As most cancer drugs are cytotoxic, they not only act on cancer cells but also on normal cells. In other words they are not selective. Vaccines which are threpeutic and act only on cancer cells are the way out. These have reached the phase III of Clinical trials. These are designed by several ways — from dendritic cells, irradiated tumour cells mixed with BCG, tumour-derived heat shock protein peptide complex.

Denaritic cell-based caccines stimulate dendritic cells ( DC ) of the patient ex vivo ( through exposure to tumour cell lysate ) to fuse with tumour cells ( virus-infected ). These are given back to patients to initiate antigens to the T cells in the effector arm of the immune system.

Irradiated tumour cells of the patient has no harmful factor in the cells. These are mixed with BCG vaccine.

Heat shock protein peptide complex are found in all cells. They act as chaperones. They carry while transporting a large reportoire of proteins and peptides. HSPs are complexed with antigenic peptides to generate immune response. These are highly useful in fibrosarcoma, leukaemia, melanoma, and lung, colon, breast and prostate cancer.

Products under clinical trials

• OncoVAX has derived cells from the excised tumour which are mixed with BCG to boost patient’s immune res response.
• Oncophase ( Vitespen ) uses HSPs and peptides derived from patient’s tumour cells.This comprises a sort of antigenic fingerprint — unique to each patient’s cancer.
• Provenge ( Sipuleucel-T ) is autologous ( patient derived DC that have been cultured with a delivery cassette that contains a version of prostate-cancer associated version of Prostatic Acid Phosphatase (PAP ) and the cytokine granulocyte-macrophase colony-stimulating factor ( GM-CSF ). It is designed to activate specialised immune cells called T cells to recognise and destroy cells bearing PAP antigen. Here patient’s own tumour is not used to initiate antigenic response but a generic antigen is used common in prostate carcinoma.

Favid uses patient-specific idio-type protein isolated from tumour biopsy. It is conjugated with keyhole limpet hemocyanin ( KLH ). This is useful in non-Hodgkin’s lymphoma.

MyVax is patient-specfic idiotype conjugated to KLH.

Stimuvax is non-patient specific vaccine. It has a synthetic peptide derived from tumour associated antigen MUC 1.

GSK 1572932A is non-patient specific consisting of a purified recombinant MAGE- A3 protein.

Vaccines are used as adjuvants or in earlier-stage disease. They are yet to be tested on larger populations.