The once-daily oral carbonic anhydrase inhibitor met its primary endpoint, reducing AHI and improving nocturnal oxygenation in adults with moderate to severe OSA.

Key takeaways:

Positive results from the phase 2 FLOW study of sulthiame, an investigational oral drug for obstructive sleep apnea (OSA), have been published in The Lancet.
The study met its primary endpoint, with all three doses of sulthiame demonstrating a dose-dependent reduction in the apnea-hypopnea index over 15 weeks.
The drug also led to significant improvements in nocturnal oxygenation, including the ODI and mean overnight oxygen saturation.
Sulthiame was generally well-tolerated among the 298 study participants, with most adverse events being mild or moderate and dose-dependent.

Apnimed Inc announced the publication of positive results in The Lancet from its phase 2 FLOW study, which evaluated sulthiame for the treatment of obstructive sleep apnea (OSA). The study found that the once-daily oral carbonic anhydrase inhibitor significantly improved key OSA metrics in adults with moderate to severe disease.

The FLOW study was a multicenter, randomized, double-blind, placebo-controlled trial that enrolled 298 adults with untreated, moderate to severe OSA across 28 sites in Europe. Patients were administered one of three dosages of sulthiame (100 mg, 200 mg, or 300 mg) once daily at bedtime for 15 weeks.

The trial met its primary endpoint—a relative change in the apnea-hypopnea index (AHI) from baseline—for all sulthiame doses, establishing a clear dose-response effect.

According to the results, all sulthiame doses produced a consistent, dose-dependent reduction in breathing disturbances. The treatment also led to significant improvements in nocturnal oxygenation, as measured by the oxygen desaturation index (ODI) and mean overnight oxygen saturation. Sulthiame demonstrated a favorable safety profile and was generally well-tolerated. Reported adverse events were consistent with the known pharmacology of carbonic anhydrase inhibitors and were primarily 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,” says Larry Miller, MD, CEO of Apnimed, in a release. “Multiple mechanisms and approaches are needed if we are to effectively tackle the large prevalence, complexity and heterogeneity of OSA. …We look forward to working with our colleagues at Shionogi to advance sulthiame into further clinical development.”

Sulthiame is an investigational drug designed to restore nighttime breathing stability. Apnimed is developing the candidate with Shionogi & Co Ltd through their joint venture, Shionogi-Apnimed Sleep Science.