Fresh trial data fortify position of Roche's oral therapy in spinal muscular atrophy battleground
With an FDA decision date looming, Roche on Wednesday unveiled positive pivotal data on its blockbuster-bound oral spinal muscular atrophy (SMA) drug in patients with the most severe form of the muscle-wasting disease.
The FDA is set to make its decision on the therapy, risdiplam, by May 24. It is expected to compete with Biogen’s Spinraza and Novartis’ Zolgensma.
Partnered with PTC Therapeutics, the Roche drug was tested in 41 patients aged 1-7 months with type 1 SMA, a rare genetic muscle-wasting disease. The trial, dubbed FIREFISH, measured efficacy via the proportion of infants sitting without support after 12 months of treatment, and longer.
The data follows another positive trial, the pivotal SUNFISH trial, meeting the threshold for change from baseline in motor function after one year of treatment in patients with type 2 or 3 SMA between 2 and 25 years old.
The new Roche data further highlights the threat that Roche and partner PTC pose in the SMA space for Biogen, which secured the first-ever SMA approval and has since been dosed in over 9,300 patients, Credit Suisse’s Evan Seigerman wrote in a note.
“While the impact of Novartis’ Zolgensma has been relatively muted, we think that the likely approval and launch of risdiplam could impact Biogen’s Spinraza franchise,” he said. “We also think that Roche could price risdiplam below Spinraza to help encourage use – especially in T2 or T3 patients.”
Spinraza, an antisense oligonucleotide, is injected in the spine every four months following initial loading doses. Zolgensma, a gene-therapy, is designed to be a one-shot cure, while risdiplam is a daily oral treatment, engineered to work by tweaking how the SMN2 gene is spliced, which raises functional SMN protein levels in both the central nervous system and peripheral tissues.
SMA is rare, affecting 1 per 8,000 to 10,000 people globally, but represents a lucrative battleground for these drugmakers. Spinraza, launched in late 2016, carries a list price of $750,000 for the first year and $375,000 annually thereafter. Zolgensma — only approved for patients under the age of 2 — caused sticker shock with its $2.1 million price tag and the inevitable pushback from payers, although Novartis has emphasized that its five-year installment plan and curative potential makes it worth it.
With Roche’s plan to make risdiplam cheaper than Spinraza, and the appeal of oral administration could make the drug an even bigger threat to the Spinraza franchise — which generated more than $1.5 billion in the first three quarters of 2019 — compared to the world’s most expensive therapy, Zolgensma.
Seigerman forecast $2.21 billion in global Spinraza sales for 2020, and estimated that number would shrink to $1.79 billion by 2022. “Spinraza is not core to our thesis at this point (yet still important), as any revenue declines seen from Spinraza could be made up for from aducanumab (if approved),” he wrote.
As for risdiplam, an approval is all but certain. Cowen analysts in November forecast sales of about $2.7 billion in 2026.
Social image: Roche