongs survival in mice. The results illustrate that the VNP‐based vaccine instigates HER2‐specific antibodies as well as effector and memory T cells, which contributes to the effectiveness of the vaccine. Given the highly aggressive course of HER2+ cancers, inhibition of disease progression by such cancer vaccines could provide a critical window for interventions with other adjuvant therapies. Moreover, the immune memory generated by this viral nanoparticle‐based cancer vaccine could mitigate relapse of the disease. Cowpea mosaic virus (CPMV) viral nanoparticle‐based human epidermal growth factor receptor 2 (HER2) vaccine stimulates a potent and sustained anti‐HER2 immune response in immunized mice. This active immunotherapy mediated by anti‐HER2 antibodies effectively delays growth of HER2+ tumors and improves survival.