Cost-effectiveness Analysis of Ocrelizumab for the Treatment of Relapsing and Primary Progressive Multiple Sclerosis in Portugal.

OBJECTIVES: Ocrelizumab demonstrated significant clinical benefit for the treatment of relapsing (RMS) and primary progressive (PPMS) multiple sclerosis (MS), an incurable disease characterized by disability progression. This study evaluated the clinical and economic impact of ocrelizumab relative to current clinical practice, including other disease-modifying therapies (DMT), available in Portugal. METHODS: Markov models for MS were adapted to estimate the impact of ocrelizumab across three patient populations: treatment-naïve RMS, previously treated RMS, and PPMS. Health states were defined according to the Expanded Disability Status Scale. For RMS, the model further captured the occurrence of relapses and progression to secondary progressive multiple sclerosis (SPMS). A lifetime time-horizon and Portuguese societal perspective were adopted. RESULTS: For RMS patients, ocrelizumab was estimated to maximize the expected time (years) without progression to SPMS (10.50) relative to natalizumab (10.10), dimethyl fumarate (8.64), teriflunomide (8.39), fingolimod (8.38), interferon ß-1a (8.33) and glatiramer acetate (8.18). As the most effective option, with quality-adjusted life year (QALY) gains between 0.3 and 1.2, ocrelizumab was found to be cost-saving relative to natalizumab and fingolimod, and presented incremental cost-effectiveness ratios (ICER) below €16,720/QALY relative to the remaining DMT. For PPMS patients, the ICER of ocrelizumab versus best supportive care was estimated at €78,858/QALY. CONCLUSIONS: Ocrelizumab provides important health benefits for RMS and PPMS patients, comparing favourably with other widely used therapies. In RMS, ocrelizumab was revealed to be either cost-saving or have costs-per-QALY likely below commonly accepted cost-effectiveness thresholds. In PPMS, ocrelizumab fills a clear clinical gap in the current clinical practice. Overall, ocrelizumab is expected to provide good value for money in addressing the need of MS patients.

Age-related shift in LTD is dependent on neuronal adenosine A2A receptors interplay with mGluR5 and NMDA receptors.

Synaptic dysfunction plays a central role in Alzheimer's disease (AD), since it drives the cognitive decline. An association between a polymorphism of the adenosine A2A receptor (A2AR) encoding gene-ADORA2A, and hippocampal volume in AD patients was recently described. In this study, we explore the synaptic function of A2AR in age-related conditions. We report, for the first time, a significant overexpression of A2AR in hippocampal neurons of aged humans, which is aggravated in AD patients. A similar profile of A2AR overexpression in rats was sufficient to drive age-like memory impairments in young animals and to uncover a hippocampal LTD-to-LTP shift. This was accompanied by increased NMDA receptor gating, dependent on mGluR5 and linked to enhanced Ca2+ influx. We confirmed the same plasticity shift in memory-impaired aged rats and APP/PS1 mice modeling AD, which was rescued upon A2AR blockade. This A2AR/mGluR5/NMDAR interaction might prove a suitable alternative for regulating aberrant mGluR5/NMDAR signaling in AD without disrupting their constitutive activity.

α-synuclein interacts with PrPC to induce cognitive impairment through mGluR5 and NMDAR2B.

Synucleinopathies, such as Parkinson's disease and dementia with Lewy bodies, are neurodegenerative disorders that are characterized by the accumulation of α-synuclein (aSyn) in intracellular inclusions known as Lewy bodies. Prefibrillar soluble aSyn oligomers, rather than larger inclusions, are currently considered to be crucial species underlying synaptic dysfunction. We identified the cellular prion protein (PrPC) as a key mediator in aSyn-induced synaptic impairment. The aSyn-associated impairment of long-term potentiation was blocked in Prnp null mice and rescued following PrPC blockade. We found that extracellular aSyn oligomers formed a complex with PrPC that induced the phosphorylation of Fyn kinase via metabotropic glutamate receptors 5 (mGluR5). aSyn engagement of PrPC and Fyn activated NMDA receptor (NMDAR) and altered calcium homeostasis. Blockade of mGluR5-evoked phosphorylation of NMDAR in aSyn transgenic mice rescued synaptic and cognitive deficits, supporting the hypothesis that a receptor-mediated mechanism, independent of pore formation and membrane leakage, is sufficient to trigger early synaptic damage induced by extracellular aSyn.

Prolactin-induced neuroprotection against glutamate excitotoxicity is mediated by the reduction of [Ca2+]i overload and NF-κB activation.

Prolactin (PRL) is a peptidic hormone that displays pleiotropic functions in the organism including different actions in the brain. PRL exerts a neuroprotective effect against excitotoxicity produced by glutamate (Glu) or kainic acid in both in vitro and in vivo models. It is well known that Glu excitotoxicity causes cell death through apoptotic or necrotic pathways due to intracellular calcium ([Ca2+] i) overload. Therefore, the aim of the present study was to assess the molecular mechanisms by which PRL maintains cellular viability of primary cultures of rat hippocampal neurons exposed to Glu excitotoxicity. We determined cell viability by monitoring mitochondrial activity and using fluorescent markers for viable and dead cells. The intracellular calcium level was determined by a fluorometric assay and proteins involved in the apoptotic pathway were determined by immunoblot. Our results demonstrated that PRL afforded neuroprotection against Glu excitotoxicity, as evidenced by a decrease in propidium iodide staining and by the decrease of the LDH activity. In addition, the MTT assay shows that PRL maintains normal mitochondrial activity even in neurons exposed to Glu. Furthermore, the Glu-induced intracellular [Ca2+]i overload was attenuated by PRL. These data correlate with the reduction found in the level of active caspase-3 and the pro-apoptotic ratio (Bax/Bcl-2). Concomitantly, PRL elicited the nuclear translocation of the transcriptional factor NF-κB, which was detected by immunofluorescence and confocal microscopy. To our knowledge, this is the first report demonstrating that PRL prevents Glu excitotoxicity by a mechanism involving the restoration of the intracellular calcium homeostasis and mitochondrial activity, as well as an anti-apoptotic action possibly mediated by the activity of NF-κB. Overall, the current results suggest that PRL could be of potential therapeutic advantage in the treatment of neurodegenerative diseases.

Glycation potentiates α-synuclein-associated neurodegeneration in synucleinopathies.

α-Synuclein misfolding and aggregation is a hallmark in Parkinson's disease and in several other neurodegenerative diseases known as synucleinopathies. The toxic properties of α-synuclein are conserved from yeast to man, but the precise underpinnings of the cellular pathologies associated are still elusive, complicating the development of effective therapeutic strategies. Combining molecular genetics with target-based approaches, we established that glycation, an unavoidable age-associated post-translational modification, enhanced α-synuclein toxicity in vitro and in vivo, in Drosophila and in mice. Glycation affected primarily the N-terminal region of α-synuclein, reducing membrane binding, impaired the clearance of α-synuclein, and promoted the accumulation of toxic oligomers that impaired neuronal synaptic transmission. Strikingly, using glycation inhibitors, we demonstrated that normal clearance of α-synuclein was re-established, aggregation was reduced, and motor phenotypes in Drosophila were alleviated. Altogether, our study demonstrates glycation constitutes a novel drug target that can be explored in synucleinopathies as well as in other neurodegenerative conditions.

Chronic and acute adenosine A2A receptor blockade prevents long-term episodic memory disruption caused by acute cannabinoid CB1 receptor activation.

Cannabinoid-mediated memory impairment is a concern in cannabinoid-based therapies. Caffeine exacerbates cannabinoid CB1 receptor (CB1R)-induced memory deficits through an adenosine A1 receptor-mediated mechanism. We now evaluated how chronic or acute blockade of adenosine A2A receptors (A2ARs) affects long-term episodic memory deficits induced by a single injection of a selective CB1R agonist. Long-term episodic memory was assessed by the novel object recognition (NOR) test. Mice received an intraperitoneal (i.p.) injection of the CB1/CB2 receptor agonist WIN 55,212-2 (1 mg/kg) immediately after the NOR training, being tested for novelty recognition 24 h later. Anxiety levels were assessed by the Elevated Plus Maze test, immediately after the NOR. Mice were also tested for exploratory behaviour at the Open Field. For chronic A2AR blockade, KW-6002 (istradefylline) (3 mg/kg/day) was administered orally for 30 days; acute blockade of A2ARs was assessed by i.p. injection of SCH 58261 (1 mg/kg) administered either together with WIN 55,212-2 or only 30 min before the NOR test phase. The involvement of CB1Rs was assessed by using the CB1R antagonist, AM251 (3 mg/kg, i.p.). WIN 55,212-2 caused a disruption in NOR, an action absent in mice also receiving AM251, KW-6002 or SCH 58261 during the encoding/consolidation phase; SCH 58251 was ineffective if present during retrieval only. No effects were detected in the Elevated Plus maze or Open Field Test. The finding that CB1R-mediated memory disruption is prevented by antagonism of adenosine A2ARs, highlights a possibility to prevent cognitive side effects when therapeutic application of CB1R drugs is desired.

Adenosine A2A Receptors Modulate α-Synuclein Aggregation and Toxicity.

Abnormal accumulation of aggregated α-synuclein (aSyn) is a hallmark of sporadic and familial Parkinson's disease (PD) and related synucleinopathies. Recent studies suggest a neuroprotective role of adenosine A2A receptor (A2AR) antagonists in PD. Nevertheless, the precise molecular mechanisms underlying this neuroprotection remain unclear. We assessed the impact of A2AR blockade or genetic deletion (A2AR KO) on synaptic plasticity and neuronal cell death induced by aSyn oligomers. We found that impairment of LTP associated with aSyn exposure was rescued in A2AR KO mice or upon A2AR blockade, through an NMDA receptor-dependent mechanism. The mechanisms underlying these effects were evaluated in SH-SY5Y cells overexpressing aSyn and rat primary neuronal cultures exposed to aSyn. Cell death in both conditions was prevented by selective A2AR antagonists. Interestingly, blockade of these receptors did not interfere with aSyn oligomerization but, instead, reduced the percentage of cells displaying aSyn inclusions. Altogether, our data raise the possibility that the well-documented effects of A2AR antagonists involve the control of the latter stages of aSyn aggregation, thereby preventing the associated neurotoxicity. These findings suggest that A2AR represent an important target for the development of effective drugs for the treatment of PD and related synucleinopathies.

The caffeine-binding adenosine A2A receptor induces age-like HPA-axis dysfunction by targeting glucocorticoid receptor function.

Caffeine is associated with procognitive effects in humans by counteracting overactivation of the adenosine A2A receptor (A2AR), which is upregulated in the human forebrain of aged and Alzheimer's disease (AD) patients. We have previously shown that an anti-A2AR therapy reverts age-like memory deficits, by reestablishment of the hypothalamic-pituitary-adrenal (HPA) axis feedback and corticosterone circadian levels. These observations suggest that A2AR over-activation and glucocorticoid dysfunction are key events in age-related hippocampal deficits; but their direct connection has never been explored. We now show that inducing A2AR overexpression in an aging-like profile is sufficient to trigger HPA-axis dysfunction, namely loss of plasmatic corticosterone circadian oscillation, and promotes reduction of GR hippocampal levels. The synaptic plasticity and memory deficits triggered by GR in the hippocampus are amplified by A2AR over-activation and were rescued by anti-A2AR therapy; finally, we demonstrate that A2AR act on GR nuclear translocation and GR-dependent transcriptional regulation. We provide the first demonstration that A2AR is a major regulator of GR function and that this functional interconnection may be a trigger to age-related memory deficits. This supports the idea that the procognitive effects of A2AR antagonists, namely caffeine, on Alzheimer's and age-related cognitive impairments may rely on its ability to modulate GR actions.

Overexpression of Adenosine A2A Receptors in Rats: Effects on Depression, Locomotion, and Anxiety.

Adenosine A2A receptors (A2AR) are a sub-type of receptors enriched in basal ganglia, activated by the neuromodulator adenosine, which interact with dopamine D2 receptors. Although this reciprocal antagonistic interaction is well-established in motor function, the outcome in dopamine-related behaviors remains uncertain, in particular in depression and anxiety. We have demonstrated an upsurge of A2AR associated to aging and chronic stress. Furthermore, Alzheimer's disease patients present A2AR accumulation in cortical areas together with depressive signs. We now tested the impact of overexpressing A2AR in forebrain neurons on dopamine-related behavior, namely depression. Adult male rats overexpressing human A2AR under the control of CaMKII promoter [Tg(CaMKII-hA2AR)] and aged-matched wild-types (WT) of the same strain (Sprague-Dawley) were studied. The forced swimming test (FST), sucrose preference test (SPT), and the open-field test (OFT) were performed to evaluate behavioral despair, anhedonia, locomotion, and anxiety. Tg(CaMKII-hA2AR) animals spent more time floating and less time swimming in the FST and presented a decreased sucrose preference at 48 h in the SPT. They also covered higher distances in the OFT and spent more time in the central zone than the WT. The results indicate that Tg(CaMKII-hA2AR) rats exhibit depressive-like behavior, hyperlocomotion, and altered exploratory behavior. This A2AR overexpression may explain the depressive signs found in aging, chronic stress, and Alzheimer's disease.

Neuroprotection afforded by adenosine A2A receptor blockade is modulated by corticotrophin-releasing factor (CRF) in glutamate injured cortical neurons.

In situations of hypoxia, glutamate excitotoxicity induces neuronal death. The release of extracellular adenosine is also triggered and is accompanied by an increase of the stress mediator, corticotrophin-releasing factor (CRF). Adenosine A(2A) receptors contribute to glutamate excitoxicity and their blockade is effective in stress-induced neuronal deficits, but the involvement of CRF on this effect was never explored. We now evaluated the interaction between A(2A) and CRF receptors (CRFR) function, upon glutamate insult. Primary rat cortical neuronal cultures (9 days in vitro) expressing both CRF(1)R and CRF(2)R were challenged with glutamate (20-1000 µM, 24 h). CRF(1)R was found to co-localize with neuronal markers and CRF(2)R to be present in both neuronal and glial cells. The effects of the CRF and A(2A) receptors ligands on cell viability were measured using propidium iodide and Syto-13 fluorescence staining. Glutamate decreased cell viability in a concentration-dependent manner. Urocortin (10 pM), an agonist of CRF receptors, increased cell survival in the presence of glutamate. This neuroprotective effect was abolished by blocking either CRF(1)R or CRF(2)R with antalarmin (10 nM) or anti-Sauvagine-30 (10 nM), respectively. The blockade of A(2A) receptors with a selective antagonist SCH 58261 (50 nM) improved cell viability against the glutamate insult. This effect was dependent on CRF(2)R, but not on CRF(1)R activation. Overall, these data show a protective role of CRF in cortical neurons, against glutamate-induced death. The neuroprotection achieved by A(2A) receptors blockade requires CRF(2)R activation. This interaction between the adenosine and CRF receptors can explain the beneficial effects of using A(2A) receptor antagonists against stress-induced noxious effects.