SAN FRANCISCO — The government hasn’t even approved Alnylam Pharmaceuticals Inc.’s first drug, but officials at the Cambridge company are so optimistic the medicine will reach the market soon that they are planning a significant expansion.
John Maraganore, chief executive of the biotech, told investors at the annual J.P. Morgan Healthcare Conference Monday that he expected the Food and Drug Administration to approve Patisiran, its treatment for a rare genetic disease, by midyear. He expects European drug regulators to follow suit later this year.
Patisiran would be Alnylam’s first approved drug since the company was founded 15 years ago. It is based on a gene-silencing technology called RNA interference that is considered so promising for the biotech’s pipeline that it has given Alnylam a market value of nearly $13 billion.
“We’re not only launching Patisiran this year,” Maraganore told a packed conference room at the Westin St. Francis Hotel. “We’re launching Alnylam.”
The company is so confident in Patisiran, which treats the deadly hereditary disease ATTR amyloidosis, and other drugs in its pipeline that Alnylam added 225 employees last year, bringing its workforce to about 725.
This year, it expects to hire as many as another 200 employees and grow to 1,250 to 1,500 employees by 2020, said Christine Lindenboom, a spokeswoman.
Most of those employees would be in Cambridge, but Alnylam also has workers in Switzerland and the United Kingdom, and it’s building a manufacturing plant in Norton, Mass.
Like many other biotechs in Cambridge, Alnylam is focusing on medicines for orphan diseases — conditions that each afflict fewer than 200,000 people in the United States. Companies enjoy generous government benefits for developing such drugs, including seven years of market exclusivity. The medicines also typically fetch breathtakingly high prices.
In response to a question from an investor, Maraganore said Patisiran would certainly command a six-figure annual price tag, given that it was costly to develop and the condition it treats is believed to afflict only about 50,000 people worldwide.
But the exact price would depend to a large degree on whether the FDA approves it for a range of patients with the disease.
“Let’s be clear,” he said. “These are orphan drugs.”
Even with prices of several hundred thousand dollars or more, biotech leaders say such drugs can actually cost less than what it takes to treat people with rare diseases for years. Patient advocates and health cost watchdogs, however, often criticize the prices as exorbitant, and health insurers sometimes balk at covering all patients.
In another development, Alnylam and the French pharmaceutical giant Sanofi have restructured their partnership.
Under the deal, Sanofi has obtained the right to develop and sell a hemophilia drug hatched by Alnylam called Fitusiran. The experimental medicine is still in clinical trials.
Jonathan Saltzman can be reached at firstname.lastname@example.org.