Reboxetine Plus Oxybutynin for OSA Treatment: A 1-Week, Randomized, Placebo-Controlled, Double-Blind Crossover Trial

Sleep Apnea and Stroke: A Narrative Review

TOPIC IMPORTANCE

Stroke is the second-leading cause of death worldwide. OSA is an independent risk factor for stroke and is associated with multiple vascular risk factors. Poststroke OSA is prevalent and closely linked with various stroke subtypes, including cardioembolic stroke and cerebral small vessel disease. Observational studies have shown that untreated poststroke OSA is associated with an increased risk of recurrent stroke, mortality, poorer functional recovery, and longer hospitalizations.

REVIEW FINDINGS

Poststroke OSA tends to be underdiagnosed and undertreated, possibly because stroke patients with OSA present atypically compared with the general population with OSA. Objective testing, such as the use of ambulatory sleep testing or in-laboratory polysomnography, is recommended for diagnosing OSA. The gold standard for treating OSA is CPAP therapy. Randomized controlled trials (RCTs) have shown that treatment of poststroke OSA using CPAP improves nonvascular outcomes such as cognition and neurologic recovery. However, findings from RCTs that have evaluated the effect of CPAP on recurrent stroke risk and mortality have been largely negative.

SUMMARY

There is a need for high-quality RCTs in poststroke OSA that may provide evidence to support the utility of CPAP (and/or other treatment modalities) in reducing recurrent vascular events and mortality. This goal may be achieved by examining treatment strategies that have yet to be trialed in poststroke OSA, tailoring interventions according to poststroke OSA endotypes and phenotypes, selecting high-risk populations, and using metrics that reflect the physiological abnormalities that underlie the harmful effects of OSA on cardiovascular outcomes.

Effects of the antipsychotic quetiapine on sleep and breathing: a review of clinical findings and potential mechanisms

Quetiapine is an antipsychotic medication indicated for schizophrenia and bipolar disorder. However, quetiapine also has hypnotic properties and as such is increasingly being prescribed at low doses 'off-label' in people with insomnia symptoms. Pharmacologically, in addition to its dopaminergic properties, quetiapine also modulates multiple other transmitter systems involved in sleep/wake modulation and potentially breathing. However, very little is known about the impact of quetiapine on obstructive sleep apnoea (OSA), OSA endotypes including chemosensitivity, and control of breathing. Given that many people with insomnia also have undiagnosed OSA, it is important to understand the effects of quetiapine on OSA and its mechanisms. Accordingly, this concise review covers the existing knowledge on the effects of quetiapine on sleep and breathing. Further, we highlight the pharmacodynamics of quetiapine and its potential to alter key OSA endotypes to provide potential mechanistic insight. Finally, an agenda for future research priorities is proposed to fill the current key knowledge gaps.

ERS International Congress 2023: highlights from the Sleep Disordered Breathing Assembly

The topic of sleep-related breathing disorders is always evolving, and during the European Respiratory Society (ERS) International Congress 2023 in Milan, Italy, the latest research and clinical topics in respiratory medicine were presented. The most interesting issues included new diagnostic tools, such as cardiovascular parameters and artificial intelligence, pathophysiological traits of sleep disordered breathing from routine polysomnography or polygraphy signals, and new biomarkers and the diagnostic approach in patients with excessive daytime sleepiness. This article summarises the most relevant studies and topics presented at the ERS International Congress 2023. Each section has been written by early career members of ERS Assembly 4.

Combination pharmacological therapy targeting multiple mechanisms of sleep apnoea: a randomised controlled cross-over trial

RATIONALE

Acetazolamide and atomoxetine-plus-oxybutynin ('AtoOxy') can improve obstructive sleep apnoea (OSA) by stabilising ventilatory control and improving dilator muscle responsiveness respectively. Given the different pathophysiological mechanisms targeted by each intervention, we tested whether AtoOxy-plus-acetazolamide would be more efficacious than AtoOxy alone.

METHODS

In a multicentre randomised crossover trial, 19 patients with moderate-to-severe OSA received AtoOxy (80/5 mg), acetazolamide (500 mg), combined AtoOxy-plus-acetazolamide or placebo at bedtime for three nights (half doses on first night) with a 4-day washout between conditions. Outcomes were assessed at baseline and night 3 of each treatment period. Mixed model analysis compared the reduction in Apnoea-Hypopnoea Index (AHI) from baseline between AtoOxy-plus-acetazolamide and AtoOxy (primary outcome). Secondary outcomes included hypoxic burden and arousal index.

RESULTS

Although AtoOxy lowered AHI by 49 (33, 62)%baseline (estimate (95% CI)) vs placebo, and acetazolamide lowered AHI by+34 (14, 50)%baseline vs placebo, AtoOxy-plus-acetazolamide was not superior to AtoOxy alone (difference: -2 (-18, 11)%baseline, primary outcome p=0.8). Likewise, the hypoxic burden was lowered with AtoOxy (+58 (37, 71)%baseline) and acetazolamide (+37 (5, 58)%baseline), but no added benefit versus AtoOxy occurred when combined (difference: -13 (-5, 39)%baseline). Arousal index was also modestly reduced with each intervention (11%baseline-16%baseline). Mechanistic analyses revealed that similar traits (ie, higher baseline compensation, lower loop gain) were associated with both AtoOxy and acetazolamide efficacy.

CONCLUSIONS

While AtoOxy halved AHI, and acetazolamide lowered AHI by a third, the combination of these leading experimental interventions provided no greater efficacy than AtoOxy alone. Failure of acetazolamide to further increase efficacy suggests overlapping physiological mechanisms.

TRIAL REGISTRATION NUMBER

NCT03892772.

Pharmacological treatment for obstructive sleep apnea: A systematic review and meta-analysis

OBJECTIVE

Summarize the evidence on drug therapies for obstructive sleep apnea.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. PubMed, Embase, Scopus, Web of Science, SciELO, LILACS, Scopus, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov were searched on February 17th, 2023. A search strategy retrieved randomized clinical trials comparing the Apnea-Hypopnea Index (AHI) in pharmacotherapies. Studies were selected and data was extracted by two authors independently. The risk of bias was assessed using the Cochrane Risk of Bias tool. RevMan 5.4. was used for data synthesis.

RESULTS

4930 articles were obtained, 68 met inclusion criteria, and 29 studies (involving 11 drugs) were combined in a meta-analysis. Atomoxetine plus oxybutynin vs placebo in AHI mean difference of -7.71 (-10.59, -4.83) [Fixed, 95 % CI, I2 = 50 %, overall effect: Z = 5.25, p < 0.001]. Donepezil vs placebo in AHI mean difference of -8.56 (-15.78, -1.33) [Fixed, 95 % CI, I2 = 21 %, overall effect: Z = 2.32, p = 0.02]. Sodium oxybate vs placebo in AHI mean difference of -5.50 (-9.28, -1.73) [Fixed, 95 % CI, I2 = 32 %, overall effect: Z = 2.86, p = 0.004]. Trazodone vs placebo in AHI mean difference of -12.75 (-21.30, -4.19) [Fixed, 95 % CI, I2 = 0 %, overall effect: Z = 2.92, p = 0.003].

CONCLUSION

The combination of noradrenergic and antimuscarinic drugs shows promising results. Identifying endotypes may be the key to future drug therapies for obstructive sleep apnea. Moreover, studies with longer follow-up assessing the safety and sustained effects of these treatments are needed.

PROSPERO REGISTRATION NUMBER

CRD42022362639.

The Combination of Aroxybutynin and Atomoxetine in the Treatment of Obstructive Sleep Apnea (MARIPOSA): A Randomized Controlled Trial

Rationale: Obstructive sleep apnea (OSA) is a common sleep disorder for which the principal treatment option, continuous positive airway pressure, is often poorly tolerated. There is currently no approved pharmacotherapy for OSA. However, recent studies have demonstrated improvement in OSA with combined antimuscarinic and noradrenergic drugs. Objectives: The aim of this study was to evaluate the efficacy and safety of AD109, a combination of the novel antimuscarinic agent aroxybutynin and the norepinephrine reuptake inhibitor atomoxetine, in the treatment of OSA. Methods: Phase II randomized, double-blind, placebo-controlled, parallel-group, 4-week trial comparing AD109 2.5/75 mg, AD109 5/75 mg, atomoxetine 75 mg alone, and placebo (www.clinicaltrials.gov identifier NCT05071612). Measurements and Main Results: Of 211 randomized patients, 181 were included in the prespecified efficacy analyses. Sleep was assessed by two baseline and two treatment polysomnograms. Apnea-hypopnea index with a 4% desaturation criterion (primary outcome) was reduced from a median (IQR) of 20.5 (12.3-27.2) to 10.8 (5.6-18.5) in the AD109 2.5/75 mg arm (-47.1%), from 19.4 (13.7-26.4) to 9.5 (6.1-19.3) in the AD109 5/75 mg arm (-42.9%; both P < 0.0001 vs. placebo), and from 19.0 (11.8-28.8) to 11.8 (5.5-21.5) with atomoxetine alone (-38.8%; P < 0.01 vs. placebo). Apnea-hypopnea index with a 4% desaturation criterion decreased from 20.1 (11.9-25.9) to 16.3 (11.1-28.9) in the placebo arm. Subjectively, there was improvement in fatigue with AD109 2.5/75 mg (P < 0.05 vs. placebo and atomoxetine). Atomoxetine taken alone decreased total sleep time (P < 0.05 vs. AD109 and placebo). The most common adverse events were dry mouth, insomnia, and urinary hesitancy. Conclusions: AD109 showed clinically meaningful improvement in OSA, suggesting that further development of the compound is warranted. Clinical trial registered with www.clinicaltrials.gov (NCT05071612).

A Narrative Review of the Clinical Trials in Sleep-Related Breathing Disorders from 2022 to Present

Sleep-related breathing disorders (SRBD) comprise obstructive sleep apnea (OSA), central sleep apnea (CSA), obesity-hypoventilation syndrome (OHS), as well as isolated sleep-related hypoxemia (ISRH), according to the recent International Classification of Sleep Disorders 3. During the last decades, there have been cumulative research reports indicating an association between the SRBD and increased cardiometabolic illness and death, as well as decreased quality of life. Notwithstanding, the results have been inconclusive, and the evidence level was not high regarding the effect of treatment for the SRBD on adverse outcomes. In the current work, we aim to give a comprehensive review of the clinical trials published from January 2022 to August 31, 2023. We highlight the heterogeneity of cardiometabolic disorders among adults with SRBD and particularly emphasize OSA management, drug therapy for OSA, positive airway pressure (PAP) therapy and cardiovascular outcomes, other effects of PAP in pregnancy and neurocognitive function, as well as the effects of surgical treatment and oral appliances. We also underline future directions in OSA management, telemonitoring, and druginduced sleep endoscopy in managing the SRBD, especially OSA. We ascertain that more studies are needed within the CSA, OHS, and ISRH research fields.

A muscarinic, GIRK channel-mediated inhibition of inspiratory-related XII nerve motor output emerges in early postnatal development in mice

In neonatal rhythmic medullary slices, muscarinic acetylcholine receptor (mAChR) activation of hypoglossal (XII) motoneurons that innervate the tongue has a net excitatory effect on XII inspiratory motor output. Conversely, during rapid eye movement sleep in adult rodents, XII motoneurons experience a loss of excitability partly due to activation of mAChRs. This may be mediated by activation of G-protein-coupled inwardly rectifying potassium (GIRK) channels. Therefore, this study was designed to evaluate whether muscarinic modulation of XII inspiratory motor output in mouse rhythmic medullary slices includes GIRK channel-mediated inhibition and, if so, when this inhibitory mechanism emerges. Local pressure injection of the mAChR agonist muscarine potentiated inspiratory bursting by 150 ± 28% in postnatal day (P)0-P5 rhythmic medullary slice preparations. In the absence of muscarine, pharmacological GIRK channel block by Tertiapin-Q did not affect inspiratory burst parameters, whereas activation with ML297 decreased inspiratory burst area. Blocking GIRK channels by local preapplication of Tertiapin-Q revealed a developmental change in muscarinic modulation of inspiratory bursting. In P0-P2 rhythmic medullary slices, Tertiapin-Q preapplication had no significant effect on muscarinic potentiation of inspiratory bursting (a negligible 6% decrease). However, preapplication of Tertiapin-Q to P3-P5 rhythmic medullary slices caused a 19% increase in muscarinic potentiation of XII inspiratory burst amplitude. Immunofluorescence experiments revealed expression of GIRK 1 and 2 subunits and M1, M2, M3, and M5 mAChRs from P0 to P5. Overall, these data support that mechanisms underlying muscarinic modulation of inspiratory burst activity change postnatally and that potent GIRK-mediated inhibition described in adults emerges early in postnatal life.NEW & NOTEWORTHY Muscarinic modulation of inspiratory bursting at hypoglossal motoneurons has a net excitatory effect in neonatal rhythmic medullary slice preparations and a net inhibitory effect in adult animals. We demonstrate that muscarinic modulation of inspiratory bursting undergoes maturational changes from postnatal days 0 to 5 that include emergence of an inhibitory component mediated by G-protein-coupled inwardly rectifying potassium channels after postnatal day 3 in neonatal mouse rhythmic medullary slice preparations.

Pharmacological management of co-morbid obstructive sleep apnoea and insomnia

INTRODUCTION

Clinical presentation of both insomnia and obstructive sleep apnea (COMISA) is common. Approximately 30% of clinical cohorts with OSA have insomnia symptoms and vice versa. The underlying pathophysiology of COMISA is multifactorial. This poses a complex clinical challenge. Currently, there are no clinical guidelines or recommendations outside of continuous positive airway pressure (CPAP) therapy and cognitive behavioral therapy for insomnia (CBTi). Clinically translatable precision medicine approaches to characterize individual causes or endotypes may help optimize future pharmacological management of COMISA.

AREAS COVERED

This review article provides an up-to-date account of COMISA and its consequences, the underlying pathophysiology of sleep apnea, insomnia and COMISA, current treatment approaches and limitations, pharmacotherapy targets and future priorities.

EXPERT OPINION

There are multiple promising emerging therapies, but clinical trial data specifically in COMISA populations are lacking. This is a priority for future investigation to inform development of evidence-based guidelines. Pharmacotherapies, particularly for insomnia, do not target the underlying causes of the disorder thus, are indicated for short-term use only and should remain second line. Future multidisciplinary research should be directed toward the multifactorial nature of COMISA and the challenges of adapting COMISA treatment in clinical practice and overcoming the practical barriers that health-care providers and consumers encounter.

Optical and pharmacological manipulation of hypoglossal motor nucleus identifies differential effects of taltirelin on sleeping tonic motor activity and responsiveness

Pharyngeal muscle activity and responsiveness are key pathophysiological traits in human obstructive sleep apnea (OSA) and strong contributors to improvements with pharmacotherapy. The thyrotropin-releasing hormone (TRH) analog taltirelin is of high pre-clinical interest given its neuronal-stimulant properties, minimal endocrine activity, tongue muscle activation following microperfusion into the hypoglossal motor nucleus (HMN) or systemic delivery, and high TRH receptor expression at the HMN compared to rest of the brain. Here we test the hypothesis that taltirelin increases HMN activity and/or responsivity to excitatory stimuli applied across sleep-wake states in-vivo. To target hypoglossal motoneurons with simultaneous pharmacological and optical stimuli we used customized "opto-dialysis" probes and chronically implanted them in mice expressing a light sensitive cation channel exclusively on cholinergic neurons (ChAT-ChR2, n = 12) and wild-type mice lacking the opsin (n = 10). Both optical stimuli applied across a range of powers (P < 0.001) and microperfusion of taltirelin into the HMN (P < 0.020) increased tongue motor activity in sleeping ChAT-ChR2 mice. Notably, taltirelin increased tonic background tongue motor activity (P < 0.001) but not responsivity to excitatory optical stimuli across sleep-wake states (P > 0.098). This differential effect on tonic motor activity versus responsivity informs human studies of the potential beneficial effects of taltirelin on pharyngeal motor control and OSA pharmacotherapy.

Targets for obstructive sleep apnea pharmacotherapy: principles, approaches, and emerging strategies

INTRODUCTION

Obstructive sleep apnea (OSA) is a common and serious breathing disorder. Several pathophysiological factors predispose individuals to OSA. These factors are quantifiable, and modifiable pharmacologically.

AREAS COVERED

Four key pharmacotherapeutic targets are identified and mapped to the major determinants of OSA pathophysiology. PubMed and Clinicaltrials.gov were searched through April 2023.

EXPERT OPINION

Target #1: Pharyngeal Motor Effectors. Increasing pharyngeal muscle activity and responsivity with noradrenergic-antimuscarinic combination is central to recent breakthrough OSA pharmacotherapy. Assumptions, knowledge gaps, future directions, and other targets are identified. #2: Upper Airway Sensory Afferents. There is translational potential of sensitizing and amplifying reflex pharyngeal dilator muscle responses to negative airway pressure via intranasal delivery of new potassium channel blockers. Rationales, advantages, findings, and potential strategies to enhance effectiveness are identified. #3: Chemosensory Afferents and Ventilatory Control. Strategies to manipulate ventilatory control system sensitivity by carbonic anhydrase inhibitors are supported in theory and initial studies. Intranasal delivery of agents to stimulate central respiratory activity are also introduced. #4: Sleep-Wake Mechanisms. Arousability is the fourth therapeutic target rationalized. Evolving automated tools to measure key pathophysiological factors predisposing to OSA will accelerate pharmacotherapy. Although not currently ready for general clinical settings, the identified targets are of future promise.

Pharmacotherapy for obstructive sleep apnea: targeting specific pathophysiological traits

INTRODUCTION

The pathophysiology of obstructive sleep apnea (OSA) is multi-factorial and complex. Varying OSA's pathophysiological traits have been identified, including pharyngeal collapsibility, upper airway muscle reactivity, arousal threshold, and regulation of the ventilatory drive. Being CPAP of difficult tolerance and other interventions reserved to specific subpopulations new pharmacological treatments for OSA might be resolutive.

AREAS COVERED

Several existing and newly developed pharmacological drugs can impact one or more endotypes and could therefore be proposed as treatment options for sleep disordered breathing. With this review we will explore different pathophysiological traits as new targets for OSA therapy. This review will summarize the most promising pharmacological treatment for OSA accordingly with their mechanisms of action on upper airway collapsibility, muscle responsiveness, arousal threshold, and loop gain.

EXPERT OPINION

Only understanding the pathophysiological traits causing OSA in each patient and placing the disease in the framework of patient comorbidities, we will be able to evolve interventions toward OSA. The development of new drug's combinations will permit different approaches and different choices beside conventional treatments. In the next future, we hope that sleep specialists will select the treatment for a specific patient on the base of its pathophysiology, defining a precision medicine for OSA.

The combination of atomoxetine and dronabinol for the treatment of obstructive sleep apnea: a dose-escalating, open-label trial

STUDY OBJECTIVES

The potential sedative effect of dronabinol and the high expression of cannabinoid receptors on the hypoglossal motor nuclei makes this agent a good candidate for obstructive sleep apnea (OSA) pharmacotherapy to be tested with atomoxetine, a noradrenergic reuptake inhibitor that reduced OSA severity in combination with oxybutynin. Here we tested the effect of atomoxetine 80 mg plus dronabinol (Ato-Dro) at 2 different doses (5 and 10 mg) vs. baseline and atomoxetine alone in a 2-center, open-label, dose-escalating trial. The primary outcome was the effect of Ato-Dro vs. baseline on OSA severity (apnea-hypopnea index, hypopneas associated with 4% oxygen desaturation). Safety of the combination and self-reported outcomes were also assessed.

METHODS

Fifteen patients with OSA received progressively increasing Ato-Dro doses (dose escalation was performed every week, starting from Ato-Dro 40-2.5 mg, then 80-5 mg and finally 80-10 mg). A clinical, in-lab polysomnography was performed at baseline, on Ato-Dro 80-5 and Ato-Dro 80-10 mg.

RESULTS

Ato-Dro 80-10 mg did not significantly reduce apnea-hypopnea index, hypopneas associated with 4% oxygen desaturation, and hypoxic burden and yielded limited clinical benefit vs. baseline and atomoxetine alone. However, Ato-Dro 80-5 mg did improve OSA severity (Δapnea-hypopnea index = 8.3[0.3, 16.3] events/h; mean [confidence interval]; Δhypoxic burden = 37.7[12.5, 62.7] %min/h) and multiple self-reported outcomes vs. baseline and/or atomoxetine alone. Ato-Dro administration was characterized by several potentially harmful side effects and treatment discontinuation in 1/3 of cases.

CONCLUSIONS

Ato-Dro 80-5 mg might be useful to reduce OSA severity and lead to self-reported improvement in those who could tolerate the combination. However, given the numerous side effects and the exploratory nature of this open-label study, our results warrant further validation in larger trials.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Title: Study for Efficacy and Dose Escalation of AD313 + Atomoxetine (SEED) (SEED); URL: https://clinicaltrials.gov/ct2/show/NCT05101122; Identifier: NCT05101122.

CITATION

Messineo L, Norman D, Ojile J. The combination of atomoxetine and dronabinol for the treatment of obstructive sleep apnea: a dose-escalating, open-label trial. J Clin Sleep Med. 2023;19(7):1183-1190.

Pharmacotherapy for obstructive sleep apnea - A systematic review and meta-analysis of randomized controlled trials

Continuous positive airway pressure is the first-line and gold-standard treatment for obstructive sleep apnea (OSA). Pharmacotherapy is not commonly used in treating OSA until recently. Combined noradrenergic and antimuscarinic agents have been clinically applied for OSA patients with variable results. This meta-analysis study aimed to investigate the efficacy of the combined regimen on OSA. A systematic literature search was performed up to November 2022 for the effects of the combined regimen on OSA. Eight randomized controlled trials were identified and systematically reviewed for meta-analysis. There were significant mean differences between OSA patients taking a combined regimen and placebo in apnea-hypopnea index (AHI) [mean difference (MD) -9.03 events/h, 95%CI (-16.22, -1.83 events/h; P = 0.01] and lowest oxygen saturation [MD 5.61%, 95% CI % (3.43, 7.80); P < 0.01]. Meta-regression showed that a higher proportion of male participants was associated with a greater reduction of AHI (p = 0.04). This study showed a positive but modest effect of pharmacotherapy in the reduction of OSA severity. The combination drugs are most applicable to male OSA patients based on their efficacy and pharmacological susceptibility. Pharmacotherapy may be applied as an alternative, adjunctive or synergistic treatment under careful consideration of its side effects.

Effects of atomoxetine plus a hypnotic on obstructive sleep apnea severity in patients with a moderately collapsible pharyngeal airway

STUDY OBJECTIVES

Pharmacotherapy for obstructive sleep apnea (OSA) regained consideration after the discovery that atomoxetine and oxybutynin greatly reduced OSA severity. However, atomoxetine and oxybutynin reduced the arousal threshold and may therefore be poorly tolerated in patients with OSA and disturbed sleep. As a result, we tested the combination of atomoxetine plus 2 hypnotics in patients with OSA. The effects of atomoxetine plus: (1) trazodone (Ato-Trazo) and (2) lemborexant vs placebo on apnea-hypopnea index, hypoxic burden, arousal threshold, and total sleep time were assessed. Drug safety was also ascertained, together with the effect of the combinations on other OSA traits, self-reported sleep quality, and next-day alertness.

METHODS

Following a baseline study, 15 patients with mild-to-severe OSA with moderate upper airway collapsibility were administered Ato-Trazo, atomoxetine and lemborexant, and matching placebo according to a double-blind, randomized, crossover design. Apnea-hypopnea index and other objective outcomes were calculated from 3 clinical, in-laboratory polysomnograms.

RESULTS

Ato-Trazo significantly reduced apnea-hypopnea index from a median [interquartile range] of 18.2 [11.8 to 31.3] on placebo to 7.4 [5.4 to 16.1] events/h, P = .024, and hypoxic burden from 46.3 [25.1 to 88.3] on placebo to 18.7 [14.9 to 43.5], P = .003. This effect was likely driven by an increase in polysomnography-estimated pharyngeal muscle activity during the events (P = .029). Atomoxetine and lemborexant had smaller statistically insignificant effects. Contrary to atomoxetine and oxybutynin, Ato-Trazo and atomoxetine and lemborexant did not reduce the arousal threshold. Both combinations had no effect on total sleep time but worsened self-reported sleep quality.

CONCLUSIONS

Ato-Trazo has the potential to become a useful drug combination, however, longer trials are needed to determine the best dosage and the subgroup of patients who may benefit most from this combination.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Crossover Trial of AD182 and AD504 in Obstructive Sleep Apnea; URL: https://clinicaltrials.gov/ct2/show/NCT04645524; Identifier: NCT04645524.

CITATION

Corser B, Eves E, Warren-McCormick J, Rucosky G. Effects of atomoxetine plus a hypnotic on obstructive sleep apnea severity in patients with a moderately collapsible pharyngeal airway. J Clin Sleep Med. 2023;19(6):1035-1042.

The placebo effect in pharmacological treatment of obstructive sleep apnea, a systematic review and meta-analysis

OBJECTIVE

New drug treatments are under development in obstructive sleep apnea (OSA). The placebo effect is well recognized in various conditions, but its relevance in OSA is debated. In the current study we determined the influence of a placebo effect in studies of drug therapy in OSA.

METHODS

A systematic review and meta-analysis (PROSPERO CRD42021229410) with searches in MEDLINE, Scopus, Web of Science and Cochrane CENTRAL from inception to 2021-01-19. Inclusion criteria were (i) RCTs of adults with OSA, (ii) drug intervention with placebo baseline and follow-up sleep study (iii) outcomes: apnea hypopnea index (AHI), mean oxygen saturation (mSaO2), oxygen desaturation index (ODI) and/or Epworth Sleepiness Scale (ESS). Risk-of-bias was assessed with Cochrane RoB 2.

RESULTS

7436 articles were identified and 29 studies included (n = 413). Studies were generally small (median n = 14), with 78% men, baseline AHI range 9-74 events/h and treatment duration range 1-120 days. Meta-analyses were conducted for main outcomes. Mean change of the primary outcome, AHI, was -0.84 (95% CI -2.98 to 1.30); mSaO2 and ODI estimations were also non-significant. ESS showed a trend towards a reduction of -1 unit. Subgroup analysis did not show significant differences. Risk-of-bias assessment indicated mostly low risk but studies were small with wide confidence intervals.

CONCLUSIONS

In this meta-analysis we did not identify systematic placebo effects on the AHI, ODI or mSaO2 while ESS score showed a trend for a small reduction. These results have an impact on the design and interpretation of drug trials in OSA.

Effects of the combination of atomoxetine and oxybutynin in Japanese patients with obstructive sleep apnoea: A randomized controlled crossover trial

BACKGROUND AND OBJECTIVE

The possibility of combination therapy with atomoxetine (ATO) and oxybutynin (OXY) has been suggested for obstructive sleep apnoea (OSA). However, the effectiveness of this treatment remains uninvestigated in Japanese OSA patients. Therefore, we performed a randomized, crossover, phase II, single-centre prospective trial to examine the effects of ATO-OXY therapy in Japanese OSA patients.

METHODS

In total, 17 OSA patients participated in this study. The effects of one night of 80-mg ATO plus 5-mg OXY administration were compared with those of no medication administered before sleep. The primary and secondary outcomes comprised the apnoea-hypopnoea index (AHI) and nadir SpO₂ , SpO₂ drop time and sleep architecture, respectively. The safety endpoints included drug side effects and adverse events.

RESULTS

The values of AHI, nadir SpO₂ , 3% oxygen desaturation index (ODI), 4% ODI, and SpO₂ drop time of <90% did not significantly differ between patients receiving ATO-OXY administration and no medication. Sleep architecture exhibited a significant change: ATO-OXY increased sleep stage N1 (p < 0.0001) and decreased stage N2 (p = 0.03), rapid eye movement (p < 0.0001) and sleep efficiency (p = 0.02). However, the subanalysis demonstrated an obvious decrease in AHI in five responder patients. Total sleep time and basal sleep efficiency tended to be lower in the responders compared with nonresponders (p = 0.065). No patients experienced severe adverse events or side effects.

CONCLUSION

Overall, ATO-OXY therapy does not reduce AHI in Japanese OSA patients, although AHI was decreased in a proportion of patients. Future studies for identifying treatment response group characteristics are warranted.

Impact of reboxetine plus oxybutynin treatment for obstructive sleep apnea on cardiovascular autonomic modulation

The combination of noradrenergic (reboxetine) plus antimuscarinic (oxybutynin) drugs (reb-oxy) reduced obstructive sleep apnea (OSA) severity but no data are available on its effects on cardiac autonomic modulation. We sought to evaluate the impact of 1-week reb-oxy treatment on cardiovascular autonomic control in OSA patients. OSA patients were randomized to a double-blind, crossover trial comparing 4 mg reboxetine plus 5 mg oxybutynin to a placebo for OSA treatment. Heart rate (HR) variability (HRV), ambulatory blood pressure (BP) monitoring (ABPM) over 24 h baseline and after treatment were performed. Baroreflex sensitivity was tested over beat-to-beat BP recordings. 16 subjects with (median [interquartile range]) age 57 [51-61] years and body mass index 30 [26-36]kg/m² completed the study. The median nocturnal HR was 65 [60-69] bpm at baseline and increased to 69 [64-77] bpm on reb-oxy vs 66 [59-70] bpm on placebo (p = 0.02). The mean 24 h HR from ABPM was not different among treatment groups. Reb-oxy administration was not associated with any modification in HRV or BP. Reb-oxy increased the baroreflex sensitivity and did not induce orthostatic hypotension. In conclusion, administration of reb-oxy did not induce clinically relevant sympathetic overactivity over 1-week and, together with a reduction in OSA severity, it improved the baroreflex function.

Placebo response in objective and subjective measures of hypersomnia in randomized clinical trials on obstructive sleep apnea. A systematic review and meta-analysis

Sleepiness is one of the outcomes most used in randomized clinical trials (RCT) on the effect of treatments for obstructive sleep apnea (OSA). Furthermore, it is known that there is a placebo effect, especially in subjective measures. Therefore, given that sleepiness is a subjective measure, the objective of this systematic review with meta-analysis and three-level meta-regression was to assess the response to different placebos (pills and sham-CPAP) used in RCTs in OSA, both on subjective (Epworth Sleepiness Scale [ESS]) and objective (Multiple Sleep Latency Test [MSLT], Maintenance Wake Test [MWT], the Osler test and the Psychomotor Vigilance Task [PVT]). We observed a statistically significant placebo effect in both subjective and objective measures of hypersomnia, and in both sham-CPAP and pills. This placebo effect was greater, even clinically significant, in subjective measures (ESS: -2.84 points) and in those RCTs that used pills as a placebo. In the meta-regression, only a higher baseline value of the ESS and Osler test was related to the placebo effect.

The norepinephrine reuptake inhibitor reboxetine alone reduces obstructive sleep apnea severity: a double-blind, placebo-controlled, randomized crossover trial

STUDY OBJECTIVES

Recent findings indicate that noradrenergic and muscarinic processes are crucial for pharyngeal muscle control during sleep. However, to date, reductions in obstructive sleep apnea (OSA) severity have only been detected when noradrenergic agents are combined with an antimuscarinic. Accordingly, this study aimed to determine if reboxetine alone and combined with oxybutynin reduces OSA severity. The pathophysiological mechanisms underpinning the effects of these agents were also investigated via endotyping analysis.

METHODS

Sixteen people (6 women) with OSA completed 3 polysomnograms (∼1-week washout) according to a double-blind, placebo-controlled, three-way crossover design across 2 sites. Single doses of 4 mg reboxetine, placebo, or 4 mg reboxetine + 5 mg oxybutynin were administered before sleep (order randomized).

RESULTS

Reboxetine reduced the apnea-hypopnea index (primary outcome) by 5.4 (95% confidence interval -10.4 to -0.3) events/h, P = .03 (-24 ± 27% in men; -0.7 ± 32% in women). Oxybutynin did not cause additional reductions in apnea-hypopnea index. Reboxetine alone reduced the 4% oxygen desaturation index by (mean ± standard deviation) 5.2 ± 7.2 events/h and reboxetine+oxybutynin by 5.1 ± 10.6 events/h vs placebo, P = .02. Nadir oxygen saturation also increased by 7 ± 11% with reboxetine and 5 ± 9% with reboxetine+oxybutynin vs placebo, P = .01. Mechanistically, reboxetine and reboxetine+oxybutynin improved pharyngeal collapsibility and respiratory control (loop gain). Larger reductions in apnea-hypopnea index with reboxetine in men were associated with higher baseline loop gain.

CONCLUSIONS

These findings show the first evidence that reboxetine alone reduces OSA severity. The data provide novel insight into the role of norepinephrine reuptake inhibitors on upper airway stability during sleep and are important to inform future pharmacotherapy development for OSA.

CLINICAL TRIAL REGISTRATION

Registry: Australian New Zealand Clinical Trials Registry; Name: Reboxetine and Combination Therapy with AD128 in Sleep Apnoea Trial: A Double-Blind, 3-Way Cross-Over Study; URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=374614&isReview=true; Identifier: ACTRN12620000662965.

CITATION

Altree TJ, Aishah A, Loffler KA, Grunstein RR, Eckert DJ. The norepinephrine reuptake inhibitor reboxetine alone reduces obstructive sleep apnea severity: a double-blind, placebo-controlled, randomized crossover trial. J Clin Sleep Med. 2023;19(1):85-96.

Effect of Pimavanserin on the Respiratory Arousal Threshold from Sleep: A Randomized Trial

Rationale: A low respiratory arousal threshold is a key endotype responsible for obstructive sleep apnea (OSA) pathogenesis. Pimavanserin is an antiserotoninergic capable of suppressing CO2-mediated arousals without affecting the respiratory motor response in animal models, and thus it holds potential for increasing the arousal threshold in OSA and subsequently reducing OSA severity. Objectives: We measured the effect of pimavanserin on arousal threshold (primary outcome), OSA severity, arousal index, and other OSA endotypes (secondary outcomes). Methods: A total of 18 OSA participants were studied in a randomized, double-blind, crossover study. Patients received a single dose of placebo or pimavanserin 34 mg 4 hours before in-lab polysomnography. Airflow was measured with an oronasal mask attached to a pneumotachograph, and ventilatory drive was recorded with an intraesophageal electromyography catheter. Results are presented as mean or median changes (Δ) and 95% confidence intervals (CIs). Results: Pimavanserin did not increase the arousal threshold, nor did it decrease OSA severity or arousal index. It, however, prolonged total sleep time (Δ[confidence interval (CI)], 39.5 [95%CI, -1.2 to 80.1] min). In an exploratory analysis, a subgroup of seven patients who had a 10% or more increase in arousal threshold on pimavanserin exhibited a decrease in AHI4 (hypopneas associated with 4% desaturation) (Δ[CI], 5.6 [95%CI, 3.6-11.1] events/h) and hypoxic burden (Δ[CI], 22.3 [95%CI, 6.6-32.3] %min/h). Conclusions: A single dose of pimavanserin did not have a significant effect on arousal threshold or OSA severity. However, in a post hoc analysis, a subset of patients who exhibited an increase in arousal threshold on pimavanserin showed a small decrease in OSA severity. Thus, if the arousal threshold could be increased with pimavanserin, perhaps with longer dosing to reach higher drug blood concentrations, then the desired effect on OSA severity might be achievable. Clinical trial registered with ClinicalTrials.gov (NCT04538755).

Combination of atomoxetine with the novel antimuscarinic aroxybutynin improves mild to moderate OSA

STUDY OBJECTIVE

Obstructive sleep apnea is a common and serious sleep disorder for which treatment remains challenging due to lack of adherence to approved therapies. Previous pharmacological studies addressing sleep-related upper airway muscle hypotonia suggested that the combination of atomoxetine and oxybutynin is effective in treating obstructive sleep apnea. The current study is with aroxybutynin (AD109), a new enantiomerically pure form of oxybutynin with better safety profile compared to racemic oxybutynin.

METHODS

This was a randomized, double-blind, placebo-controlled, crossover study in patients with mild to moderate obstructive sleep apnea. Each received low-dose AD109 (37.5/2.5 mg), high-dose AD109 (75/2.5 mg), and placebo at bedtime across 3 overnight periods in a randomized order. Adverse events were collected by telephone contact with participants during each washout period. The primary endpoint was change in hypoxic burden and secondary endpoint was apnea-hypopnea index.

RESULTS

Patients treated with both the high and low doses of AD109 had a statistically significant and clinically meaningful difference from placebo in hypoxic burden. Median [interquartile range] hypoxic burden for participants on placebo was 13.9[4.5-21.9] (%min)/h vs 2.3[0.1-10.5] (%min)/h for patients on the high dose (P < .001) and to 7.3[2-12.5] (%min)/h on the low dose (P < .01). Apnea-hypopnea index went from a median of 13.2[8.0-19.1] events/h on placebo reduced to 5.5[2.2 to 9.6] events/h on the high dose (P < .001) and to 7.8[4-13.7] events/h on the low dose (P < .05). AD109 demonstrated a favorable safety profile.

CONCLUSIONS

This study provides additional support that a pharmacological intervention for obstructive sleep apnea, namely the combination of atomoxetine and aroxybutynin, offers promising results. Additional development of this compound and others is warranted.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: AD109 Dose Finding in Mild to Moderate OSA; URL: https://clinicaltrials.gov/ct2/show/NCT04631107; Identifier: NCT04631107.

CITATION

Rosenberg R, Abaluck B, Thein S. Combination of atomoxetine with the novel antimuscarinic aroxybutynin improves mild to moderate OSA. J Clin Sleep Med. 2022;18(12):2837-2844.

Topical Potassium Channel Blockage Improves Pharyngeal Collapsibility: A Translational, Placebo-Controlled Trial

BACKGROUND

Potassium channel inhibition has been identified in animal models as a potential target to increase pharyngeal dilator muscle activity and to treat OSA. However, these findings have not yet been translated to humans.

RESEARCH QUESTION

Does a novel, potent, TWIK-related acid-sensitive K⁺ (TASK) 1/3 channel antagonist, BAY2586116, improve pharyngeal collapsibility in pigs and humans, and secondarily, what is the optimal dose and method of topical application?

STUDY DESIGN AND METHODS

In the preclinical study, pharyngeal muscle activity and upper-airway collapsibility via transient negative pressure application was quantified in 13 anesthetized pigs during administration of placebo, 0.3 μg, 3 μg, and 30 μg nasal drops of BAY2586116. In the clinical study, 12 people with OSA instrumented with polysomnography equipment, an epiglottic pressure catheter, pneumotachograph, and nasal mask to monitor sleep and breathing performed up to four detailed upper airway sleep physiology studies. Participants received BAY2586116 or placebo nasal spray (160 μg) before sleep via a double-masked, randomized, crossover design. Most participants also returned for three additional overnight visits: (1) nasal drops (160 μg), (2) half-dose nasal spray (80 μg), and (3) direct endoscopic application (160 μg). The upper-airway critical closing pressure during sleep was quantified at each visit.

RESULTS

Consistent and sustained improvements in pharyngeal collapsibility to negative pressure were found with 3 and 30 μg of BAY2586116 vs placebo in pigs. Similarly, BAY2586116 improved pharyngeal collapsibility by an average of approximately 2 cm H₂O vs placebo, regardless of topical application method and dose (P < .008, mixed model) in participants with OSA.

INTERPRETATION

Acute topical application of BAY2586116 improves upper-airway collapsibility in anesthetized pigs and sleeping humans with OSA. These novel physiologic findings highlight the therapeutic potential to target POTASSIUM channel mechanisms to treat OSA.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT04236440; URL: www.

CLINICALTRIALS

gov.

Atomoxetine and fesoterodine combination improves obstructive sleep apnoea severity in patients with milder upper airway collapsibility

BACKGROUND AND OBJECTIVE

The combination of the noradrenergic atomoxetine plus the anti-muscarinic oxybutynin acutely increased genioglossus activity and reduced obstructive sleep apnoea (OSA) severity. However, oxybutynin has shorter half-life than atomoxetine and side effects that might discourage long-term usage. Accordingly, we aimed to test the combination of atomoxetine and fesoterodine (Ato-Feso), a newer anti-muscarinic with extended release formulation, on OSA severity and endotypes.

METHODS

Twelve subjects with OSA underwent a randomized, double-blind, crossover trial comparing one night of atomoxetine plus fesoterodine (80-4 mg) to placebo. Parameters of OSA severity (e.g., apnoea-hypopnoea index [AHI], nadir oxygen desaturation and hypoxic burden) were calculated from two clinical, in-lab polysomnographic studies. OSA endotypes (including collapsibility per VMIN and arousal threshold) were derived from validated algorithms.

RESULTS

Compared to placebo, Ato-Feso did not reduce the AHI (34.2 ± 19.1 vs. 30.1 ± 28.2 events/h, p = 0.493), but reduced the apnoea index (12.9 [28.8] vs. 1.8 [9.1] events/h, median [interquartile range], p = 0.027) and increased nadir desaturation (76.8 [8.0] vs. 82.2 [8.8] %, p = 0.003); a non-significant trend for improved hypoxic burden was observed (52.4 [50.5] vs. 29.7 [78.9] %min/h, p = 0.093). Ato-Feso lowered collapsibility (raised VMIN ; 43.7 [29.8-55.7] vs. 56.8 [43.8-69.8] %VEUPNOEA , mean [CI], p = 0.002), but reduced the arousal threshold (129.3 [120.1-138.6] vs. 116.7 [107.5-126] %VEUPNOEA , p = 0.038). In post hoc analysis, 6/6 patients with milder collapsibility (VMIN  > 43%) exhibited OSA resolution (drop in AHI > 50% and residual AHI < 10 events/h) and improved hypoxaemia.

CONCLUSION

While inefficacious in unselected patients, Ato-Feso administered for one night suppressed OSA in patients with milder collapsibility. Ato-Feso may hold some promise as an alternative OSA treatment in certain subgroups of individuals.

New pharmacologic agents for obstructive sleep apnoea: what do we know and what can we expect?

PURPOSE OF REVIEW

This review provides a condensed description of pharmacological remedies explored in patients with obstructive sleep apnoea (OSA) as well as projections of what we might expect in terms of clinical performance of these drugs.

RECENT FINDINGS

Conventional drug therapies explored in OSA have generally produced disappointing results and there is a shortage of pharmacological treatment alternatives in this disorder. Recent insights into pathophysiological mechanisms potentially involved in OSA suggest that the condition may be divided into distinct subgroups based on clusters or defined by means of unique functional endotypic criteria. In fact, positive outcomes in clinical trials have now resulted in several drug candidates that show a convincing reduction of sleep disordered breathing in both short and intermediate term. Such drugs may be particularly useful in certain variants of OSA but not in others. These insights have also raised the ambition to create personalized therapies in OSA. Another recent development is the insight that OSA-linked conditions such as obesity, daytime somnolence and various forms of cardiovascular/metabolic disease may provide drug-based targets. For instance, pharmacological obesity therapy may provide not only positive metabolic effects but may also be a way to eliminate the anatomic component in obese OSA patients.

SUMMARY

Recent insights into the pathophysiology of OSA have opened possibilities to develop personalized therapy. Drugs addressing fundamental aspects of the sleep and breathing disorder provide a particularly promising avenue for development of novel forms of treatment in OSA.

Pharmacotherapy for Obstructive Sleep Apnoea and Coupled Life: A Descriptive Phenomenological Study of a Complex Interaction

BACKGROUND

Obstructive Sleep Apnoea (OSA) is a common chronic sleep-related breathing disorder. Drug therapy is a recent approach to treating OSA, and no data is available regarding its effects on a couple's life. The aim of this study was to investigate the impact on couples' lives of a novel drug treatment for OSA.

METHODS

Participants of a trial on new drug therapy (reboxetine plus oxybutynin) for OSA were interviewed. The study was conducted using a descriptive phenomenological approach by Sundler et al. Results: Ten patients and six of their partners were recruited through a purposive sampling between February and April 2021. The results indicate that drug treatment of OSA had a favourable impact on the couples' lives. Pharmacotherapy improved self-reported sleep quality, as the absence of CPAP allows people to sleep closer to the bed partner and because the patient does not have to sleep in a forced position. Moreover, the couples developed teamwork from the beginning which appeared to be crucial during the trial, especially when some difficulties and adverse events occurred.

CONCLUSIONS

This study presents the presence of a positive closed loop that could be considered a predictor of adherence to drug therapy.

Differential pharmacological and sex-specific effects of antimuscarinic agents at the hypoglossal motor nucleus in vivo in rats

Successful cholinergic-noradrenergic pharmacotherapy for obstructive sleep apnea (OSA) is thought to be due to effects at the hypoglossal motor nucleus (HMN). Clinical efficacy varies with muscarinic-receptor (MR) subtype affinities. We hypothesized that oxybutynin (cholinergic agent in successful OSA pharmacotherapy) is an effective MR antagonist at the HMN and characterized its efficacy with other antagonists. We recorded tongue muscle activity of isoflurane anesthetized rats (121 males and 60 females, 7–13 per group across 13 protocols) in response to HMN microperfusion with MR antagonists with and without: (i) eserine-induced increased endogenous acetylcholine at the HMN and (ii) muscarine. Eserine-induced increased acetylcholine decreased tongue motor activity (p < 0.001) with lesser cholinergic suppression in females versus males (p = 0.017). Motor suppression was significantly attenuated by the MR antagonists atropine, oxybutynin, and omadacycline (MR2 antagonist), each p < 0.001, with similar residual activity between agents (p ≥ 0.089) suggesting similar efficacy at the HMN. Sex differences remained with atropine and oxybutynin (p < 0.001 to 0.05) but not omadacycline (p = 0.722). Muscarine at the HMN also decreased motor activity (p < 0.001) but this was not sex-specific (p = 0.849). These findings have translational relevance to antimuscarinic agents in OSA pharmacotherapy and understanding potential sex differences in HMN suppression with increased endogenous acetylcholine related to sparing nicotinic excitation.

Turning Over a New Leaf-Pharmacologic Therapy in Obstructive Sleep Apnea

Despite extensive research, there is currently no approved drug for obstructive sleep apnea (OSA) treatment. OSA is a heterogeneous condition that involves multiple dominating pathophysiological traits. Drug development in this field needs to address both pathophysiological mechanisms and associated comorbid conditions in order to meet requirements for long-term therapy in OSA. Several drug candidates have been proposed and ongoing phase II trials that target various forms of sleep-disordered breathing have been initiated. The field is moving toward tailored therapeutic approaches in patients with OSA.

Current and Novel Treatment Options for OSA

Obstructive sleep apnoea is a challenging medical problem due to its prevalence, its impact on quality of life and performance in school and professionally, the implications for risk of accidents, and comorbidities and mortality. Current research has carved out a broad spectrum of clinical phenotypes and defined major pathophysiological components. These findings point to the concept of personalised therapy, oriented on both the distinct clinical presentation and the most relevant pathophysiology in the individual patient. This leads to questions of whether sufficient therapeutic options other than positive airway pressure (PAP) alone are available, for which patients they may be useful, if there are specific indications for single or combined treatment, and whether there is solid scientific evidence for recommendations. This review describes our knowledge on PAP and non-PAP therapies to address upper airway collapsibility, muscle responsiveness, arousability and respiratory drive. The spectrum is broad and heterogeneous, including technical and pharmaceutical options already in clinical use or at an advanced experimental stage. Although there is an obvious need for more research on single or combined therapies, the available data demonstrate the variety of effective options, which should replace the unidirectional focus on PAP therapy.

The analysis of individual pathophysiological composition opens new directions towards personalised treatment of OSA, focusing not only on pharyngeal dilation, but also on technical or pharmaceutical interventions on muscle function or breathing regulationhttps://bit.ly/3sayhkd

Obstructive Sleep Apnea and Adherence to Continuous Positive Airway Pressure (CPAP) Treatment: Let's Talk about Partners!

BACKGROUND

Continuous positive airway pressure (CPAP) is the gold standard treatment for obstructive sleep apnea (OSA). The benefits of this therapy were studied and analyzed over time; patient adherence is often poor, as many factors negatively influence it. A topic that needs clarification is whether adherence to CPAP treatment in a patient with OSA is influenced by the behavior of a partner or spouse.

METHODS

A scoping review was conducted to evaluate the role of partner involvement in the CPAP treatment management in a patient with OSA. The research project was performed between August and September 2021 by consulting the main biomedical databases: CINHAL, Embase, PsycINFO, and PubMed.

RESULTS

Among 21 articles considered valid for our aim, 15 are qualitative studies, 5 are quantitative and 1 presents a mixed method. We identified several thematic areas and "key" elements, which are prevalent in the studies evaluated.

CONCLUSIONS

The presence of a partner promotes adherence to CPAP therapy in patients with OSA, resulting in ameliorating their overall quality of life. To increase CPAP adherence, a trained nurse could represent a reference figure to technically and emotionally support couples during the adaptation period and in the long term.

Efficacy of atomoxetine plus oxybutynin in the treatment of obstructive sleep apnea with moderate pharyngeal collapsibility

Purpose

Preliminary studies have shown a significant decrease in severity of obstructive sleep apnea (OSA) with the use of a combination of atomoxetine and oxybutynin, with patients having moderate pharyngeal collapsibility during sleep more likely to respond. This study evaluated the efficacy and safety of AD036 (atomoxetine 80 mg and oxybutynin 5 mg) in the treatment of OSA.

Methods

This trial was a phase 2, randomized, placebo-controlled crossover study comparing AD036, atomoxetine 80 mg alone, and placebo during three home sleep studies, each separated by about 1 week. The trial included patients with OSA and moderate pharyngeal collapsibility as defined by a higher proportion of hypopneas to apneas and mild oxygen desaturation.

Results

Of 62 patients who were randomized, 60 were included in efficacy analyses. The apnea–hypopnea index (AHI) from a median (interquartile range) of 14.2 (5.4 to 22.3) events/h on placebo to 6.2 (2.8 to 13.6) with AD036 and 4.8 (1.4 to 11.6) with atomoxetine alone (p < .0001). Both drugs also decreased the oxygen desaturation index (ODI) and the hypoxic burden (p < .0001). AD036, but not atomoxetine alone, reduced the respiratory arousal index and improved ventilation at the respiratory arousal threshold (greater V_active). There was a trend for total sleep time to be decreased more with atomoxetine alone than with AD036. The most common adverse event was insomnia (12% with AD036, 18% with atomoxetine).

Conclusion

AD036 significantly improved OSA severity in patients with moderate pharyngeal collapsibility. Atomoxetine may account for the majority of improvement in OSA severity, while the addition of oxybutynin may mitigate the disruptive effect of atomoxetine on sleep and further improve ventilation.

Trial registration

Clinical trial registered with www.clinicaltrials.gov (NCT04445688).

The Combination of Betahistine and Oxybutynin Increases Respiratory Control Sensitivity (Loop Gain) in People with Obstructive Sleep Apnea: A Randomized, Placebo-Controlled Trial

RATIONALE

There are widespread histaminergic projections throughout the brain, including hypoglossal nuclei, that modulate pharyngeal muscle tone and respiratory control. Hence, histaminergic stimulation pharmacologically may increase pharyngeal muscle tone and stabilize respiratory control (loop gain) to reduce obstructive sleep apnea (OSA) severity. Antimuscarinics also increase REM pharyngeal muscle tone in rats. Thus, a combination of histaminergic and anti-muscarinic drugs may be a novel target for OSA pharmacotherapy. However, this has not been investigated. Accordingly, we aimed to test the effects of betahistine (Beta), an H3-autoreceptor antagonist which thereby increases histamine levels, in combination with the antimuscarinic oxybutynin (Oxy), on OSA severity, OSA endotypes, polysomnography parameters and next-day sleepiness and alertness.

METHODS

Thirteen adults with OSA received either Beta-Oxy (96-5mg) or placebo according to a randomized, crossover, double-blind design, prior to polysomnography. Participants completed the Karolinska Sleep Scale and Leeds Sleep Evaluation Questionnaire and a driving simulation task to quantify next-day sleepiness and alertness. OSA endotypes were estimated through validated algorithms using polysomnography.

RESULTS

Compared to placebo, Beta-Oxy increased respiratory control sensitivity (loop gain) (0.52[0.24] vs 0.60[0.34], median [IQR], P = 0.021) without systematically changing OSA severity (34.4±17.2 vs 40.3±27.3 events/h, mean±SD, P = 0.124), sleep efficiency, arousal index or markers of hypoxemia. Beta-Oxy was well tolerated and did not worsen next-day sleepiness/alertness.

CONCLUSION

Rather than stabilize breathing during sleep, Beta-Oxy increases loop gain, which is likely to be deleterious for most people with OSA. However, in certain conditions characterized by blunted respiratory control (eg, obesity hypoventilation syndrome), interventions to increase loop gain may be beneficial.

Upper airway muscles: influence on obstructive sleep apnoea pathophysiology and pharmacological and technical treatment options

PURPOSE OF REVIEW

Obstructive sleep apnoea (OSA) is highly prevalent with numerous deleterious effects on neurocognitive and cardiovascular health. It is characterized by collapse of the upper airway during sleep, due to the decrease in both basal and compensatory UA muscle activities. However, the leading treatment, continuous positive airway pressure, is often poorly tolerated. This review presents latest works focusing on novel interventions targeting upper airway muscles to alleviate OSA severity.

RECENT FINDINGS

In the last years, researchers have focused on the development of alternative treatment strategies targeting UA muscle activation, including pharmacological and nonpharmacological interventions.

SUMMARY

Among the nonpharmacological treatments, hypoglossal nerve stimulation aims to increase upper airway muscle phasic activity during sleep through electrical stimulation, while myofunctional therapy improves the activity and coordination of upper airway dilator muscles.Regarding OSA pharmacotherapy, recent findings strongly suggest that selective norepinephrine reuptake inhibitors such as atomoxetine and reboxetine, when administered with antimuscarinics such as oxybutynin, can alleviate OSA in most patients increasing pharyngeal dilator muscles activity during sleep. New combinations of norepinephrine reuptake inhibitors and antimuscarinics have further been explored with variable success and animal models showed that leptin, thyrothropin releasing hormone analogues and gene therapy hold potential for the future of OSA pharmacotherapy.