Results from clinical trials of risdiplam (RG7916; Genentech, South San Francisco, CA) for treatment of infants with spinal muscle atrophy (SMA) were presented at the World Muscle Society Congress in Mendoza, Argentina.
In the interim clinical trial data presented, patients with Type 1 SMA who were treated with risdiplam in the open-label study FIREFISH (NCT ) met motor milestones after 8 months of treatment (Table). In the double-blind placebo-controlled SUNFISH (NCT )study, patients with Type 2/3 SMA treated with risdiplam for 1 year or more had improvements in motor function. No patients withdrew from any of the 3 trials underway because of drug-related safety concerns.
Of the 20 patients enrolled in the FIREFISH study, 19 have survived and 3 have reached age 24 months. Since starting treatment, none of the 19 still-enrolled patients have needed tracheostomy or ventilatory support or lost the ability to swallow.
“We are highly encouraged by these data showing infants treated with risdiplam surviving and achieving developmental milestones beyond the natural history of this devastating disease,” said Sandra Horning, MD, chief medical officer and head of Global Product Development. “SMA therapies that produce a sustained increase in SMN protein in both the CNS and periphery may provide comprehensive benefits to people diagnosed with SMA, and we look forward to sharing additional data on risdiplam as the clinical program progresses.”
Although SMA is a rare disease, it is one of the most common genetic diseases, affecting approximately 1 in 11,000 babies. Until the first treatment, nusinersen (Spinraza, Biogen; Cambridge, MA) became available in late 2016, SMA was considered a fatal disease with the majority of patients—those with Type 1 SMA—not surviving past early childhood. Patients born with Type 2 or Type 3 SMA have longer life expectancies, although with significant disability including loss of physical strength and ability to walk, eat, or breathe significantly diminished.