Daridorexant, formerly known as nemorexant, is a selective dual orexin receptor antagonist used to treat insomnia. Insomnia is characterized by difficulties with sleep onset and/or sleep maintenance and impairment of daytime functioning. It chronically affects the person’s daily functioning and long-term health effects, as insomnia is often associated with comorbidities such as hypertension, diabetes, and depression. Conventional treatments for insomnia include drugs targeting gamma-aminobutyric acid type-A (GABA-A), serotonin, histamine, or melatonin receptors; however, undesirable side effects are frequently reported, such as next-morning residual sleepiness, motor incoordination, falls, memory and cognitive impairment. Novel drugs that target orexin receptors gained increasing attention after discovering the role of orexin signalling pathway in wakefulness and [almorexant], an orexin receptor antagonist that improved sleep. Daridorexant was designed via an intensive drug discovery program to improve the potency and maximize the duration of action while minimizing next-morning residual activity. Daridorexant works on orexin receptors OX1R and OX2R to block the binding of orexins, which are wake-promoting neuropeptides and endogenous ligands to these receptors. Daridorexant reduces overactive wakefulness: in the investigational trials, daridorexant reportedly improved sleep and daytime functioning in patients with insomnia. It was approved by the FDA on January 10, 2022, under the name QUVIVIQ. as the second orexin receptor antagonist approved to treat insomnia following [suvorexant]. Daridorexant was approved by the European Commission on May 3, 2022, as the first dual orexin receptor antagonist approved in the market, and by Health Canada on April 26, 2023.
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Daridorexant
Drug Overview
What is Daridorexant?
Masuu Global provides end-to-end Environmental Risk Assessment (ERA) support for pharmaceutical and healthcare products, covering Phase I environmental exposure assessment, Phase II environmental fate and effects assessment, data-gap analysis, testing strategy, laboratory coordination and final regulatory-ready reporting.
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Regulatory Framework
Assessment Methodology
Masuu Global follows a science-based, tiered and risk-based ERA methodology, aligned with applicable international regulatory requirements. For human medicinal products, our approach is primarily guided by the EMA Guideline EMEA/CHMP/SWP/4447/00 Rev. 1, effective 1 September 2024, together with relevant OECD Test Guidelines and regional regulatory requirements.
EMA — Environmental Risk Assessment
Assessment of potential environmental exposure associated with the use, manufacture and disposal of medicinal products, with a structured approach to determine whether further environmental assessment is required.
Phase I — Environmental Exposure Assessment
Initial screening to determine potential environmental exposure, covering PEC calculation, physicochemical properties, usage and dosage data, environmental entry pathways, and persistence and fate considerations.
Phase II — Environmental Fate & Effects Assessment
Where Phase I indicates further assessment is required, Phase II provides detailed evaluation of environmental fate, persistence and ecological effects — including biodegradation, bioaccumulation, aquatic toxicity, PNEC derivation and PEC/PNEC risk characterisation.
OECD & International Testing Principles
Where laboratory studies are required, testing strategies are designed with consideration of relevant OECD Test Guidelines, GLP expectations and applicable regulatory requirements.
Risk-Based Environmental Assessment
Integration of physicochemical data, environmental fate information, ecotoxicological data, existing literature, published studies, regulatory databases, usage data, and environmental monitoring data.
Weight-of-Evidence (WoE) Approach
A scientifically justified WoE approach integrates existing data and avoids unnecessary testing wherever scientifically and regulatorily justified.
ERA Assessment Pathway
Phase I → Phase II → Risk Characterization
Each phase builds on the prior tier — screening first, escalating only when the evidence demands it.
Environmental Exposure Assessment
Initial screening to determine whether the substance requires progression to Phase II.
- Product and substance information review
- Indication, dose and usage assessment
- PEC calculation and environmental exposure estimation
- Physicochemical property review
- Initial environmental risk screening
- Determination of Phase II requirement
Environmental Fate & Effects
Detailed evaluation when Phase I triggers further assessment.
- Biodegradation, hydrolysis & photolysis
- Adsorption/desorption behaviour
- Bioaccumulation potential
- Algal, Daphnia and fish toxicity
- Chronic ecotoxicity, where required
- PEC/PNEC risk characterisation
Laboratory Coordination & Study Execution
When regulatory testing is mandatory, Masuu coordinates with qualified GLP/appropriate testing laboratories and specialized scientific partners — giving clients a single point of contact across the full testing lifecycle.
Final ERA Report — Contents
- Executive summary
- Substance & product information
- Environmental exposure assessment
- Phase I evaluation
- Phase II assessment (where applicable)
- Environmental fate assessment
- Ecotoxicological assessment
- PEC/PNEC calculations
- Risk characterisation
- Data gap evaluation
- Testing rationale
- Risk mitigation considerations
- References and supporting scientific evidence
How We Work
Report Preparation Process
Every ERA follows a structured, tiered workflow designed to deliver scientifically defensible and regulator-ready assessments.
Comprehensive Data Collection
Product, substance, usage, physicochemical, toxicological, environmental and regulatory information collected and reviewed.
Phase I Environmental Screening
Environmental exposure assessment and determination of whether the assessment can conclude at Phase I or requires progression.
Phase II Evaluation
Detailed environmental fate and ecotoxicological assessment when Phase II is triggered.
Data Gap & Testing Strategy
Missing information identified and available alternatives evaluated before recommending additional testing.
Consortium Testing Support
Where testing is mandatory, Masuu coordinates with qualified testing partners through its Consortium Model.
Scientific & Regulatory Review
Integration and critical review of generated and existing data by experienced scientific and regulatory experts.
Final ERA Delivery
Comprehensive ERA report with transparent methodology, scientific rationale, calculations, conclusions and regulatory recommendations.
Ex-Agency Advantage
Why Masuu Global?
Our experienced regulatory and scientific experts bring a practical regulatory perspective — helping clients understand not only what data are required, but why they are required and how regulators may evaluate them.
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