Efficacy of remimazolam versus midazolam for procedural sedation: post hoc integrated analyses of three phase 3 clinical trials.

Background and study aims Remimazolam is an ultra-short acting, fast onset/fast offset benzodiazepine for intravenous use in procedural sedation, general anesthesia, and Intensive Care Unit sedation. The aim of this work was to compare the efficacy of remimazolam versus midazolam dosed according to medical practice (real-world midazolam) and midazolam dosed according to US prescribing information (on-label midazolam) for procedural sedation. Patients and methods This post hoc analysis was performed using integrated data from three randomized, placebo, and active (midazolam) controlled, phase 3 clinical trials in patients undergoing colonoscopy and bronchoscopy. Statistical comparisons between treatment groups, without adjustment for potential confounding factors, were exploratory and observational in nature. Results The mean ±â€ŠSD dose of midazolam in the real-world midazolam group was 6.2 ±â€Š3.1 mg, compared with 3.5 ±â€Š1.5 mg in the on-label midazolam group. remimazolam showed significantly shorter time from first dose to start of procedure (median 3 minutes) compared to on-label midazolam (median 8 minutes). Recovery time from end of procedure to fully alert was significantly shorter for remimazolam (median 6 minutes) than real-world midazolam (median 14 minutes), enabling earlier transfer of patients from the procedure room to the recovery area with a lower requirement for patient monitoring. The onset and recovery times with remimazolam showed significantly less inter-patient variability than with on-label midazolam and real-world midazolam, respectively. Patients treated with remimazolam received significantly less fentanyl for analgesia (78.2 ±â€Š28.4 µg) than did those treated with real-world midazolam (113.6 ±â€Š60.1 µg) and on-label midazolam (92.5 ±â€Š40.0 µg). Conclusions Remimazolam offers advantages over midazolam in terms of faster recovery and less fentanyl requirement, which may facilitate increased procedural throughput in clinical practice.

Correlation of Vital Signs and Depth of Sedation by Modified Observer's Assessment of Alertness and Sedation (MOAA/S) Scale in Bronchoscopy.

BACKGROUND: With complex, lengthy bronchoscopies, there is a need for safe, effective sedation. Most bronchoscopists strive for moderate sedation, though often difficult without compromising vital signs. The Modified Observer's Assessment of Alertness and Sedation (MOAA/S) scale is a validated 6-point scale assessing responsiveness of patients coinciding with the American Society of Anesthesiologists (ASA) continuum of sedation. It is commonly used in studying bronchoscopic sedation, but depth of sedation by MOAA/S and correlation with vital signs and adverse events has not been determined. METHODS: This study was a post hoc analysis of a prospective, double-blind, randomized trial evaluating the safety and efficacy of remimazolam. MOAA/S and corresponding vital signs were used to assess the effect of the level of sedation on vital signs and adverse events. RESULTS: A total of 23,341 MOAA/S scores from 431 patients were recorded. Older and higher ASA class patients spent more time in deeper sedation (MOAA/S 0 to 1) (6% vs. 2%, P=0.01). Oxygen saturation was equal in deep sedation (MOAA/S 0 to 1) (97±3%) compared with moderate sedation (96±3%) (P=0.11). Mean systolic and diastolic blood pressures were significantly lower when comparing MOAA/S 0 to 1 to MOAA/S 5 (systolic blood pressure: 126±19 vs. 147±24 mm Hg, P<0.01; diastolic blood pressure: 68±14 vs. 84±15 mm Hg, P<0.01). There was a nonsignificant trend towards lower heart rate at deep versus moderate sedation (84±15 vs. 94±18 beats/min, P=0.07). Respiratory rate was also comparable with moderate and deep sedation (17±5 vs. 18±6 beats/min, P=0.94). CONCLUSION: There was no clinically meaningful correlation between vital signs and depth of sedation assessed by MOAA/S. Older and higher ASA class patients spend more time in deeper sedation. However, when in deep sedation, there was no difference in vital signs other than a slightly increased incidence of clinically insignificant hypotension.

Pharmacokinetic properties of remimazolam in subjects with hepatic or renal impairment.

BACKGROUND: Remimazolam is a new benzodiazepine for procedural sedation and general anaesthesia. The aim of this study was to characterise its pharmacokinetic properties and safety in renally and hepatically impaired subjects. METHODS: Two separate trials were conducted in patients with hepatic (n=11) or renal impairment (n=11) compared with matched healthy subjects (n=9 and n=12, respectively). The hepatic impairment trial was an open-label adaptive 'Reduced Design' trial, using a single bolus of remimazolam 0.1 mg kg-1 i.v., whereas the renal impairment trial was an open-label trial of a single bolus dose of remimazolam 1.5 mg i.v. Remimazolam plasma concentrations over time were analysed by population pharmacokinetic modelling. RESULTS: Remimazolam pharmacokinetic properties were adequately described by a three-compartment, recirculatory model. Exposure in subjects with severe hepatic impairment was 38.1% higher (i.e. clearance was 38.1% lower) compared with healthy volunteers. This increase caused a slightly delayed recovery (8.0 min for healthy, 12.1 min for moderate, and 16.7 min for severe hepatic impairment). With renal impairment, plasma clearance was comparable with that measured in healthy subjects. Simulations of Cmax after a bolus dose of 10 mg showed no relevant impact of hepatic or renal impairment. The overall incidence of adverse events was low, and all adverse events were mild. CONCLUSIONS: As Cmax after a remimazolam bolus i.v. was not affected by hepatic or renal impairment, no dose adjustments are required. No unexpected adverse events related to remimazolam were seen in subjects with renal or hepatic impairment. CLINICAL TRIAL REGISTRATION: Hepatic impairment trial: ClinicalTrials.gov, NCT01790607 (https://clinicaltrials.gov/ct2/show/NCT01790607). Renal impairment trial: EudraCT Number: 2014-004575-23.

A population pharmacodynamic Markov mixed-effects model for determining remimazolam-induced sedation when co-administered with fentanyl in procedural sedation.

The clinical effects of remimazolam (an investigational, ultra-short acting benzodiazepine being studied in procedural sedation) were measured using the Modified Observer's Assessment of Awareness/Sedation Scale (MOAA/S). The objective of this analysis was to develop a population pharmacokinetic/pharmacodynamic model to describe remimazolam-induced sedation with fentanyl over time in procedural sedation. MOAA/S from 10 clinical phase I-III trials were pooled for analysis, where data were collected after administration of placebo or remimazolam with or without concomitant fentanyl. A Markov model described transition states for 35,356 MOAA/S-time observations from 1071 subjects. Effect-compartment models of remimazolam and fentanyl linked plasma concentrations to the Markov model, and drug effects were described using a synergistic maximum effect (Emax ) model. Simulations were performed to identify the optimal remimazolam-fentanyl combination doses in procedural sedation. Fentanyl showed synergistic effects with remimazolam in sedation. Increasing age was related to longer recovery from sedation. Patients with body mass index greater than 25 kg/m2 had ~30% higher rates of distribution from plasma to the effect site (keo), indicating a slightly faster onset of sedation. Simulations showed that remimazolam 5 mg was more appropriate than 4 or 6 mg when administered with fentanyl 50 µg. The model and simulations support that a combination of remimazolam 5 mg with fentanyl 50 µg is an appropriate dosing regimen and the dose of remimazolam does not need to be changed in elderly patients, but some elderly patients may have a longer duration of sedation.

Population Pharmacokinetics of Remimazolam in Procedural Sedation With Nonhomogeneously Mixed Arterial and Venous Concentrations.

Remimazolam is an ultra-short acting benzodiazepine under development for procedural sedation and general anesthesia. Population pharmacokinetic analysis (PopPK) was conducted for remimazolam with arterial and venous samples previously, but results were limited by arterial-venous concentration differences and inaccurate central volume of distribution (V1) estimates. A new model was developed to describe covariate effects after accounting for arterial-venous differences. Arterial and venous plasma concentration-time data from 11 clinical trials were pooled for PopPK. Data from two constant-rate infusion studies were used to account for venous-to-arterial (VtoA) ratio within residual error and to accurately estimate V1. V1 and VtoA ratio from the pilot model were applied to the full dataset, where the optimal fixed/random effects and covariates were assessed. VtoA ratio was described using a maximum effect (Emax ) model during infusion and as a constant postdose. V1 was estimated as 4.83 L for a 70 kg subject and interindividual variability (IIV) on V1 could only be estimated in studies with early concentrations. IIV on clearance was low (22.9%). Covariates included effects of sex on clearance (women 10% > men), and race on clearance and steady-state volume of distribution (African Americans 16% < other races). Arterial-venous concentration differences were best described using an Emax model during infusion with a constant ratio after infusion, resulting in low residual error (20.7%). There are no clinically relevant dose adjustments needed for any covariates based on pharmacokinetic differences.

Safety and efficacy of remimazolam in high risk colonoscopy: A randomized trial.

BACKGROUND: Procedural sedation of ASA III/IV patients has increased risk. Remimazolam (an ultra-short-acting benzodiazepine) has proven safe and efficient for outpatient colonoscopy sedation. METHODS: A double-blind, randomized, multi-center, parallel group trial was performed, comparing remimazolam to placebo with an additional open-label arm for midazolam in procedural sedation of 79 ASA III/IV patients undergoing colonoscopy. This was the third of 3 Phase III trials for remimazolam in the procedural sedation program. The primary end point was the safety of remimazolam. RESULTS: Of 79 patients randomized at 3 US sites, 77 underwent sedation and colonoscopy (31 received remimazolam, 16 placebo and 30 midazolam). Incidence and frequency of treatment emergent adverse events (TEAEs) were comparable in all three treatment arms, and independent of ASA status. One TEAE leading to discontinuation and one serious TEAE were reported; both in the open label midazolam arm. The efficacy endpoint was achieved for remimazolam, placebo, and midazolam in 87.1%, 0%, and 13.3% of patients (p<0.00001 for remimazolam versus placebo and versus midazolam, respectively). CONCLUSIONS: Remimazolam is safe and efficient in procedural sedation of high risk ASA patients undergoing colonoscopy, showing a safety profile comparable to that in low risk ASA.

Pharmacokinetics and pharmacodynamics of intranasal remimazolam-a randomized controlled clinical trial.

PURPOSE: Remimazolam is a novel and ultra-short-acting sedative currently developed for intravenous use in procedural sedation, general anesthesia, and ICU sedation. However, intravenous administration is not always appropriate, depending on the patient or setting. This study evaluated intranasal administration as a potential alternative route. METHODS: The study used a randomized, double-blind, 9 period cross-over design to compare the pharmacokinetics, pharmacodynamics, and safety of single intranasal doses of 10, 20, and 40 mg remimazolam (as powder or solution) with intranasal placebo and 4 mg intravenous remimazolam. RESULTS: Intranasal remimazolam powder had a consistent absolute bioavailability of approximately 50%; Tmax was 10 min; AUC and Cmax were dose-proportional. The higher doses of intranasal solution, however, resulted in decreasing bioavailability and loss of dose-proportionality in AUC and Cmax despite complete drug absorption due to partial swallowing of dose and the resulting first-pass effect. Pharmacodynamics were generally consistent with PK. Peak effects (drowsiness, relaxation, any, memory, response time) were in similar ranges after intranasal (10 to 40 mg) as intravenous (4 mg) dosing and were partially, but not consistently, dose-related. Safety results were generally consistent with other benzodiazepines; however, intranasal remimazolam (but not placebo) caused nasal discomfort/pain, in some cases even severe. CONCLUSIONS: Intranasal administration of remimazolam was safe and caused sedative effects. However, the severe pain and discomfort caused by intranasal remimazolam prohibit its use by this route of administration, at least with the currently available intravenous formulation.

Remimazolam Has Low Oral Bioavailability and No Potential for Misuse in Drug-Facilitated Sexual Assaults, with or Without Alcohol: Results from Two Randomised Clinical Trials.

BACKGROUND AND OBJECTIVES: Remimazolam is a new ultra-short-acting benzodiazepine currently being developed for intravenous use in procedural sedation, general anaesthesia, and intensive care unit sedation. Benzodiazepines represent a drug class associated with drug-facilitated sexual assaults, especially in combination with alcohol. Two clinical trials were designed to evaluate the oral bioavailability and pharmacokinetics/pharmacodynamics of remimazolam and to assess the potential for remimazolam misuse in drug-facilitated sexual assaults via oral ingestion. METHODS: Trial 1 was conducted in 14 healthy volunteers to evaluate the oral bioavailability of remimazolam. Part 1 of trial 2 was conducted in 21 healthy female volunteers to find the minimal biologically active dose of oral remimazolam. Part 2 of trial 2 was conducted in 11 healthy female volunteers to evaluate the pharmacokinetics/pharmacodynamics of oral remimazolam in combination with alcohol. RESULTS: Remimazolam undergoes rapid and extensive first-pass metabolism upon oral administration. The oral bioavailability of remimazolam was negligible (2.2% based on total systemic exposure and 1.2% based on maximum plasma concentration). Plasma clearance of both remimazolam and its metabolite was fast (elimination half-life 20‒40 min and 1.75‒2 h, respectively). Alcohol did not appear to inhibit the rapid first-pass metabolism of remimazolam. No clear sedative effects were observed for remimazolam without alcohol. Significant sedation was observed in one of ten subjects after remimazolam 360 mg (18 drug product vials) + 40% v/v alcohol. CONCLUSION: The oral bioavailability of remimazolam is negligible, which-together with its distinct bitter taste-suggests no meaningful potential for misuse in drug-facilitated sexual assaults via oral ingestion, with or without alcohol. CLINICAL TRIAL REGISTRATION NUMBERS: Trial 1 (NCT04113564) and trial 2 (NCT04113343) both retrospectively registered on 2 October 2019.

Randomized Crossover Trial to Compare Abuse Liability of Intravenous Remimazolam Versus Intravenous Midazolam and Placebo in Recreational Central Nervous System Depressant Users.

Remimazolam (RMZ) is a new and ultra-fast-acting, short-duration intravenous benzodiazepine, a drug class associated with abuse potential. This trial was designed to compare the abuse potential of remimazolam with placebo and midazolam (MDZ), a well-characterized member of the same pharmacological class in healthy, recreational drug users 18-55 years-of-age, who demonstrated good drug tolerance and were able to discriminate between midazolam and placebo. At equipotent intravenous doses selected to produce effects ranging from mild/moderate to relatively strong sedation without loss of consciousness (RMZ: 5, 10 mg versus MDZ: 2.5, 5 mg), peak scores (Emax or Emin , respectively) for drug liking, good/bad/any effects, and sedation (drowsiness and relaxation) were significantly greater than placebo for both active drugs and were broadly comparable between RMZ and MDZ. In contrast, areas under the effect-time curves (TA_AUE) were notably lower for RMZ versus MDZ, particularly for measures of good and any effects, reflecting the shorter duration of action and consistent with the more rapid observed plasma clearance for RMZ versus MDZ and the lack of an active RMZ metabolite. Scores for willingness to take drug again were also lower for RMZ versus MDZ, but not significantly so. We concluded that the abuse potential of RMZ is comparable to or lower than that of MDZ, a drug known to have a low potential for intravenous abuse.

Population pharmacokinetic/pharmacodynamic modeling for remimazolam in the induction and maintenance of general anesthesia in healthy subjects and in surgical subjects.

STUDY OBJECTIVE: To evaluate factors affecting variability in response to remimazolam in general anesthesia. DESIGN: Plasma concentration-time data from 11 Phase 1-3 clinical trials were pooled for the population pharmacokinetic (popPK) analysis and concentration-bispectral index (BIS) data were pooled from 8 trials for popPK-PD analysis. A 3-compartment model with allometric exponents on clearance and volume described remimazolam concentrations over time. An effect compartment model with an inhibitory sigmoid Emax model was fit to the concentration-BIS data. Simulations were performed to assess sedation in general anesthesia and post-surgical sedation in healthy and sensitive populations. SETTING: General anesthesia and post-surgical sedation. PATIENTS: 689 subjects included in popPK and 604 subjects included in popPK-PD. Most subjects (>85%) were ASA Class 1 or 2, with the remaining subjects being ASA Class 3. INTERVENTIONS: Serial plasma concentrations and BIS scores. MEASUREMENTS: Standard intra-operative monitoring. MAIN RESULTS: PopPK model included an effect of extracorporeal circulation, ASA class, and sex on PK and a time-dependent clearance (~30% lower at 24 h) that was not related to cumulative dose. Co-administered remifentanil had a synergistic decrease in BIS with remimazolam. Remimazolam IC50 increased with cumulative dose. Onset was faster in overweight subjects and slower in Asian subjects. If using a weight-based regimen, simulations showed that remimazolam 6 mg/kg/h until loss of consciousness followed by 1 mg/kg/h during general anesthesia and 0.25 mg/kg/h for post-surgical sedation for up to 24 h is optimal, regardless of ASA class or sensitivity of subjects. CONCLUSIONS: If using a weight-based regimen, results illustrated an appropriate regimen of remimazolam for general anesthesia and post-surgical sedation in general and sensitive populations, although lower doses can be considered in elderly patients with a significant disease burden or in ASA Class 3 patients. The time-dependent change in clearance is not clinically relevant for up to 24 h.

Potential strategy for assessing QT/QTc interval for drugs that produce rapid changes in heart rate: Electrocardiographic assessment of the effects of intravenous remimazolam on cardiac repolarization.

AIMS: Remimazolam is a new, ultra-short-acting benzodiazepine developed for intravenous (IV) use during procedural sedation and in general anaesthesia. Two trials were conducted to characterize its effects on cardiac repolarization. METHODS: A thorough QT/QTc (TQT) study assessed electrocardiography effects of therapeutic and supratherapeutic doses of remimazolam and midazolam. To investigate whether RR-QT hysteresis effects due to rapid heart rate changes might have confounded the QTc assessments in the TQT trial, a second trial used continuous IV remimazolam infusion to achieve stable heart rates during periods of stable remimazolam plasma concentration. RESULTS: During the TQT, both compounds produced a 10-20-beats/min increase in heart rate within 30 seconds, persisting for 5-10 minutes. Within 30 seconds, the upper bound of the 2-sided 90% confidence interval for the placebo-corrected change from baseline for QTcI (ΔΔQTcI) exceeded 10 ms for both doses of remimazolam (ΔΔQTcI 7.2 [3.2, 11.2] ms for the 10 mg dose and 10.4 [6.5, 14.3] ms for the 20 mg dose) as well as for the 7.5-mg dose of midazolam (8.2 [4.4, 12.1] ms). At 2 minutes after IV bolus, the upper bound of the 2-sided 90% confidence interval for ΔΔQTcI exceeded 10 ms only for the remimazolam 20-mg dose (6.3 [2.3, 10.2] ms). During the second study, during periods of stable heart rate, remimazolam had no clinically significant effect on QTc (peak ΔΔQTcI 3.4 [-1.1, 7.6] ms). CONCLUSION: Remimazolam does not prolong cardiac repolarization (QTc). The methods reported here may allow assessment of the QTc effects of other drugs given by IV bolus.

Time-to-Event Modeling for Remimazolam for the Indication of Induction and Maintenance of General Anesthesia.

Remimazolam is an ultra-short-acting benzodiazepine being investigated for induction and maintenance of general anesthesia and for procedural sedation. This dose-response analysis of 4 phase 2-3 studies evaluated covariates that may impact the pharmacodynamic profile (based on theoretical pharmacokinetic principles) and require dose adjustments in subpopulations, particularly elderly, and if remimazolam has cumulative properties. Covariates affecting the time to loss of consciousness and time to extubation were evaluated using Cox proportional hazards models. Factors affecting steady-state infusion rate required to produce adequate sedation were evaluated using linear regression. Variability in time to loss of consciousness was explained by induction dose, age, body mass index, and time from initiation of opioids to initiation of remimazolam. The steady-state infusion rate producing adequate sedation was higher in European than Japanese subjects due to differences in study design. American Society of Anesthesiologists physical status class 3 subjects had a 28% lower maintenance infusion rate than class 1 subjects. Other statistically significant covariates (American Society of Anesthesiologists class 2, estimated glomerular filtration rate, and sex) resulted in small (≤14%), non-clinically relevant differences. Factors affecting time to extubation included the last infusion rate (ie, tapering), the bispectral index score at the end of infusion, and sex. The time to extubation after remimazolam did not increase with increased cumulative dose of remimazolam or duration of surgery. This evaluation of remimazolam's pharmacodynamic profile, in the absence of pharmacokinetic data, informed dosing recommendations and showed that remimazolam does not have cumulative properties in the general anesthesia setting.

Safety and Efficacy of Remimazolam Compared With Placebo and Midazolam for Moderate Sedation During Bronchoscopy.

BACKGROUND: While the complexity of flexible bronchoscopy has increased, standard options for moderate sedation medications have not changed in three decades. There is a need to improve moderate sedation while maintaining safety. Remimazolam was developed to address shortcomings of current sedation strategies. METHODS: A prospective, double-blind, randomized, multicenter, parallel group trial was performed at 30 US sites. The efficacy and safety of remimazolam for sedation during flexible bronchoscopy were compared with placebo and open-label midazolam. RESULTS: The success rates were 80.6% in the remimazolam arm, 4.8% in the placebo arm (P < .0001), and 32.9% in the midazolam arm. Bronchoscopy was started sooner in the remimazolam arm (mean, 6.4 ± 5.82 min) compared with placebo (17.2 ± 4.15 min; P < .0001) and midazolam (16.3 ± 8.60 min). Time to full alertness after the end of bronchoscopy was significantly shorter in patients treated with remimazolam (median, 6.0 min; 95% CI, 5.2-7.1) compared with those treated with placebo (13.6 min; 95% CI, 8.1-24.0; P = .0001) and midazolam (12.0 min; 95% CI, 5.0-15.0). Remimazolam registered superior restoration of neuropsychiatric function compared with placebo and midazolam. Safety was comparable among all three arms, and 5.6% of the patients in the remimazolam group had serious treatment-emergent adverse events as compared with 6.8% in the placebo group. CONCLUSIONS: Remimazolam administered under the supervision of a pulmonologist was effective and safe for moderate sedation during flexible bronchoscopy. In an exploratory analysis, it demonstrated a shorter onset of action and faster neuropsychiatric recovery than midazolam.