Biomarin Drug Provides 'Substantial Benefit' to Kids with Rare, Fatal Brain Disease

Updated from 7:48 am EST.

An experimental treatment developed by Biomarin Pharmaceuticals (BMRN) helped young children with a rare and fatal neurodegenerative disease maintain the ability to walk and talk over one year, according to results from a clinical trial presented Wednesday night.

Based on the data from the study, Biomarin intends to submit U.S. and European marketing applications in the middle of the year. If approved, the Biomarin drug, cerliponase alfa, will become the first effective treatment for CLN2 disease, a form of Batten disease.

Kids with CLN2 disorder look healthy at birth but by the age of 3, they start to lose the ability to speak and walk. The disease progresses fairly rapidly and most patients die at approximately 12 years old. Biomarin believes the disease affects approximately 1,200 to 1,600 children worldwide but accessing all those patients is likely to be difficult.

RBC Capital analyst Michael Yee estimates cerliponase alfa could achieve peak sales of $200 million to $300 million if Biomarin can treat about one-third of the CLN2 patients. The rarity of the disease means Biomarin will set a high price for cerliponase of around $300,000 per year.

Biomarin's clinical trial enrolled 24 patients with early to moderate CLN2 disease. All the patients are treated with cerliponase alfa every two weeks. In order for the drug to reach the cells of the brain and central nervous system, the patients undergo surgery to implant a special reservoir in the skull that allows the drug to be infused into the fluid surrounding the brain.

The primary endpoint of the study measured change over one year in the ability to walk and talk on a six-point scale. (Normal function is six points, with the walk/talk score dropping as patients lose function over time.)

The mean decline in 21 evaluable patients treated with cerliponase alfa was 0.43 units over 48 weeks. Fifteen of 23 patients in the study experienced no disease progression at all over 48 weeks, Biomarin said.

Three patients were not included in the efficacy analysis. One patient dropped out of the study after receiving a single infusion of cerliponase alfa. Two additional patients entered the study with no degradation of walking or talking ability and remained stable throughout the study. No patient discontinued from the study due to side effects.

The study also lacked a control arm but Biomarin compared the outcomes of cerliponase-treated patients with a natural history study of 41 untreated patients which showed an average of 2.1 units of decline over 48 weeks.

"BioMarin is humbled by the substantial benefit that cerliponase alfa has shown for many of the children with CLN2 disease in this trial. Maintaining one or two points on the CLN2 disease-specific rating scale could mean the important difference between a child being able to continue to walk and talk or not," said Biomarin Chief Medical Officer Hank Fuchs, in a statement.

CLN2 disease is caused by an inherited mutation in the CLN2 gene. The CLN2 gene directs production of an enzyme known as TPP1 needed to remove certain proteins and lipids from nerve cells. When the CLN2 gene is mutated, deficient TPP1 is unable to clear these toxic waste products from the nerve cells.

Cerliponase alfa is designed to replace the defective TPP1 enzyme so that the body can remove the toxic proteins and lipids from nerve cells.

Wednesday night's cerliponase data presentation was the start of a crucial two-month period for Biomarin during which the company's ability to internally develop new treatments for rare diseases will come under renewed investor scrutiny.

Later in March, Biomarin expects to announce results from a pivotal, phase III study of a new drug for phenylketonuria. In April, the company is holding a research meeting for investors that will focus on clinical updates from two drug development programs addressing dwarfism and a gene therapy for hemophilia.

If the clinical updates on four pipeline programs go well over the next two months, Biomarin could have two new rare disease drugs on the market in 2017 with two more products, each with blockbuster sales potential, moving toward approval. Investors might finally start to forget and forgive the FDA drisapersen rejection debacle of January and focus on the company's future.

Biomarin shares are up 2% to $89.42 in Thursday trading.

 

Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.

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