Deals, Pricing

GSK’s flop Potiga is picked up and headed for a quick makeover for pediatric epilepsy. Any bets on the prospective price?

GlaxoSmithKline took a considerable amount of heat last year when the pharma giant decided to yank a drug called Potiga, which had been approved as an anti-convulsant for adults but often sold off label to treat an extremely rare form of epilepsy caused by an errant KCNQ2 gene. The drug was considered a lifesaver by the small group of kids and their families that benefited from it, but GSK didn’t see enough of a commercial return to make it worthwhile. So they discarded it, along with other parts of the company that have been stripped away in pursuit of making the company more profitable in the long run.

“If there was a nonprofit pharmaceutical manufacturer that wanted to jump in, this is the sort of place that could be a good possibility,” Aaron Kesselheim, an associate professor of medicine at Harvard Medical School, told the Chicago Tribune.

Now, though, a Canadian biotech called Xenon Pharmaceuticals $XENE wants to see if this old drug has some commercial potential that GSK was blind to. And there’s no sign that they see this as a charitable venture.

The drug was only approved for adults, never among children, though there was a big demand for it from the small number of children who relied on it. According to the Chicago Tribune piece, researchers never explored the pediatric use because Potiga earned a black box warning for some dangerous side effects, such as blue tinged skin and vision problems, which the families and kids who relied on it evidently learned to live with.

Simon Pimstone

Xenon, though, says it has a green light from the FDA to run the active ingredient in Potiga — ezogabine, now dubbed XEN496 — through a tiny, pivotal 20-patient study to prove what GSK proved in adults and what the families have been saying for years: The drug controls seizures among children with the genetic trigger. And they are working on a specific pediatric formulation which they say “may” address the safety issues.

“We have done an immense amount of diligence leading up to the addition of XEN496 to our novel and robust pipeline of ion-channel, anti-epileptic drugs,” says Simon Pimstone, the CEO at Xenon. “Based on feedback from key opinion leaders, advocacy groups, pre-existing literature, and promising data generated to date, we believe there is tremendous support for us to vigorously pursue the development and commercialization of XEN496 in order to reach the pediatric KCNQ2-EE patient population as rapidly as possible.”

GSK, for its part, said they lost exclusivity on the drug in the US market in 2016. And they’re giving Xenon access to its drug data — to be used in their application — for free. The drug can be ordered from a Canadian pharmacy at a cost of $189 for a bottle of 84 50 mg pills; that’s $2.25 per pill.

Typically, if an approval is in the works for the US this would be followed by a high, 6-figure commercial price following a small, once-off study. I’ve asked the company for some guidance on their expectations, but haven’t heard back.

Repurposing old drugs and applying sky-high prices on them has become a regular, though often controversial, strategy in biotech. Marathon studied an old steroid drug never approved in the US specifically for Duchenne muscular dystrophy, and then stirred up a hornets nest of trouble as lawmakers caught wind of their price. That drug wound up at PTC. And of course Martin Shkreli made a similar approach globally unpopular as he took control of an old generic and simply hiked the price 5000%.

One of the ironies here is that the drug may not be as effective as a ketogenic diet, something that Johns Hopkins has been studying for decades as a first approach to childhood epilepsy. There have also been studies that indicate that a keto diet — low carbs, moderate protein and high fat — also works in this particular genetic subset, among others.

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Sr. Manager, Regulatory Affairs, CMC
CytomX Therapeutics San Francisco, CA
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Catalytic Data Science Charleston, SC
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Flatiron Health New York City or San Francisco

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