Satsuma to submit STS101 NDA filing in Q1, seeking commercialization partner

Satsuma Pharmaceuticals provided an update on its STS101 development program and corporate update. Recapping results from the STS101 SUMMIT Phase 3 efficacy trial, the largest-ever clinical trial conducted with any DHE product: High proportions of subjects’ treated migraine attacks had symptoms predictive of poor response to treatment. STS101 demonstrated numerical but not statistically significant differences versus placebo on the study co-primary endpoints. STS101 demonstrated robust and sustained effects on the key study endpoints, freedom from pain and freedom from MBS, at all post-dose timepoints after 2 hours. As detailed below, STS101 demonstrated robust and sustained antimigraine effects across numerous secondary endpoints considered clinically relevant and recommended for assessment in efficacy trials by the U.S. Food and Drug Administration in its current industry guidance document and/or the International Headache Society’s guidelines for controlled trials of acute treatment of migraine attacks. In addition, STS101 demonstrated efficacy in subjects who experienced common and difficult-to-treat migraine attack types, including migraine with allodynia and menstrually-associated migraine. Consistent with clinical trial experience to date in subjects who have administered more than 10,000 doses of STS101 to treat their migraine attacks, STS101 demonstrated a favorable safety and tolerability profile in SUMMIT. The only treatment-emergent adverse event reported by more than 5% of SUMMIT subjects who self-administered STS101 was nasal discomfort, reported by 8.3% and 1.5% of subjects who self-administered STS101 and placebo, respectively. No treatment-related serious adverse events or cardiovascular events occurred. STS101 demonstrates differentiated profile with primary market research conducted post-SUMMIT trial readout indicating potential for broad use. The Company believes STS101 has the potential to address the unmet needs of many of the ~40 million people with migraine in the U.S. given its differentiated profile characterized by demonstration of robust and sustained single-dose antimigraine effects in a large, randomized, placebo-controlled clinical trial; elegant simplicity and ease-of-use; and favorable safety and tolerability. Qualitative and quantitative primary market research with headache specialists and prescribers of migraine therapeutics undertaken by Satsuma following announcement of SUMMIT trial results, and which utilized an updated STS101 product profile incorporating SUMMIT trial results, indicate physicians view STS101 as having broad potential therapeutic utility across a variety of migraine patient- and attack types. Interviewed and surveyed physicians expressed strong interest in prescribing STS101 for a broad range of migraine patient and migraine attack types, with surveyed physicians indicating intent to prescribe STS101 for approximately 30% of their patients with migraine4. The results of this primary market research are consistent with previous market research conducted by Satsuma indicating that physicians’ strong interest in and intent to prescribe STS101 was minimally dependent on the magnitude of effect size demonstrated by STS101 against co-primary endpoints at two hours post-dosing in a Phase 3 efficacy trial, and rather was driven by the unique overall profile and attributes of STS101. Based on its communications with FDA in multiple Type C meetings and the May 2022 Type B clinical pre-NDA meeting, Satsuma believes the results of its STS101 clinical trial program, and in particular results from the Phase 1 comparative PK study completed in 2021 and the on-going ASCEND long-term, open-label safety trial, support a planned NDA filing in Q1 2023 and potential approval. In addition, based on input from expert legal-regulatory and statistical consultants, Satsuma believes there is a compelling rationale, with regulatory precedents, for including a portion of the SUMMIT trial efficacy results in the STS101 prescribing information, despite STS101 not achieving statistical significance versus placebo on study co-primary endpoints at the primary timepoint of two hours post-treatment. Consistent with prior guidance, Satsuma remains on track to submit the STS101 NDA in the first quarter of 2023. In parallel, the Company is working to secure a commercialization partner for STS101.