Japanese pharma Nippon Shinyaku (NS Pharma) has announced its candidate for Duchenne musuclar dystrophy (DMD) has been submitted to the FDA for approval – to the dismay of rival Sarepta.
Sarepta was dealt a significant blow in August when its new DMD treatment Vyondys 53 was rejected by the FDA.
Now, NS Pharma’s drug viltolarsen could infringe on Sarepta’s market lead, and become the first drug approved to treat patients with the exon 53 mutation. Although the FDA has not yet set an approval decision date, if there are no significant issues viltolarsen could enter the market by mid-2020.
The rejection of Vyondys 53 was based on concerns about kidney toxicity observed in preclinical studies, but Sarepta says the US regulator placed too much emphasis on what it argued are insignificant data signals.
The treatment is a follow-up to Sarpeta’s Exondys 51, the first and currently only disease-modifying treatment approved in the US for the inherited muscle-wasting disease.
Vyondys uses the same ‘exon skipping’ mechanism, but helps patients with the exon 53 mutation rather than on exon 51. These patients represent around 8% of the DMD population, while those with the exon 51 mutation account for around 13%.
NS Pharma’s candidate also aims to help DMD patients with the exon 53 mutation – the only treatment for this version of the disease are steroids.
Although Sarepta has not revealed any robust plan to counter the FDA concerns which led to the rejection, it did say that it would work with the US regulator to address the issues to help aid in an eventual approval.
At the time of the rejection, Sarepta also said that it had requested an immediate meeting with the FDA to seek guidance on what its next steps should be, but no update has been issued as of yet.
NS Pharma’s Viltolarsen was granted a Rare Paediatric Disease Designation, Orphan Drug Designation and Fast Track Designation in the US and ‘SAKIGAKE designation’ and ‘Orphan drug designation’ in Japan, where NS Pharma has also submitted the drug for approval with its Ministry of Health, Labour and Welfare on 26 September 2019.