Experimental Facioscapulohumeral Dystrophy Drug Found Safe and Tolerable in Phase 1 Study

A recent press release from Fulcrum Therapeutics, a Massachusetts-based biotechnology company, announced preliminary findings of the company’s phase 1 clinical study of losmapimod in the treatment of facioscapulohumeral dystrophy.

Losmapimod is a drug with a surprisingly lengthy history. Earlier this year, Fulcrum acquired global rights to the drug after it busted out of R&D at GlaxoSmithKline following a failed phase 3 study of the drug’s ability to reduce major heart events in patients with acute coronary syndrome.

About Facioscapulohumeral Dystrophy

Facioscapulohumeral dystrophy (FSHD) is a genetically inherited muscular disorder that most notably affects muscles of the face, neck, and rest of the upper body — including the shoulders and upper arms.

Like other forms of muscular dystrophy, FSHD is characterized by the progressive weakening and deterioration of muscle mass. Although symptoms of FSHD begin in the upper body, many cases develop to involve a variety of muscles throughout the body.

The condition is the result of mutations to an area towards the end of the long arm on chromosome 4. These changes lead to the abnormal activation of a gene called DUX4. In most adult cells, DUX4 is silent. It isn’t known how, but the abnormal activation of this gene appears to be linked to the destruction of muscle cells that characterizes FSHD.

Treatment options for FSHD patients are relatively limited, and currently no therapy exists that can halt or reverse the progression of the condition. However, FSHD tends to develop relatively slowly — most cases do not develop quickly enough to involve the respiratory tract, meaning FSHD is rarely itself fatal.

Losmapimod Found Tolerable in Phase 1 Study

Losmapimod was originally owned by pharmaceutical giant GSK. Originally intended to treat acute coronary syndrome, losmapimod flunked out of clinical study when it failed a phase 3 study investigating its ability to effectively reduce adverse heart events associated with the syndrome.

Enter Fulcrum Therapeutics, who acquired rights to losmapimod back in April. Fulcrum researchers thought the drug made a compelling candidate for the treatment of FSHD, so the drug was repositioned.

Drug repositioning is a popular technique pharmaceutical developers use to keep costs down and to improve research efficiency. Rather than develop treatments from entirely new formulas, which can be time-consuming and incredibly expensive, some drugs are “repositioned” and investigated for use in the treatment of conditions different from those originally investigated.

In the first leg of losmapimod’s new clinical life, it was found to be safe and tolerable in patients with FSHD. This is relatively unsurprising however, since losmapimod already has a long clinical history and since its formulation has been observed to be safe in over 3,500 individuals.

Future studies will require greater degrees of scrutiny towards losmapimod’s efficacy — that is, whether or not it actually works. The drug made it relatively far down the development pipeline at GSK before failing; Fulcrum researchers and FSHD patients alike are hopeful for better results this time around.


Currently very few treatments exist to help FSHD patients manage their symptoms. What do you think of this exciting news? Share your thoughts with Patient Worthy!

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