The United States Patent and Trademark Office (“USPTO”) has agreed to reconsider patents on Gilead’s HIV drug Viread, according to a report by The Mercury News.

The Mercury News reported:

The Public Patent Foundation, a consumer advocacy group, claimed in a petition filed with the agency in March that the patents shouldn’t have been issued because key facts about the makeup of Viread – generically dubbed tenofovir – had been made public previously. . . .

Invalidating the patents would let other companies seek federal permission to sell the same drug, which could make Viread more widely available and lower its price, said Daniel Ravicher, the foundation’s executive director. Retail prices for drugs vary, but a 30-day supply of Viread can easily cost more than $1,000.

Viread sales were nearly $690 million in 2006, so it goes without saying that the invalidation of these patents could potentially be very costly for Gilead.  Moreover, Viread is a key component of two other Gilead drugs, Truvada and Atripla.  Thus, the invalidation of the patents could potentially impact the sales of those drugs as well.

Should Gilead be concerned?  The USPTO agrees to reconsider a large number of patents each year and only a small percentage of those patents are actually invalidated, so the odds of these patents being invalidated are probably relatively small.  Still, Gilead has to have some concerns, since the invalidation of these patents is likely to have a very real impact on the company’s bottom line.