The Food and Drug Administration (FDA) approved a unique cancer treatment ("vaccine") to help boost the body's immune system to fight prostate cancer that has spread and which is no longer susceptible to hormonal therapy. Dendreon Corporation manufactures the drug, called Provenge. It is the first autologous cellular immunotherapy for the treatment of asymptomatic or minimally symptomatic metastatic castrate resistant (hormone refractory) prostate cancer. Provenge (pronounced PROH-venj) is designed to stimulate a patient’s immune system to target prostate cancer cells. It is called a "vaccine" even though it treats disease rather than prevents it. The approval is a jump-start for an entirely new approach to cancer therapy and will add a new and unique weapon to the arsenal of urologists, urologic oncologists and medical oncologists.
The FDA's approval action was based on a clinical trial studying the effects of Provenge compared with a patient’s non-activated immune cells. In this trial, men in the Provenge group lived an average of 4.1 months longer (more than twice as long as chemotherapy) and had a 22.5% reduction in the risk of death compared with men in the control group. It increased three-year survival by 38%.
Unlike vaccines like those for measles, hepatitis or even newer ones such as for cervical cancer, which prevent a viral infection that causes the cancer, Provenge is not a preventive vaccine. It is a so-called therapeutic vaccine, used after prostate cancer has already been diagnosed. Clearly, many patients will face disappointment, as the company said it could produce only enough vaccine to supply only 2,000 patients in the next year. Dendreon will make the new drug available at first only in 50 centers that participated in the clinical trials. But manufacturing capacity will be expanded greatly in the coming year.
Provenge must be personalized for each patient. Each patient’s own white blood cells are collected through a process often used for blood donations, and then certain immune cells are separated out. The cells are grown via incubation with a protein often found on prostate tumors and then is combined with a booster for the immune system. The extracted, altered cell mixture is then infused back into the patient three times over the course of one month.
Full treatment costs are estimated at $93,000. Company spokespersons defended their pricing stating that it was in line with those of other cancer drugs in terms of cost per extra month of life provided by the drug. Prior to Provenge's approval, the only approved treatment for these men was the chemotherapy drug Taxotere (docetaxel) which in clinical trials extended lives by about two or three months.
One major question after FDA approval of any drug is will it be covered by my insurance? The FDA does not regulate the cost of approved products. Patients and doctors will have to confer with the company regarding information regarding potential coverage. Also, each insurer will have to be consulted prior to treatment to determine coverage or any other cost issues associated with the administration of Provenge. Many men with prostate cancer who have heard about the Dendreon drug, and for one reason or another don’t meet the criteria in the prescribing label and therefore won’t have full insurance coverage, will find the price a major issue. While Provenge is an expensive drug and will add expense for CMS (Center for Medicare and Medicaid Services), the VA (Veterans Administration), and for large insurers, it is not unusually expensive for a cancer drug.
Provenge can cause serious reactions. In controlled clinical trials for the treatment of prostate cancer, serious reactions reported in patients in the Provenge group include reactions resulting from the infusion of the drug, which occurred within 1 day of infusion, and strokes. Severe infusion reactions included chills, fever, fatigue, weakness, breathing problems (shortness of breath, decreased oxygen level, and wheezing), dizziness, headache, high blood pressure, muscle ache, nausea, and vomiting. Patients are urged to immediately contact their physician if they experience breathing problems, chest pains, racing heart or irregular heartbeats, dizziness, nausea, or vomiting after receiving their infusion of Provenge because any of these may be signs of heart or lung problems. The most common side effects are chills, fatigue, fever, back pain, nausea, joint ache, and headache.