Pediatric Exclusivity for Viagra?! It's No Joke

You can be forgiven for skipping yesterday's Cardiovascular and Renal Drugs Advisory Committee. After an incredible series of important committee topics (Avandia! Qnexa! Opioid REMS! Avastin! Brilinta!), a day long session focused on pediatric study endpoints for pulmonary arterial hypertension drugs doesn't exactly cry out for attention.

But it was a doozy. Not so much for what the committee decided...or maybe failed to decide. Heck, this was a mess of a meeting, and our colleagues did an amazing job to make sense of the outcome in "The Pink Sheet" DAILY.

No, this was a doozy of a meeting because it is laying the groundwork for what could be a very interesting regulatory decision by FDA: granting a six-month pediatric exclusivity extension for sildenafil, the active ingredient in Pfizer's PAH drug Revatio and another product you might have heard of called Viagra.

Yes, it is true: Pfizer is (we think) going to get a six month pediatric exclusivity extension for an erectile dysfunction product. In fact, we would go so far as to say after the meeting, by any fair interpretation of how the program works, Pfizer should get an extension.

Viagra? Viagra has no role in the pediatric population--except to increase the numbers of children in the US. (Badda Bing!)


Okay, okay: the pediatric extension won't be for Viagra; it will be for Revatio--a truly important therapy for the rare but debilitating condition of PAH. And all indications are that the Pfizer product does have an important role in treating the 500-600 children in the US who suffer from the disease. Pfizer has done extensive research on that population, despite significant challenges finding a viable endpoint given that no one wants to run long-term placebo controlled trials in this setting.


The pediatric exclusivity program was created in 2002 to encourage sponsors to conduct studies in children, by granting them an extra half-year of patent life/exclusivity for completing studies pursuant to a written request by FDA. Pediatric research, everyone agrees, is a very challenging and neglected field, and the law has clearly worked to encourage many more studies than would have occured without it. The Revatio program looks exactly what the law was supposed to deliver.

But the law (as implemented by FDA) is clear: the extension applies to the active ingredient, and so--if Pfizer gets a reward--the basic sildenafil patent will be extended from March 27, 2012 until September, 2012.


That is obviously a big deal for Pfizer. Revatio sales in the US were $300 million last year, so an extra six months is nothing to sneeze at. But Viagra is almost $1 billion, so that's where all the action is. (Badda Bing!, again.)

Now, Pfizer claims Viagra will be protected from generic competition until 2019, thanks to a use patent covering the ED claim. However, use patents tend not to hold up against generic challenges, and Pfizer is already facing a challenge from Teva. On the other hand, given the unusual circumstances of Viagra's development, the use patent on ED may be more robust than most.

Nevertheless, the patent extension will still matter. Obviously it delays the earliest possible date for a generic Viagra in the event Pfizer loses the case. In the more likely event that litigation is still pending, it will delay by six months the earliest possible date that Teva could consider an "at risk" generic launch. That in turn would affect the terms of any possible settlement of the litigation (assuming pending "pay for delay" legislation in Congress doesn't put the kibosh on settlements altogether.)

The extension will also put off the date on which Pfizer will have to wrestle with the possiblity that generic versions of Revatio will start eating into the Viagra market. Revatio is marketed as a 20 mg pill, while Viagra is available as 25, 50 and 100 mg pills. As brands, Revatio retails for slightly less per pill than Viagra ($15.60 vs. $17 on drugstore.com), but it certainly doesn't make economic sense to take two Revatios instead of one Viagra. If Revatio generics are widely available, those economics could change.

So, no matter how you look at it, Viagra will benefit from the pediatric exclusivity award.

Here's the thing: the pediatric exclusivity program has strong support, but it isn't without its critics. When the program came up for reauthorization in 2007, some members of Congress wondered why a sponsor might be given an extra six months of sales for a multi-billion brand in exchange for conducting a relatively small, inexpensive study in children.

It is fair to say those arguments will come up again in 2012--especially if FDA grants an extension to Viagra, every politician's favorite target for criticizing Big Pharma.

Look for more coverage of how the advisory committee wrestled with this issue in an upcoming issue of The RPM Report.