Supernus hopes successful XR strategy will keep going

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After being thrust into the spotlight following a patent hiccup with its lead drug, Supernus Pharmaceuticals’ epilepsy understudy, SPN-804, has come good by securing US approval at its first pass. With one product approval in the bag and another launch expected by the third quarter of next year, Supernus looks as if it might be meeting the very high expectations that have surrounded it since its float in May.

While the focus will remain on keeping up the momentum on the extended-release CNS drug strategy that has seen its shares move from their float price of $5 to $12.26, investors might want to brace themselves for a cash call as the company gears up for next year’s commercial launches.

Dead cert

There was little doubt that SPN-804, now more snappily titled Oxtellar XR, was going to make the grade. The drug is an extended-release version of a molecule with a well-established track record and as such was filed using bioequivalence studies, with supporting clinical data, meaning that it can be used as a direct substitute to Novartis’s Trileptal in a front-line setting (Event – Second chance Supernus aims for approvalAugust 20, 2012).

Consensus sales forecasts for the drug stand at $105m for 2018, according to EvaluatePharma, and make it the second-fastest growth driver at the company. Analysts at Cowen expect Oxtellar XR to take 20% of the oxcarbazepine prescription market by 2018, largely thanks to the smaller number of generics in the space and the fact that other products are still plagued by safety and tolerability issues. Oxtellar XR is expected to be launched in the first quarter of 2013.

But in a sense Oxtellar XR is the warm-up act for Supernus’s real superstar, Trokendi XR, an extended-release, once-daily version of Johnson & Johnson’s Topamax. Earlier this year the drug was granted provisional approval from the FDA, but was denied a launch thanks to Johnson & Johnson still holding the paediatric exclusivity on its product until June 2013.

Bigger fish

Cowen estimates that the oxcarbazepine market is roughly a fifth of the size of that of Topomax, indicating why Supernus will be keen to get Trokendi XR on the shelves as soon as possible. The bank also believes that given its once-daily administration and smooth release into the blood, Trokendi XR could take a 10% stake of the topiramate market six years after approval. While the bank has pencilled in sales of $310m by 2018, consensus is running at a slightly more sceptical $237m in the same year.

But if the drug does offer significant advantages over topiramate, by increasing compliance through its once-daily dosing and pharmacokinetics, the sales estimates might prove to be a little conservative, especially as many of the patients in the pivotal trials preferred the once-daily regimen.

Next for Supernus will be forming a sales team to sell the products and gearing up for the potential launch of two drugs next year to senior neurologists. But with $76.4m in the bank at June 30, expected to last until the middle of next year, it is highly likely that Supernus will take advantage of its current share price to go back to the market to raise money.

But the group might want to get a move on tapping investors for more cash. Despite the good news with Oxtellar, today Supernus’s shares were 5% lower and over the past six days have fallen by 7% as investors have moved to take profits.

For those willing to hold on there might be more catalysts on the horizon. Phase IIb data are due for the group’s third drug, SPN-810, in impulsive aggression in ADHD by the end of the year. If these too are positive Supernus will have provided further validation of its bead drug delivery technology and bioequivalence regulatory strategy, and could start to look like an attractive M&A target.

Other winners

Supernus was not the only winner this week in the epilepsy space, and Eisai yesterday reported that it too had got the backing of US regulators over its first-in-class adjunct epilepsy drug Fycompa (perampanel).

Approved for partial seizures, Fycompa is set to be used as an adjunct to other products already on the market. As to how it will fare in the crowded and largely generic epilepsy space might come down to its more convenient once-daily dosing and the fact that it has a new mechanism of action (Event – Eisai looks to new drug class to boost CNS pipelineSeptember 28, 2012).

Fycompa is a post-synaptic AMPA glutamate receptor agonist that blocks the action of the neurotransmitter glutamate, which is thought to cause seizures at high concentrations.

This is an important win for the Japanese company, which is still trying to find ways to offset the patent expiry of its biggest drug, Aricept. With sales forecast to hit $354m by 2018, while not plugging the gaping hole, this will at least play a small part in Eisai’s recovery strategy.

To contact the writer of this story email Lisa Urquhart in London at lisau@epvantage.com

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