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 Random effects meta-analyses were performed on published and unpublished trials directed at drinking reduction using the changes in heavy drinking days (HDDs) and daily total alcohol consumption (TAC) from baseline to the primary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.

Clinical relevance of as-needed treatment with nalmefene in alcohol-dependent patients.

Nalmefene is the first drug approved for reduction of alcohol consumption. The aim of this study was to evaluate the clinical relevance of treatment with nalmefene in alcohol-dependent patients with a high drinking risk level from two randomised placebo-controlled 6-month studies (NCT00811720 and NCT00812461). Response criteria were based on alcohol consumption, Clinical Global Impression, and Short Form Health Survey mental component summary scores at month 6, analysed using logistic regression. The proportion of responders was higher in the nalmefene group than in the placebo group with odds ratios significantly in favour of nalmefene for all responder criteria; numbers-needed-to-treat ranged from 6 to 10. Significant differences from placebo in clinician-rated and patient-reported outcomes, and liver enzymes further supported the clinical relevance of the treatment effect. In conclusion, this study supports the clinical relevance of nalmefene treatment in patients with alcohol dependence. Nalmefene may help to reduce the alcohol-related burden and the large treatment gap, with currently less than 10% of alcohol-dependent patients in Europe receiving treatment.

Long-term efficacy, tolerability and safety of nalmefene as-needed in patients with alcohol dependence: A 1-year, randomised controlled study.

This study evaluated the long-term efficacy and safety of nalmefene treatment in reducing alcohol consumption. We randomised (1:3) 675 alcohol-dependent patients ≥ 18 years of age to 52 weeks of as-needed treatment with placebo or nalmefene 18 mg/day: A total of 112 patients (68%) in the placebo group and 310 (62%) in the nalmefene group completed the study. At month 6, the co-primary outcome variables showed no statistically-significant differences between the treatment groups; but at month 13, nalmefene was more effective than placebo, both in the reduction of the number of heavy drinking days (HDDs) (- 1.6 days/month (95% CI - 2.9; - 0.3); p = 0.017) and the reduction of total alcohol consumption (TAC) (- 6.5 g/day last month (95% CI - 12.5; - 0.4); p = 0.036). In a subgroup analysis of patients with high/very high drinking risk levels at screening and at randomisation (the target population), there was a significant effect in favour of nalmefene on TAC at month 6, and on both HDD and TAC at month 13. Improvements in Clinical Global Impression and liver enzymes were greater with nalmefene, compared to placebo. Most adverse events were mild or moderate, and transient; adverse events, including those leading to dropout, were more common with nalmefene. This study provides evidence for the long-term safety and efficacy of nalmefene as-needed in alcohol-dependent patients whom continue to drink heavily, following a brief intervention.

Efficacy of as-needed nalmefene in alcohol-dependent patients with at least a high drinking risk level: results from a subgroup analysis of two randomized controlled 6-month studies.

AIMS: The aim of the study was to investigate the efficacy and safety of as-needed use of nalmefene 18 mg versus placebo in reducing alcohol consumption in patients who did not reduce their alcohol consumption after an initial assessment, i.e. the pooled subgroup of patients with at least a high drinking risk level (men: >60 g/day; women: >40 g/day) at both screening and randomization from the two randomized controlled 6-month studies ESENSE 1 (NCT00811720) and ESENSE 2 (NCT00812461). METHODS: Nalmefene 18 mg and placebo were taken on an as-needed basis. All the patients also received a motivational and adherence-enhancing intervention (BRENDA). The co-primary outcomes were number of heavy drinking days (HDDs) and mean total alcohol consumption (g/day) in Month 6 measured using the Timeline Follow-back method. Additionally, data on clinical improvement, liver function and safety were collected throughout the study. RESULTS: The pooled population consisted of 667 patients: placebo n = 332; nalmefene n = 335. There was a superior effect of nalmefene compared with placebo in reducing the number of HDDs [treatment difference: -3.2 days (95% CI: -4.8; -1.6); P < 0.0001] and total alcohol consumption [treatment difference: -14.3 g/day (-20.8; -7.8); P < 0.0001] at Month 6. Improvements in clinical status and liver parameters were greater in the nalmefene group compared with the placebo group. Adverse events and adverse events leading to dropout were more common with nalmefene than placebo. CONCLUSION: As-needed nalmefene was efficacious in reducing alcohol consumption in patients with at least a high drinking risk level at both screening and randomization, and the effect in this subgroup was larger than in the total population.

A randomised, double-blind, placebo-controlled, efficacy study of nalmefene, as-needed use, in patients with alcohol dependence.

This study evaluated the efficacy of as-needed use of the opioid system modulator nalmefene in reducing alcohol consumption in patients with alcohol dependence. Seven hundred and eighteen patients (placebo=360; nalmefene=358), ≥ 18 years of age, with a diagnosis of alcohol dependence, ≥ 6 heavy drinking days and an average alcohol consumption ≥ WHO medium drinking risk level in the 4 weeks preceding screening, were randomised (1:1) to 24 weeks of as-needed placebo or nalmefene 18 mg/day. The co- primary efficacy analyses showed a significantly superior effect of nalmefene compared to placebo in the change from baseline to month 6 in heavy drinking days (group difference: -1.7 days/month [95% CI -3.1; -0.4]; p=0.012) and a better but not significant effect in reducing total alcohol consumption (group difference: -5.0 g/day last month [95% CI -10.6; 0.7]; p=0.088). A subgroup analysis showed that patients who did not reduce their drinking prior to randomisation benefitted more from nalmefene. Improvements in Clinical Global Impression and reductions in liver enzymes were greater in the nalmefene group than in the placebo group. Adverse events were more common with nalmefene; the incidence of adverse events leading to dropout was similar in both groups. This study provides evidence for the efficacy of nalmefene, which constitutes a new pharmacological treatment paradigm in terms of treatment goal (reduced drinking) and dosing regimen (as-needed), in alcohol dependent patients unable to reduce alcohol consumption on their own.

Extending the treatment options in alcohol dependence: a randomized controlled study of as-needed nalmefene.

BACKGROUND: There is a large treatment gap in alcohol dependence, and current treatments are only moderately effective in preventing relapse. New treatment modalities, allowing for reduction of alcohol consumption as a treatment goal are needed. This study evaluated the efficacy of as-needed use of the opioid system modulator nalmefene in reducing alcohol consumption in patients with alcohol dependence. METHODS: Six hundred and four patients (placebo = 298; nalmefene = 306),≥18 years of age, with a diagnosis of alcohol dependence,≥6 heavy drinking days, and average alcohol consumption≥World Health Organization medium drinking risk level in the 4 weeks preceding screening, were randomized (1:1) to 24 weeks of as-needed placebo or nalmefene 18 mg. RESULTS: Patients taking placebo (n = 289) and patients taking nalmefene (n = 290) were included in the efficacy analyses. At Month 6, there was a significant effect of nalmefene compared with placebo in reducing the number of heavy drinking days (-2.3 days [95% confidence interval:-3.8 to-.8]; p = .0021) and total alcohol consumption (-11.0 g/day [95% confidence interval:-16.8 to-5.1]; p = .0003). Improvements in Clinical Global Impression and liver enzymes were larger in the nalmefene group compared with placebo at Week 24. Adverse events (most mild or moderate) and dropouts due to adverse events were more common with nalmefene than placebo. The number of patients with serious adverse events was similar in the two groups. CONCLUSIONS: Nalmefene provides clinical benefit, constitutes a potential new pharmacological treatment paradigm in terms of the treatment goal and dosing regimen, and provides a method to address the unmet medical need in patients with alcohol dependence that need to reduce their alcohol consumption.

Discovery of phosphoric acid mono-{2-[(E/Z)-4-(3,3-dimethyl-butyrylamino)-3,5-difluoro-benzoylimino]-thiazol-3-ylmethyl} ester (Lu AA47070): a phosphonooxymethylene prodrug of a potent and selective hA(2A) receptor antagonist.

The discovery and structure-activity relationship of a series of hA(2A) receptor antagonists is described. Compound 28 was selected from the series as a potent and selective compound and was shown to be efficacious in an in vivo model of Parkinson's disease. It had acceptable ADME properties; however, the low intrinsic solubility of this compound was limiting for its developability, because the oral bioavailability from dosing in suspension was significantly lower than the oral bioavailability from solution dosage. As a consequence, prodrugs of 28 were prepared with dramatically increased aqueous solubility. The prodrugs efficiently delivered 28 into systemic circulation, with no detectable levels of prodrug in plasma samples. From this investigation, we selected 32 (Lu AA47070), a phosphonooxymethylene prodrug of 28, as a drug candidate.

Hit-to-lead optimization of a series of carboxamides of ethyl 2-amino-4-phenylthiazole-5-carboxylates as novel adenosine A2A receptor antagonists.

Herein we describe the discovery of a series of novel adenosine A(2A) receptor antagonists. A successful hit-to-lead optimization of an HTS hit led to replacement of a metabolically labile ester moiety with a heteroaromatic group. A compound from the series, (cyclopropanecarboxylic acid [5-(5-methyl-[1,2,4]oxadiazol-3-yl)-4-phenyl-thiazol-2-yl]-amide, compound 13), was shown to be effective in reversing haloperidol-induced hypolocomotion, a model of motor dysfunction in Parkinson's Disease.

High-dose erythropoietin alters platelet reactivity and bleeding time in rodents in contrast to the neuroprotective variant carbamyl-erythropoietin (CEPO).

The haematopoietic hormone erythropoietin (EPO) has neuroprotective properties and is currently being explored for treatment of stroke and other neurological disorders. Short-term, high-dose treatment with EPO seems to improve neurological function of stroke patients but may be associated with increased thrombotic risk, whereas alternative non-erythropoietic neuroprotective derivatives of EPO, such as carbamylated EPO (CEPO), may be devoid of such side-effects. We investigated the effects of short-term, high-dose treatment with EPO and CEPO on platelet function and haemostasis in healthy mice and rats. Animals received three daily doses of EPO or CEPO (50 microg/kg), and blood was compared with respect to alterations in haematology and platelet reactivity. In rats, treatment with EPO increased the haematocrit to >50% and the mean platelet volume by 37%, while CEPO had no effect on these parameters. Platelets from EPO-treated rats showed an increased sensitivity to thrombin receptor agonist peptides and elevated plasma levels of soluble P-selectin (sP-selectin) were found in treated mice. Further indicators of platelet hyperreactivity in EPO, but not CEPO-treated animals, were significantly increased aggregatory responses to collagen in whole blood and platelet-rich plasma (PRP). The increased platelet reactivity was paralleled by a decreased bleeding time after tail transection in rats. Samples from EPO-treated rats showed an attenuated response to ADP in whole blood aggregometry and thrombelastography (TEG) platelet mapping but not in apyrase-treated PRP, suggesting involvement of ADP receptor desensitization. These findings suggest that while EPO affects various aspects of platelet function, CEPO is devoid of such effects.

The Sonic hedgehog pathway mediates carbamylated erythropoietin-enhanced proliferation and differentiation of adult neural progenitor cells.

Carbamylated erythropoietin (CEPO), a well characterized erythropoietin (EPO) derivative, does not bind to the classical EPO receptor and does not stimulate erythropoiesis. Using neural progenitor cells derived from the subventricular zone of the adult mouse, we investigated the effect of CEPO on neurogenesis and the associated signaling pathways in vitro. We found that CEPO significantly increased neural progenitor cell proliferation and promoted neural progenitor cell differentiation into neurons, which was associated with up-regulation of Sonic hedgehog (Shh), its receptor ptc, and mammalian achaete-scute homolog 1 (Mash1), a pro-neuron basic helix-loop-helix protein transcription factor. Blockage of the Shh signaling pathway with a pharmacological inhibitor, cyclopamine, abolished the CEPO-induced neurogenesis. Attenuation of endogenous Mash1 expression by short-interfering RNA blocked CEPO-promoted neuronal differentiation. In addition, recombinant mouse Shh up-regulated Mash1 expression in neural progenitor cells. These results demonstrate that the Shh signaling pathway mediates CEPO-enhanced neurogenesis and Mash1 is a downstream target of the Shh signaling pathway that regulates CEPO-enhanced neuronal differentiation.

Erythropoietin and carbamylated erythropoietin are neuroprotective following spinal cord hemisection in the rat.

The cytokine erythropoietin (EPO) has been shown to be neuroprotective in a variety of models of central and peripheral nervous system injury. Derivatives of EPO that lack its erythropoietic effects have recently been developed, and the initial reports suggest that they have a neuroprotective potential comparable to that of EPO. One such derivative is carbamylated EPO (CEPO). In the current study we compared the effects of treatment with EPO and CEPO on some of the early neurodegenerative events that occur following spinal cord injury (SCI) induced by hemisection. Adult male Wistar rats received a unilateral hemisection of the spinal cord. Thirty minutes and 24 h following injury, animals received an intraperitoneal injection of saline, EPO (40 microg/kg) or CEPO (40 microg/kg). Results indicated that 3 days post-injury, both CEPO and EPO decreased to a similar extent the size of the lesion compared with control animals. Both compounds also decreased the number of terminal transferase-mediated dUTP nick-end labelling (TUNEL)-labelled apopotic nuclei around the lesion site, as well as the number of axons expressing the injury marker beta-amyloid precursor protein. EPO and CEPO also increased Schwann cell infiltration into the lesion site, although neither compound had any effect on macrophage infiltration either within the lesion site itself or in the surrounding intact tissue. In addition, immunohistochemistry showed an increased expression of both the EPO receptor and the beta common receptor subunit, the components of the receptor complex proposed to mediate the neuroprotective effects of EPO and CEPO in neurons near the site of the injury. The results show that not only does CEPO have an efficacy comparable to that of EPO in its neuroprotective potential following injury, but also that changes in the receptors for these compounds following SCI may underlie their neuroprotective efficacy.

Reduced functional deficits, neuroinflammation, and secondary tissue damage after treatment of stroke by nonerythropoietic erythropoietin derivatives.

Carbamylerythropoietin (CEPO) does not bind to the classical erythropoietin (EPO) receptor. Nevertheless, similarly to EPO, CEPO promotes neuroprotection on the histologic level in short-term stroke models. In the present study, we investigated whether CEPO and other nonerythropoietic EPO analogs could enhance functional recovery and promote long-term histologic protection after experimental focal cerebral ischemia. Rats were treated with the compounds after focal cerebral ischemia. Animals survived 1, 7, or 60 days and underwent behavioral testing (sensorimotor and foot-fault tests). Brain sections were stained and analyzed for Iba-1, myeloperoxidase, Tau-1, CD68 (ED1), glial fibrillary acidic protein (GFAP), Fluoro-Jade B staining, and overall infarct volumes. Treatment with CEPO reduced perifocal microglial activation (P<0.05), polymorphomonuclear cell infiltration (P<0.05), and white matter damage (P<0.01) at 1 day after occlusion. Carbamylerythropoietin-treated rats showed better functional recovery relative to vehicle-treated animals as assessed 1, 7, 14, 28, and 50 days after stroke. Both GFAP and CD68 were decreased within the ipsilateral thalamus of CEPO-treated animals 60 days postoperatively (P<0.01 and P<0.05, respectively). Furthermore, behavioral analysis showed efficacy of CEPO treatment even if administered 24 h after the stroke. Other nonerythropoietic derivatives such as carbamylated darbepoetin alfa and the mutant EPO-S100E were also found to protect against ischemic damage and to improve postischemic neurologic function. In conclusion, these results show that postischemic intravenous treatment with nonerythropoietic EPO derivatives leads to improved functional recovery, which may be linked to their long-term effects against neuroinflammation and secondary tissue damage.

Nonhematopoietic erythropoietin derivatives prevent motoneuron degeneration in vitro and in vivo.

Chronic treatment with asialo erythropoietin (ASIALO-EPO) or carbamylated erythropoietin (CEPO) improved motor behavior and reduced motoneuron loss and astrocyte and microglia activation in the cervical spinal cord of wobbler mice, an animal model of amyotrophic lateral sclerosis, but had no effect on hematocrit values. ASIALO-EPO and CEPO, like the parent compound EPO, protected primary motoneuron cultures from kainate-induced death in vitro. Both EPO receptor and the common CD131 beta chain were expressed in cultured motoneurons and in the anterior horn of wobbler mice spinal cord. Our results strongly support a role for the common beta chain CD131 in the protective effect of EPO derivatives on motoneuron degeneration. Thus CEPO, which does not bind to the classical homodimeric EPO receptor and is devoid of hematopoietic activity, could be effective in chronic treatment aimed at reducing motoneuron degeneration.

Derivatives of erythropoietin that are tissue protective but not erythropoietic.

Erythropoietin (EPO) is both hematopoietic and tissue protective, putatively through interaction with different receptors. We generated receptor subtype-selective ligands allowing the separation of EPO's bioactivities at the cellular level and in animals. Carbamylated EPO (CEPO) or certain EPO mutants did not bind to the classical EPO receptor (EPOR) and did not show any hematopoietic activity in human cell signaling assays or upon chronic dosing in different animal species. Nevertheless, CEPO and various nonhematopoietic mutants were cytoprotective in vitro and conferred neuroprotection against stroke, spinal cord compression, diabetic neuropathy, and experimental autoimmune encephalomyelitis at a potency and efficacy comparable to EPO.

Neuroprotective effect of the neurotensin analogue JMV-449 in a mouse model of permanent middle cerebral ischaemia.

The neuroprotective effect of the neurotensin analogue H-Lys-psi(CH2NH)Lys-Pro-Tyr-Ile-Leu-OH (JMV-449) was assessed in a mouse model of permanent distal middle cerebral artery occlusion. Mice were injected with 0.6 nmol JMV-449 or vehicle i.c.v. immediately after ischaemia. The core temperature declined by 6-7 degrees C after 30 min and the hypothermia persisted for 4-5 h. JMV-449 treatment was able to reduce the infarct volume significantly both at 24 h and 14 days after onset of ischaemia. No neuroprotective effect could be seen if the mice were kept normothermic after the JMV-449 treatment suggesting that the neuroprotective effect is mediated via the hypothermia.

Asialoerythropoietin is a nonerythropoietic cytokine with broad neuroprotective activity in vivo.

Erythropoietin (EPO) is a tissue-protective cytokine preventing vascular spasm, apoptosis, and inflammatory responses. Although best known for its role in hematopoietic lineages, EPO also affects other tissues, including those of the nervous system. Enthusiasm for recombinant human erythropoietin (rhEPO) as a potential neuroprotective therapeutic must be tempered, however, by the knowledge it also enlarges circulating red cell mass and increases platelet aggregability. Here we examined whether erythropoietic and tissue-protective activities of rhEPO might be dissociated by a variation of the molecule. We demonstrate that asialoerythropoietin (asialoEPO), generated by total enzymatic desialylation of rhEPO, possesses a very short plasma half-life and is fully neuroprotective. In marked contrast with rhEPO, this molecule at doses and frequencies at which rhEPO exhibited erythropoiesis, did not increase the hematocrit of mice or rats. AsialoEPO appeared promptly within the cerebrospinal fluid after i.v. administration; intravenously administered radioiodine-labeled asialoEPO bound to neurons within the hippocampus and cortex in a pattern corresponding to the distribution of the EPO receptor. Most importantly, asialoEPO exhibits a broad spectrum of neuroprotective activities, as demonstrated in models of cerebral ischemia, spinal cord compression, and sciatic nerve crush. These data suggest that nonerythropoietic variants of rhEPO can cross the blood-brain barrier and provide neuroprotection.