Weak evidence on nalmefene creates dilemmas for clinicians and poses questions for regulators and researchers

A critical scientific evaluation of a purportedly negative data report - response to Seneviratne et al. 2022

A core principle in the pursuit of scientific knowledge is that science is self-correcting and that important results should be replicable. Hypotheses need to be reinforced, adjusted, or rejected when novel results are obtained. Replication of results confirms hypotheses and enhances their integration into scientific practice. In contrast, publication of substantiated and replicated negative findings (i.e., non-significant or opposite findings) can be the basis to reject erroneous hypotheses or develop alternative strategies for investigation. Replication is a problem in all research fields. The Psychology Reproductivity Project reported that only 36% of 'highly influential' published research in highly ranked journals were reproduced. Similar to positive data, negative data can be flawed. Errors in a negative data set can be based on methodology, statistics, conceptual defects, and flawed peer review. The peer review process has received progressive scrutiny. A large-scale review of the peer review process of manuscripts submitted to the British Medical Journal group indicated that the process could be characterized as inconsistent, inaccurate, and biased. Further analysis indicated that the peer process is easily manipulated, indicative of a failed system, is a major factor behind the lack of replication in science (acceptance of flawed manuscripts), suppresses opposing scientific evidence and views, and causes gaps in and lack of growth of science. Complicating the integrity of scientific publication is the role of Editors/Researchers. Ethical guidelines exist for major publishing houses about editorial ethics, behavior, and practice.

The pharmacotherapeutic management of comorbid bipolar disorder and alcohol use disorder

INTRODUCTION

Comorbidity of bipolar disorder (BD) and alcohol use disorder (AUD) is very frequent resulting in detrimental outcomes, including increased mortality. Diagnosis of AUD in BD and vice versa is often delayed as symptoms of one disorder mimic and obscure the other one. Evidence for pharmacotherapies for people with comorbid BD and AUD remains limited, and further proof-of-concept studies are urgently needed.

AREAS COVERED

This paper explores the currently available pharmacotherapies for AUD, BD and their usefulness for comorbid BD and AUD. It also covers to some degree the epidemiology, diagnosis, and potential common neurobiological traits of comorbid BD and AUD.

EXPERT OPINION

The authors conclude that more controlled studies are needed before evidence-based guidance can be drawn up for clinician's use. Since there are no relevant pharmacological interactions, approved medications for AUD can also be used safely in BD. For mood stabilization, lithium should be considered first in adherent persons with BD and comorbid AUD. Alternatives include valproate, lamotrigine, and some atypical antipsychotics, with partial D2/D3 receptor agonism possibly being beneficial in AUD, too.

Alcohol Use Disorder: Neurobiology and Therapeutics

Alcohol use disorder (AUD) encompasses the dysregulation of multiple brain circuits involved in executive function leading to excessive consumption of alcohol, despite negative health and social consequences and feelings of withdrawal when access to alcohol is prevented. Ethanol exerts its toxicity through changes to multiple neurotransmitter systems, including serotonin, dopamine, gamma-aminobutyric acid, glutamate, acetylcholine, and opioid systems. These neurotransmitter imbalances result in dysregulation of brain circuits responsible for reward, motivation, decision making, affect, and the stress response. Despite serious health and psychosocial consequences, this disorder still remains one of the leading causes of death globally. Treatment options include both psychological and pharmacological interventions, which are aimed at reducing alcohol consumption and/or promoting abstinence while also addressing dysfunctional behaviours and impaired functioning. However, stigma and social barriers to accessing care continue to impact many individuals. AUD treatment should focus not only on restoring the physiological and neurological impairment directly caused by alcohol toxicity but also on addressing psychosocial factors associated with AUD that often prevent access to treatment. This review summarizes the impact of alcohol toxicity on brain neurocircuitry in the context of AUD and discusses pharmacological and non-pharmacological therapies currently available to treat this addiction disorder.

Clinical moderators of response to nalmefene in a randomized-controlled trial for alcohol dependence: An exploratory analysis

BACKGROUND

Nalmefene is the only medication marketed to reduce the consumption of alcohol in patients with alcohol dependence, but it remains unclear which patients could most benefit from it. This study aimed to identify clinical moderators that affect treatment response to nalmefene in patients with alcohol dependence.

METHODS

In a multicenter, randomized, controlled, double-blind, phase 3 study of nalmefene on Japanese patients with alcohol dependence, the relationship between the reduction of heavy drinking days (HDD) and total alcohol consumption (TAC) at 12 and 24 weeks of treatment and baseline variables of the participants were analyzed in a linear regression and multiple adjusted analysis.

RESULTS

Age < 65, no family history of problem drinking, age at onset of problem drinking ≥ 25, and not currently smoking were possible positive moderators. Nalmefene showed a significant HDD reduction in patients with age < 65 or no family history of problem drinking, and a significant TAC reduction in patients with age at onset of problem drinking ≥ 25 or who were not currently smoking. After multiple adjusted analyses, age < 65 (p = .028), no family history of problem drinking (p = .047), and age at onset of problem drinking ≥ 25 (p = .030) were statistically significant. Not currently smoking (p = .071) was marginally significant. In combination, these moderators indicated synergistic effects.

CONCLUSIONS

Alcohol-dependent patients with favorable prognostic factors such as non-smoking status, no family history of problem drinking, and a late-onset of problem drinking selectively benefit from nalmefene. Further research is needed to validate these exploratory results.

Neuroimmune and Mu-Opioid Receptor Alterations in the Mesocorticolimbic System in a Sex-Dependent Inflammatory Pain-Induced Alcohol Relapse-Like Rat Model

Evidence concerning the role of alcohol-induced neuroinflammation in alcohol intake and relapse has increased in the last few years. It is also proven that mu-opioid receptors (MORs) mediate the reinforcing properties of alcohol and, interestingly, previous research suggests that neuroinflammation and MORs could be related. Our objective is to study neuroinflammatory states and microglial activation, together with adaptations on MOR expression in the mesocorticolimbic system (MCLS) during the abstinence and relapse phases. To do so, we have used a sex-dependent rat model of complete Freund's adjuvant (CFA)-induced alcohol deprivation effect (ADE). Firstly, our results confirm that only CFA-treated female rats, the only experimental group that showed relapse-like behavior, exhibited specific alterations in the expression of phosphorylated NFκB, iNOS, and COX2 in the PFC and VTA. More interestingly, the analysis of the IBA1 expression revealed a decrease of the microglial activation in PFC during abstinence and an increase of its expression in the relapse phase, together with an augmentation of this activation in the NAc in both phases that only occur in female CFA-treated rats. Additionally, the expression of IL1β also evidenced these dynamic changes through these two phases following similar expression patterns in both areas. Furthermore, the expression of the cytokine IL10 showed a different profile than that of IL1β, indicating anti-inflammatory processes occurring only during abstinence in the PFC of CFA-female rats but neither during the reintroduction phase in PFC nor in the NAc. These data indicate a downregulation of microglial activation and pro-inflammatory processes during abstinence in the PFC, whereas an upregulation can be observed in the NAc during abstinence that is maintained during the reintroduction phase only in CFA-female rats. Secondly, our data reveal a correlation between the alterations observed in IL1β, IBA1 levels, and MOR levels in the PFC and NAc of CFA-treated female rats. Although premature, our data suggest that neuroinflammatory processes, together with neural adaptations involving MOR, might play an important role in alcohol relapse in female rats, so further investigations are warranted.

New approved and emerging pharmacological approaches to alcohol use disorder: a review of clinical studies

introduction: The number of medications approved for AUD is small and they generally have limited efficacy. We need new pharmacotherapies for the management of AUD.Areas covered: In this review, the authors aim to synthesise literature for new approved and emerging pharmacotherapies for AUD. Recently approved medications include nalmefene, which was approved in Europe and Australia for the purposes of controlled drinking. Baclofen has also been approved in France but not in other countries. Off label medications including topiramate and gabapentin have received significant attention with multiple RCTs and meta-analyses and have widespread use in several countries including the USA. Several novel medications have emerged over the last decade but further work is required to determine their efficacy and safety for the widespread management of AUD.Expert opinion: Despite significant advances in our understanding of the neurobiological basis of factors that contribute to the development and maintenance of AUD, there have been few new AUD medications approved for almost 20 years. There are many challenges to the development and introduction of new pharmacotherapies for AUD. Strategies for improving the translational pipeline include drug repurposing and utilisation of human acute laboratory models.

[Pharmacotherapy of alcohol withdrawal: update and new developments]

Bislang sind nur wenige Medikamente zur pharmakologischen Rückfallprophylaxe der Alkoholabhängigkeit zugelassen. Neben dem in Deutschland nicht mehr vertriebenen Disulfiram sind es die Opioidantagonisten Naltrexon und Nalmefen sowie das vermutlich über glutamaterge Neurone wirkende Acamprosat. Baclofen und γ‑Hydroxybutyrat (GHB) sind in einzelnen Ländern zugelassen. Wirkstoffe wie z. B. Vareniclin, Gabapentin und Topiramat können für die Rückfallprophylaxe der Alkoholabhängigkeit von Interesse sein, jedoch ist bislang keine Zulassung erfolgt. Vor dem Hintergrund der zur Revision anstehenden S3-Leitlinie zur Diagnose und Behandlung alkoholbezogener Störungen wird der heutige Kenntnisstand zur Pharmakotherapie der Alkoholabhängigkeit dargestellt.

Evidence-Based Pharmacotherapies for Alcohol Use Disorder: Clinical Pearls

Pathologic alcohol use affects more than 2 billion people and accounts for nearly 6% of all deaths worldwide. There are three medications approved for the treatment of alcohol use disorder by the US Food and Drug Administration (FDA): disulfiram, naltrexone (oral and long-acting injectable), and acamprosate. Of growing interest is the use of anticonvulsants for the treatment of alcohol use disorder, although currently none are FDA approved for this indication. Baclofen, a γ-aminobutyric acid B receptor agonist used for spasticity and pain, received temporary approval for alcohol use disorder in France. Despite effective pharmacotherapies, less than 9% of patients who undergo any form of alcohol use disorder treatment receive pharmacotherapies. Current evidence does not support the use of pharmacogenetic testing for treatment individualization. The objective of this review is to provide knowledge on practice parameters for evidenced-based pharmacologic treatment approaches in patients with alcohol use disorder.

Pharmacotherapies and personalized medicine for alcohol use disorder: a review

Alcohol use disorder (AUD) is highly prevalent and among the leading causes of morbidity and mortality in the United States. Pharmacotherapies for AUD are limited, thus making identification of patient subgroups that are most likely to respond favorably crucial. In this article, pharmacogenetic research on US FDA-approved and commonly prescribed off-label medications for the treatment of AUD is comprehensively reviewed. While the field has advanced in understanding pharmacotherapies for AUD and potential genetic moderators of treatment responses, the pharmacogenetic data to guide the prescribing clinician are limited and should be interpreted with caution. Precision medicine for AUD with more beneficial treatment responses and minimal side effects remains a high priority for further research.

Are animal models of addiction useful?

BACKGROUND

Pre-clinical research involving non-human animals has made important contributions to our understanding of risk factors for addiction, neuroadaptations that follow chronic drug exposure and to the development of some efficacious pharmacotherapies for addiction. Despite these contributions, we argue that animal models of addiction have impeded progress in our understanding of addiction and its treatment in humans.

ARGUMENT

First, the majority of pharmacological treatments that were initially developed using animal models have failed to prove effective for the treatment of addiction in humans, resulting in a huge waste of resources. Secondly, we demonstrate that prevailing animal models that portray addiction as a disorder of compulsion and habit cannot be reconciled with observations that psychoactive drug use in humans is a goal-directed operant behaviour that remains under the control of its consequences, even in people who are addicted. Thirdly, addiction may be a uniquely human phenomenon that is dependent on language, which necessarily limits the validity of animal models. Finally, we argue that addicted brains must be understood as one component of broader networks of symptoms and environmental and social factors that are impossible to model in laboratory animals.

CONCLUSIONS

A case can be made that animal models of addiction have not served us well in understanding and treating addiction in humans. It is important to reconsider some widely held beliefs about the nature of addictive behaviour in humans that have arisen from the zeal to translate observations of laboratory animals.

Nalmefene in alcohol-dependent patients with a high drinking risk: Randomized controlled trial

AIMS

Reducing alcohol consumption is one treatment approach for alcohol-dependent patients. This study compared nalmefene 20 mg and 10 mg with placebo, combined with psychosocial support, in alcohol-dependent Japanese patients with a high or very high drinking risk level (DRL).

METHODS

This was a multicenter, randomized, double-blind, phase 3 study conducted in alcohol-dependent patients with a high or very high DRL. Patients were randomized to 24 weeks of treatment with as-needed nalmefene 20 mg, 10 mg, or placebo with psychosocial support. The primary endpoint was change in heavy drinking days (HDD) from baseline to week 12. A key secondary endpoint was the change in total alcohol consumption (TAC) from baseline to week 12.

RESULTS

At week 12, 234, 206, and 154 patients who received placebo, nalmefene 20 mg, and 10 mg were included in the primary endpoint analysis. Compared with placebo, nalmefene was associated with significant reductions in HDD at week 12 (difference in 20 mg group, -4.34 days/month; 95% confidence interval [CI]: -6.05 to -2.62; P < 0.0001; difference in 10 mg group, -4.18 days/month; 95%CI: -6.05 to -2.32; P < 0.0001), as well as a significant reduction in TAC at week 12 (P < 0.0001). The incidence of treatment-emergent adverse events was 87.9%, 84.8%, and 79.2% in the groups receiving nalmefene 20 mg, 10 mg, and placebo, respectively. These events were mostly of mild or moderate severity.

CONCLUSIONS

Nalmefene 20 mg or 10 mg effectively reduced alcohol consumption and was well tolerated in alcohol-dependent patients with a high or very high DRL.

Stellungnahme Dachgesellschaft Sucht:

Zusammenfassung. Hintergrund: Unterschiede in der Therapiezielfindung bei der Behandlung von Alkoholkonsumstörungen, die sich zwischen völliger Abstinenz, vermindertem Konsum (Schadensvermeidung) und „kontrolliertem Konsum“ aufspannen, werden seit vielen Jahren z. T. kontrovers diskutiert. Ziel: Ziel der Stellungnahme der Dachgesellschaft Sucht ist es, vorhandene empirische Erkenntnisse zu diesem Themenbereich zusammenzutragen und daraus Empfehlungen für den praktischen Umgang mit verschiedenen Therapiezielen wie Trinkmengenreduktion oder Abstinenz für die Patienten oder Klienten abzuleiten. An der Erstellung des Positionspapiers haben sich Vertreter verschiedener Fachgesellschaften (DG Suchtmedizin, der DG Suchtforschung und Suchttherapie sowie die Deutsche Gesellschaft für Suchtpsychologie) beteiligt. Eine Reihe von Forschungsdesideraten wird benannt.

Drinking Levels and Profiles of Alcohol Addicted Rats Predict Response to Nalmefene

Background: Pharmacotherapeutic options supporting the treatment of alcohol dependence are recommended and available but underutilized, partly due to questions about efficacy. Nalmefene, a μ-opioid receptor antagonist and partial kappa receptor agonist, is recommended for reduction of alcohol consumption, but evidence about its effectiveness has been equivocal; identifying factors which predict response will help optimize treatment.

Methods: The alcohol deprivation effect paradigm is a tightly controlled procedure comprising repeated deprivation and reintroduction phases, leading to increased preference for alcohol; reintroduction approximates relapse. Using a digital drinkometer system measuring high-resolution drinking behavior, we examined the effects of nalmefene on relapse drinking behavior in alcohol addicted rats. We also tested whether drinking behavior in the relapse phase prior to nalmefene administration predicted treatment response. We further examined whether longitudinal drinking behavior and locomotor activity predicted treatment response.

Results: Our results showed that nalmefene (0.3 mg/kg) reduced relapse-like consumption significantly (∼20%) compared to vehicle on the first 2 days of alcohol reintroduction. Examining the first 6 h of a preceded treatment-free relapse episode revealed drinking patterns clustering the rats into responders (reduction of >40%, n = 17) and non-responders (reduction of <40%, n = 7) to subsequent nalmefene treatment. During the first 6 h of the preceding relapse phase, responders consumed more alcohol than non-responders; the amount of alcohol consumed during each drinking approach was larger but frequency of drinking did not differ. Longitudinal drinking behavior and locomotor activity did not significantly predict response.

Conclusion: Our results suggest that nalmefene reduces alcohol intake during a relapse-like situation but effectiveness can differ greatly at the individual level. However, who responds may be informed by examining drinking profiles and rats that show high drinking levels prior to treatment are more likely to respond to nalmefene.

Diagnosis and Pharmacotherapy of Alcohol Use Disorder: A Review

Importance

Alcohol consumption is associated with 88 000 US deaths annually. Although routine screening for heavy alcohol use can identify patients with alcohol use disorder (AUD) and has been recommended, only 1 in 6 US adults report ever having been asked by a health professional about their drinking behavior. Alcohol use disorder, a problematic pattern of alcohol use accompanied by clinically significant impairment or distress, is present in up to 14% of US adults during a 1-year period, although only about 8% of affected individuals are treated in an alcohol treatment facility.

Observations

Four medications are approved by the US Food and Drug Administration to treat AUD: disulfiram, naltrexone (oral and long-acting injectable formulations), and acamprosate. However, patients with AUD most commonly receive counseling. Medications are prescribed to less than 9% of patients who are likely to benefit from them, given evidence that they exert clinically meaningful effects and their inclusion in clinical practice guidelines as first-line treatments for moderate to severe AUD. Naltrexone, which can be given once daily, reduces the likelihood of a return to any drinking by 5% and binge-drinking risk by 10%. Randomized clinical trials also show that some medications approved for other indications, including seizure disorder (eg, topiramate), are efficacious in treating AUD. Currently, there is not sufficient evidence to support the use of pharmacogenetics to personalize AUD treatments.

Conclusions and Relevance

Alcohol consumption is associated with a high rate of morbidity and mortality, and heavy alcohol use is the major risk factor for AUD. Simple, valid screening methods can be used to identify patients with heavy alcohol use, who can then be evaluated for the presence of an AUD. Patients receiving a diagnosis of the disorder should be given brief counseling and prescribed a first-line medication (eg, naltrexone) or referred for a more intensive psychosocial intervention.

Pharmacologically controlled drinking in the treatment of alcohol dependence or alcohol use disorders: a systematic review with direct and network meta-analyses on nalmefene, naltrexone, acamprosate, baclofen and topiramate

BACKGROUND AND AIMS

Pharmacologically controlled drinking in the treatment of alcohol dependence or alcohol use disorders (AUDs) is an emerging concept. Our objective was to explore the comparative effectiveness of drugs used in this indication.

DESIGN

Systematic review with direct and network meta-analysis of double-blind randomized controlled trials (RCTs) assessing the efficacy of nalmefene, naltrexone, acamprosate, baclofen or topiramate in non-abstinent adults diagnosed with alcohol dependence or AUDs. Two independent reviewers selected published and unpublished studies on Medline, the Cochrane Library, Embase, ClinicalTrials.gov, contacted pharmaceutical companies, the European Medicines Agency and the Food and Drug Administration, and extracted data.

SETTING

Thirty-two RCTs.

PARTICIPANTS

A total of 6036 patients.

MEASUREMENTS

The primary outcome was total alcohol consumption (TAC). Other consumption outcomes and health outcomes were considered as secondary outcomes.

FINDINGS

No study provided direct comparisons between drugs. A risk of incomplete outcome data was identified in 26 studies (81%) and risk of selective outcome reporting in 17 (53%). Nalmefene [standardized mean difference (SMD) = -0.19, 95% confidence interval (CI) = -0.29, -0.10; I²  = 0%], baclofen (SMD = -1.00, 95% CI = -1.80, -0.19; one study) and topiramate (SMD = -0.77, 95% CI = -1.12, -0.42; I²  = 0%) showed superiority over placebo on TAC. No efficacy was observed for naltrexone or acamprosate. Similar results were observed for other consumption outcomes, except for baclofen (the favourable outcome on TAC was not reproduced). The number of withdrawals for safety reasons increased under nalmefene and naltrexone. No treatment demonstrated any harm reduction (no study was powered to explore health outcomes). Indirect comparisons suggested that topiramate was superior to nalmefene, naltrexone and acamprosate on consumption outcomes, but its safety profile is known to be poor.

CONCLUSIONS

There is currently no high-grade evidence for pharmacological treatment to control drinking using nalmefene, naltrexone, acamprosate, baclofen or topiramate in patients with alcohol dependence or alcohol use disorder. Some treatments show low to medium efficacy in reducing drinking across a range of studies with a high risk of bias. None demonstrates any benefit on health outcomes.

Review article: pharmacotherapy for alcohol dependence - the why, the what and the wherefore

BACKGROUND

The development of alcohol dependence is associated with significant morbidity and mortality. For the majority of affected people the most appropriate goal, in terms of drinking behaviour, is abstinence from alcohol. Psychosocial intervention is the mainstay of the treatment but adjuvant pharmacotherapy is also available and its use recommended.

AIM

To provide an updated analysis of current and potential pharmacotherapeutic options for the management of alcohol dependence. In addition, factors predictive of therapeutic outcome, including compliance and pharmacogenetics, and the current barriers to treatment, including doctors' unwillingness to prescribe these agents, will be explored.

METHODS

Relevant papers were selected for review following extensive, language- and date-unrestricted, electronic and manual searches of the literature.

RESULTS

Acamprosate and naltrexone have a substantial evidence base for overall efficacy, safety and cost-effectiveness while the risks associated with the use of disulfiram are well-known and can be minimised with appropriate patient selection and supervision. Acamprosate can be used safely in patients with liver disease and in those with comorbid mental health issues and co-occurring drug-related problems. A number of other agents are being investigated for potential use for this indication including: baclofen, topiramate and metadoxine.

CONCLUSION

Pharmacotherapy for alcohol dependence has been shown to be moderately efficacious with few safety concerns, but it is substantially underutilised. Concerted efforts must be made to remove the barriers to treatment in order to optimise the management of people with this condition.

Binge Drinking: Current Diagnostic and Therapeutic Issues

The concept of binge drinking (BD) refers to patterns of heavy episodic alcohol consumption, with BD primarily occurring among adolescents and young adults. Several official definitions of BD have been proposed, in particular by the World Health Organization, the National Institute on Alcoholism and Alcohol Abuse, and the Substance Abuse and Mental Health Services Administration. Nevertheless, none of these definitions address the psychosocial and medical consequences of the type of alcohol use seen in BD. In practice, BD can thus correspond to either hazardous or harmful use of alcohol (HUA), while the episodic nature of heavy drinking in BD means that it does not meet the criteria for 'alcohol dependence'. This diagnostic differentiation is important because it determines which type of intervention is recommended. Psychosocial, rather than pharmacological, interventions are recommended as first-line treatment for adults with HUA, while pharmacological treatment is recommended for alcohol dependence; however, HUA appears to be associated with much poorer outcomes in adolescents, which could thus warrant early use of pharmacotherapy in this patient group. For HUA, and especially in adolescents, there is currently a severe lack of data regarding the efficacy and safety of the different drugs that have been approved for adults with alcohol dependence. Various guidelines propose the use of drugs for some types of BD but that use remains off-label and empirical, which raises important safety and ethical concerns. Future research on BD should systematically assess the criteria for HUA to better differentiate its subtypes with actual consequences and better address the heterogeneity of BD in terms of both clinical profiles and outcomes. Regarding pharmacotherapy, some national guidelines have recommended nalmefene for 'mild' dependence or second-line treatment for HUA, but such recommendations are not supported by evidence. Only naltrexone has been investigated in HUA but not in adolescents. More clinical trials should be conducted among adolescents with BD and HUA criteria to determine the most appropriate use of drugs in this particularly vulnerable population of subjects.

Reduced Drinking in Alcohol Dependence Treatment, What Is the Evidence?

Abstinence from alcohol has been the prevailing treatment goal for individuals with alcohol dependence (AD) within the context of specialty alcohol treatment. Yet, alcohol use has been conceptualized as existing on a continuum. Importantly, most people who meet criteria for AD and could benefit from treatment never receive treatment. About half of these individuals do not seek treatment because they report a desire to continue drinking. To increase acceptability of treatment, reductions in alcohol consumption have been examined as alternative outcomes in treatment trials for AD. The current study reviews data which indicate that long-term reduction in alcohol consumption among patients with AD is possible. Controlled studies have tested reduced alcohol consumption and show sustained improvements in drinking reductions for many patients following behavioral treatments and pharmacotherapy. Evidence-based treatment guidelines and medicines development guidance authorities have taken note of these developments and accept "intermediate harm reduction" (European Medicines Agency) or "low-risk drinking limits" (US Federal Drug Administration) as optional trial endpoints. In conclusion, while abstinence remains the safest treatment goal for individuals with AD, evidence supports that reduced drinking approaches may be an important extension in the treatment of AD.

Nalmefene for the management of alcohol dependence: review on its pharmacology, mechanism of action and meta-analysis on its clinical efficacy

Nalmefene, a mu- and delta-opioid receptor (MOR, DOR) antagonist and a partial kappa-opioid receptor (KOR) agonist, is approved in the European Union and other countries for the reduction of alcohol consumption in alcohol dependent patients with a high drinking risk level according to WHO ("target population"). This review presents an overview of nalmefene׳s pharmacology, its mechanisms of action and a meta-analysis on its efficacy in reducing alcohol consumption. The review was based on a systematic search of the literature. Random effects meta-analyses were performed on published and unpublished trials directed at drinking reduction using the changes in heavy drinking days (HDDs) and daily total alcohol consumption (TAC) from baseline to the primary endpoint. For each included study and each dose, Hedges' g was used as an unbiased estimator of the standardised mean differences between nalmefene and placebo. Preclinical data suggests that nalmefene counters alcohol-induced dysregulations of the MOR/endorphine and the KOR/dynorphin system. Evidence further suggests that reduced alcohol consumption is an effective treatment strategy that appeals to patients not ready for abstinence. Finally, meta-analyses confirmed the efficacy of 20mg nalmefene for reducing HDDs in the ITT population (Hedge׳s g=-0.20; 95% CI -0.30 to -0.09) and the target population (Hedge׳s g=-0.33; 95% CI -0.48 to -0.18). Similar results were seen for TAC. Several meta-analyses, including this new meta-analysis, support nalmefene׳s efficacy in reducing alcohol consumption. In conclusion, because it does not require abstinence, this treatment has the potential to motivate more patients for treatment and thus helps to address a major public health concern.

Evaluation in alcohol use disorders - insights from the nalmefene experience

Nalmefene was the first treatment approved by the European Medicines Agency for reducing alcohol consumption in adult patients with alcohol dependence. It is often presented as a paradigm shift in therapeutics, but major issues limit the interpretation of the evidence supporting its use. The randomised trials submitted provided no evidence of harm reduction, the differences on consumption outcomes were of questionable clinical relevance, the target population was defined a posteriori and the drug was compared to a placebo although naltrexone was already used off-label. No post-approval randomised study is currently designed to clearly address these issues. In addition, nalmefene trials have been uncritically cited, even in guidelines. This experience reveals weaknesses in drug evaluations in alcohol dependence, which call for changes. We propose to dispense with alcohol consumption as a surrogate outcome, to consider comparative effectiveness issues, and to recommend randomised post-approval studies in case of controversial approval.

Weak evidence on nalmefene creates dilemmas for clinicians and poses questions for regulators and researchers

BACKGROUND AND AIMS

Nalmefene has been approved in Europe for the treatment of alcohol dependence and subsequently recommended by the UK National Institute for Health and Care Excellence (NICE). This study examines critically the evidence base underpinning both decisions and the issues arising.

METHODS

Published studies of nalmefene were identified through a systematic search, with documents from the European Medicines Agency, the NICE appraisal and public clinical trial registries also examined to identify methodological issues.

RESULTS

Efficacy data used to support the licensing of nalmefene suffer from risk of bias due to lack of specification of a priori outcome measures and sensitivity analyses, use of post-hoc sample refinement and the use of inappropriate comparators. Despite this, evidence for the efficacy of nalmefene in reducing alcohol consumption in those with alcohol dependence is, at best, modest, and of uncertain significance to individual patients. The relevance of existing trial data to routine primary care practice is doubtful.

CONCLUSIONS

Problems with the registration, design, analysis and reporting of clinical trials of nalmefene did not prevent it being licensed and recommended for treating alcohol dependence. This creates dilemmas for primary care clinicians and commissioning organisations where nalmefene has been heavily promoted, and poses wider questions about the effectiveness of the medicines regulation system and how to develop the alcohol treatment evidence base.