Incannex Healthcare Inc, a pharmaceutical company developing medicinal cannabinoid pharmacotherapies and psychedelic medicine therapies, announced that an independent Institutional Review Board (IRB) has approved the protocol for the company’s phase 2/3 clinical trial to be conducted in the United States to assess IHL-42X in patients with obstructive sleep apnea (OSA). 

IRB approval of the protocol is a key step in the activation of clinical trial sites for the RePOSA study, a randomized, double-blind clinical trial to determine the safety and efficacy of IHL-42X in subjects with OSA who are intolerant, non-compliant, or naïve to positive airway pressure, such as that administered via a continuous positive airway pressure machine.

The RePOSA study consists of two component studies. A four-week phase 2 dose-ranging trial will determine the optimal dose of IHL-42X based on safety and efficacy in OSA patients, and a 52-week phase 3 factorial trial will compare the optimal dose of IHL-42X to the component APIs, dronabinol and acetazolamide, at equivalent doses, as well as placebo. The study is designed to facilitate a seamless transition between phase 2 and phase 3, reducing downtime and accelerating development timelines.

At least 560 patients will be recruited, with a total of 355 patients receiving IHL-42X over the course of the study. 

Start-up for the phase 2/3 trial is in progress, with 24 sites selected in the United States, 13 in Germany, four in Spain, and two in Finland. IRB approval of the protocol allows the US-based sites to proceed with site-specific approval, which is a critical step in site activation.

The RePOSA study follows a phase 2 proof-of-concept study whereby IHL-42X reduced the apnea-hypopnea index (AHI) by greater than 50% at the optimal dose, which was the low dose in the study. At the low dose of IHL-42X patient changes in AHI relative to baseline revealed that, during the treatment period, 62.5% of patients experienced a reduction in AHI of greater than 50%, and 25 % of patients experienced a reduction in AHI of greater than 80%.

IHL-42X also improved participant oxygen desaturation index, sleep efficiency, and patient reported sleep quality. IHL-42X was well tolerated in the study.