As part of the ongoing Year of Endocrinology, the Endocrine Society has reached out to experts in various specialties to get their comments on the science and practice of endocrinology, as well as where the future of the field is heading.
For Men’s Health Month, we reached out to Glenn Cunningham, MD, professor of medicine-endocrinology at Baylor College of Medicine in Houston, Texas. He graciously agreed to share his thoughts:
What are the most important recent developments in men’s health research or clinical care?
Two large clinical trials evaluating the efficacy of testosterone replacement in men with symptoms have been published this year. Brock and colleagues treated 715 males 18 years old or older (mean age = 55.3 years) with total testosterone levels <300 ng/dL and decreased sexual function and/or decreased energy with a 2% testosterone or placebo solution for 12 weeks. Testosterone treatment improved sexual desire, erectile function and sexual activity (p<0.001).
Snyder and colleagues assigned 790 men 65 years of age or older (mean age = 72.2 years) with a serum testosterone concentration <275 ng/dL and symptoms of decreased sexual function, decreased energy and/or mobility impairment to receive either 1% testosterone gel or placebo gel for 1 year. Sexual desire, erectile function and sexual activity were moderately improved (p<0.001), and participants experienced some improvement in mood and depressive symptoms but no benefit with respect to vitality or walking distance.
We remain concerned that testosterone replacement therapy could increase cardiovascular or prostate cancer risk. Basaria and colleagues evaluated the effects of testosterone on surrogate cardiovascular endpoints in a placebo-controlled, double-blind, parallel-group randomized trial involving 308 men 60 years or older with low or low-normal testosterone levels (100-400 ng/dL; free testosterone <50 pg/mL). They treated the men with 7.5 g of a 1% testosterone gel or placebo gel for 3 years. No significant difference in the rates of change in either common carotid artery intima-media thickness or coronary artery calcium were observed.
What should we expect to discover in the immediate future in the field?
The T Trials also evaluated the effects of testosterone treatment on known and unexplained causes of anemia in the elderly, bone density, and bone strength and cognition. The results of these trials will be published in 2016 or 2017.
A better understanding of the risks of testosterone treatment in middle-aged and older men will be provided by recently completed and future trials. We should learn the results of the Cardiovascular Trial that was conducted in a subset of participants in the T Trials. This study evaluated the effects of testosterone and placebo treatment for one year on non-calcified and calcified plaques in the coronary arteries.
The Registry of Hypogonadism in Men (RHYME) is a multi-national patient registry assessing prostate health and other outcomes associated with testosterone treatment in men. About 750 men were treated with testosterone, and 250 men with low testosterone levels were untreated. We can anticipate publication of two-year data reporting cardiovascular events and newly diagnosed clinical prostate cancer.
The FDA is requiring pharmaceutical companies that sell non-generic testosterone delivery systems to conduct a clinical trial addressing the potential cardiovascular risk of testosterone treatment. It is anticipated that the protocol for this trial will be finalized and approved by the FDA this summer. This trial will need to enroll about 5,000 men with low testosterone levels and a history of cardiovascular disease or at least increased cardiovascular risk. It is estimated that the trial will take five to six years to enroll and complete.