Tardy marketing application filing, trial failure trouble Supernus investors
Two key updates surfaced in CNS-focused Supernus Pharmaceuticals third-quarter results on Tuesday.
The drugmaker has not yet filed a marketing application for its ADHD drug SPN-812 — and a late-stage study testing another therapy, SPN-810, for use in impulsive aggression (IA) in patients with ADHD, has failed.
Shares of the Rockville, Maryland-based company $SUPN — which also posted Q3 revenue and profit that underwhelmed Wall Street expectations — tumbled more than 26% to $21.50 in Wednesday premarket trading.
Based on previous management commentary, Jefferies analyst David Steinberg said he had expected Supernus to have filed the marketing application for ‘812 by now. “Previously, mgt had indicated a 2H19 filing with good likelihood for launch during the critical ‘back to school period’ next fall, when typically 40% of Rx switching in ADHD takes place.”
Supernus said it would submit the application this month.
The drug will now likely win approval next Nov/Dec, with a launch in early 2021, Steinberg predicted. He cut his full-year 2023 sales estimate to $125 million from $173 million, noting that generics for Supernus’ anti-epileptic drug Trokendi are also expected to hit in 2023.
SPN-810, meanwhile, was being tested in a 325-patient placebo-controlled study in patients aged 6 to 11. Two doses of the drug (18 mg and 36 mg) — which is a different formulation of the existing antipsychotic molindone hydrochloride — were evaluated.
In the first tranche of the trial, the median percent reduction in the weekly frequency of impulsive aggression episodes from baseline for the 36 mg dose was 60% versus the placebo, which registered at 48.6% — a statistically significant improvement (p= 0.029). However, following the interim analysis, in the second stage of the study, the performance of the 36 mg arm dipped — adversely impacting the combined results and triggering the study failure.
“This was not a major surprise. We had pegged success at ~60%,” Steinberg wrote on Wednesday.
Overall, 98% of the trial’s enrollment was complete — but Supernus is ceasing enrolling more patients until it analyzes the dataset. Meanwhile, enrollment in a separate late-stage trial testing the drug in adolescents has been paused until a final decision is reached regarding the SPN-810 program in IA, the company said.
As of September 30, Supernus had about $893 million in cash, cash equivalents, and securities.
“It’s possible there could now be increased urgency for SUPN to execute a transaction targeting late-stage or on-market assets in neurology/psychiatry. That said, mgt has been discussing BD for several years now and has been very disciplined in its approach – refusing to overpay for commercial assets and avoiding those that don’t meet its growth aspirations,” Steinberg said.