Risdiplam showed effectiveness for reducing long-term symptoms of spinal muscular atrophy (SMA) without major adverse effects, according to a press release by Genentech.

The promising results of risdiplam in patients with SMA were reported in pivotal studies. The first was an open-label, 2-part clinical trial named FIREFISH, which included 21 infants who received escalating doses of risdiplam and demonstrated overall safety. The second part recorded how 41 infants diagnosed with type 1 SMA responded to treatment for 2 years, observing an improvement to sitting without support for at least 5 seconds.

Another trial is SUNFISH, a double-blind placebo-controlled study where patients aged from 2 to 25 years with type 2 and 3 SMA showed increased motor function after 1-year treatment with risdiplam above the placebo group. Benefits of the drug continued for 3 years, with side effects progressively diminishing. Furthermore, all adverse reactions were reflective of SMA and did not lead to any withdrawal.


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“In treating people with SMA, our aim is to enable or preserve their independence and patients in the SUNFISH study reported continuous improvement or stabilization in the level of help needed for daily living,” said Laurent Servais, MD, PhD, professor of Paediatric Neuromuscular Diseases at the Muscular Dystrophy United Kingdom Oxford Neuromuscular Centre.

Read more about SMA experimental therapies

So far, over 5000 patients have received risiplam; regardless, more data are yet to be collected and analyzed regarding efficacy, dosing, safety, and overall recommendations. An open-label exploratory trial called JEWELFISH has already completed recruitment to assess safety, tolerability, pharmacokinetics, and pharmacodynamics.

RAINBOWFISH, an open-label, single-arm, multicenter study, will investigate the efficacy, safety, pharmacokinetics, and pharmacodynamics in infants born to 6 weeks of age who have not yet developed symptoms. Finally, MANATEE, a global phase 2/3 clinical study, will determine the safety and efficacy of a novel antimyostatin (GYM329) in combination with risiplam in patients with SMA.

Risiplam is a splicing modifier in the survival motor neuron (SMN) 2. Recalling SMA involves a mutation in chromosome 5q that causes deficiency in the SMN protein, essential for neurological functions. The developers hypothesized that a drug that targets its deficit could treat and prevent motor symptoms seen in SMA. Risiplam was therefore tested in animal models first, and after promising results, the clinical trials began.

Reference

New data for Genetech’s Evrysdi (risdipam) demonstrate long-term efficacy and safety in a broad population of people with spinal muscular atrophy (SMA). News release. Genentech; March 16, 2022.