Mavoglurant (AFQ056)

Mavoglurant (AFQ056) for the treatment of levodopa-induced dyskinesia in patients with Parkinson's disease: a meta-analysis

Background: Mavoglurant (AFQ056), a selective metabotropic glutamate receptor 5 (mGluR5) inhibitor, was tested for t levodopa-induced dyskinesia (LID) in patients with Parkinson's Disease (PD). However, clinical trials showed inconsistent results regarding the efficacy of mavoglurant in treating LID in patients with Parkinson's disease (PD). Methods: A computer literature search of PubMed, Scopus, Web of science, and Cochrane CENTRAL was conducted until March 2021. We selected relevant randomized controlled trials comparing mavoglurant to placebo. Study data were extracted and pooled as mean difference (MD) in the meta-analysis model. Results: Six RCTs were included in this meta-analysis with a total of 485 patients. Mavoglurant was not significantly superior to placebo in terms of the "off-time" (MD -0.27 h, 95% CI -0.65 to 0.11), "on time" (MD 0.29 h, 95% CI -0.09 to 0.66), Lang-Fahn activities of daily living dyskinesia scale (MD -0.95, 95% CI -1.98 to 0.07), UPDRS-III (MD -0.51, 95% CI -1.66 to 0.65), or UPDRS-IV (MD -0.41, 95% CI -0.85 to 0.03). However, the pooled modified abnormal involuntary movement scale favored the mavoglurant group than the placebo group (MD -2.53, 95% CI -4.23 to -0.82). Conclusions: This meta-analysis provides level one evidence that mavoglurant is not effective in treating the LID in patients with PD.

Mavoglurant (AFQ056) in combination with increased levodopa dosages in Parkinson's disease patients

Long-term use of levodopa (L-dopa) in patients with Parkinson's disease is associated with development of dyskinesia. This study explored whether Parkinson's disease patients with L-dopa-induced dyskinesia experience improved OFF-time from higher L-dopa doses without worsening of dyskinesias when receiving adjunctive mavoglurant. Patients with moderate-to-severe L-dopa-induced dyskinesia were randomized to receive mavoglurant or placebo. Mavoglurant (AFQ056) was up-titrated over two weeks from 25 mg twice daily (bid) to 100 mg bid (L-dopa kept stable), followed by three weeks during which the daily L-dopa dosage was increased by up to 300 mg/day. A sample size of 30 was initially planned; however, the study was terminated prematurely due to enrollment challenges. OFF-time showed greater improvements in the mavoglurant group (n = 7) compared with the placebo group (n = 7); difference at week 5 was -2.77 h (90% confidence interval -5.44, -0.09 h; p = 0.09). ON-time without troublesome dyskinesia increased more from baseline to week 5 in the mavoglurant group (4.38 h) versus the placebo group (0.63 h). Clinician-rated measures were conflicting. The Modified Abnormal Involuntary Movement Scale scores showed a slight improvement with mavoglurant compared with placebo, while the Unified Dyskinesia Rating Scale parts III and IV worsened slightly with mavoglurant compared with placebo. Due to the low patient numbers and conflicting clinician-rated outcomes data, our findings are not conclusive. However, our results suggest that mavoglurant combined with higher doses of L-dopa may be effective in treating patients with Parkinson's disease experiencing L-dopa-related motor fluctuations and dyskinesias.

AFQ056/mavoglurant, a novel clinically effective mGluR5 antagonist: identification, SAR and pharmacological characterization

Here we describe the identification, structure-activity relationship and the initial pharmacological characterization of AFQ056/mavoglurant, a structurally novel, non-competitive mGlu5 receptor antagonist. AFQ056/mavoglurant was identified by chemical derivatization of a lead compound discovered in a HTS campaign. In vitro, AFQ056/mavoglurant had an IC50 of 30 nM in a functional assay with human mGluR5 and was selective over the other mGluR subtypes, iGluRs and a panel of 238 CNS relevant receptors, transporter or enzymes. In vivo, AFQ056/mavoglurant showed an improved pharmacokinetic profile in rat and efficacy in the stress-induced hyperthermia test in mice as compared to the prototypic mGluR5 antagonist MPEP. The efficacy of AFQ056/mavoglurant in humans has been assessed in L-dopa induced dyskinesia in Parkinson's disease and Fragile X syndrome in proof of principle clinical studies.

Post-traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) is characterized by symptoms of re-experiencing, avoidance, negative alterations in cognition and mood, and marked alterations in arousal and reactivity following exposure to a traumatic event. PTSD can be assessed by structured interviews and screening measures in psychiatric and nonpsychiatric settings. Evidence-based psychotherapies are the first-line treatment of PTSD, with cognitive behavioral therapies, such as prolonged exposure, cognitive processing therapy, and eye movement desensitization and reprocessing having the largest body and highest quality of evidence. Serotonin reuptake inhibitors are the first-line pharmacologic treatments for PTSD and are often used in conjunction with other therapeutic interventions.

Inhibiting mGluR5 activity by AFQ056/Mavoglurant rescues circuit-specific functional connectivity in Fmr1 knockout mice

Previous work has demonstrated that neuroimaging biomarkers which capture functional connectivity of the brain can be used to define a specific and robust endophenotype in Fmr1^-/y mice, a well-established animal model of human Fragile-X Syndrome (FXS). However, it is currently unknown whether this macroscopic measure of brain connectivity is sufficiently sensitive to reliably detect changes caused by pharmacological interventions. Here we inhibited the activity of the metabotropic glutamate receptor-5 (mGluR5) using AFQ056/Mavoglurant, a drug that is assumed to normalize excitatory/inhibitory neural signaling imbalances in FXS. We employed resting-state-fMRI (rs-fMRI) and diffusion-weighted imaging (DWI) to test whether Mavoglurant re-established brain connectivity - at least partly - within some of the affected circuits in Fmr1^-/y mice that are related to social behavior deficits. In line with previous findings, we observed that Fmr1^-/y mice exhibited impaired social interaction, reduced connectivity in three main functional networks and altered network topology. At the group level, Mavoglurant did neither rescue abnormal social behavioral nor white matter abnormalities; however, for some, but not all of these circuits Mavoglurant had a genotype-specific effect of restoring functional connectivity. These results show that rs-fMRI connectivity is sufficiently sensitive to pick up system-level changes after the pharmacological inhibition of mGluR5 activity. However, our results also show that the effects of Mavoglurant are confined to specific networks suggesting that behavioral benefits might be restricted to narrow functional domains.