Positive pivotal data on Supernus’ $SUPN ADHD drug in children gave investors pause earlier this month because of the lack of dose response at the higher 400 mg dose, which weighed on the shares. On Thursday, the drug developer followed up with largely similar Phase III data from an adolescent study, but the drug’s swift onset of action, as seen in previous trials with children, may be a key differentiator from existing ADHD non-stimulant medications.
Two doses (200 mg/400 mg) of the drug, SPN-812, were tested against a placebo in the 310-patient adolescent study P302. At week 6, patients receiving SPN-812 200 mg and 400 mg had a -16.0 point change (p=0.0232) and a -16.5 point change (p=0.0091) on an ADHD rating scale, versus -11.4 for those on the placebo — meeting the main goal of the study. Overall, patients receiving 200 mg and 400 mg had an effect size of 0.47 and 0.50, respectively. Significantly, the higher dose started to work as soon as the first week, the company said.
“These data further reinforce the effectiveness of SPN-812 in patients with ADHD…with a favorable safety and tolerability profile,” said CEO Jack Khattar in a statement. “We now have positive data proving the efficacy and safety of SPN-812 in all ADHD patient populations; positive Phase III data in children 6-11 years old and adolescents 12-17 years old, and positive Phase IIa data in adults.”
Another Phase III study (P304) in adolescents is expected to read out in the first quarter of 2019. But buoyed by the data so far, Supernus expects to submit a marketing application by the end of the first quarter of 2019 and to launch — pending FDA approval — in the second half of 2020, it said on Thursday. The company’s shares edged up about 2.5% before the bell.
In the first week of December, twin studies evaluating the experimental non-stimulant drug in children showed similar effect sizes. In the P301 study, the 100 mg and 200 mg demonstrated an effect size of 0.54 and 0.57, respectively. In the P303 trial, patients receiving 200 mg and 400 mg had an effect size of 0.46 and 0.49. Three out of the four doses were observed to have started working in week 1. But the company’s stock fell because of the lack of dose-response seen with the higher 400 mg dose, and worries that the drug may have not performed well enough to differentiate itself from existing ADHD drugs such as Lilly’s Stattera and Shire’s Intuniv.
Lilly’s $LLY Strattera — which achieved an effect size of 0.4 to 0.6 in trials — was the first non-stimulant medication approved for ADHD, but it can take more than 6 weeks to start working. Last year it went generic, and is used for both children and adolescents.
In a note earlier this month, Jefferies’ David Steinberg suggested that the overall profile of SPN-812 was favourable. If approved, it is set to reap peak sales of $400 million, he said.
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