From structure to clinic: Design of a muscarinic M1 receptor agonist with potential to treatment of Alzheimer's disease.

Current therapies for Alzheimer's disease seek to correct for defective cholinergic transmission by preventing the breakdown of acetylcholine through inhibition of acetylcholinesterase, these however have limited clinical efficacy. An alternative approach is to directly activate cholinergic receptors responsible for learning and memory. The M1-muscarinic acetylcholine (M1) receptor is the target of choice but has been hampered by adverse effects. Here we aimed to design the drug properties needed for a well-tolerated M1-agonist with the potential to alleviate cognitive loss by taking a stepwise translational approach from atomic structure, cell/tissue-based assays, evaluation in preclinical species, clinical safety testing, and finally establishing activity in memory centers in humans. Through this approach, we rationally designed the optimal properties, including selectivity and partial agonism, into HTL9936-a potential candidate for the treatment of memory loss in Alzheimer's disease. More broadly, this demonstrates a strategy for targeting difficult GPCR targets from structure to clinic.

Safety, pharmacokinetics and pharmacodynamics of HTL0009936, a selective muscarinic M1 -acetylcholine receptor agonist: A randomized cross-over trial.

AIMS: HTL0009936 is a selective M1 muscarinic receptor agonist in development for cognitive dysfunction in Alzheimer's disease. Safety, tolerability and pharmacokinetics and exploratory pharmacodynamic effects of HTL0009936 administered by continuous IV infusion at steady state were investigated in elderly subjects with below average cognitive functioning (BACF). METHODS: Part A was a four-treatment open label sequential study in healthy elderly investigating 10-83 mg HTL0009936 (IV) and a 24 mg HTL0009936 single oral dose. Part B was a five-treatment randomized, double-blind, placebo and physostigmine controlled cross-over study with IV HTL0009936 in elderly subjects with BACF. Pharmacodynamic assessments were performed using neurocognitive and electrophysiological tests. RESULTS: Pharmacokinetics of HTL0009936 showed dose-proportional increases in exposure with a mean half-life of 2.4 hours. HTL0009936 was well-tolerated with transient dose-related adverse events (AEs). Small increases in mean systolic blood pressure of 7.12 mmHg (95% CI [3.99-10.24]) and in diastolic of 5.32 mmHg (95% CI [3.18-7.47]) were noted at the highest dose in part B. Overall, there was suggestive, but no definitive, positive or negative pharmacodynamic effects. Statistically significant effects were observed on P300 with HTL0009936 and adaptive tracking with physostigmine. CONCLUSIONS: HTL0009936 showed well-characterized pharmacokinetics and single doses were safe and generally well-tolerated in healthy elderly subjects. Due to physostigmine tolerability issues and subject burden, the study design was changed and some pharmacodynamic assessments (neurocognitive) were performed at suboptimal drug exposures. Therefore no clear conclusions can be made on pharmacodynamic effects of HTL0009936, although an effect on P300 is suggestive of central target engagement.

First-in-man study to investigate safety, pharmacokinetics and exploratory pharmacodynamics of HTL0018318, a novel M1 -receptor partial agonist for the treatment of dementias.

AIMS: HTL0018318 is a selective M1 receptor partial agonist currently under development for the symptomatic treatment of cognitive and behavioural symptoms in Alzheimer's disease and other dementias. We investigated safety, tolerability, pharmacokinetics and exploratory pharmacodynamics (PD) of HTL0018318 following single ascending doses. METHODS: This randomized, double-blind, placebo-controlled study in 40 healthy younger adult and 57 healthy elderly subjects, investigated oral doses of 1-35 mg HTL0018318. Pharmacodynamic assessments were performed using a battery of neurocognitive tasks and electrophysiological measurements. Cerebrospinal fluid concentrations of HTL0018318 and food effects on pharmacokinetics of HTL0018318 were investigated in an open label and partial cross-over design in 14 healthy subjects. RESULTS: Pharmacokinetics of HTL0018318 were well-characterized showing dose proportional increases in exposure from 1-35 mg. Single doses of HTL0018318 were associated with mild dose-related adverse events of low incidence in both younger adult and elderly subjects. The most frequently reported cholinergic AEs included hyperhidrosis and increases in blood pressure up to 10.3 mmHg in younger adults (95% CI [4.2-16.3], 35-mg dose) and up to 11.9 mmHg in elderly subjects (95% CI [4.9-18.9], 15-mg dose). There were no statistically significant effects on cognitive function but the study was not powered to detect small to moderate effect sizes of clinical relevance. CONCLUSION: HTL0018318 showed well-characterized pharmacokinetics and following single doses were generally well tolerated in the dose range studied. These provide encouraging data in support of the development for HTL0018318 for Alzheimer's disease and other dementias.

A phase 1b/2a multicenter study of the safety and preliminary pharmacodynamic effects of selective muscarinic M1 receptor agonist HTL0018318 in patients with mild-to-moderate Alzheimer's disease.

INTRODUCTION: This study examined the safety and pharmacodynamic effects of selective muscarinic M1 receptor orthosteric agonist HTL0018318 in 60 patients with mild-to-moderate Alzheimer's disease (AD) on background donepezil 10 mg/day. METHODS: A randomized, double-blind, placebo-controlled 4-week safety study of HTL0018318 with up-titration and maintenance phases, observing exploratory effects on electrophysiological biomarkers and cognition. RESULTS: Treatment-emergent adverse events (TEAEs) were mild and less frequently reported during maintenance versus titration. Headache was most commonly reported (7-21%); 0 to 13% reported cholinergic TEAEs (abdominal pain, diarrhea, fatigue, nausea) and two patients discontinued due to TEAEs. At 1 to 2 hours post-dose, HTL0018318-related mean maximum elevations in systolic and diastolic blood pressure of 5 to 10 mmHg above placebo were observed during up-titration but not maintenance. Postive effects of HTL0018318 were found on specific attention and memory endpoints. DISCUSSION: HTL0018318 was well tolerated in mild-to-moderate AD patients and showed positive effects on attention and episodic memory on top of therapeutic doses of donepezil.

Safety and Pharmacokinetics of HTL0018318, a Novel M1 Receptor Agonist, Given in Combination with Donepezil at Steady State: A Randomized Trial in Healthy Elderly Subjects.

INTRODUCTION: HTL0018318 is a selective muscarinic M1 receptor partial agonist under development for the symptomatic treatment of dementias, including Alzheimer's disease. Clinically, HTL0018318 would likely be used alone or in conjunction with cholinesterase inhibitors (e.g. donepezil). OBJECTIVE: We investigated the safety, tolerability, and pharmacokinetics of HTL0018318 given alone and in combination with donepezil. METHODS: This was a randomized, double-blind, placebo-controlled trial in 42 (to deliver 36 with combination treatment) healthy elderly subjects investigating the effects of oral HTL0018318 15 and 25 mg given alone and combined with donepezil 10 mg at steady state on adverse events (AEs), vital signs, saliva production, sleep quality, pulmonary function, subjective feelings, and pharmacokinetics. RESULTS: AEs were reported by lower percentages of subjects after HTL0018318 alone than after donepezil alone. There was no increase in the percentage of subjects reporting AEs after co-administration than after donepezil alone. Supine systolic blood pressure was 1.6 mmHg (95% confidence interval [CI] -3.1 to -0.1) lower after HTL0018318 alone than after combination treatment. This was comparable with results from placebo alone: 1.7 mmHg (95% CI -3.2 to 0.2) lower than with combination treatment. Supine pulse rate was 3.3 bpm (95% CI 1.5-5.1) higher after HTL0018318 alone than with co-administration. HTL0018318 and donepezil did not meaningfully affect each other's pharmacokinetics. CONCLUSION: HTL0018318 was well tolerated when given alone and in combination with donepezil. HTL0018318 and donepezil do not demonstrate pharmacokinetic or pharmacodynamic interactions, indicating that HTL0018318 can be safely administered in combination with donepezil. CLINICAL TRIAL REGISTRATION: Netherlands Trial register identifier NL5915, registered on 28 October 2016.

Safety, pharmacokinetics and exploratory pro-cognitive effects of HTL0018318, a selective M1 receptor agonist, in healthy younger adult and elderly subjects: a multiple ascending dose study.

BACKGROUND: The cholinergic system and M1 receptor remain an important target for symptomatic treatment of cognitive dysfunction. The selective M1 receptor partial agonist HTL0018318 is under development for the symptomatic treatment of Dementia's including Alzheimer's disease (AD) and dementia with Lewy bodies (DLB). We investigated the safety, tolerability, pharmacokinetics and exploratory pharmacodynamics of multiple doses of HTL0018318 in healthy younger adults and elderly subjects. METHODS: This randomised, double blind, placebo-controlled study was performed, investigating oral doses of 15-35 mg/day HTL0018318 or placebo in 7 cohorts of healthy younger adult (n = 36; 3 cohorts) and elderly (n = 50; 4 cohorts) subjects. Safety, tolerability and pharmacokinetic measurements were performed. Pharmacodynamics were assessed using a battery of neurocognitive tasks and electrophysiological biomarkers of synaptic and cognitive functions. RESULTS: HTL0018318 was generally well-tolerated in multiple doses up to 35 mg/day and were associated with mild or moderate cholinergic adverse events. There were modest increases in blood pressure and pulse rate when compared to placebo-treated subjects, with tendency for the blood pressure increase to attenuate with repeated dosing. There were no clinically significant observations or changes in blood and urine laboratory measures of safety or abnormalities in the ECGs and 24-h Holter assessments. HTL0018318 plasma exposure was dose-proportional over the range 15-35 mg. Maximum plasma concentrations were achieved after 1-2 h. The apparent terminal half-life of HTL0018318 was 16.1 h (± 4.61) in younger adult subjects and 14.3 h (± 2.78) in elderly subjects at steady state. HTL0018318 over the 10 days of treatment had significant effects on tests of short-term (working) memory (n-back) and learning (Milner maze) with moderate to large effect sizes. CONCLUSION: Multiple doses of HTL0018138 showed well-characterised pharmacokinetics and were safe and generally well-tolerated in the dose range studied. Pro-cognitive effects on short-term memory and learning were demonstrated across the dose range. These data provide encouraging data in support of the development of HTL0018138 for cognitive dysfunction in AD and DLB. TRIAL REGISTRATION: Netherlands Trial Register identifier NTR5781 . Registered on 22 March 2016.

Cholinergic muscarinic M1 and M4 receptors as therapeutic targets for cognitive, behavioural, and psychological symptoms in psychiatric and neurological disorders.

Cholinergic dysfunction is involved in a range of neurological and psychiatric disorders, including schizophrenia, dementia and Lewy body disease (LBD), leading to widespread use of cholinergic therapies. However, such drugs have focused on increasing the availability of acetylcholine (ACh) generally, with relatively little work done on the muscarinic system and specific muscarinic receptor subtypes. In this review, we provide an overview of the major cholinergic pathways and cholinergic muscarinic receptors in the human brain and evidence for their dysfunction in several neurological and psychiatric disorders. We discuss how the selectivity of cholinergic system dysfunction suggests that targeted cholinergic therapeutics to the muscarinic receptor subtypes will be vital in treating several disorders associated with cognitive dysfunction and behavioural and psychological symptoms.

Treatment of elderly primary insomnia patients with EVT 201 improves sleep initiation, sleep maintenance, and daytime sleepiness.

OBJECTIVE: Two doses of EVT 201, a partial positive allosteric modulator of the GABA(A) system, were evaluated in elderly primary insomnia patients with daytime sleepiness. PATIENTS AND METHODS: Participants were 149 elderly patients with DSM-IV primary insomnia including evidence of daytime sleepiness (53 males, 96 females; mean age 71.3yrs, range 65-86yrs). A randomized, multicentre, double-blind, placebo-controlled, parallel-group design was used to assess the hypnotic efficacy of EVT 201 1.5 and 2.5mg during seven consecutive nights. Polysomnography (PSG) was performed on nights 1, 6 and 7 of treatment. Daytime assessments on Day 8 included the multiple sleep latency test (MSLT), Rey Auditory Verbal Learning Test (RAVLT), Psychomotor Vigilance Task (PVT) and the Karolinska Sleepiness Scale (KSS). The primary endpoint was total sleep time (TST) and the key secondary endpoint was mean MSLT latency. RESULTS: Compared to placebo, EVT 201 1.5 and 2.5mg increased TST (30.9, 56.4min, respectively; p=0.0001, p<0.0001); reduced wake after sleep onset (WASO; -15.2, -36.1min, respectively; p=0.014, p<0.0001); reduced latency to persistent sleep (LPS; -15.9, -19.9min, respectively; p=0.009, p=0.001). The 2.5mg dose also reduced WASO in hours 5-8 (-16.3min, p=0.001). Both doses also improved subjective sleep quality and usual subjective efficacy measures. A significantly longer mean MSLT latency was observed on Day 8 with both doses, compared to placebo (2min increase; p=0.03, both doses). The PVT, RAVLT, and POMS did not differ among treatment groups. No serious or unexpected treatment emergent adverse events were noted. CONCLUSION: EVT 201 improved PSG measures of sleep onset and sleep maintenance and significantly reduced daytime physiological sleep tendency. These findings suggest that treatment of primary insomnia in older patients has the potential to improve daytime sleepiness as well as sleep.

The partial positive allosteric GABA(A) receptor modulator EVT 201 is efficacious and safe in the treatment of adult primary insomnia patients.

OBJECTIVE: To evaluate polysomnographic (PSG) and self-reported measures of the efficacy and safety of EVT 201 in patients with primary insomnia. PATIENTS AND METHODS: Following clinical and PSG screening, 75 patients (mean age: 45.1+/-11.2 y; 50 f, 25 m) meeting DSM-IV criteria for primary insomnia entered this crossover study and were randomly assigned to double-blind treatment sequences of 1.5 mg or 2.5 mg EVT 201, or placebo using a balanced Latin square design. For each study condition study medication was administered on two consecutive nights and PSG and self-reported data were collected. Safety assessments included physical examination, clinical laboratory measures, electrocardiogram, documentation of adverse events, and the digit symbol substitution test (DSST) and self-reported sleepiness/alertness ratings to detect residual sedation. Data were collected at five US sleep laboratories. Efficacy analyses were performed for the 67 patients completing the study. Safety analyses included all 75 randomized patients. RESULTS: On PSG measures compared to placebo, EVT 201 1.5 mg and 2.5 mg increased total sleep time (TST; 33.1, 45.0 min; both p<0.0001), reduced wake after sleep onset (WASO; -16.7, -25.7 min; both p<0.0001), reduced latency to persistent sleep (LPS; -17.0, -20.7 min; both p<0.0001), and reduced the number of awakenings (-1.2, -2.6; both p<0.0001). Significant reduction of wake time was seen with 1.5 mg during each of the first three quarters of the night (p<0.0001-0.002), and with 2.5 mg in all four quarters (p<0.0001-0.0005). Both doses also improved all key self-reported measures of sleep including total sleep time (rTST; 51.9, 51.1 min; both p<0.0001), wake after sleep onset (rWASO; -29.3, -29.6 min; both p<0.0001), sleep latency (rSL; -24.0 min, p<0.004; -25.1 min, p<0.0002), and number of awakenings (rNAW; -1.1, -1.2; both p<0.0001). Sleep quality was also improved by both doses. Self-rated sleepiness in the morning did not differ from placebo for either dose; however, there was a small negative effect on the DSST for both doses. Both doses had similar effects on sleep architecture including an increase in Stage 2 sleep and REM latency and a small, but significant decrease in REM (REM -5.7, -8.3 min; p=0.0175, p=0.0006). No effect on other sleep architecture parameters, including SWS, was seen. EVT 201 was well tolerated. No serious or unexpected adverse events were reported. CONCLUSION: This first study of EVT 201 in adult patients with primary insomnia demonstrated improved measures of sleep onset and sleep maintenance, including during the third and fourth quarters of the night. Adverse events were infrequent and all were mild to moderate in severity.