Prostate cancer

Treatment.

Anti-tumor immunotherapy is based on applying the anti-tumor xenogenic polyantigenic vaccine (ÕPV) that has been developed in the Institute of Clinical Immunology (a patent of RF ¹ 2192884). The structural distinctions of the xenogenic tumor-associated antigens from the human homological analogs render these antigens highly immunogenic for human. As a consequence, XPV is highly efficient in inducing anti-tumor reactions in cancer patients (a patent of RF ¹. RF ¹ 2192883).

The inducing course of vaccinotherapy consists of 10 subcutaneous immunizations (five at weekly and five at fortnight intervals) and takes about 3 months. The further vaccination schedule is determined depend upon both a disease stage and a health state of a patient.

The treatment is conducted on an outpatient basis.

Infectious safety.

XPV is prepared from murine tumor cells not containing infectious agents which could potentially be pathogenic for humans.

Side effects.

The development of an influenza-like syndrome in the form of a body temperature rise up to 380 C and musculoskeletal discomfort is possible. Those symptoms are usually self- limited. The immunotherapy has no severe side effects attributable to conventional chemoradiotherapy.

Clinical effect.

The vaccine-induced, immune processes destroy the tumor cells and suppress the development of residual disease.

Xenovaccinotherapy of prostate cancer

The systemic treatment of patients with metastatic proatate cancer is mainly based on hormonotherapy that is directed to inhibiting testosterone production and action in the body. However, irrespective of used treatment regime, all patients ultimately become unresponsivive to hormonotherapy. This typically occurs at 12-to-18 months after therapy initiation. The median survival in the patients with hormone-independent prostate cancer is within the limits of 6–to-8 months. The standard treatment of such patients is usually palliative and directed to support the quality of their life. Consequently, a lot of attention is now focused on a relatively new approach to treatment of prostate cancer called immunotherapy. The goal of immunotherapy is to boost the body's immune system to more effectively fight off or destroy cancer cells.

Therapeutic vaccination is a strategy that uses tumor-associated antigens (TAAs) to induce an tumor-specific immune process. The xenogenic (murine) polyantigenic vaccine (XPV) -in which there are main families of common tumor associated antigens (TAA)- has been developed in the Institute of Clinical immunology (a patent RF ¹ 2192884). Xenovaccinotherapy has significant advantages over the vaccinal approaches based on applying homologous (autological or allogeneic) tumor cells or their antigenic derivates. First, immediately after being entered the human body, xenogenic cell membranes are opsonized with natural antibodies and further –via the FcR-mediated mechanism- phagocytized by professional antigen-presenting cells (macrophage, dendritic cell) which are capable of effectively generating the development of antitumor T-cell responses ( a patent RF ¹219283). Second, the small structural distinctions of xenogenic TAA from their human analogues render these TAA highly immunogenic and capable of inducing immune-mediated, antitumor responses in a patient not only at early, but also at late stages of a disease, when tumor-derived immunosuppression is significant.

The specific immunotherapy is able to generate a selective and long-term antitumor effect. Such therapy incorporates the possibility of a complete recovery from residual disease and has no complications attributable to chemotherapy.

Our own experience suggests that a clinical effect of various grades (complete or partial response, disease stabilization) with a duration not shorter than 6 months may be achieved in nearly 75 % patients with stage IV prostate cancer. These results are undoubtedly very encouraging. They must be considered as preliminary because they are based on a very small number of patients with very advanced disease.

For more information see the publications.

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