Impression Healthcare signs deal to progress cannabis medicine ‘dronabinol’ towards treatment of sleep apnoea

Impression Healthcare’s (ASX: IHL) dronabinol project has taken on anther dimension after the company signed a memorandum of understanding and exclusivity agreement with RespireRx Pharmaceuticals.

Dronabinol was the first ever cannabinoid medicine permitted for patient use by the Food and Drug Administration in the United States and a synthetic dronabinol has been marketed under the trade name Marinol since in 1986.

The deal means Impression has the right to licence, partner, or complete a joint venture over proprietary information associated with completed phase 2 clinical trials for the use of dronabinol to treat obstructive sleep apnoea.

Sleep apnoea is a serious sleep disorder that is characterised by interrupted breathing during sleep.

The disorder represents a significant global health challenge, which according to Australia’s largest provider of sleep studies, SNORE Australia, affects around 9% of women and 25% of men in Australia.

The issue is further exacerbated and potentially made worse due to an ageing population and rising obesity.

Its traditionally been treated using mechanical devices sold by the likes of big players, including Resmed and Somnomed. However, the gold standard being the CPAP machine is cumbersome and uncomfortable to use leading to patient non-conformance over time.

The term sheet will allow Impression to capitalise on a market opportunity for its existing dronabinol project and complements its existing activities for treating snoring and sleep apnoea.

Impression is currently enjoying growing sales of its mandibular advancement device, the Sleep Guardian Dorsal, which is sold through its preferred practitioner network of about 116 dental practices.

If successful, Impression wants to grow its footprint in the global sleep apnoea market, with the devices market valued at around US$5.5 million (A$7.7 million) in 2017.

Testing phases

To date, dronabinol has progressed through various testing phases for sleep apnoea and has recently completed phase 2B clinical trials.

Impression’s new MoU partner, Respire completed the trials in conjunction with the University of Illinois and Northwestern University in the US and is now progressing towards phase 3 trials.

The latest trial looked at the effectiveness of treating obstructive sleep apnoea and demonstrated that dronabinol “significantly improves” patient outcomes as measured by the Apnoea Hypopnea Index (AHI) and the Epworth Sleepiness Scale (ESS), which measures subsequent daytime sleepiness.

In the trial that enrolled 73 subjects with moderate to severe obstructive sleep apnoea and a baseline AHI of 26.0±11.6, reductions in the AHI of -9.7±4.1 (p=0.02) and 13.2±4.0 (p=0.001) were observed for the 2.5mg and 10mg doses, respectively.

Should results such as this continue, dronabinol has the potential to reduce severe sleep apnoea to moderate sleep apnoea and so on.

The Pharmacotherapy of Apnoea by Cannabimimetic Enhancement (PACE) trial was fully funded by a grant of around US$5 million (A$7 million) from the National Heart Lung and Blood Institute of the National Institutes of Health (NIH).

The study’s subjects received a placebo or either with a 2.5mg or 10mg dronabinol. Randomised subjects completed daily self-administration of the drug for six weeks with regular monitoring including overnight polysomnography (PSG) and physical examinations to ascertain progress.

“The PACE Trial demonstrates that dronabinol is effective in lowering AHI in patients with moderate obstructive sleep apnoea,” said Dr David Rapoport, professor of medicine at the Mount Sinai School of Medicine.

“There is a growing recognition that mild to moderate OSA is a very prevalent condition and may affect not only quality of life but also long-term cardiovascular and cerebrovascular health. Recent work also suggests a link of the AHI to memory loss and progression of Alzheimer Disease biomarkers. These data point to the possibility of a benefit of treating even asymptomatic individuals with elevated AHI,” said Dr Rapoport.

Dr Rapoport went on to say that “dronabinol is easy to take, appears to have a low side effect profile and now has been shown to be effective. It may, therefore, help address the significant medical need for alternative treatments for OSA. These promising early results should encourage the medical community of sleep specialists to explore this alternative therapy with appropriate patients.”

Looking to impress

Impression told the market in December that it had licenced a drug master file for the creation of dronabinol for long standing treatment applications being loss of appetite and supressing of nausea and vomiting.

Interest in treatment of sleep apnoea with dronabinol has the potential to increase the market for dronabinol over time.

“Dronabinol has the potential to change the way in which sleep apnoea is treated throughout the world and we’re excited to work with Respire towards our mutual goal to open this new market for dronabinol,” said Joel Latham, chief executive officer of Impression.

“With approximately half of all patients ceasing to use the CPAP in the first year of prescription due to discomfort, there is a major opportunity for viable alternative solutions to this significant health problem,” added Mr Latham.