Long-term use of AndroGel (testosterone gel) 1 per cent CIII is safe and effective for men with hypogonadism, a condition sometimes referred to as low testosterone, according to a new study published in the May issue of the Journal of Clinical Endocrinology & Metabolism. The study, the first to examine safety and efficacy of testosterone gel up to 42 months, was conducted at multiple research centres in the U.S. under the direction of investigators at the Research and Education Institute (REI) at Harbor-UCLA Medical Center. Dr. Christina Wang was the lead author.
With continuous AndroGel treatment, men in the study experienced rapid and sustained improvements in sexual function and mood. Decreases in fat mass and increases in lean body mass were persistent with treatment. Additionally, gradual and progressive increases in bone mineral density were seen in the spine and hip.
"This AndroGel study is the first to demonstrate long-term benefits and safety with testosterone gel -- that's great news for men suffering from low testosterone," said Ronald Swerdloff, MD, REI Investigator in the Division of Endocrinology, Metabolism & Nutrition, Harbor-UCLA General Clinical Research Center. "The results show 3+ years of continued benefits and provide new information on the degree of safety for men treated with testosterone. Nevertheless, doctors must monitor their patients throughout therapy."
It is estimated that four to five million American men have low testosterone. It also is estimated that low testosterone affects about one in 10 men between the ages of 40 and 60 and more than two in 10 men over the age of 60. Studies show that men lose testosterone at a rate of approximately 10 per cent each decade after age 30. Symptoms of low testosterone include diminished interest in sex, erectile dysfunction (ED), reduced lean body mass, decreased bone mineral density, depressed mood and fatigue.
Researchers studied 163 hypogonadal men (mean age = 51) who elected to receive continuous replacement with testosterone gel for up to 42 months: 70 per cent of the patients received testosterone gel for at least 30 months. Patients were treated with one per cent testosterone gel (AndroGel) at 5, 7.5 or 10 g per day. Dosage could be adjusted by the investigator at each study center depending on the patient's clinical symptoms and serum testosterone levels.
All patients had previously participated in a six-month study comparing the efficacy of AndroGel with a testosterone patch. The six-month study was then extended to allow for 42 months of treatment. Safety data was compiled for all the participants; data analyses for efficacy included 123 subjects. AndroGel is manufactured by Unimed Pharmaceuticals, Inc., a Solvay Pharmaceuticals, Inc. Company.
The study results showed significant improvements in mood and sexual performance, motivation and activity soon after initiating testosterone replacement. These improvements were maintained throughout treatment. Lean body mass increased (average of about 3 kg or 6.6 pounds) as early as three months after beginning treatment and was sustained with continuous treatment.
Additionally, an increase in muscle strength associated with the increase in lean mass was reported. Bone mineral density (BMD) increased by 0.76, 1.47 and 1.60 per cent at the hip and 0.99, 3.10 and 3.80 per cent at the spine after 6, 18 and 30 months of treatment. Hematocrit and hemoglobin levels increased as anticipated with androgen replacement, but the increase reached the maximum level at six to 12 months with no further increases with continued testosterone gel treatment. Prostate disorders were seen in six patients.
Skin irritability was reported as minimal and caused discontinuation in only one patient. Investigators recommend monitoring serum PSA levels and conducting a digital rectal examination in patients prior to initiating therapy and periodically throughout treatment.