Genentech, announced earlier this month new two-year data from the JEWELFISH study evaluating Evrysdi® (risdiplam) in people with Type 1, 2 or 3 SMA aged 6 months to 60 years at time of enrollment. Patients had been previously treated with other approved or investigational SMA-targeting therapies, including Spinraza® or Zolgensma®. Data showed Evrysdi improved or maintained motor function and led to rapid increases in SMN protein levels which were sustained after two years of treatment.
The JEWELFISH study enrolled the broadest and most diverse patient population ever studied in an SMA trial. Of the 174 people enrolled, 36% (n=63) were adults, 63% (n=105) had a Hammersmith Functional Motor Scale Expanded (HFMSE) score of less than 10 at baseline, meaning their disease was very severe, and 83% (n=139) had scoliosis. Forty-four percent (n=76) of those enrolled had previously been treated with nusinersen (Spinraza), 41% (n=71) with olesoxime*, 8% (n=14) with onasemnogene abeparvovec (Zolgensma) and 7% (n=13) with RG7800*.
People with SMA are unable to produce enough survival motor neuron (SMN) protein, leading to debilitating and potentially fatal muscle weakness. The study showed Evrysdi led to a two-fold increase in median SMN protein levels versus baseline after four weeks of treatment in all patient groups, irrespective of previous treatment. The SMN protein levels achieved after four weeks of treatment were maintained for over two years.
Observed through exploratory efficacy endpoints, the study also suggests maintenance of motor function was sustained at two years of treatment as measured by change from baseline in Motor Function Measure 32 (MFM-32), Revised Upper Limb Module (RULM) and HFMSE total scores compared to the natural history of SMA in untreated patients. A recent survey conducted by patient advocacy group SMA Europe showed that more than 96% of people with SMA viewed disease stabilization as progress in terms of their expectations of treatment.
The overall adverse event (AE) and serious adverse event (SAE) profiles observed with Evrysdi treatment in JEWELFISH were reflective of underlying disease. The rate of AEs decreased by more than 50% between the first and second six-month period, and then remained stable thereafter.
Genentech leads the clinical development of Evrysdi as part of a collaboration with the SMA Foundation and PTC Therapeutics.
*RG7800 and olesoxime are no longer in development as investigational treatments for patients with SMA.
* This data was presented at the 27th World Muscle Society (WMS) congress, October 11-15, 2022.