PTC Therapeutics has reported results from Part 2 of the pivotal FIREFISH trial of Evrysdi (risdiplam), which demonstrated that infants with type 1 spinal muscular atrophy (SMA) continued to show improvements in survival and key motor milestones after two years of treatment.

A survival motor neuron 2 (SMN2)-directed RNA splicing modifier, Evrysdi can potentially treat SMA caused by mutations in chromosome 5q that lead to SMN protein deficiency.

Discover B2B Marketing That Performs

Combine business intelligence and editorial excellence to reach engaged professionals across 36 leading media platforms.

Find out more

The open-label, two-part pivotal trial in infants with Type 1 SMA had two parts. Part 1, a dose-escalation study, enrolled 21 infants with the primary objective of evaluating the safety profile of risdiplam and determining the dose for Part 2.

Part 2, a pivotal, single-arm study enrolled 41 infants with Type 1 SMA who were treated for two years and was followed by an open-label extension.

At 24 months of treatment, 93% of infants were alive and 83% were alive without permanent ventilation, results from Part 2 of the trial showed.

No new deaths were reported between 12 and 24 months and 92% of the infants receiving Evrysdi maintained the ability to feed orally at month 24.

GlobalData Strategic Intelligence

US Tariffs are shifting - will you react or anticipate?

Don’t let policy changes catch you off guard. Stay proactive with real-time data and expert analysis.

By GlobalData

As per the exploratory data, similar maintenance of 95% ability to swallow was noted.

Furthermore, hospitalisations reduced during the second year on treatment with Evrysdi compared with the natural course of the disease, with 34% of infants not needing hospitalisation during 24 months of treatment.

The study also met the primary endpoint of the percentage of infants able to sit without needing support for at least five seconds at 12 months.

PTC Therapeutics CEO Stuart Peltz said: “We’re encouraged to see these patients reach key motor and mobility milestones, which would never have been realised in the natural course of the disease.

“The long-term data presented today build upon the robust pool of evidence supporting Evrysdi as a safe, effective and convenient at-home treatment option for SMA patients globally.”

The US Food and Drug Administration recently approved Evrysdi for treating SMA in adults and children aged two months and above.

As part of a partnership with the SMA Foundation and PTC Therapeutics, the clinical development of Evrysdi is led by Roche.

Clinical Trials Arena Excellence Awards - Nominations Closed

Nominations are now closed for the Clinical Trials Arena Excellence Awards. A big thanks to all the organisations that entered – your response has been outstanding, showcasing exceptional innovation, leadership, and impact

Excellence in Action
Science 37 has won the Research and Development Award in the Site Innovation category for its FDA inspected Direct-to-Patient Site model, delivering nationwide access, faster enrollment and higher retention. Explore how its virtual-first, in home approach is reshaping trial operations and accelerating time to data-driven decisions..

Discover the Impact