uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Safety, efficacy, and biomarker findings of PBT2 in targeting A beta as a modifying therapy for Alzheimer's disease: a phase IIa, double-blind, randomised, placebo-controlled trial
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences.
Show others and affiliations
2008 (English)In: Lancet Neurology, ISSN 1474-4422, E-ISSN 1474-4465, Vol. 7, no 9, 779-786 p.Article in journal (Refereed) Published
Abstract [en]

Background PBT2 is a metal-protein attenuating compound (MPAC) that affects the Cu2+-mediated and Zn2+-mediated toxic oligomerisation of A beta seen in Alzheimer's disease (AD). Strong preclinical efficacy data and the completion of early, clinical safety studies have preceded this phase IIa study, the aim of which was to assess the effects of PBT2 on safety, efficacy, and biomarkers of AD. Methods Between December 6, 2006, and September 21, 2007, community-dwelling patients over age 55 years were recruited to this 12-week, double-blind, randomised trial of PBT2. Patients were randomly allocated to receive 50 mg PBT2, 250 mg PBT2, or placebo. Inclusion criteria were early AD (mini-mental state examination [MMSE] score between 20 and 26 points or Alzheimer's disease assessment scale-cognitive subscale (ADAS-cog) score between 10 and 25 points), taking a stable dose of acetylcholinesterase inhibitor (donepezil, galantamine, or rivastigmine) for at least 4 months, a modified Hachinski score of 4 points or less, and CT or MRI results that were consistent with AD. The principal outcomes were safety and tolerability. Secondary outcomes were plasma and CSF biomarkers and cognition. Analysis was intention to treat. The trial is registered with ClinicalTrials.gov, number NCT00471211. Findings 78 patients were randomly assigned (29 to placebo, 20 to PBT2 50 mg, and 29 to PBT2 250 mg) and 74 (95%) completed the study. 42 (54%) patients had at least one treatment emergent adverse event (10 [50%] on PBT2 50 mg, 18 [62%] on PBT2 250 mg, and 14 [48%] on placebo). No serious adverse events were reported by patients on PBT2. Patients treated with PBT2 250 mg had a dose-dependent (p=0.023) and significant reduction in CSF A beta(42) concentration compared with those treated with placebo (difference in least squares mean change from baseline was -56.0 pg/mL, 95% Cl -101.5 to -11.0; p=0.006). PBT2 had no effect on plasma biomarkers of AD or serum Zn2+ and Cu2+ concentrations. Cognition testing included ADAS-cog, MMSE, and a neuropsychological test battery (NTB). Of these tests, two executive function component tests of the NTB showed significant improvement over placebo in the PBT2 250 mg group: category fluency test (2.8 words, 0.1 to 5.4; p=0.041) and trail making part B (-48.0 s, -83.0 to -13.0; p=0.009). Interpretation The safety profile is favourable for the ongoing development of PBT2. The effect on putative biomarkers for AD in CSF but not in plasma is suggestive of a central effect of the drug on A beta metabolism. Cognitive efficacy was restricted to two measures of executive function. Future trials that are larger and longer will establish if the effects of PBT2 on biomarkers and cognition that are reported here translate into clinical effectiveness.

Place, publisher, year, edition, pages
2008. Vol. 7, no 9, 779-786 p.
National Category
Medical and Health Sciences
URN: urn:nbn:se:uu:diva-152131DOI: 10.1016/S1474-4422(08)70167-4ISI: 000258988400013OAI: oai:DiVA.org:uu-152131DiVA: diva2:412521
Available from: 2011-04-25 Created: 2011-04-25 Last updated: 2011-04-25Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text
By organisation
Department of Public Health and Caring Sciences
In the same journal
Lancet Neurology
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 134 hits
ReferencesLink to record
Permanent link

Direct link