Supernus clears PhII ADHD drug hurdle, but shares drip downward

Specialty pharma Supernus ($SUPN) has posted positive data from its childhood ADHD midstage test as it looks to start Phase III trials next year--but its shares ticked down as some decided to “sell the news” instead of buying into it.

The data were good: The topline results, coming out from its Phase IIb dose-ranging test of the selective norepinephrine reuptake inhibitor SPN-812 in children with ADHD, showed the experimental med hit its primary endpoint with a statistically significant improvement in the symptoms of ADHD, from baseline, to end of the study period.

As a result, the Rockville, MD-based biotech said Phase III would start as soon as possible--and has slated it for 2017--coming after it has an end of Phase II talk with the FDA.

“We are very excited about these results and that SPN-812 met the objectives of the study with an encouraging and strong clinical profile,” said Jack Khattar, president and CEO of Supernus Pharmaceuticals.

“We believe SPN-812 has the potential of being a well differentiated treatment for ADHD that sets itself apart from current treatment options.”

But despite the positive data, investors appeared to sell the news, with shares down as much as 8% first thing Tuesday morning--although they did start rebound later on, but still finished down 6.8% at the end of trading, with a market cap of just under $1.2 billion.

ADHD is already well catered for, but Supernus is hoping to carve out a big space for SPN-812 as a non-stimulant for the treatment of the disorder, believing that it has a better safety profile than other non-stimulants.

In a call with investors, Khattar said: “This is a $2.5 billion plus market opportunity for Supernus. But from what we know today, first of all, you can never really expect a non-stimulant to be exactly like a stimulant, as far as efficacy.

“On the stimulant side, clearly they will always be a very strong efficacy kind of products. And that's why they have 92% of the market. However, you have to deal with the other issues as far as abuse and tolerability,” something he says that can be remedied by non-stimulants therapies.

It’s main rival in the space is Lilly’s ($LLY) selective norepinephrine reuptake inhibitor Strattera (atomoxetine).

When asked by investors about how it might compare to this med, Khattar said: “With our drug, in the high dose range, well this is kicking in in week one/two. Strattera, I think it’s more in the four to six weeks as far as time to onset when you start seeing an effect on the ADHD symptoms. So, we’re very encouraged with that as well, and we think we have a very strong profile there as far as the onset to reduction in symptoms in ADHD.”

He added that there were also others researching in this space. “The other product we are aware of that is fairly in late stage testing is the Sunovian product, which is a dopamine and norepinephrine reuptake inhibitor, and so looks like it's a dual mechanism. That’s the other one as far as we know; and we don’t really know how far they are along, whether they are a little bit ahead of us, or we’re ahead of them. It’s something of a two-horse race I’d say at the moment.”