One of the world's top-selling drugs—GlaxoSmithKline PLC's $8-billion-a-year asthma treatment Advair—became more vulnerable to generic competition after the U.S. Food and Drug Administration issued guidance on the regulatory hurdles generics companies need to clear to gain approval of a knockoff version.
In documents published late Monday, the FDA laid out the kind of scientific studies generic companies need to submit to be considered for approval.
The patent on Advair's active ingredients expired in the U.S. in 2010; the patent on the drug's inhalation device expires in the U.S. in 2016. The new clarity could allow for generics to potentially hit the market by 2016 or 2017, some analysts said, though some cautioned that the complexity of producing an exact copy could still delay generics to a later date.
Many analysts had doubted that generics could hit the market by 2016 because of the difficulty of copying inhaled drugs and confusion about what regulators would require before approving copies.
Advair combines two drugs in a fine powder inhaled through an intricate device called a Diskus. Few generic companies have the know-how to make complicated inhaled drugs, and even the ones that do have found Advair a tough one to crack.
The stakes for Glaxo are high: Advair had global sales of £5 billion ($8 billion) last year, making up about 20% of Glaxo's global sales of £26.4 billion.
The challenge illustrates an important change in the generics wars. For years, the most profitable drugs—mostly pills made of chemicals—have been fairly easy for generics companies to copy, requiring a straightforward chemical synthesis.
But a new wave of blockbusters include more complicated inhaled drugs and others made of complex biological ingredients. Replicating them requires skills that some generics makers don't have.
Mylan Inc., Teva Pharmaceutical Industries Inc. and Novartis AG's generic-drug division, Sandoz, are among the companies that have been attempting to develop Advair copies in recent years.
In an emailed statement Tuesday, Mylan President Rajiv Malik said: "We are pleased that the FDA's draft guidelines are fully in-line with our expectations…. That said, we still believe that the hurdles for a generic Advair remain high and that there will be a very limited number of companies who are able to successfully bring a generic version of this complex product to market."
A Novartis spokesman declined to comment. Teva didn't immediately respond to a request for comment.
Advair is sold under the brand name Seretide outside the U.S. In addition to asthma, the drug is also prescribed for chronic obstructive pulmonary disease, or COPD.
In an emailed statement, Glaxo said it continues to "believe the manufacture of combination respiratory medicines such as Advair presents significant hurdles and remains extremely challenging. GSK remains fully committed to Advair and we believe it will continue to be one of the cornerstones of asthma and COPD management."
Glaxo also said it is making progress developing new respiratory medicines, including Breo, a COPD drug approved for sale in the U.S. in May.
Another Glaxo drug, Anoro, is still under regulatory review as a potential COPD treatment, and was discussed at an FDA advisory committee meeting Tuesday.
The panel voted 11-2 to support approval of the product, which amounts to a recommendation that the FDA approve the new medicine. The agency isn't required to follow the panel's advice but typically does. A decision is expected by Dec. 18.
In draft guidance posted online late Monday, the FDA detailed a series of studies, including a four-week clinical trial in humans, that it likely will require of companies seeking approval of generic Advair. Generic makers generally must prove that their version enters the body in the same fashion as Advair and triggers the same response at the same dose level—something that is easy to show with a pill but hard to demonstrate with an inhaled drug.
Among other things, the FDA's guidance also suggests that in order for Advair copies to be "substitutable"—meaning that a pharmacist could dispense the generic even if a patient has a prescription for branded Advair—generic companies need to develop an inhalation device that is of similar shape and size to Advair's Diskus, and that works in a similar way.
Glaxo shares fell four cents in New York trading, to $50.42, after dropping about 3% Tuesday on the London Stock Exchange.
