Penn researchers investigate testosterone replacement therapy

Testosterone, the male sex hormone, could restore vigor and vitality to aging men — or it could do nothing at all.

Scientists at Penn, the National Institute on Aging and Solvay Pharmaceuticals will run a year-long study to test the benefits of testosterone hormone replacement therapy for men with low testosterone caused by aging, according to Peter Snyder, professor at Penn’s School of Medicine and the study’s lead investigator.

Twelve test centers nationwide are currently recruiting 800 men over the age of 65 with low testosterone levels not caused by any known disorder, Snyder said. The men will be given either testosterone or a placebo, then checked over the course of a year for improvements in physical, cognitive and sexual function, vitality, anemia, cardiovascular disease and blood glucose levels.

Low testosterone levels caused by disorders of the pituitary gland or testes have been known to cause a loss of vigor, decreased sexual and cognitive function, anemia, high blood sugar and osteoporosis. Testosterone replacement therapy was approved by the Food and Drug Administration over 10 years ago as a treatment for men with disordered testosterone levels.

However, some doctors have been prescribing testosterone replacement against FDA recommendations for men with naturally lower testosterone levels caused by aging.

“This is an area where there are doctors whose entire practices are based on giving hormones to elderly men in the absence of clear evidence of efficacy,” Snyder said. “The doctors who practice [anti-aging] medicine are giving it not for the original reason that the drug was approved.”

Some in the medical community have compared with alarm the use of testosterone replacement therapy in elderly men to the once-widespread practice of hormone replacement therapy in menopausal women.

HRT fell out of favor after a 2002 Women’s Health Initiative study found that estrogen and progestin HRT was linked to higher rates of breast cancer and cardiovascular disease.

This study was proposed after an earlier, 6,000-man, six-year study was blocked by the NIA. The larger study was intended to test whether testosterone replacement therapy in men who didn’t have testosterone-lowering disorder placed them at greater risk for certain diseases, particularly prostate cancer, Snyder said.

However, an Institute of Medicine blue-ribbon panel concluded that there was not enough evidence that testosterone was beneficial in that population to justify a large-scale test of the side effects. The panel pointed out that from 1977 to 2003, there had been only 31 placebo-controlled testosterone replacement studies, most with fewer than 100 participants.

Neither Penn nor the NIA stands to benefit financially from the study. However, Savoy Pharmaceuticals could earn profits as the manufacturer of AndroGel, a topical gel treatment for low testosterone.

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