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Apnimed preparing for sleep apnea drug approval with USD 150m debt, royalty deal

Cambridge, Massachusetts-based Apnimed, Inc. has secured up to USD 150 million in debt financing from HealthCare Royalty Partners to support commercial preparation and the planned US launch of AD109, its oral candidate for obstructive sleep apnea (OSA), ahead of a New Drug Application (NDA) expected this year.

The financing takes the form of a senior secured credit facility structured in three tranches of USD 50 million each. Apnimed receives the first tranche at closing. The second becomes available upon US FDA approval of AD109, and the third is contingent on reaching a pre-specified sales milestone. The facility carries an interest-only period of four years, extendable to five years upon achievement of a net sales threshold. As part of the arrangement, Apnimed agreed to pay a synthetic royalty equal to a low single-digit percentage of net sales of AD109 and certain other specified revenues. HealthCare Royalty Partners, known as HCRx, is majority owned by KKR & Co. Inc. (NYSE: KKR).

AD109 is a once-daily oral combination of aroxybutynin, a novel antimuscarinic, and atomoxetine, a selective norepinephrine reuptake inhibitor. The two agents are designed to act on complementary neurochemical pathways governing upper airway muscle tone during sleep. Atomoxetine increases noradrenergic drive to hypoglossal motor neurons, while aroxybutynin reduces inhibitory muscarinic signaling at the same neurons — a mechanism intended to prevent the pharyngeal muscle atonia that underlies airway collapse in OSA. Apnimed describes AD109 as a first-in-class pharmacological approach to the condition.

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The scientific basis for the combination draws on peer-reviewed research published before and alongside Apnimed's clinical program, including work published in the American Journal of Respiratory and Critical Care Medicine in 2018 documenting apnea severity reduction with an atomoxetine and oxybutynin combination, and subsequent studies including in the Annals of the American Thoracic Society.

AD109 has completed two registrational Phase III trials — SynAIRgy and LunAIRo — in patients with mild, moderate, and severe OSA. Both trials have reported results that Apnimed said will support the NDA filing. A continuation protocol is listed as enrolling by invitation. The NDA submission is expected later in Q2 2026, the company said.


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