The authors would like to thank the participants of the Aberdeen 1936 Birth Cohort (ABC36). Image acquisition and image analysis for ABC36 were funded by the Alzheimer's Research Trust (now Alzheimer's Research UK). A.D.M., C.J.M., S.S., L.J.W., and R.T.S. have received grants from: Chief Scientist Office, Department of Health, Scottish Government; Biotechnology and Biological Sciences Research Council ; Peer reviewed ; Postprint
Acknowledgments: We remain grateful to the kindness of the staff at the Scottish Council for Research in Education who allowed us access to their archive and remained supportive and gracious throughout our collaboration. We thank the many people of Aberdeen who volunteered generously and committed to the long-term success of this program. We thank Victoria Bourne, who made substantial contributions to study design, data collection, data analysis and hypothesis generation. Jen Herbert (deceased) recruited the ABC36 participants, collected data (sessions I and II) and, through her encouragement and professionalism, ensured the continued involvement of many participants. She was much loved by participants and the study team. Funding: The Aberdeen Birth Cohort 1921 and 1936 research program was established in 1997 with funding from the Henry Smith (Kensington Estates) Charity and continued by The UK Biotechnology and Biological Sciences Research Council (1999–2002), The Wellcome Trust (2001–2006), The Scottish Government (2000–2002), the Medical Research Council (2003), Alzheimer Research UK (2002–2005) and the University of Aberdeen Development Trust (2007–2010, 2014). ; Peer reviewed ; Publisher PDF
Acknowledgements This work was supported by the Economic and Social Research Council/Biotechnology and Biological Sciences Research Council BioSocial initiative (Grant Number ES/N00048X/1; PH, ADM, LHP, RS, AF-S, MR). PH, GWH, and GH acknowledge the support of the Scottish Government's Rural and Environment Science and Analytical Services Division (RESAS). The sequencing was carried out at the Aberdeen Centre for Genome-Enabled Biology and Medicine. The authors would like to acknowledge the support of the Maxwell Compute Cluster funded by the University of Aberdeen. The authors would also like to thank the participants of the Aberdeen 1936 Birth Cohort, without whom this research would not have been possible. ; Peer reviewed ; Publisher PDF
BackgroundLeuco-methylthioninium bis(hydromethanesulfonate; LMTM), a stable reduced form of the methylthioninium moiety, acts as a selective inhibitor of tau protein aggregation both in vitro and in transgenic mouse models. Methylthioninium chloride has previously shown potential efficacy as monotherapy in patients with Alzheimer's disease. We aimed to determine whether LMTM was safe and effective in modifying disease progression in patients with mild to moderate Alzheimer's disease.MethodsWe did a 15-month, randomised, controlled double-blind, parallel-group trial at 115 academic centres and private research clinics in 16 countries in Europe, North America, Asia, and Russia with patients younger than 90 years with mild to moderate Alzheimer's disease. Patients concomitantly using other medicines for Alzheimer's disease were permitted to be included because we considered it infeasible not to allow their inclusion; however, patients using medicines carrying warnings of methaemoglobinaemia were excluded because the oxidised form of methylthioninium in high doses has been shown to induce this condition. We randomly assigned participants (3:3:4) to 75 mg LMTM twice a day, 125 mg LMTM twice a day, or control (4 mg LMTM twice a day to maintain blinding with respect to urine or faecal discolouration) administered as oral tablets. We did the randomisation with an interactive web response system using 600 blocks of length ten, and stratified patients by severity of disease, global region, whether they were concomitantly using Alzheimer's disease-labelled medications, and site PET capability. Participants, their study partners (generally carers), and all assessors were masked to treatment assignment throughout the study. The coprimary outcomes were progression on the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) and the Alzheimer's Disease Co-operative Study-Activities of Daily Living Inventory (ADCS-ADL) scales from baseline assessed at week 65 in the modified intention-to-treat population. This trial is registered with Clinicaltrials.gov (NCT01689246) and the European Union Clinical Trials Registry (2012-002866-11).FindingsBetween Jan 29, 2013, and June 26, 2014, we recruited and randomly assigned 891 participants to treatment (357 to control, 268 to 75 mg LMTM twice a day, and 266 to 125 mg LMTM twice a day). The prespecified primary analyses did not show any treatment benefit at either of the doses tested for the coprimary outcomes (change in ADAS-Cog score compared with control [n=354, 6·32, 95% CI 5·31-7·34]: 75 mg LMTM twice a day [n=257] -0·02, -1·60 to 1·56, p=0·9834, 125 mg LMTM twice a day [n=250] -0·43, -2·06 to 1·20, p=0·9323; change in ADCS-ADL score compared with control [-8·22, 95% CI -9·63 to -6·82]: 75 mg LMTM twice a day -0·93, -3·12 to 1·26, p=0·8659; 125 mg LMTM twice a day -0·34, -2·61 to 1·93, p=0·9479). Gastrointestinal and urinary effects were the most common adverse events with both high doses of LMTM, and the most common causes for discontinuation. Non-clinically significant dose-dependent reductions in haemoglobin concentrations were the most common laboratory abnormality. Amyloid-related imaging abnormalities were noted in less than 1% (8/885) of participants.InterpretationThe primary analysis for this study was negative, and the results do not suggest benefit of LMTM as an add-on treatment for patients with mild to moderate Alzheimer's disease. Findings from a recently completed 18-month trial of patients with mild Alzheimer's disease will be reported soon.FundingTauRx Therapeutics.
