- Fresh results from two studies of Roche’s experimental oral therapy for spinal muscular atrophy (SMA) support the treatment’s benefit for patients with both severe and later-onset forms of the muscular disorder, helping the Swiss drugmaker’s drug stay relevant in a shifting therapeutic space.
- After eight months of treatment with risdiplam, six out of 14 infants with Type 1 SMA were able to sit and maintain upright head control, showed data from Roche’s Phase 2/3 FIREFISH study presented at the World Muscle Society’s annual meeting. Three achieved unassisted stable sitting, a key developmental milestone typically not reached in infants with Type 1 SMA.
- Initial results from another Phase 2/3 study, called SUNFISH, indicated it helped maintain motor function in Type 2 and Type 3 infants. Roche, which licensed the drug from PTC Therapeutics, hopes to submit risdiplam for approval in 2019.
Approval of Biogen’s Spinraza (nusinersen) in 2016 marked a major advance in treatment for SMA, which is generally fatal before age two in its most severe form.
Clinical results which showed the drug improved motor function and reduced the risk of death have translated into commercial success for Biogen. The biotech earned nearly $900 million from Spinraza last year and, despite concerns of slowing sales, the drug remains a key asset.
Roche and Novartis, however, aim to soon bring rival therapies to market which could further shift how the condition is treated.
Results for risdiplam remain early; data from both FIREFISH and SUNFISH come from the initial dose-finding stage of each trial.
In FIREFISH, which only included Type 1 SMA patients, 19 of 21 enrolled infants remained alive, with three now more than two years old. No infant has lost the ability to swallow, Roche said.
At Day 245, 13 out of 14 babies — or 93% — had achieved a four-point or greater improvement on a measure used to gauge motor function that’s known as CHOP-INTEND. By way of rough comparison, data on Spinraza’s label show 71% of patients on Biogen’s drug surpassed that mark at the final study analysis.
Results were not yet available, however, on FIREFISH’s primary endpoint assessing the percentage of infants who are sitting without support after one year of treatment.
In SUNFISH, meanwhile, 63% of Type 2 and Type 3 SMA patients treated with risdiplam for at least one year experienced a median increase in motor function (on another measure called MFM32) of three points versus baseline.
While the results are supportive of risdiplam’s benefit, the rubric by which Roche’s data are judged may change.
Early Phase 1 results for Novartis’ gene replacement therapy AVXS-101 were dramatic, showing all 15 patients treated were alive at 20 months of age. Eleven of the 12 given a higher dose of the therapy sat unassisted and nine were able to roll over.
Fresh data from that Phase 1 study and an ongoing Phase 3 trial called STR1VE are also expected to be presented this week at the World Muscle Society meeting.
For Novartis, the results for AVXS-101 need to be transformative, given that it paid nearly $9 billion to buy the therapy’s developer Avexis earlier this year.
Novartis intends to submit the therapy for U.S. approval in the second half of this year, supported by Phase 1 results and preliminary data from STR1VE.
How Roche’s and Novartis’ plans shape up will mean much for Biogen, which hopes to retain its share and remain a player in treating SMA.
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