By Bill Berkrot
April 27 (Reuters) - Biomarin Pharmaceuticals Inc said the annual price for its drug, which won U.S. approval on Thursday, to treat a rare and fatal type of pediatric brain disease is expected to be $486,000 after mandatory government discounts and rebates.
The Food and Drug Administration approved Brineura, an enzyme replacement therapy, for patients aged 3 and older to slow the loss of walking ability, making it the first approved medicine for the progressive type of Batten disease known as late infantile neuronal ceroid lipofuscinosis type 2, or CLN2.
The approval was based on data from just 22 treated patients between the ages of 3 and 8, who were compared with 42 untreated patients. The therapy is infused directly into the fluid in the brain.
"The FDA is committed to approving new and innovative therapies for patients with rare diseases, particularly where there are no approved treatment options," Julie Beitz, of the agency's Office of Drug Evaluation, said in a statement.
Biomarin said it will offer a co-pay program to assist with out of pocket costs.
Extremely high prices for treatments for very rare conditions are not uncommon and are typically covered by health insurers because there are so few patients.
Biomarin said on a conference call that it expects European approval of the medicine at the end of this quarter after receiving a positive opinion from regulators.
The company said about 20 children are born in the United States with CLN2 every year. As a condition of approval, Biomarin must further evaluate the safety of Brineura in CLN2 patients below the age of 2, including device related adverse events and complications with routine use. Data from that study could expand the approval to the youngest CLN2 patients.
Biomarin must also conduct a 10-year patient registry study to determine long-term safety of the treatment. The company said it does not yet know what the duration of benefit of the treatment will be. It currently has data out to 96 weeks.
Rapidly progressing CLN2 disease affects less than one in one million U.S. residents.
Symptoms of CLN2 disease often do not present until age 3, at which point children experience seizures and language delays. As the condition progresses, eyesight and ability to walk and talk rapidly diminish. (Reporting by Bill Berkrot in New York and Akankshita Mukhopadhyay in Bengaluru; Editing by Shounak Dasgupta and Tom Brown)