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 show 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. "This study shows 3+ years of continued benefits and provides 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 percent 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 received continuous replacement with testosterone gel for up to 42 months: 70 percent of the patients received testosterone gel for at least 30 months. Patients were treated with one percent 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 percent at the hip and 0.99, 3.10 and 3.80 percent 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 disease was 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.
In April, Dr. Swerdloff received the Distinguished Andrologist Award from the American Society of Andrologists (ASA) for his outstanding contributions to the progress of andrology.
The Research & Education Institute at Harbor-UCLA Medical Center is one of the largest independent, not-for-profit biomedical research institutes in Los Angeles County. Affiliated with both the David Geffen School of Medicine at UCLA and the Harbor-UCLA Medical Center, the Institute has an annual budget of over $65 million and currently supports more than 1,000 research studies in areas such as cardiology, emerging infections, cancer, women's health, reproductive health, vaccine research, respiratory physiology, neonatology, molecular biology, and genetics. REI also plays a pivotal role in the training of young physician - scientists and scientists-to-be and is active in promoting the health and well being of nearby communities through community service programs that meet a variety of social and medical needs.