A Phase 2 clinical trial of PF-05212377 (SAM-760) in subjects with mild to moderate Alzheimer's disease with existing neuropsychiatric symptoms on a stable daily dose of donepezil.

BACKGROUND: Symptomatic benefits have been reported for 5-HT6 receptor antagonists in Alzheimer's disease (AD) trials. SAM-760 is a potent and selective 5-HT6 receptor antagonist that has demonstrated central 5-HT6 receptor saturation in humans at a dose of 30 mg. METHODS: This was a randomized, double-blind, placebo-controlled, parallel-group, multicenter trial evaluating the efficacy and safety of SAM-760 30 mg once daily (QD) for 12 weeks in subjects with AD on a stable regimen of donepezil 5 to 10 mg QD. The study included an interim analysis with stopping rules for futility or efficacy after 180 subjects completed the week 12 visit. Up to 342 subjects with AD (Mini-Mental State Examination (MMSE) score 10-24) and neuropsychiatric symptoms (Neuropsychiatric Inventory (NPI) total score ≥ 10) were to be enrolled if the study continued after the interim analysis. After a 4-week, single-blind, placebo run-in period, subjects entered the 12-week double-blind period and were randomized to either SAM-760 or placebo. The primary and key secondary efficacy endpoints were the change from baseline in Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog13) and NPI total scores. Mixed models for repeated measures were used to analyze the data. RESULTS: At the interim analysis, when 186 subjects had been randomized and 163 had completed the week 12 visit, the study met futility criteria and was stopped. The mean week 12 treatment difference was 0.70 points (P = 0.43) for ADAS-cog13 and 2.19 points (P = 0.20) for NPI score, both of which were numerically in favor of placebo. Other secondary endpoints did not demonstrate any significant benefit for SAM-760. In total, 46.2% of SAM-760 subjects reported adverse events (AE) versus 44.7% for placebo, and there were 5 (5.5%) serious AEs in the SAM-760 group versus 3 (3.2%) for placebo. There were two deaths, one prior to randomization and one in the SAM-760 group (due to a traffic accident during washout of active treatment). CONCLUSIONS: SAM-760 was safe and well tolerated, but there was no benefit of SAM-760 on measures of cognition, neuropsychiatric symptoms, or daily function. Differences in trial design, study population, region, or pharmacological profile may explain differences in outcome compared with other 5-HT6 receptor antagonists. TRIAL REGISTRATION: Clinicaltrials.gov, NCT01712074 . Registered 19 October 2012.

First-In-Human safety and long-term exposure data for AAB-003 (PF-05236812) and biomarkers after intravenous infusions of escalating doses in patients with mild to moderate Alzheimer's disease.

BACKGROUND: In the First-In-Human (FIH), 39-week, randomized, adaptive design study, safety, tolerability, pharmacokinetics and biomarkers were measured in patients with mild-to-moderate Alzheimer's disease (AD) after infusion of a humanized monoclonal antibody to amyloid ß, AAB-003 (NCT01193608; registered 19 August 2010). AAB-003 was developed by modifying bapineuzumab to reduce Fc-receptor-mediated effector function as a strategy to reduce the removal of amyloid from vessel walls associated with amyloid-related imaging abnormalities with edema/effusions (ARIA-E) without diminishing overall amyloid clearance. METHODS: Eighty-eight patients with AD received up to three infusions of AAB-003 (or placebo) 13 weeks apart at doses of 0.5, 1, 2, 4 or 8 mg/kg in the FIH trial. Dose escalation was based on safety data reviews using a Bayesian escalation algorithm. Subjects who completed the FIH study were permitted to enter a 1-year open-label extension trial with four additional intravenous infusions of AAB-003 (NCT01369225; registered 10 May 2011). RESULTS: Dose-dependent increases in plasma amyloid ß and AAB-003 were observed. No significant changes in cerebral spinal fluid biomarkers were observed. Pharmacokinetics elimination half-life (21-28 days) clearance and volume of distribution values were consistent across dose groups indicating linearity. ARIA-E was the most notable safety finding detected by magnetic resonance imaging (MRI) at 8 mg/kg in two patients. Three cases of microhemorrhage were observed. No new safety findings or MRI abnormalities were observed for the 52 subjects who received AAB-003 in the extension trial. CONCLUSION: Based on integrated review of laboratory, electrocardiogram, adverse events, and MRI, AAB-003 was safe and well tolerated up to 8 mg/kg for up to 91 weeks (FIH and extension trials) in patients with mild to moderate AD. Asymptomatic and resolvable ARIA-E was observed after the first or second infusion of AAB-003, similar to bapineuzumab. The AAB-003 dose at which ARIA-E was observed was higher compared to bapineuzumab, supporting the hypothesis that reducing Fc-receptor effector function may reduce the ARIA associated with monoclonal antibodies targeting cerebral amyloid.

Clinical trial of an inhibitor of RAGE-Aß interactions in Alzheimer disease.

OBJECTIVE: To examine safety, tolerability, and efficacy of PF-04494700, an inhibitor of the receptor for advanced glycation end products (RAGE), in mild to moderate Alzheimer disease (AD). METHODS: Double-blind, placebo-controlled trial at 40 academic centers (United States). Subjects with AD and Mini-Mental State Examination score 14-26 were randomized to PF-04494700 60 mg/day × 6 days, then 20 mg daily (high dose); 15 mg/day × 6 days, then 5 mg daily (low dose); or placebo, for 18 months. Clinical and laboratory measures were used to evaluate safety and tolerability. The primary efficacy measure was the Alzheimer's Disease Assessment Scale-cognitive (ADAS-cog). Secondary measures assessed clinical stage, function, behavior, MRI, and CSF biomarkers. RESULTS: A total of 399 subjects were randomized. In a prespecified interim analysis, when 50% of subjects had completed the 6-month visit, the high dose was associated with confusion, falls, and greater ADAS-cog decline and was discontinued. A second prespecified analysis compared low-dose and placebo groups for futility and safety approximately 12 months after all subjects were randomized. This analysis met criteria for futility, and treatment was discontinued. There were no safety concerns in the low-dose group. Analyses including post-futility data showed decreased decline on the ADAS-cog in the low-dose group at month 18. Other clinical and biomarker measures showed no differences between low-dose treatment and placebo. CONCLUSIONS: PF-04494700 at 20 mg/d was associated with increased adverse events and cognitive decline. At 5 mg/d, PF-04494700 had a good safety profile. A potential benefit for this low dose on the ADAS-cog is not conclusive, because of high dropout and discontinuation rates subsequent to the interim analyses. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that in patients with AD high-dose PF-04494700 increased cognitive decline at 6 months and Class IV evidence that low-dose PF-04494700 slowed cognitive decline at 18 months.

Safety and pharmacokinetics of PF-04360365 following a single-dose intravenous infusion in Japanese subjects with mild-to-moderate Alzheimer's disease: a multicenter, randomized, double-blind, placebo-controlled, dose-escalation study.

OBJECTIVE: PF-04360365 is a humanized IgG(2)Δa anti-amyloid ß (Aß) antibody designed to improve outcome in Alzheimer's disease (AD). Single doses of 0.1 - 10 mg/kg were safe and well tolerated in Western (mostly Caucasian) subjects with mild-to-moderate AD. This Phase 1, multicenter, randomized, double-blind, dose-escalation study was the first to evaluate the safety, pharmacokinetics, pharmacodynamics, and immunogenicity of PF-04360365 in Japanese subjects. MATERIALS AND METHODS: 30 subjects with mild-to-moderate AD were enrolled. In each cohort, 3 subjects received PF-04360365 (0.1, 0.5, 1, 5, or 10 mg/kg) and 1 subject received placebo as a single 2-hour intravenous infusion. Subjects were monitored as inpatients for 24 hours and then as outpatients for 1 year. RESULTS: All subjects completed the study. There were no serious or National Cancer Institute Common Terminology Criteria for Adverse Events grade ≥ 3 adverse events, hypersensitivity reactions, or antidrug antibodies. No clinical or MRI evidence of brain microhemorrhage, cerebral edema, or encephalitis was observed. PF-04360365 plasma concentrations increased with dose, and pharmacokinetics were consistent with a small steady-state volume of distribution, slow clearance, and long elimination half-life. Cerebrospinal fluid (CSF):plasma ratios were < 0.5%. Plasma Aß species showed dose-dependent increases in C(max) and AUC(∞), but CSF biomarkers did not differ clearly between treatment arms. CONCLUSIONS: PF-04360365 was safe and well tolerated in Japanese subjects. Pharmacokinetics and plasma pharmacodynamic responses in Japanese subjects were comparable to those in Western subjects. *No longer affiliated with Pfizer.

Safety and pharmacology of ponezumab (PF-04360365) after a single 10-minute intravenous infusion in subjects with mild to moderate Alzheimer disease.

OBJECTIVE: Ponezumab (PF-04360365) is a humanized anti-amyloid beta (Aß) monoclonal antibody designed for treatment of Alzheimer disease (AD). A single 2-hour intravenous infusion of 0.1 to 10 mg/kg was previously shown to be safe and well tolerated in subjects with mild to moderate AD, with measurable effects on plasma and cerebrospinal fluid Aß. This phase I, dose-escalation, open-label study evaluated the safety, pharmacokinetics, and pharmacodynamics of a single 10-minute intravenous infusion. METHODS: Subjects with mild to moderate AD received ponezumab 1 mg/kg (n = 3), 3 mg/kg (n = 3), 5 mg/kg (n = 4), or 10 mg/kg (n = 5). They were followed up as outpatients for 6 months. RESULTS: All subjects completed the trial. Ponezumab was safe and well tolerated with no deaths, withdrawals, or drug-related moderate, severe, or serious adverse events. Mild drug-related adverse events included headache (3 patients) and lethargy and hypoesthesia (both in 1 patient). No infusion reactions, clinically meaningful laboratory abnormalities, vital sign changes, electrocardiographic changes, or antidrug antibodies were detected. There was no evidence of brain microhemorrhage, vasogenic edema, encephalitis, or other imaging abnormality. Cognitive function showed no treatment-related trends. Ponezumab displayed approximately dose-proportional increases in plasma exposure. Steady-state volume of distribution was 113 to 172 mL/kg, clearance was 2.7 to 3.0 mL/d/kg, and terminal half-life was 35 to 52 days. Plasma maximum observed concentration and the area under the plasma concentration-time profile from time 0 extrapolated to infinite time of Aß(1-x) and Aß(1-40) increased dose-dependently. CONCLUSIONS: Administration of ponezumab as a 10-minute infusion was safe and well tolerated and produced effects on plasma Aß species comparable with a 2-hour infusion. Shorter infusions may provide more flexibility, comfort, and convenience for patients and caregivers.

Safety and pharmacology of a single intravenous dose of ponezumab in subjects with mild-to-moderate Alzheimer disease: a phase I, randomized, placebo-controlled, double-blind, dose-escalation study.

OBJECTIVES: Ponezumab is a humanized antiamyloid beta (Aß) monoclonal antibody designed to treat Alzheimer disease (AD). METHODS: This randomized, double-blind, single-dose-escalation study evaluated the safety, pharmacokinetics, and pharmacodynamics of 0.1, 0.3, 1, 3, and 10 mg/kg ponezumab (n = 4, 4, 4, 6, and 8, respectively) versus placebo (n = 11) after a 2-hour intravenous infusion in subjects with mild-to-moderate AD. Cerebrospinal fluid (CSF) samples were obtained from the 1- and 10-mg/kg groups at baseline and at day 29. The subjects were followed for 1 year. RESULTS: All subjects completed the trial. Ponezumab was well tolerated with no drug-attributed serious adverse events. The most common adverse events were upper respiratory tract infection, headache, and back pain, all mild to moderate. One subject (10 mg/kg) experienced a mild hypersensitivity reaction. Another subject (0.1 mg/kg) demonstrated slight enlargement of a preexisting midbrain lesion. Electrocardiography and laboratory values (including CSF) were unremarkable. No evidence of new microhemorrhage, vasogenic edema, or meningoencephalitis was noted. Plasma maximum observed concentration increased approximately dose proportionally, and the area under the plasma concentration-time profile from time zero extrapolated to infinite time (AUC(inf)) increased slightly more than dose proportionally. Mean terminal half-life was approximately 6 weeks. Two subjects (10 mg/kg) had measurable CSF ponezumab concentrations (~0.5% of plasma values) at day 29. Plasma Aß(1-x) and Aß(1-40) increased dose dependently, and mean CSF Aß(1-x) increased 38% from baseline with 10 mg/kg (P = 0.002 vs placebo). CONCLUSIONS: A 2-hour infusion of 0.1 to 10 mg/kg ponezumab was well tolerated in subjects with mild-to-moderate AD. Plasma pharmacokinetic profile was approximately linear. Plasma Aß increased with dose, and CSF Aß increased at the highest dose, suggesting that intravenous ponezumab alters central Aß levels.