SUPN reported mixed positive results today for its final phase 3 trial for SPN-812 in attention deficit hyperactivity disorder (ADHD).* The trial met a statistical significance threshold for the 400 mg but not the 600 mg dose. That is disappointing because investors were hoping for a higher effect size at the higher dose. Instead the data looked worse than the 400 mg cohort, although unfortunately effect sizes were not provided by SUPN today. Overall, the data for SPN 812 from 4, phase 3 trials reported out in the past quarter or so, looks pretty consistently good enough for FDA approval, but is it good enough for SPN 812 to be commercially successful over generic non-stimulant ADHD drugs?
Many question whether this anti-stimulant ADHD drug is better than the Eli Lilly anti-stimulant, Strattera, which is now available in generic form. SUPN claims onset of action and consistency of clinical data sets it apart. Regarding onset of action, we find a prior Eli Lilly meta-data analysis that showed 3-4 week onset for Strattera without prior stimulant treatment, but as early as 1 week onset with prior stimulant use.** We see that the entry criteria for SPN-812's latest Ph3 trial did not rule out prior stimulant meds. Therefore, we are not certain of SUPN's claims of earlier onset vs. Strattera.
SUPN has had pretty good commercial success with marketing improved versions of generic drugs with Trokendi XR and Oxtellar XR, reaching $400M in sales last year. Therefore, this spinoff from Shire appears to have some commercial and marketing horsepower that could help convince the market that SPN 812 is superior to Strattera. SUPN plans to file for regulatory approval later this year for SPN-812, and to get approval before the back-to-school season in 2020, which is important. In the pipeline, SUPN plans to release results from 2 phase 3 trials for SPN 810 by years-end. This drug is exciting as possibly the first approved drug to treat impulsive aggressiveness in ADHD, bipolar disorder and post-traumatic stress disorder.