Brand Name: Viadur
Active Ingredient: leuprolide acetate implant
Indication: Palliative treatment of advanced prostate cancer
Company Name: ALZA Corporation
Availability: Approved by FDA on March 3, 2000
Viadur: Introduction
This year, more than 180,000 new cases of prostate cancer will be diagnosed in the US. In patients with advanced prostate cancer, decreasing the production of the hormone testosterone often reduces prostate cancer growth and relieves symptoms, such as pain and problems urinating. The main method of achieving such hormone suppression has been through frequent injections of a drug called leuprolide.
Now men with prostate cancer who need this form of therapy have a new choice: Viadur (leuprolide acetate), an implant manufactured by ALZA Corporation and approved by the FDA in March. Viadur is implanted in the patient’s inner upper arm once a year in his doctor’s office, and provides continuous 12-month testosterone suppression. After the first year of therapy, the implant is removed and a new one inserted.
Viadur: How Does It Work?
The leuprolide in Viadur works by reducing the amount of testosterone produced by a man’s testicles. Since testosterone is needed for prostate cancer cells to grow, depriving the tumor of this vital hormone usually causes the prostate cancer to shrink or stop growing. Viadur is not a cure for prostate cancer, but is a palliative treatment that may help relieve pain, urinary problems, and other symptoms of the disease. The leuprolide in Viadur is encased in a miniature titanium cylinder that steadily releases the needed amount of leuprolide. Titanium is a metal that is well tolerated by the body and is therefore commonly used in implanted medical devices.
Viadur: Clinical Study Results
Two studies evaluated the effectiveness of Viadur in 131 men with advanced prostate cancer. The amount of testosterone in their blood rose within the first few days of implanting Viadur, but then fell to levels lower than those at the beginning of the study. By the fourth week of the trial, 99% of the men experienced a significant reduction in their testosterone levels, and this suppression remained throughout the treatment period. Moreover, testosterone levels stayed at these low levels after the implant was removed after one year and the second implant was put in place. Blood levels of prostate-specific antigen (PSA), a measure of prostate cancer growth, also fell in men treated with Viadur.
Viadur: What You Should Know
The most common side effects associated with Viadur were those expected with other drugs in its class, including hot flashes, lack of energy, depression, sweating, headache, bruising at the implant site, and breast enlargement. Most implantation site reactions began and resolved in the first two weeks. Patients should avoid heavy lifting and physical activity for 48 hours after the implantation. Patients may experience a worsening of symptoms, such as pain and urinary problems, when testosterone levels increase at the beginning of treatment.
“Leuprolide is well established as a palliative treatment for advanced prostate cancer, and the once-yearly dosing regimen provided by Viadur may present a convenient alternative for patients,” said Dr. James Gottesman, Clinical Professor of Urology at the University of Washington Medical School in Seattle.
Jennifer is a clinical pharmacologist. She helps doctors of all medical specialties choose medications. Jennifer consults about drug dosage, interactions, and side effects.