UPDATED: Alexion grabs an FDA OK--the 41st of '15--for rare-disease drug Kanuma

Seven months after Alexion ($ALXN) bagged the rare-disease drug Kanuma in its $8.4 billion buyout of Synageva, the FDA has come through with a marketing approval. The agency has now approved 41 new therapies in 2015, matching the chart-topping record for all of last year.

Kanuma (sebelipase alfa) is designed to treat lethal cases of early-onset lysosomal acid lipase (LAL) deficiency, an inherited disease that often kills infants in a matter of months. The FDA provided its breakthrough therapy designation for the drug back in 2013, not long after the program started.

LAL deficiency causes a reduction in enzyme activity that allows fat to build up in certain cells, triggering an assortment of fatal complications for infants. The new approval will give the rare-disease specialists at Alexion their third drug for the marketing team, which has been building revenue for Soliris, the world's most expensive drug. Strensiq was approved by the FDA in October and has since run into opposition from U.K. regulators who balked at the $552,000 price tag.

The agency approved the use of genetically engineered chickens to make a recombinant form of human lysosomal acid lipase (rhLAL) protein in their egg whites. The biologic is then purified from the egg whites and given to patients to make up for the deficiency.

"Using this technology, these patients for the first time ever have access to a treatment that may improve their lives and chances of survival," noted CDER Director Janet Woodcock.

UBS analyst Matthew Roden noted this afternoon that the drug should garner about $60 million in 2016 sales, growing to $410 million by 2019 with the potential to reach $1.5 billion in peak sales. Barclay's Geoff Meacham, meanwhile, estimated 2020 sales will hit $800 million. Alexion is expected to reveal the price on Kanuma this evening.

"We reviewed all of the data to ensure that the hens do produce rhLAL in their egg whites, without suffering any adverse health effects from the introduced rDNA construct," said the FDA's Bernadette Dunham. "The company has taken rigorous steps to ensure that neither the chickens nor the eggs will enter the food supply, and we have confirmed their containment systems by inspecting the manufacturing facilities."

Alexion also wins a priority review voucher in the FDA approval, an incentive that the agency has used to encourage the development of new rare-disease drugs. The actual utility of the incentive has been hotly debated, but these vouchers have been garnering a big premium for developers, with prices running into the hundreds of millions of dollars.

The agency is now one new drug OK away from setting a fresh 19-year record on approvals. Several years ago the agency was under intense fire from the industry, which wanted to see regulators work at a faster pace. The biopharma industry was rewarded with the breakthrough drug program and other fast-track review processes that have helped accelerate the regulatory process, though now the criticism this year has often centered on whether the FDA has become too liberal in its approach to drug reviews.

- here's the release

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