Ruzurgi Available in Canada After Brief Interruption

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by Marta Figueiredo PhD |

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Ruzurgi in Canada

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Health Canada has re-issued its approval of Ruzurgi (amifampridine) for the treatment of Lambert-Eaton myasthenic syndrome (LEMS) in patients 6 and older.

The decision comes two months after the Federal Court in Canada cancelled the therapy’s approval in the country due to data protection-related issues filed by Catalyst Pharmaceuticals, which commercializes Firdapse (amifampridine phosphate), a similar therapy approved only for adults with LEMS.

The court’s decision required Health Canada to reconsider Ruzurgi’s approval, issued last August, in light of those legal issues, and the regulatory agency decided to reaffirm its position.

Ruzurgi’s supply has been resumed immediately by Médunik Canada through its UnikAccess Patient Support Program. Médunik Canada is commercializing Ruzurgi in the country in collaboration with Jacobus Pharmaceuticals, the therapy’s original developer.

“We are very pleased that this situation has been resolved quickly and satisfactorily by Health Canada so that we can resume the supply of this important treatment to Canadian patients,” Dany Hallé, vice president of Médunik’s commercial affairs, said in a press release.

“We are keenly aware of how crucial this treatment is to the Canadians who receive it and thank Health Canada for its rapid resolution of this situation,” Hallé added.

LEMS is a rare autoimmune disease characterized by abnormal immune attacks against voltage-gated calcium channel (VGCC), a protein found at the sites where nerve cells communicate with muscles. These abnormal attacks impair nerve cells’ ability to send signals to muscles, leading to muscle weakness, reduced reflexes, and high fatigability.

Ruzurgi works by blocking another protein channel found on nerve cells called voltage-dependent potassium channels, thereby giving cells more time for the remaining healthy VGCCs to stay open and send signals. As such, Ruzurgi, given as an oral tablet, is expected to improve nerve-muscle communication and increase muscle strength.

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Firdapse, a more stable oral formulation developed by BioMarin Pharmaceutical and sold by Catalyst Pharmaceuticals in North America, was approved in Europe in 2009 and in the U.S. in 2018 for treating LEMS patients ages 17 and older. In 2019, Ruzurgi was approved in the U.S. as the first treatment for children, ages 6–17, with LEMS.

Notably, Ruzurgi was granted approval by Health Canada for the same indication on Aug. 10, 2020, 10 days after the regulatory agency approved Firdapse as an innovative therapy for older patients.

Later that month, Catalyst and its Canadian sublicensee, KYE Pharmaceuticals, filed a lawsuit with the Federal Court challenging Health Canada’s decision to approve Ruzurgi.

The companies saw Ruzurgi’s approval as incorrect and unreasonable given that it went against the agency’s regulations that prevent other pharmaceutical companies from being able to use the innovative therapy’s data in regulatory applications for their products for eight years from the date of the innovative therapy’s approval.

Ruzurgi’s scientific description and regulatory application contains toxicity data from Firdapse’s pivotal nonclinical studies, and that’s why Catalyst and KYE claimed that Health Canada allowed Médunik to use Catalyst’s protected data in its Ruzurgi application during the data exclusivity period.

In May, the Canadian Federal Court found the lawsuit legitimate, and requested that Health Canada re-evaluate its decision on Ruzurgi, which no longer was authorized for sale in the country.

On June 24, the regulatory agency re-issued the approval of Ruzurgi, making it available again.

“We are obviously disappointed with Health Canada’s decision to re-issue an [notice of compliance] for Ruzurgi,” Patrick J. McEnany, Catalyst’s chairman and CEO, said in a separate press release.

“Our effort to get Firdapse approved in Canada commenced three years ago, at a time when there was no approved therapy in Canada to treat LEMS patients,” McEnany said. He added that the company’s interest was “to assure that all adult LEMS patients had access to a Health Canada approved therapy, despite recognizing that our market opportunity in Canada was always expected to be small.”

Catalyst and KYE now are evaluating their legal options to challenge the regulatory agency’s most recent decision, since it means the data protection that Catalyst and KYE are entitled to under Canadian law has not been recognized by Health Canada.

Prior to Health Canada’s decision, Ruzurgi had been made available for people with LEMS through a special access program, which provides patients access to therapies that have not yet been approved, but are deemed to have the potential to treat serious conditions with unmet medical needs.

Its approval in Canada and in the U.S. was supported by data from the Phase 2 DAPPER trial (NCT01511978), which showed that Ruzurgi was able to reduce muscle weakness and improve motor function in adults with LEMS.