Study shows hormone combination improved strength and function in FSHD patients

New research has demonstrated that a combined regimen of growth hormone and testosterone is safe, well-tolerated, and is associated with meaningful improvements in muscle mass, strength, and mobility for men living with facioscapulohumeral muscular dystrophy (FSHD). Researchers believe that this regime could benefit patients with other forms of muscular dystrophy.

“We’ve never seen a therapy in FSHD deliver both real gains in strength and lasting benefit after treatment stops,” said Chad Heatwole, MD, director of the University of Rochester Center for Health + Technology, and principal investigator and lead author of the study in Neurology Genetics. “This hormone combination could mark the first treatment to not only slow this disease, but help patients regain function.”

FSHD is a genetic muscle disorder that usually begins in adulthood. It causes gradual weakness of the face, shoulders, upper arms, and hips. Over time, many patients struggle to walk independently and perform everyday tasks, and there are currently no treatments that can slow or reverse these losses.

Duo of rhGH and Testosterone Boosts Muscle and Mobility

Heatwole and his team enrolled 20 adult men with FSHD who were still able to walk on their own. For six months, participants gave themselves a daily injection of recombinant human growth hormone (rhGH), which helps cells grow and regenerate, and received a testosterone shot every two weeks to support muscle building.

During treatment, the researchers monitored safety through blood tests and tracked changes in body composition, walking ability, and overall strength. After the six-month treatment period, everyone stopped the hormones for three months so the team could see how long any improvements would last.

Nearly every participant (19 out of 20) completed the program without serious side effects—most only reported mild soreness at the injection site. By the end of six months, the men had gained an average of about 4.5 lbs. of lean muscle and lost around 3 lbs. of fat.

In a simple walking test—where patients walk as far as they safely can in six minutes—participants improved by roughly 37 meters (120 feet), enough to make everyday outings, like walking to the mailbox or down the hallway, noticeably easier.

Muscle strength increased by about 3 percent over what was expected for their age and size, and men reported a reduction in their overall disease burden, as measured by the FSHD-HI, a clinical trial outcome measure developed at the University of Rochester with extensive patient input. Importantly, many of these gains remained even three months after they stopped the hormone injections.

Implications and Next Steps

The success of the Phase 1/2 clinical trial paves the way for larger studies. Heatwole’s team is planning larger, controlled, multi-center, randomized studies to confirm these benefits, fine-tune dosing, and include women with FSHD.  If future research supports these findings, the combination of growth hormone and testosterone could become the first treatment not only to slow FSHD but to restore strength and improve quality of life for patients.

Heatwole emphasizes that this therapy has potential across multiple muscular dystrophies. He specifically notes that while many companies are pursuing genetic therapies for common muscular dystrophies, there are hundreds of different types of neuromuscular diseases with no effective treatments. The combination therapy could be a generic approach applicable to many of these rare and undertreated conditions.

Additional co-authors include Elizabeth Luebbe, Johanna Hamel, Phillip Mongiovi, Emma Ciafaloni, Nuran Dilek, William Martens, David Weber, Hani Rashid, Jamie Allen, Claire Smith, Samantha Howell, Spencer Rosero, Katy Eichinger, Lindsay Baker, Jeanne Dekdebrun, Jim Hilbert, Anika Varma, Charles Thornton, Michael McDermott, and Richard Moxley with the University of Rochester Medical Center.  The study was supported by the National Institute of Neurological Disorders and Stroke and Pfizer.