Bavarian Nordic’s cancer immunotherapy candidates, PROSTVAC and CV-301 both employ the VF-TRICOM technology, which includes a vaccinia-based priming dose (V) followed by multiple fowlpox-based boosting doses (F), and incorporates 3 human immune costimulatory molecules (TRICOM: TRIad of COstimulatory Molecules) engineered to enhance immune system response to the tumor target. Both the priming and boosting doses encode one or more tumor-associated antigens, intended to activate the body’s immune system against these antigens.

The data from clinical studies conducted to date suggest that this heterologous prime/boost regimen leads to an anticancer immune response of greater magnitude and quality than regimens using only a homologous repeating treatment approach.

How it works

Active Immunotherapy
  Poxvirus-based “prime/boost” platform robustly stimulates the innate and adaptive immune systems   Tumor-associated antigens (TAAs) are expressed on antigen-presenting cells (APCs) and stimulate a specific, progressively expanding immune response   TRICOM (TRIad of COstimulatory Molecules) includes the genes for 3 natural human costimulatory molecules intended to facilitate T cell/APC interaction and strengthen the anticancer immune response


  • Targeted tumor-associated antigens
    Both the prime and boost doses express a well-established tumor antigen, enabling them to provoke specific immune responses to principally target only those cells with that target protein, known also as the tumor-associated antigen (TAA). Bavarian Nordic’s poxvirus-based immunotherapy is designed to alert the immune system to the danger posed by cancer cells with that TAA

  • TRICOM (TRIad of COstimulatory Molecules)
    Each recombinant immunotherapy candidate contains genes for the 3 natural human immune-enhancing costimulatory molecules, LFA-3, ICAM-1, and B7.1, collectively designated TRICOM. Recombinant immunotherapies co-expressing these 3 costimulatory molecules have been shown to have synergistic effects on anticancer responses in mice compared with immunotherapies expressing costimulatory molecules individually

Prime/boost vaccination strategy

Data from preclinical and clinical studies suggest that the immune response can be optimized by using a poxvirus-based “prime/boost” immunotherapeutic regimen. As a result, our poxvirus-based active immunotherapy regimens include a vaccinia-based priming dose followed by multiple fowlpox-based boosting doses. This strategy has shown an enhanced immune response compared with either agent alone.

Prime Boost Regimen

Gulley JL, Madan RA, Tsang KT, et al. Immune impact induced by PROSTVAC (PSA-TRICOM), a therapeutic vaccine for prostate cancer. Cancer Immunol Res. 2014;2:133-141.

Mandl SJ, Rountree RB, Dalpozzo K, et al. Immunotherapy with MVA-BN®-HER2 induces HER-2-specific Th1 immunity and alters the intratumoral balance of effector and regulatory T cells. Cancer Immunol Immunother. 2012;61:19-29.