Apnimed’s sulthiame's demonstrates efficacy in obstructive sleep apnoea

Apnimed has announced positive results from the Phase 2 FLOW study evaluating sulthiame, a differentiated, once-daily oral carbonic anhydrase inhibitor, in the treatment of obstructive sleep apnoea (OSA). The study demonstrated that sulthiame significantly improved important OSA metrics in adults with moderate to severe OSA.

Sulthiame has a different mechanism of action from Apnimed's lead programme, AD109, with the potential to address other aspects of the pathophysiology of OSA. Apnimed is developing sulthiame in partnership with Shionogi & Co, through their joint venture, Shionogi-Apnimed Sleep Science (SASS).

The FLOW study is a multi-centre, randomised, double-blind, placebo-controlled, dose-finding trial, evaluated three dosages of sulthiame (100mg, 200mg and 300mg) administered once daily at bedtime for 15 weeks. The study enrolled 298 adult patients with untreated, moderate to severe OSA across 28 sites in five European countries. The primary endpoint, relative change in the apnoea-hypopnea index (AHI3a) from baseline to Week 15, was met for all sulthiame doses. A dose-response effect was identified and well-characterised.

Key findings from the FLOW study included:

• Significant Reduction in OSA Severity: All sulthiame doses demonstrated a consistent and dose-dependent reduction in breathing disturbances, as measured by AHI3a.

• Improved Nocturnal Oxygenation: Sulthiame led to significant improvements in oxygen desaturation index (ODI) and mean overnight oxygen saturation, indicating improved nocturnal oxygenation.

• Favourable Safety Profile: Sulthiame was generally well-tolerated, with adverse events consistent with prior experience and the known pharmacology of carbonic anhydrase inhibitors. Most adverse events were mild or moderate and dose-dependent.

"The positive data from the FLOW trial confirm previous proof-of-concept study results and suggest that sulthiame offers the potential to treat obstructive sleep apnea with a mechanism of action that is distinct from other investigational drugs, including that of our lead asset AD109," said Dr Larry Miller, CEO of Apnimed. "Multiple mechanisms and approaches are needed if we are to effectively tackle the large prevalence, complexity and heterogeneity of OSA.”

Sulthiame has successfully completed two Phase 2 trials in over 300 European OSA patients,studied for a duration of up to three months. It has been used clinically in non-sleep indications outside the US and has demonstrated a favourable efficacy profile, enabling further clinical trials.

Apnimed previously acquired the intellectual property and exclusive global rights to develop and commercialise sulthiame from Desitin Arzneimittel.