Publications by authors named "Michael Rabbia"

8 Publications

  • Page 1 of 1

Disease Modification in Alzheimer's Disease: Current Thinking.

Ther Innov Regul Sci 2020 03 6;54(2):396-403. Epub 2020 Jan 6.

Biostatistics and Research Decision Sciences, Merck Research Laboratories (MRL), Merck & Co, Inc, Kenilworth, NJ, USA.

Alzheimer's disease (AD) has increasingly been recognized as a huge unmet medical need. Currently, there is no approved drug to cure, prevent, or even slow down the disease. It is imperative to develop disease-modifying treatments for AD to alter the underlying disease progression. This paper reviews the most up-to-date regulatory guidance on how to demonstrate disease modification and provides an overview of available methodologies and applications to clinical trials. The intent is to assist the field with future clinical trials designed to demonstrate disease-modifying effect in AD. The methodologies may be generalizable to broader neurodegenerative diseases.
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March 2020

Effect of the mGluR5-NAM Basimglurant on Behavior in Adolescents and Adults with Fragile X Syndrome in a Randomized, Double-Blind, Placebo-Controlled Trial: FragXis Phase 2 Results.

Neuropsychopharmacology 2018 02 17;43(3):503-512. Epub 2017 Aug 17.

Solid Biosciences, Cambridge, MA, USA.

Preclinical data suggest that inhibition of the metabotropic glutamate receptor 5 (mGluR5) receptor might hold therapeutic benefits in Fragile X syndrome (FXS). Treatment of Fmr1 knockout mice with mGluR5-negative allosteric modulators (NAMs) has been reported to correct a broad range of phenotypes related to FXS. The early short-term clinical trials with mGluR5 NAMs, including basimglurant, assessing the effects in individuals with FXS, were supportive of further exploration in larger, well-controlled trials. We evaluated basimglurant, a potent and selective mGluR5 NAM, in a 12-week, double-blind, parallel-group study of 183 adults and adolescents (aged 14-50, mean 23.4 years) with FXS. Individuals with an FMR1 full mutation were randomized to placebo or one of two doses of basimglurant. The primary efficacy endpoint was the change from baseline in behavioral symptoms using the Anxiety Depression and Mood Scale (ADAMS) total score. All treatment arms showed marked behavioral improvements from baseline to week 12 with less improvement in the basimglurant 1.5 mg arm than placebo; however, basimglurant 0.5 mg was inferior to placebo in the ADAMs total score. Treatment with basimglurant was overall well-tolerated. A higher incidence of adverse events classified as psychiatric disorders were reported in patients treated with basimglurant, including three patients with hallucinations or psychosis. In this phase 2 clinical trial, basimglurant did not demonstrate improvement over placebo. Evaluation of the overall risk-benefit in younger patient populations is an important consideration for the design of potential further investigations of efficacy with this class of medications.
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February 2018

Efficacy and Safety of Basimglurant as Adjunctive Therapy for Major Depression: A Randomized Clinical Trial.

JAMA Psychiatry 2016 Jul;73(7):675-84

Pharmaceutical Research and Early Development, Translational Medicine Neuroscience, Ophthalmology, and Rare Diseases, Roche Innovation Center, Basel, Switzerland.

Importance: Antagonism of the postsynaptic metabotropic glutamate subtype 5 receptor is a novel approach to modulate glutamatergic function and has proven efficacy in a number of preclinical behavioral models of depression.

Objective: To evaluate the safety and efficacy of basimglurant modified-release (MR) vs placebo as adjunctive therapy to ongoing antidepressant medication therapy in patients with MDD who had inadequate response within the current episode.

Design, Setting, And Participants: In this phase 2b, double blind, randomized clinical trial of 333 adult patients with a DSM-IV-TR diagnosis of MDD across 59 research clinics globally, patients were assigned to 1 of 2 doses of basimglurant MR (0.5 or 1.5 mg) or placebo once daily, adjunctive to ongoing antidepressant medication therapy (selective serotonin reuptake inhibitor or serotonin and norepinephrine reuptake inhibitor). Patients were enrolled from October 5, 2011, through July 26, 2013.

Interventions: Six-week treatment with 0.5 mg of basimglurant MR, 1.5-mg basimglurant MR, or placebo once daily, adjunctive to ongoing antidepressant medication therapy.

Main Outcomes And Measures: The primary end point was the mean change from baseline score on the Montgomery-Åsberg Depression Rating Scale (MADRS), as rated by the clinician at week 6. Other measures included patient-rated MADRS, Quick Inventory of Depressive Symptomatology-Self-Report, Clinical Global Impression-Improvement, Patient Global Impression-Improvement, and Clinical Global Impression-Severity Scales and adverse events.

Results: A total of 596 patients were screened, and 333 were randomized into the study (mean [SD] age, 47 [11.2] years; 216 female [65.1%]). The primary end point (mean change in clinician-rated MADRS score from baseline to end of treatment) was not met (effect size [ES] = 0.16, P = .42; intent-to-treat [ITT] mixed-effects model for repeated measures [MMRM] analysis for comparing 1.5-mg basimglurant MR and placebo). Across secondary and exploratory end points, 1.5-mg basimglurant MR revealed larger improvements vs placebo on the patient-rated MADRS (-16.2 vs -13.3, ES = 0.28, nominal P = .04), Quick Inventory of Depressive Symptomatology-Self-Report (-7.5 vs -5.8; ES = 0.37, nominal P = .009), Clinical Global Impression-Improvement mean score, and Patient Global Impression-Improvement mean score. Improvements were also seen in the patient-rated MADRS remission rate (36.0% vs 22.0%; nominal P = .03) and response rate (50.5% vs 40.4%; nominal P = .13), A 0.5-mg dose of basimglurant MR had no benefit over placebo in any of these measures. The most common adverse event was dizziness, which was mostly transient and of mild intensity.

Conclusions And Relevance: No difference was observed on the study's primary outcome measure, the clinician-rated MADRS change from baseline to end of treatment, between adjunctive basimglurant MR vs placebo. Adjunctive 1.5-mg basimglurant MR daily revealed, however, an antidepressant effect across secondary end points, particularly in patient-rated measures. These findings combined with good tolerability warrant further investigation with this compound in depressive disorders.

Trial Registration: Identifier: NCT01437657.
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July 2016

Defining Regions in Multiregional Clinical Trials: An Analytical Approach to Considering Impact of Intrinsic and Extrinsic Factors.

Ther Innov Regul Sci 2016 Jan;50(1):91-100

3 Merck & Co Inc, Kenilworth, NJ, USA.

Background: This article describes follow-up work extended from Tanaka et al (2011) in defining the region in multiregional clinical trials (MRCTs). The previous paper advocated a systematic approach to defining regions and recommended the sponsor to think through carefully, prespecify, and justify any regional definitions as well as obtain regulatory concurrence prior to study conduct. Particular attention was advised for intrinsic and extrinsic factors such as race/ethnicity, disease epidemiology, medical practice, and geographic proximity. An analytical approach such as a cluster method to define region was introduced, and references on observed regional differences were provided.

Methods: A closer review of those references and others from a more comprehensive literature search was conducted to gain a deeper understanding of intrinsic and extrinsic factors in relation to the observed regional differences in the treatment effect. The application of a k-means cluster method to define region was explored, as well as the implication to regional sample size for MRCTs.

Results: Of extrinsic factors, diagnostic capabilities, medical/clinical practice such as aspirin use, patient care such as site's usual practice, intervention, capability, and concomitant medications were considered potential contributors to differences in clinical outcomes or measures. Commonly reported intrinsic factors were underlying etiology, epidemiology, genetics, and patient characteristics (age, ethnicity, race, risk factors).

Conclusion: Using a checklist to identify intrinsic/extrinsic factors that might lead to differences in treatment effect allows one to scientifically define more meaningful regions from the identified factors, which will help with estimating the relative treatment outcome as well as exploring appropriate regional sample size.
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January 2016

Effects of high dose aleglitazar on renal function in patients with type 2 diabetes.

Int J Cardiol 2011 Sep 15;151(2):136-42. Epub 2010 Sep 15.

F. Hoffmann-La Roche AG, Basel, Switzerland.

Background: Aleglitazar is a new, balanced dual peroxisome proliferator-activated receptor (PPAR)α/γ agonist designed to optimize lipid and glycemic benefits and minimize PPAR-related adverse effects.

Methods: SESTA R was a 26-week, randomized, double-blind, multicenter study comparing the effects of a supratherapeutic dosage of aleglitazar (600 μg/day) with pioglitazone (45 mg/day) on change in measured GFR (mGFR) in 174 patients with type 2 diabetes and normal to mildly impaired renal function (estimated GFR [eGFR] 60 to 120 ml/min/1.73 m(2)).

Results: In 118 patients with evaluable GFR measurements, baseline mean (± SD) mGFR was 97.6 ± 17.5 ml/min/1.73 m(2) in the aleglitazar group and 101.9±21.6ml/min/1.73m(2) in the pioglitazone group. Mean percent change from baseline mGFR was -16.9% (90% confidence interval -22.0 to -11.5) with aleglitazar and -4.6% (-10.15 to 1.35) with pioglitazone, a mean treatment difference of -13.0% (-19.0 to -6.5). The 17% decrease from baseline in mGFR was consistent with the 19% decrease in eGFR Modification of Diet in Renal Disease (MDRD) observed with aleglitazar, which reached a plateau after 4weeks, with no further progression until treatment discontinuation. Following aleglitazar withdrawal, eGFR values returned to pretreatment levels within the 4-8-week follow-up, which suggests reversible hemodynamic changes in renal function.

Conclusions: Despite the increased incidence of expected, dose-dependent PPAR class side effects (e.g., peripheral edema, weight gain, and congestive heart failure) limiting further development of this supratherapeutic dosage of aleglitazar (600 μg/day), these data, together with the data from the dose-ranging SYNCHRONY study, suggest aleglitazar may be a potential new treatment for cardiovascular risk reduction in post-acute coronary syndrome patients at the therapeutic 150 μg daily dose.
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September 2011

Induction pegylated interferon alfa-2a and high dose ribavirin do not increase SVR in heavy patients with HCV genotype 1 and high viral loads.

Gastroenterology 2010 Dec 30;139(6):1972-83. Epub 2010 Sep 30.

Division of Gastroenterology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.

Background & Aims: Patients infected with hepatitis C virus (HCV) genotype 1, body weight ≥85 kg, and high baseline viral load respond poorly to standard doses of pegylated interferon (peginterferon) and ribavirin. We evaluated intensified therapy with peginterferon alfa-2a plus ribavirin.

Methods: This double-blind randomized trial included HCV genotype 1-infected outpatients from hepatology clinics with body weight ≥85 kg and HCV RNA titer ≥400,000 IU/mL. Patients were randomized to 180 μg/wk peginterferon alfa-2a for 48 weeks plus 1200 mg/day ribavirin (standard of care) (group A, n = 191) or 1400/1600 mg/day ribavirin (group B, n = 189). Additional groups included 360 μg/wk peginterferon alfa-2a for 12 weeks then 180 μg/wk peginterferon alfa-2a for 36 weeks plus 1200 mg/day ribavirin (group C, n = 382) or 1400/1600 mg/day ribavirin (group D, n = 383). Follow-up lasted 24 weeks after treatment.

Results: Sustained virologic response rates (HCV RNA level <15 IU/mL at end of follow-up) in groups A, B, C, and D were 38%, 43%, 44%, and 41%, respectively. There were no significant differences among the 4 groups or between pooled peginterferon alfa-2a regimens (A + B vs C + D: odds ratio [OR], 1.08; 95% confidence interval [CI], 0.83-1.39; P = .584) or pooled ribavirin regimens (A + C vs B + D: OR, 1.00; 95% CI, 0.79-1.28; P = .974).

Conclusions: In patients infected with HCV genotype 1 who are difficult to treat (high viral load, body weight ≥85 kg), a 12-week induction regimen of peginterferon alfa-2a and/or higher-dose ribavirin is not more effective than the standard regimen.
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December 2010

Effect of the dual peroxisome proliferator-activated receptor-alpha/gamma agonist aleglitazar on risk of cardiovascular disease in patients with type 2 diabetes (SYNCHRONY): a phase II, randomised, dose-ranging study.

Lancet 2009 Jul 8;374(9684):126-35. Epub 2009 Jun 8.

Department of Medicine, University of California at San Diego and VA San Diego Healthcare System, San Diego, CA 92161, USA.

Background: Despite previous reports of potential adverse cardiovascular effects of peroxisome proliferator-activated receptor (PPAR) agonists, the promise for PPAR agonists to positively affect risk of cardiovascular disease in patients with type 2 diabetes is of continued interest. The SYNCHRONY study aimed to establish the glucose-lowering and lipid-modifying effects, and safety profile, of the dual PPAR-alpha and PPAR-gamma agonist aleglitazar.

Methods: In this double-blind study, patients with type 2 diabetes (either drug-naive or pre-treated with
Findings: The efficacy analysis excluded six patients (n=0 in pioglitazone group; n=1 in each of placebo, 50 mug, 150 mug, and 600 mug aleglitazar groups; and n=2 in 300 mug aleglitazar group). Aleglitazar significantly reduced baseline HbA(1c) versus placebo in a dose-dependent manner, from -0.36% (95% CI 0.00 to -0.70, p=0.048) with 50 mug to -1.35% (-0.99 to -1.70, p<0.0001) with 600 mug. The trend of changes over time suggests that the maximum effect of aleglitazar on HbA(1c) concentration was not yet reached after 16 weeks of treatment. Oedema, haemodilution, and weight gain occurred in a dose-dependent manner. However, at aleglitazar doses less than 300 mug, no patients had congestive heart failure, frequency of oedema was similar to placebo (one case at 50 mug, two at 150 mug, and three with placebo) and less than with pioglitazone (four cases), and bodyweight gain was less than with pioglitazone (0.52 kg at 150 mug vs 1.06 kg).

Interpretation: The favourable balance in the safety and efficacy profile of aleglitazar represents encouraging short-term clinical data for this agent and provides good evidence to enter phase III investigation.

Funding: F Hoffmann-La Roche AG (Switzerland).
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July 2009

Pharmacogenetic analysis of adverse drug effect reveals genetic variant for susceptibility to liver toxicity.

Pharmacogenomics J 2002 ;2(5):327-34

F Hoffmann-La Roche Ltd, Basel, Switzerland.

A retrospective pharmacogenetic study was conducted to identify possible genetic susceptibility factors in patients in whom the administration of the anti-Parkinson drug, tolcapone (TASMAR), was associated with hepatic toxicity. We studied 135 cases of patients with elevated liver transaminase levels (ELT) of >/=1.5 times above the upper limit of normal, in comparison with matched controls that had also received the drug but had not experienced ELT. DNA samples were genotyped for 30 previously described or newly characterized bi-allelic single nucleotide polymorphisms (SNPs), representing 12 candidate genes selected based on the known metabolic pathways involved in the tolcapone elimination. SNPs located within the UDP-glucuronosyl transferase 1A gene complex, which codes for the enzymes involved in the main elimination pathway of the drug, were found to be significantly associated with the occurrence of tolcapone-associated ELTs.
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May 2003