After a second review, the FDA approved Zevra Therapeutics’ treatment for Niemann-Pick disease type C, a progressive rare genetic disease caused by the accumulation of certain fatty substances.
Arimoclomol is for patients aged 2 years and older with neurological manifestations of Niemann-Pick. The thrice-daily pill will be marketed as Miplyffa.
Zevra did not immediately disclose the list price of the therapy. It plans to host a conference call on Monday, according to a company spokesperson. It also wasn’t immediately clear whether the FDA had given Zevra a priority review voucher, though the company is eligible to receive one. Zevra’s stock $ZVRA was halted shortly after Friday’s opening bell.
Niemann-Pick disease is part of a category of rare diseases called lysosomal storage disorders, in which key enzymes responsible for recycling substances in the body don’t function properly. As a result, toxic substances build up and can cause damage to various organs in the body. William Blair analyst Lachlan Hanbury-Brown estimates that the US patient population is about 300 to 350 people.
The FDA approval comes after outside experts voted 11-5 in favor of Zevra’s drug at an advisory committee meeting in August.
The experts who voted in favor of approval said that they believed the clinical trial data and patient testimonies showed the drug may stabilize the disease, and in some cases improve symptoms, though the treatment was not dramatically effective.
The company had conducted a reanalysis of the pivotal clinical trial data after the drug was initially rejected by the FDA in 2021, using a revamped scale for the primary endpoint.
The scale re-scored measures of swallowing, a skill that becomes more challenging for people with Niemann-Pick as their disease progresses. It also removed measures of cognition after the FDA raised concerns about the reliability of the data.
Patients in the clinical trial received Zevra’s drug on top of standard of care. For 78% of patients in the trial, that included off-label use of Zavesca, which is marketed by Johnson & Johnson in the US for certain patients with Gaucher disease. The drug is approved for Niemann-Pick disease in the EU, Canada and Japan, but not in the US, where it was rejected by the FDA in 2010.
A key issue raised by the advisory committee was teasing out Miplyffa’s effects from those of Zavesca. However, FDA officials noted that the drug would likely be administered on top of standard of care, which includes off-label Zavesca.
Zevra’s drug was originally developed by Danish biotech company Orphazyme, which was known as a “meme stock” company that saw high valuations before the FDA’s rejection. Zevra acquired Orphazyme and the drug in 2022 for $12.8 million.
Zevra was previously known as KemPharm, but the company rebranded in early 2023.
Max Gelman contributed reporting.