The US Food and Drug Administration (FDA) has approved Provenge (sipuleucel-T), a breakthrough development in the treatment of prostate cancer.
Provenge, developed by biotechnology company and cancer specialists, Dendreon, has been described as the first cancer 'vaccine' even though it treats the disease rather than prevents it.
"The FDA approval of Provenge is a testament to the courage of the patients and researchers who participated in our studies and is the culmination of nearly 15 years of research and development by our dedicated employees," said Dr Mitchell H Gold, president and CEO of Dendreon.
The therapy has been approved for advanced cases of prostate cancer where the disease has spread to other parts of the body and is resistant to standard hormone treatment.
It works by using the patient's own immune system to fight the cancer, inducing a response against prostatic acid phosphatase (PAP), an antigen expressed in most prostate cancers, and is the first in a new therapeutic class known as autologous cellular immunotherapies.
Dr Philip Kantoff, professor of medicine at Harvard Medical School and chief clinical research officer at Dana-Farber Cancer Institute, saw the approval as "a significant scientific and clinical advancement for the treatment of prostate cancer".
He added: "Cancer immunotherapies that use the patient's own immune system will likely create an entirely new treatment paradigm for patients with cancer."
Dendreon has said it intends to make Provenge available through around 50 centres in the US, all of which were approved clinical trial sites for the therapy. Capacity is also expected to increase next year as a result of the anticipated licensure of expanded New Jersey, Atlanta, Georgia and California facilities in 2011.
Full treatment with Provenge will cost $93,000 according to Dendreon. The high cost is due to the individually tailored nature of the therapy, with each dose manufactured by obtaining a patient's immune cells from their blood. These cells are then exposed to a protein found in most prostate cancers in order to enhance the cell's response to the disease. After this process, the cells are returned to the patient to treat the cancer.
There are three doses of the treatment, administered intravenously at two-week intervals.
The treatment was approved after a randomised, double-blind, placebo-controlled, multi-centre trial study involving 512 patients with metastatic hormone treatment refractory prostate cancer.
The median rate of survival for patients who received Provenge treatments was 25.8 months, whereas the survival rate for patients who did not receive the treatment was 21.7 months. This demonstrated a median improvement of 4.1 months survival after taking Provenge, with risk of death reduced by 22.5 per cent.
Adverse reactions were reported in almost all patients who received the therapy, though the majority of these were mild or moderate in severity, including chills, fatigue and headache. Chemotherapy, currently used in the treatment of prostate cancer, is seen as having more extreme common side-effects, including hair loss, anaemia and diarrhoea.
Serious adverse reactions were reported in around one quarter of Provenge patients, including some acute infusion reactions and stroke. Cerebrovascular events, including haemorrhagic and ischemic strokes, were also observed in 3.5 per cent of patients in the Provenge group compared with 2.6 per cent of patients in the control group.
Dendreon will conduct a registry of around 1,500 patients for continued evaluation of potential safety signals of cerebrovascular events.
News of the therapy's approval comes as the FDA has announced a safety review of certain hormone suppressing therapies used in the treatment of prostate cancer.
Gonadotropin-Releasing Hormones (GnRH) agonists have been linked to an increase in the risk of diabetes, heart attack, stroke and sudden death in men.