T cell-specific STAT3 deficiency abrogates lupus nephritis.

Signal transducer and activator of transcription (STAT) 3 is a regulator of T-cell responses to external stimuli, such as pro-inflammatory cytokines and chemokines. We have previously shown that STAT3 is activated (phosphorylated) at high levels in systemic lupus erythematosus (SLE) T cells and mediates chemokine-induced migration and T:B cell interactions. Stattic, a small molecular STAT3 inhibitor, can partially ameliorate lupus nephritis in mice. To understand the role of STAT3 better in T-cell pathophysiology in lupus nephritis and its potential as a treatment target, we silenced its expression in T cells using a cd4-driven CRE-Flox model. We found that lupus-prone mice that do not express STAT3 in T cells did not develop lymphadenopathy, splenomegaly, or glomerulonephritis. Moreover, the production of anti-dsDNA antibodies was decreased in these mice compared to controls. To dissect the mechanism, we also used a nephrotoxic serum model of nephritis. In this model, T cell-specific silencing of STAT3 resulted in amelioration of nephrotoxic serum-induced kidney damage. Taken together, our results suggest that in mouse models of autoimmune nephritis, T cell-specific silencing of STAT3 can hamper their ability to help B cells to produce autoantibodies and induce cell tissue infiltration. We propose that STAT3 inhibition in T cells represents a novel approach in the treatment of SLE and lupus nephritis in particular.

Further analyses of the safety of verubecestat in the phase 3 EPOCH trial of mild-to-moderate Alzheimer's disease.

BACKGROUND: Verubecestat, a BACE1 inhibitor that reduces Aß levels in the cerebrospinal fluid of humans, was not effective in a phase 3 trial (EPOCH) of mild-to-moderate AD and was associated with adverse events. To assist in the development of BACE1 inhibitors, we report detailed safety findings from EPOCH. METHODS: EPOCH was a randomized, double-blind, placebo-controlled 78-week trial evaluating verubecestat 12 mg and 40 mg in participants with mild-to-moderate AD diagnosed clinically. The trial was terminated due to futility close to its scheduled completion. Of 1957 participants who were randomized and took treatment, 652 were assigned to verubecestat 12 mg, 652 to verubecestat 40 mg, and 653 to placebo. Adverse events and relevant laboratory, vital sign, and ECG findings were assessed. RESULTS: Verubecestat 12 mg and 40 mg were associated with an increase in the percentage of participants reporting adverse events versus placebo (89 and 92% vs. 82%), although relatively few participants discontinued treatment due to adverse events (8 and 9% vs. 6%). Adverse events that were increased versus placebo included falls and injuries, suicidal ideation, weight loss, sleep disturbance, rash, and hair color change. Most were mild to moderate in severity. Treatment differences in suicidal ideation emerged within the first 3 months but did not appear to increase after 6 months. In contrast, treatment differences in falls and injuries continued to increase over time. CONCLUSIONS: Verubecestat was associated with increased risk for several types of adverse events. Falls and injuries were notable for progressive increases over time. While the mechanisms underlying the increased adverse events are unclear, they may be due to BACE inhibition and should be considered in future clinical development programs of BACE1 inhibitors. TRIAL REGISTRATION: ClinicalTrials.gov NCT01739348 , registered on 29 November 2012.

Lessons that can be learnt from the failure of verubecestat in Alzheimer's disease.

Introduction: The amyloid-beta (Aß) cascade hypothesis is that reducing Aß levels in the brain will be beneficial in treating Alzheimer's disease. Aß is formed by the cleavage of amyloid precursor protein by ß-site amyloid precure protein cleaving enzyme (BACE1) and the BACE1 inhibitor verubecestat was developed to lower the brain levels of Aß. However, in the EPOCH trial of verubecestat in mild-to-moderate Alzheimer's disease, it was not beneficial and increased adverse effects.Areas covered: Prior to completing EPOCH, APECS, which trialled verubecestat in prodromal Alzheimer's disease, was commenced. Like EPOCH, APECS was terminated early. In APECS, verubecestat 40 mg worsened cognition and increased adverse effects.Expert opinion: In recruiting subjects to clinical trials in Alzheimer's disease, a clinical diagnosis involving the measurement of Aß should be undertaken for all subjects, as this may help to clarify the findings. In my opinion, the failure of verubecestat in EPOCH and APECS probably could have been avoided if a safety and potential efficacy trial (phase 2) had been completed prior to starting phase 3. It seems to me that, as we have a poor understanding of the underlying mechanisms/cause of Alzheimer's disease, this is where the research emphasis should be, not phase 3 clinical trials.

Safety, Tolerability, and Pharmacokinetics of the ß-Site Amyloid Precursor Protein-Cleaving Enzyme 1 Inhibitor Verubecestat (MK-8931) in Healthy Elderly Male and Female Subjects.

ß-site amyloid precursor protein-cleaving enzyme 1 (BACE1) is required for the production of ß-amyloid peptides, which are implicated in the etiology of Alzheimer's disease. The safety and pharmacokinetics of the BACE1 inhibitor verubecestat have previously been studied in young adults aged 19-45 years. In this randomized, placebo-controlled, phase I study (protocol MK-8931-006), we investigated the safety, tolerability, and pharmacokinetics of a single dose (100 mg) or multiple doses (30, 80, and 120 mg) once daily for 28 days of verubecestat in healthy elderly subjects. Safety end points were assessed at baseline and during the duration of the study period and indicated that verubecestat was generally well tolerated. Verubecestat pharmacokinetics were similar between healthy elderly male and female subjects and similar to those reported in healthy young males in previous studies. These data supported subsequent studies to assess the potential efficacy of verubecestat in subjects with Alzheimer's disease.

Randomized Trial of Verubecestat for Prodromal Alzheimer's Disease.

BACKGROUND: Prodromal Alzheimer's disease offers an opportunity to test the effect of drugs that modify the deposition of amyloid in the brain before the onset of dementia. Verubecestat is an orally administered ß-site amyloid precursor protein-cleaving enzyme 1 (BACE-1) inhibitor that blocks production of amyloid-beta (Aß). The drug did not prevent clinical progression in a trial involving patients with mild-to-moderate dementia due to Alzheimer's disease. METHODS: We conducted a randomized, double-blind, placebo-controlled, 104-week trial to evaluate verubecestat at doses of 12 mg and 40 mg per day, as compared with placebo, in patients who had memory impairment and elevated brain amyloid levels but whose condition did not meet the case definition of dementia. The primary outcome was the change from baseline to week 104 in the score on the Clinical Dementia Rating Scale-Sum of Boxes (CDR-SB; scores range from 0 to 18, with higher scores indicating worse cognition and daily function). Secondary outcomes included other assessments of cognition and daily function. RESULTS: The trial was terminated for futility after 1454 patients had been enrolled; 485 had been assigned to receive verubecestat at a dose of 12 mg per day (the 12-mg group), 484 to receive verubecestat at a dose of 40 mg per day (the 40-mg group), and 485 to receive placebo. A total of 234 patients, 231 patients, and 239 patients per group, respectively, completed 104 weeks of the trial regimen. The estimated mean change from baseline to week 104 in the CDR-SB score was 1.65 in the 12-mg group, 2.02 in the 40-mg group, and 1.58 in the placebo group (P = 0.67 for the comparison between the 12-mg group and the placebo group and P = 0.01 for the comparison between the 40-mg group and the placebo group), suggesting a worse outcome in the higher-dose group than in the placebo group. The estimated rate of progression to dementia due to Alzheimer's disease was 24.5, 25.5, and 19.3 events per 100 patient-years in the 12-mg group, the 40-mg group, and the placebo group, respectively (hazard ratio for 40 mg vs. placebo, 1.38; 97.51% confidence interval, 1.07 to 1.79, not adjusted for multiple comparisons), favoring placebo. Adverse events were more common in the verubecestat groups than in the placebo group. CONCLUSIONS: Verubecestat did not improve clinical ratings of dementia among patients with prodromal Alzheimer's disease, and some measures suggested that cognition and daily function were worse among patients who received verubecestat than among those who received placebo. (Funded by Merck Sharp & Dohme; ClinicalTrials.gov number, NCT01953601.).

Randomized Trial of Verubecestat for Mild-to-Moderate Alzheimer's Disease.

BACKGROUND: Alzheimer's disease is characterized by the deposition of amyloid-beta (Aß) plaques in the brain. Aß is produced from the sequential cleavage of amyloid precursor protein by ß-site amyloid precursor protein-cleaving enzyme 1 (BACE-1) followed by γ-secretase. Verubecestat is an oral BACE-1 inhibitor that reduces the Aß level in the cerebrospinal fluid of patients with Alzheimer's disease. METHODS: We conducted a randomized, double-blind, placebo-controlled, 78-week trial to evaluate verubecestat at doses of 12 mg and 40 mg per day, as compared with placebo, in patients who had a clinical diagnosis of mild-to-moderate Alzheimer's disease. The coprimary outcomes were the change from baseline to week 78 in the score on the cognitive subscale of the Alzheimer's Disease Assessment Scale (ADAS-cog; scores range from 0 to 70, with higher scores indicating worse dementia) and in the score on the Alzheimer's Disease Cooperative Study Activities of Daily Living Inventory scale (ADCS-ADL; scores range from 0 to 78, with lower scores indicating worse function). RESULTS: A total of 1958 patients underwent randomization; 653 were randomly assigned to receive verubecestat at a dose of 12 mg per day (the 12-mg group), 652 to receive verubecestat at a dose of 40 mg per day (the 40-mg group), and 653 to receive matching placebo. The trial was terminated early for futility 50 months after onset, which was within 5 months before its scheduled completion, and after enrollment of the planned 1958 patients was complete. The estimated mean change from baseline to week 78 in the ADAS-cog score was 7.9 in the 12-mg group, 8.0 in the 40-mg group, and 7.7 in the placebo group (P=0.63 for the comparison between the 12-mg group and the placebo group and P=0.46 for the comparison between the 40-mg group and the placebo group). The estimated mean change from baseline to week 78 in the ADCS-ADL score was -8.4 in the 12-mg group, -8.2 in the 40-mg group, and -8.9 in the placebo group (P=0.49 for the comparison between the 12-mg group and the placebo group and P=0.32 for the comparison between the 40-mg group and the placebo group). Adverse events, including rash, falls and injuries, sleep disturbance, suicidal ideation, weight loss, and hair-color change, were more common in the verubecestat groups than in the placebo group. CONCLUSIONS: Verubecestat did not reduce cognitive or functional decline in patients with mild-to-moderate Alzheimer's disease and was associated with treatment-related adverse events. (Funded by Merck; ClinicalTrials.gov number, NCT01739348 .).

Relative contributions of presystemic and systemic peptidases to oral exposure of a novel metabotropic glutamate 2/3 receptor agonist (LY404039) after oral administration of prodrug pomaglumetad methionil (LY2140023).

Pomaglumetad methionil (LY2140023) is the prodrug of a novel metabotropic glutamate 2/3 receptor agonist (LY404039) being investigated for the treatment of schizophrenia. Using accelerator mass spectrometry (AMS) and an intravenous (i.v.) radiolabeled tracer approach, the absolute bioavailability of the prodrug and the extent of its conversion to active moiety (LY404039) were estimated at presystemic (intestinal/first pass) and systemic sites after simultaneous oral and i.v. dosing in healthy subjects. The mean absolute bioavailability of prodrug (80 mg oral) was 0.68. On the basis of these data and a previous radiolabeled mass balance study in which no prodrug was recovered in feces, we concluded that 0.32 of the dose is converted to active drug in the intestinal tract. The fraction of prodrug converted to active moiety was approximately 1, indicating complete conversion of the prodrug that reaches the systemic circulation to the active moiety. Prodrug (80 mg oral and 100 µg i.v.) and active moiety (100 µg i.v.) were well tolerated in healthy subjects. Thus, the absolute bioavailability of prodrug LY2140023 and the fraction converted presystemically and systemically to active moiety LY404039 were estimated simultaneously using radiolabeled tracer microdosing and AMS.

Down-regulation of the Notch pathway mediated by a gamma-secretase inhibitor induces anti-tumour effects in mouse models of T-cell leukaemia.

BACKGROUND AND PURPOSE: gamma-Secretase inhibitors (GSIs) block NOTCH receptor cleavage and pathway activation and have been under clinical evaluation for the treatment of malignancies such as T-cell acute lymphoblastic leukaemia (T-ALL). The ability of GSIs to decrease T-ALL cell viability in vitro is a slow process requiring >8 days, however, such treatment durations are not well tolerated in vivo. Here we study GSI's effect on tumour and normal cellular processes to optimize dosing regimens for anti-tumour efficacy. EXPERIMENTAL APPROACH: Inhibition of the Notch pathway in mouse intestinal epithelium was used to evaluate the effect of GSIs and guide the design of dosing regimens for xenograft models. Serum Abeta(40) and Notch target gene modulation in tumours were used to evaluate the degree and duration of target inhibition. Pharmacokinetic and pharmacodynamic correlations with biochemical, immunohistochemical and profiling data were used to demonstrate GSI mechanism of action in xenograft tumours. KEY RESULTS: Three days of >70% Notch pathway inhibition was sufficient to provide an anti-tumour effect and was well tolerated. GSI-induced conversion of mouse epithelial cells to a secretory lineage was time- and dose-dependent. Anti-tumour efficacy was associated with cell cycle arrest and apoptosis that was in part due to Notch-dependent regulation of mitochondrial homeostasis. CONCLUSIONS AND IMPLICATIONS: Intermittent but potent inhibition of Notch signalling is sufficient for anti-tumour efficacy in these T-ALL models. These findings provide support for the use of GSI in Notch-dependent malignancies and that clinical benefits may be derived from transient but potent inhibition of Notch.

The effects of NN414, a SUR1/Kir6.2 selective potassium channel opener, in healthy male subjects.

The aim of the present study was to investigate the effect of a single dose of NN414 (a selective SUR1/Kir6.2 potassium channel opener). Sixty-four healthy male subjects were enrolled at 8 dose levels (0.625-12.5 mg/kg or placebo). The study consisted of a baseline day and a dosing day. NN414 or placebo was administered in the evening about 10 pm. On both study days, an oral glucose tolerance test (OGTT) was performed following an overnight fast (corresponding to 9 hours postdose), and glucose, insulin, glucagon, and growth hormone concentrations were determined. NN414 was well tolerated, with no clinically relevant changes in safety parameters, although there was an increase in gastrointestinal side effects. NN414 treatment lowered glucose during the OGTT and 24-hour insulin and glucose levels. In conclusion, a single dose of NN414 is associated with improvements in glucose-related parameters in healthy male subjects.

NN-414. Novo Nordisk.

Novo Nordisk is developing NN-414, an orally active beta-cell-selective regulator of insulin release, for the potential treatment of type 1 and type 2 diabetes. Phase 1 efficacy trials were underway by November 2000; these trials were ongoing in February 2002 and had been concluded by February 2003.

Novel antiarthritic agents with 1,2-isothiazolidine-1,1-dioxide (gamma-sultam) skeleton: cytokine suppressive dual inhibitors of cyclooxygenase-2 and 5-lipoxygenase.

Various 1,2-isothiazolidine-1,1-dioxide (gamma-sultam) derivatives containing an antioxidant moiety, 2,6-di-tert-butylphenol substituent, were prepared. Some compounds, which have a lower alkyl group at the 2-position of the gamma-sultam skeleton, showed potent inhibitory effects on both cyclooxygenase (COX)-2 and 5-lipoxygenase (5-LO), as well as production of interleukin (IL)-1 in in vitro assays. They also proved to be effective in several animal arthritic models without any ulcerogenic activities. Among these compounds, (E)-(5)-(3,5-di-tert-butyl-4-hydroxybenzylidene)-2-ethyl-1, 2-isothiazolidine-1,1-dioxide (S-2474) was selected as an antiarthritic drug candidate and is now under clinical trials. The structure-activity relationships (SAR) examined and some pharmacological evaluations are described.

A bridging study of fananserin in schizophrenic patients.

Fananserin is a potential antipsychotic compound with high affinity for both D4 and 5-HT2A receptors, and negligible affinity for D2 receptors. Because the tolerance for antipsychotic compounds often differs between schizophrenic patients and healthy subjects, this bridging study was designed to evaluate the tolerability of fananserin, to define the slow titration maximum tolerated dose in the target population, and to identify the most rapid well-tolerated rate of titration for this compound. Three rates of titration regimens were examined in a total of 26 schizophrenic patients in a parallel group design, following a 3-day placebo washout period from previous antipsychotic medication. The slow rate of titration (reaching the maximum dose of 600 mg/day in 16 days with 100-mg increases every 3 days) was well tolerated, but a rapid titration schedule (reaching 600 mg/day in 8 days with 200-mg increases every 3 days) resulted in hypotension in 3 of 6 patients and termination of the group on Day 10. An intermediate rate of titration (reaching 600 mg/day in 10 days with 100-mg increases every 2 days) was then examined and was well tolerated, with transient episodes of mild hypotension reported in 2 of 10 patients. Thus, although hypotension was identified as the dose-limiting adverse event in this study, a reduction in the titration rate was effective in reducing the incidence and severity of this side effect. In this study, schizophrenic patients administered multiple doses of fananserin tolerated doses 400 percent greater than the maximum tolerated single dose in healthy volunteers.