Cancer Vaccinations; The different vaccine types and the treatment results of melanoma and prostate cancer vaccines

Abstract

Objective – The conventional methods of treating cancer are not always effective enough and in both human and veterinary medicine cancer vaccines could be a significant asset. There are many different vaccine types that have been used, but the most progress has been made with two approved therapeutic vaccines; Provenge® in human prostate cancer and Oncept® in canine melanoma. This literature study focuses on the different vaccine types in general and the treatment results of prostate cancer and melanoma in human and canine patients.

Vaccine types – There are four types of therapeutic cancer vaccines; peptides, genetic (DNA and mRNA), cellular (whole cell or dendritic cell) and recombinant vaccines. In general, all vaccines only cause low grade adverse effects such as irritation around the injection site and each type has its own advantages. Recombinant, whole cell and mRNA vaccines provide the best immune response, whereas genetic and peptide vaccines are the easiest and cheapest to produce. Depending on patient and tumor characteristics, one of the groups can be more appropriate. The most progress in malignant melanoma and prostate cancer has been made with genetic and dendritic vaccines.

Prostate cancer – Prostate cancer, an adenocarcinoma is a spontaneous arising tumor that can be castration-resistant (dogs and late stages in humans) or androgen-dependent (humans). Prostate cancer vaccines have been investigated in humans, while in dogs research is in its early stages and still focuses on inducing prostate cancer. The most investigated human vaccines are Prostvac (recombinant), Sipuleucel-T (Provenge®, dendritic cell) and GVAX (whole cell).

Malignant Melanoma – Malignant melanoma is a common and aggressive tumor of mucosal (dogs) or cutaneous surfaces (dogs and humans). It has the same predilection sites and metastatic properties in both species, and the tumors are chemo and radiation resistant. The most progress in canines has been made with a DNA vaccine (Oncept®), but cellular vaccines have also been investigated. In human research, DNA, dendritic cell and whole cell vaccines have been researched, with comparable results as in prostate cancer.

Discussion and conclusion – All the studies are difficult to compare to each other due to different vaccine types, patient groups, selection criteria, protocols and end points. In prostate cancer GVAX and Sipuleucel-T (Provenge®) are the most promising, in canine melanoma a DNA vaccination even though results in human melanoma research are comparable. Developing vaccines requires a specific and patient-centered approach in which vaccine protocols cannot easily be exchanged between species or cancer types and should not be used as a monotherapy. Further research is therefore not only warranted but also necessary.