Current OSA Treatments
Continuous Positive Airway Pressure (CPAP) is the most common treatment for OSA. CPAP devices work by blowing pressurized air into the nose, which keeps the pharyngeal airway open. CPAP is not curative, and patients must use the mask whenever they sleep. Reduction of the apnoea/hypopnea index (AHI) is the standard objective measure of therapeutic response in OSA. In the sleep laboratory, CPAP is highly effective at reducing the AHI. However, the device is cumbersome and difficult for many patients to tolerate. Most studies describe that 25-50% of patients refuse to initiate or completely discontinue CPAP use within the first several months and that most patients who continue use the device only intermittently. Studies in 2023 suggest that CPAP may not be the best choice for first line therapy.
C-PAP Device
Dental Devices
Surgery
Exercises and Stimulant Drug for Next Day Sleepiness
C-Pap is the standard treatment for OSA
Low Compliance Rate Reduces C-PAP Effectiveness
30% of patients prescribed CPAP never initiate treatment when prescribed a machine
Over 50% of patients stop using CPAP in the first year
Dronabinol for patients who cannot or will not tolerate CPAP
Oral devices may be an option for patients who cannot tolerate CPAP. Several dental devices are available including the Mandibular Advancement Device (MAD) and the Tongue Retaining Device (TRD). In November 2023, the US FDA provided 510(k) clearance for the treatment severe obstructive sleep apnea (OSA) in adults with removable CARE (Complete Airway Repositioning and/or Expansion) oral appliances. MAD is currently the most widely used dental device for sleep apnea and is similar in appearance to a sports mouth guard. It forces the lower jaw forward and down slightly which keeps the airway more open. The TRD is a splint that holds the tongue in place to keep the airway as open as possible. CARE appliances include a DNA oral appliance, a mRNA oral appliance and a mmRNA oral appliance which basically change the positioning of the jaw and/or expand the palate and claim to target the root cause of OSA. Like CPAP, oral devices are not curative for patients with OSA. The cost of these devices tends to be high and side effects associated with them include night-time pain, dry lips, tooth discomfort, and excessive salivation.
Patients with clinically significant OSA who cannot be adequately treated with CPAP or oral devices can elect to undergo surgery. The most common surgery is uvulopalatopharyngoplasty (UPPP), which involves the removal of excess tissue in the throat to make the airway wider. Other possible surgeries include tracheostomies, rebuilding of the lower jaw, and nose surgery. Patients who undergo surgery for the treatment of OSA risk complications, including infection, changes in voice frequency, and impaired sense of smell. Surgery is often unsuccessful, and at present, no method exists to reliably predict therapeutic outcome from any form of OSA surgery.
Another surgical option has become available based on upper airway stimulation. It is a combination of an implantable nerve stimulator and an external remote controlled by the patient. The hypoglossal nerve is a motor nerve that controls the tongue. The implanted device monitors every breath the patient takes and based on the unique breathing patterns, delivers mild stimulation to the nerve, to increase muscle tone to prevent the tongue and other soft tissues from collapsing. The surgically implanted device which is implanted via three incisions in the chest and neck in an approximately three hour surgical procedure under general anesthesia, is turned on at night and off in the morning by the patient with the remote.
Given the limited efficacy of most of the surgical options and the associated risks and the poor long-term compliance for mechanical devices, there exists a significant unmet medical need for a safe and effective treatment for OSA. A drug for the treatment for OSA has been sought for many years, but effective agents remain to be identified. Discovery efforts have been hampered by an incomplete understanding of the basic pathological mechanisms leading to apnea, lack of appropriate animal models to develop and test treatment strategies, and the multi-factorial nature of OSA.