Updated on 28 August 2012
Antibody conjugates, historically, consisting of a cytotoxic agent linked covalently to an antibody or antibody fragment directed towards a specific cell surface target expressed by tumor cells which faced several hurdles particularly poor conjugate in-vivo stability that have been identified and overcome in the new developments. A number of targets, drugs, and linkers are being evaluated. The last few years have seen a remarkable momentum in the development of antibody-drug conjugates which are expected to get approval in next few years.
Researchers have explored four main avenues using antibodies to target cytotoxic agents to malignant cells, including antibody-protein toxin (or antibody fragment-protein toxin) recombinant fusion conjugates; antibody-chelated radionuclide conjugates; antibody-small molecule drug conjugates and their nano-particles and nano-vesicles; and antibody-enzyme conjugates administered along with small-molecule prodrugs that require metabolism by the conjugated enzyme to release the activated species.
So far, only antibody-radionuclide conjugates and antibody-drug conjugates have reached the regulatory approval stage, and nearly 20 antibody conjugates are currently in clinical trials. It seems this technology might bring a new hope for the cancer patients.
Do cancer vaccines hold the promise?
Most cancer vaccines usually prime the immune system to attack cancer cells in the body to treat cancer or to prevent it from coming back. Some cancers are caused by viruses, which can be prevented by prophylactic vaccines that help protect against infectious viruses such as some strains of human papilloma virus (HPV), linked to cervical, anal, throat and some other cancers and chronic hepatitis B virus (HBV) probably linked to liver cancer.
The prophylactic vaccines for HPV and HBV are successfully in the clinics for several years. Researchers are trying to explore the other prophylactic vaccines which could modulate the immune system to regret the cancers. So far, the BCG vaccine has been approved for urinary bladder cancer as an adjuvant therapy.