Tilavonemab in early Alzheimer's disease: results from a phase 2, randomized, double-blind study.

Tau accumulation in patients with Alzheimer's disease tracks closely with cognitive decline and plays a role in the later stages of disease progression. This phase 2 study evaluated the safety and efficacy of tilavonemab, an anti-tau monoclonal antibody, in patients with early Alzheimer's disease. In this 96-week, randomized, double-blind, placebo-controlled study (NCT02880956), patients aged 55-85 years meeting clinical criteria for early Alzheimer's disease with a Clinical Dementia Rating-Global Score of 0.5, a Mini-Mental State Examination score of 22 to 30, a Repeatable Battery for the Assessment of Neuropsychological Status-Delayed Memory Index score of ≤85, and a positive amyloid PET scan were randomized 1:1:1:1 to receive one of three doses of tilavonemab (300 mg, 1000 mg, or 2000 mg) or placebo via intravenous infusion every 4 weeks. The primary end point was the change from baseline up to Week 96 in the Clinical Dementia Rating-Sum of Boxes (CDR-SB) score. Safety evaluations included adverse event monitoring and MRI assessments. A total of 453 patients were randomized, of whom 337 were treated with tilavonemab (300 mg, n = 108; 1000 mg, n = 116; 2000 mg, n = 113) and 116 received placebo. Baseline demographics and disease characteristics were comparable across groups. The mean age was 71.3 (SD 7.0) years, 51.7% were female, and 96.5% were White. At baseline, the mean CDR-SB score was 3.0 (1.2), which worsened through Week 96 for all treatment groups. The least squares mean change from baseline at Week 96 in the CDR-SB score with tilavonemab was not significantly different compared with placebo [300 mg (n = 85): -0.07 (95% confidence interval, CI: -0.83 to 0.69); 1000 mg (n = 91): -0.06 (95% CI: -0.81 to 0.68); 2000 mg (n = 81): 0.16 (95% CI: -0.60 to 0.93); all P ≥ 0.05]. The incidence of any adverse event and MRI findings were generally comparable across groups. Tilavonemab was generally well tolerated but did not demonstrate efficacy in treating patients with early Alzheimer's disease. Further investigations of tilavonemab in early Alzheimer's disease are not warranted.

Safety and efficacy of tilavonemab in progressive supranuclear palsy: a phase 2, randomised, placebo-controlled trial.

BACKGROUND: Progressive supranuclear palsy is a neurodegenerative disorder associated with tau protein aggregation. Tilavonemab (ABBV-8E12) is a monoclonal antibody that binds to the N-terminus of human tau. We assessed the safety and efficacy of tilavonemab for the treatment of progressive supranuclear palsy. METHODS: We did a phase 2, multicentre, randomised, placebo-controlled, double-blind study at 66 hospitals and clinics in Australia, Canada, France, Germany, Italy, Japan, Spain, and the USA. Participants (aged ≥40 years) diagnosed with possible or probable progressive supranuclear palsy who were symptomatic for less than 5 years, had a reliable study partner, and were able to walk five steps with minimal assistance, were randomly assigned (1:1:1) by interactive response technology to tilavonemab 2000 mg, tilavonemab 4000 mg, or matching placebo administered intravenously on days 1, 15, and 29, then every 28 days through to the end of the 52-week treatment period. Randomisation was done by the randomisation specialist of the study sponsor, who did not otherwise participate in the study. The sponsor, investigators, and participants were unaware of treatment allocations. The primary endpoint was the change from baseline to week 52 in the Progressive Supranuclear Palsy Rating Scale (PSPRS) total score in the intention-to-treat population. Adverse events were monitored in participants who received at least one dose of study drug. Prespecified interim futility criteria were based on a model-based effect size of 0 or lower when 60 participants had completed the 52-week treatment period and 0·12 or lower when 120 participants had completed the 52-week treatment period. This study is registered at ClinicalTrials.gov, number NCT02985879. FINDINGS: Between Dec 12, 2016, and Dec 31, 2018, 466 participants were screened, 378 were randomised. The study was terminated on July 3, 2019, after prespecified futility criteria were met at the second interim analysis. A total of 377 participants received at least one dose of study drug and were included in the efficacy and safety analyses (2000 mg, n=126; 4000 mg, n=125; placebo, n=126). Least squares mean change from baseline to week 52 in PSPRS was similar in all groups (between-group difference vs placebo: 2000 mg, 0·0 [95% CI -2·6 to 2·6], effect size 0·000, p>0·99; 4000 mg, 1·0 [-1·6 to 3·6], -0·105, p=0·46). Most participants reported at least one adverse event (2000 mg, 111 [88%]; 4000 mg, 111 [89%]; placebo, 108 [86%]). Fall was the most common adverse event (2000 mg, 42 [33%]; 4000 mg, 54 [43%]; placebo, 49 [39%]). Proportions of patients with serious adverse events were similar among groups (2000 mg, 29 [23%]; 4000 mg, 34 [27%]; placebo, 33 [26%]). Fall was the most common treatment-emergent serious adverse event (2000 mg, five [4%]; 4000 mg, six [5%]; placebo, six [5%]). 26 deaths occurred during the study (2000 mg, nine [7%]; 4000 mg, nine [7%]; placebo, eight [6%]) but none was drug related. INTERPRETATION: A similar safety profile was seen in all treatment groups. No beneficial treatment effects were recorded. Although this study did not provide evidence of efficacy in progressive supranuclear palsy, the findings provide potentially useful information for future investigations of passive immunisation using tau antibodies for progressive supranuclear palsy. FUNDING: AbbVie Inc.

Pharmacokinetics, Safety, Tolerability, and Pharmacodynamics of Alicapistat, a Selective Inhibitor of Human Calpains 1 and 2 for the Treatment of Alzheimer Disease: An Overview of Phase 1 Studies.

Alicapistat is an orally active selective inhibitor of calpain 1 and 2 whose overactivation has been linked to Alzheimer disease (AD). Three studies were conducted in healthy subjects (18-55 years), 1 in healthy elderly subjects (≥65 years), and 1 in patients with mild to moderate AD. Four studies assessed pharmacokinetics, 1 study in healthy subjects assessed pharmacodynamics (sleep parameters, particularly rapid eye movement [REM], as a measure of central nervous system [CNS] penetration and activity), and all studies assessed safety. Participants received single doses or multiple twice-daily doses of alicapistat for up to 14 days. Maximum alicapistat plasma concentrations were reached in 2 to 5 hours; half-life was 7 to 12 hours postdose. Alicapistat exposure was dose proportional in the alicapistat 50- to 1000-mg dose range. Exposure of the alicapistat R,S diastereomer was approximately 2-fold greater than exposure of the R,R diastereomer in healthy young and elderly subjects and patients with AD. Alicapistat at 400- or 800-mg twice-daily doses had no effect on REM sleep parameters, whereas the active control, donepezil at 10 mg twice daily, affected sleep parameters. Across all trials, the incidence of treatment-emergent adverse events was similar in the placebo and alicapistat groups. There were no clinically significant changes in vital signs and laboratory measurements. The lack of an effect of alicapistat on sleep suggests that concentrations in the CNS were inadequate or that preclinical studies do not predict alicapistat effects in humans.

Mitigating the Metabolic Liability of Carbonyl Reduction: Novel Calpain Inhibitors with P1' Extension.

Dysregulation of calpains 1 and 2 has been implicated in a variety of pathological disorders including ischemia/reperfusion injuries, kidney diseases, cataract formation, and neurodegenerative diseases such as Alzheimer's disease (AD). 2-(3-Phenyl-1H)-pyrazol-1-yl)nicotinamides represent a series of novel and potent calpain inhibitors with high selectivity and in vivo efficacy. However, carbonyl reduction leading to the formation of the inactive hydroxyamide was identified as major metabolic liability in monkey and human, a pathway not reflected by routine absorption, distribution, metabolism, and excretion (ADME) assays. Using cytosolic clearance as a tailored in vitro ADME assay coupled with in vitro hepatocyte metabolism enabled the identification of analogues with enhanced stability against carbonyl reduction. These efforts led to the identification of P1' modified calpain inhibitors with significantly improved pharmacokinetic profile including P1' N-methoxyamide 23 as potential candidate compound for non-central nervous system indications.

A Phase 2, Double-Blind, Placebo-Controlled Randomized Trial Assessing the Efficacy of ABT-436, a Novel V1b Receptor Antagonist, for Alcohol Dependence.

Alcohol use disorder has been linked to dysregulation of the brain stress systems, producing a negative emotional state leading to chronic relapsing behavior. Vasopressin receptors appear to have a regulatory role in stress, anxiety, and alcohol. This study evaluated the novel compound, ABT-436, a V1b receptor antagonist, in alcohol-dependent participants in a 12-week clinical trial. Men and women (n=150) who met criteria for DSM-IV alcohol dependence were recruited across four sites. Participants received double-blind ABT-436 or placebo, and a computerized behavioral intervention. ABT-436 was titrated to 800 mg/day during weeks 2-12. Although the primary outcome, percentage of heavy drinking days, was lower in participants receiving ABT-436 compared with placebo, this difference was not statistically significant (31.3 vs 37.6, respectively; p=0.172; d=0.20). However, participants receiving ABT-436 had significantly greater percentage of days abstinent than those receiving placebo (51.2 vs 41.6, respectively; p=0.037; d=0.31). No significant differences were found between treatment groups on any other measures of drinking, alcohol craving, or alcohol-related consequences. Smokers receiving ABT-436 smoked significantly fewer cigarettes per week than those receiving placebo (p=0.046). ABT-436 was well tolerated, with diarrhea (mild-to-moderate severity) being the most common side effect. In subgroup analyses, participants with relatively higher baseline levels of stress responded better to ABT-436 than placebo on select drinking outcomes, suggesting there may be value in testing medications targeting the vasopressin receptor in high stress, alcohol-dependent patients.

A double-blind, randomized, placebo-controlled study of the dopamine D3 receptor antagonist ABT-925 in patients with acute schizophrenia.

There is substantial preclinical and clinical evidence to suggest a potential role for the dopamine D3 receptor in the treatment of schizophrenia. ABT-925 is a selective dopamine D3 receptor antagonist with an approximately 100-fold higher in vitro affinity for dopamine D3 versus D2 receptors. This double-blind, randomized, placebo-controlled, escalating-dose, parallel-group study assessed the efficacy and safety of ABT-925 in the treatment of patients with acute exacerbation of schizophrenia. One hundred fifty-five patients were assessed over a 6-week double-blind treatment period (placebo: n = 48; ABT-925 50 mg once daily [QD]: n = 53; ABT-925 150 mg QD: n = 54). The primary efficacy measure was mean change from baseline to final evaluation on the Positive and Negative Syndrome Scale total score. Secondary measures of efficacy and pharmacokinetic parameters were also assessed. Safety assessments included adverse event monitoring, laboratory tests, vital signs, movement rating scales, and electrocardiogram measures. No statistically significant treatment effect was observed with ABT-925 50 mg QD or 150 mg QD compared with placebo on primary or secondary efficacy end points. Pharmacokinetic parameter estimates increased with dose in a linear fashion. ABT-925 50 mg QD and 150 mg QD were generally well tolerated, with adverse event profiles similar to that of placebo. Findings from a concurrent positron emission tomography study among healthy volunteers suggest that the ABT-925 doses used in this study may not have been sufficient to adequately occupy D3 receptors, thereby underscoring the importance of pharmacodynamic markers, such as PET, in determining appropriate compound doses before embarking on studies in a target population.