Sleep apnoea drug firm Apnimed files for IPO

Apnimed has joined the IPO queue on the Nasdaq, hoping to raise additional funding for its late-stage oral therapy for obstructive sleep apnoea (OSA).

Founded in 2017, Cambridge, Massachusetts-based Apnimed is focused on developing AD109, a once-daily pill combining the novel antimuscarinic drug aroxybutynin and selective norepinephrine reuptake inhibitor (sNRI) atomoxetine that was filed for FDA approval in April, with a fast-track designation, and is heading for a decision in the first quarter of 2027.

OSA results in repeated interruptions in breathing during sleep caused by a narrowing and collapse of the airway. Untreated, it can lead to serious complications, such as heart attack, glaucoma, diabetes, cancer, and cognitive and behavioural disorders.

AD109 – which has the proposed trade name Oxnimbi – was studied in the phase 3 SynAIRgy and LunAIRo trials as an oral medication, taken at bedtime, designed to target the underlying neuromuscular causes of airway collapse in OSA and position the drug as the first oral therapy for the disorder.

In SynAIRgy, treatment with AD109 achieved a 44.1% reduction in apnoea-hypopnoea index (AHI) – which measures the average number of times breathing stops (apnoea) or becomes dangerously shallow (hypopnoea) per hour of sleep – at 26 weeks compared to placebo. The LunAIRo trial showed a 33.7% reduction.

The studies involved patients who couldn't tolerate or refused continuous positive airway pressure (CPAP) devices, the standard treatment approach. Taking AD109 before bedtime reduced the number of AHI events by approximately four per hour. Meanwhile, about 21% of patients in the treatment arm discontinued treatment due to adverse events, compared to 3% with placebo.

OSA impacts 80 million adults in the US, with more than 20 million living with moderate-to-severe symptoms, but it is estimated that a large majority (around 85%) of cases go undiagnosed and therefore untreated.

In late 2024, Eli Lilly's injectable GIP/GLP-1 agonist Zepbound (tirzepatide) became the first FDA-approved therapy for OSA, in combination with a reduced-calorie diet and increased physical exercise, in adults with obesity.

According to Apnimed's IPO prospectus, proceeds from the IPO will be used to fund the regulatory process for Oxnimbi and to prepare for the commercial launch of the drug.

"We believe a novel, oral, and convenient treatment option that targets the underlying cause of OSA is well positioned to address significant unmet need. A pharmacological option could unlock latent demand for treatment and expand overall awareness, screening, diagnosis, and treatment of OSA," according to the prospectus.

"Therefore, we designed Oxnimbi as an oral, once-daily, rapid-onset therapy to improve upper airway muscle activity during sleep, a crucial underlying cause of all OSA," it goes on. "If approved, we believe Oxnimbi has the potential to become a standard of care for the treatment of OSA."

Apnimed intends to list on the Nasdaq under the APMD symbol.