Julie Satterwhite

Early Changes in Biochemical Markers of Bone Formation Predict BMD Response to Teriparatide in Postmenopausal Women With Osteoporosis

The relationship between early changes in biochemical markers of bone turnover and the subsequent BMD response to daily teriparatide therapy in women with postmenopausal osteoporosis was studied. Changes in five biochemical markers, obtained from a subset of women enrolled in the Fracture Prevention Trial, were examined. Early increases in the PICP and the PINP were the best predictors of BMD response to teriparatide in this analysis.

Safety, tolerability, and changes in amyloid β concentrations after administration of a γ-secretase inhibitor in volunteers

Amyloid β (Aβ) may play a central role in the pathogenesis of Alzheimer disease. A functional γ-secretase inhibitor, LY450139, was developed that inhibits Aβ formation in whole cell assays, transgenic mice, and beagle dogs. The authors wished to determine the safety and tolerability of this drug, and the reduction of Aβ in plasma and cerebrospinal fluid (CSF) after multiple doses. Volunteer subjects (N = 37) were studied using doses from 5 to 50 mg/day given for 14 days. Plasma and CSF concentrations of LY450139, Aβ1-40 and Aβ1-X (“Aβtotal”) were determined, and safety and tolerability were assessed. The plasma half-life of LY450139 was approximately 2.5 hours. Pharmacokinetic analyses showed a linear relationship between dose and plasma concentrations, with a Cmax of 828 ± 19.2 ng/mL after a 50-mg dose. Plasma Aβ concentrations decreased in a dose-dependent manner over a 6-hour interval following drug administration, with a maximum decrease of approximately 40% relative to baseline. After returning to baseline, Aβ concentrations were transiently increased. CSF Aβ concentrations were unchanged. Adverse events reported by subjects taking 5-mg, 20-mg, or 40-mg doses were similar to those reported by subjects taking placebo. Two of 7 subjects taking 50 mg/day experienced adverse events that may have been drug related. In this phase 1 volunteer study, reported adverse events after taking LY450139 were manageable. A dose-dependent reduction in plasma Aβ was demonstrated, and changes in plasma Aβ concentrations were temporally related to the pharmacokinetic characteristics of LY450139.

The Skeletal Response to Teriparatide Is Largely Independent of Age, Initial Bone Mineral Density, and Prevalent Vertebral Fractures in Postmenopausal Women With Osteoporosis†

In a recent study of women with postmenopausal osteoporosis, treatment with teriparatide for a median of 19 months increased bone mineral density and decreased the risk of vertebral and nonvertebral fractures. Using the same cohort, the current study evaluated the relationship between these therapeutic effects and the patients baseline age, vertebral bone mineral density, and prevalent vertebral fractures. In women over 65 years of age, treatment resulted in a greater increase in vertebral bone mineral density than in younger women (treatment‐by‐age interaction, p = 0.037), but baseline age had no effect on the relative risk reduction for vertebral fractures (treatment‐by‐age interaction, p = 0.558). In women receiving placebo (with calcium and vitamin D), there was an inverse relationship between baseline vertebral bone mineral density and vertebral fracture risk. When compared across bone mineral density tertiles, the effects of teriparatide on the relative risk for developing new vertebral fractures and increase in vertebral bone mineral density did not differ significantly (p = 0.817 and p = 0.615, respectively). Teriparatide treatment significantly decreased vertebral fracture risk in patients with a vertebral bone mineral density T score of less than −3.3 or a score between −2.1 and −3.3 (p < 0.001 and p = 0.027, respectively) and showed a trend toward reduced fracture risk in the group with a T score greater than −2.1 (p = 0.115). Placebo‐treated women with two or more prevalent vertebral fractures had a significantly greater risk of developing new vertebral fractures than women with zero or one prevalent vertebral fracture (p < 0.001). When compared within prevalent vertebral fracture subgroups, the effects of teriparatide on the relative risk for developing new vertebral fractures were similar. The results of this study indicate that teriparatide offers clinical benefit to patients across a broad range of age and disease severity.

Anabolic and catabolic bone effects of human parathyroid hormone (1-34) are predicted by duration of hormone exposure

Parathyroid hormone (PTH)(1-34), given once daily, increases bone mass in a variety of animal models and humans with osteoporosis. However, continuous PTH infusion has been shown to cause bone loss. To determine the pharmacokinetic profile of PTH(1-34) associated with anabolic and catabolic bone responses, PTH(1-34) pharmacokinetic and serum biochemical profiles were evaluated in young male rats using dosing regimens that resulted in either gain or loss of bone mass. Once-daily PTH(1-34) or 6 PTH(1-34) injections within 1 h, for a total daily dose of 80 microg/kg, induced equivalent increases in proximal tibia bone mass. In contrast, 6 PTH(1-34) injections/day over 6 h for a total dose of 80 microg/kg/day or 3 injections/day over 8 h for a total of 240 microg/kg/day decreased tibia bone mass. The PTH(1-34) pharmacokinetics of the different treatment regimens were distinctive. The magnitude of the maximum serum concentrations (Cmax) of PTH(1-34) and area under the curve (AUC) did not predict the catabolic bone outcome. Compared to the anabolic pharmacokinetic profile of a transient increase in PTH(1-34) with rapid decreases in serum calcium and phosphate, the catabolic regimen was associated with PTH(1-34) concentrations remaining above baseline values during the entire 6-h dosing period with a trend toward an increase in serum calcium and a prolonged decrease in phosphate. The pharmacokinetic profiles suggest that the anabolic or catabolic response of bone to PTH(1-34) is determined primarily by the length of time each day that serum concentrations of PTH(1-34) remain above baseline levels of endogenous PTH and only secondarily by the Cmax or AUC of PTH(1-34) achieved.

Tabalumab, an anti-BAFF monoclonal antibody, in patients with active rheumatoid arthritis with an inadequate response to TNF inhibitors

Objective To evaluate the efficacy and safety of tabalumab, a monoclonal antibody that neutralises membrane-bound and soluble B-cell activating factor (BAFF), in patients with active rheumatoid arthritis (RA) who showed inadequate response to tumour necrosis factor (TNF) inhibitors. Methods Patients on stable methotrexate and with inadequate response to one or more TNF inhibitors were randomised to placebo (n=35), 30 mg tabalumab (n=35) or 80 mg tabalumab (n=30) given intravenously at 0, 3 and 6 weeks. The primary outcome was the proportion of patients achieving an American College of Rheumatology 50% response (ACR50) at week 16 (all tabalumab-treated patients vs placebo). Results At week 16, no significant differences were observed in the combined tabalumab group versus placebo in ACR50 (12.7% vs 2.9%, p=0.101) or ACR20 response rates (27.0% vs 17.1%, p=0.198). However, significant differences between the combined tabalumab group and placebo were observed at earlier time points for ACR20, ACR50 and Disease Activity Score in 28 joints (DAS28)-C-reactive protein (CRP) reduction. Treatment-emergent adverse events (AEs) were similar with 30 mg tabalumab (65.7%), 80 mg tabalumab (76.7%) and placebo (71.4%), although certain events occurred more often with tabalumab than placebo (eg, infection, anaemia and gastrointestinal events). Serious AEs occurred in two (6.7%) patients receiving 80 mg tabalumab and three (8.6%) receiving placebo, with one serious infection in the placebo group. Initial increases in total and mature B cells were followed by progressive decreases, despite declines in serum tabalumab. Conclusions At week 16, the primary end point was not achieved, but an indication of efficacy was observed at earlier time points. Safety findings for tabalumab were consistent with other biological RA therapies. Clinical trial registration number NCT00689728.

The safety and tolerance of xanomeline tartrate in patients with Alzheimer's disease

Xanomeline tartrate (active ingredient xanomeline) is a muscarinic agonist that has demonstrated specificity for the M1 receptor in preclinical studies and has been well tolerated at dosages up to 50 mg three times a day in healthy elderly subjects. To define the maximum tolerated dose (MTD) of xanomeline tartrate in patients with Alzheimers disease, 48 patients (20 men, 28 women) with probable Alzheimers disease were enrolled in a double‐blind, placebo‐controlled inpatient study to determine the safety and tolerability of 8 fixed dosages of xanomeline tartrate (25, 35, 50, 60, 75, 90, 100, and 115 mg, all three times a day) given for 7 days. For each dosage the treatment panel consisted of six patients (four taking xanomeline tartrate and two taking placebo). With the discontinuation of two patients because of severe intolerable adverse events, a minimum intolerated dose was reached at 115 mg three times a day, and 100 mg three times a day was defined as the MTD. This MTD in patients was two‐fold greater than the MTD previously determined in healthy elderly volunteers.

A phase 2 dose-ranging study of subcutaneous tabalumab for the treatment of patients with active rheumatoid arthritis and an inadequate response to methotrexate

Objectives To assess the dose-response relationship, efficacy and safety of tabalumab, a human monoclonal antibody that neutralises membrane-bound and soluble B-cell activating factor (BAFF), in patients with rheumatoid arthritis (RA) with inadequate response to methotrexate (MTX). Methods In this phase 2, 24-week, double-blind, placebo-controlled, dose-ranging study, patients with RA (N=158) on stable MTX were randomised by Bayesian-adaptive method to receive 1, 3, 10, 30, 60, or 120 mg tabalumab or placebo subcutaneously every 4 weeks for 24 weeks. The primary objective was to test for a significant dose-response relationship using a statistical model of the proportion of patients having ≥50% improvement in American College of Rheumatology (ACR) criteria (ACR50) at week 24 (prespecified α=0.10). Results At week 24, a significant dose-response relationship was observed using ACR50 (p=0.059) and ACR20 (p=0.044) response rates. Using model-estimated data, only 120 mg had significantly higher ACR50 and ACR20 response rates versus placebo (p<0.05). Observed response rates were significantly higher for 120 mg versus placebo as measured by ACR50 at weeks 12 (p=0.039) and 20 (p=0.018), but not week 24, and by ACR20 at weeks 12 (p=0.011) and 24 (p=0.039). Mean DAS28 C-reactive protein improved with 120 mg at week 24 (p=0.048). Frequency of TEAEs was similar across groups (range 50–69%, p=0.884). Ten (8.2%) tabalumab and 5 (13.9%) placebo patients reported a serious adverse event (SAE). Infections occurred more frequently in patients exposed to tabalumab (30.3% vs 19.4%). Serious infections were reported in 3 (2.5%) tabalumab-treated patients only. Conclusions A dose-response relationship was detected with monthly subcutaneous tabalumab. A significant effect was detected with the 120 mg dose with no unexpected safety signals. Clinical Trial # NCT00785928.

Population exposure–response model to support dosing evaluation of ixekizumab in patients with chronic plaque psoriasis

Ixekizumab (LY2439821), a humanized immunoglobulin G subclass 4 (IgG4) monoclonal antibody that selectively binds and neutralizes interleukin (IL) 17A has demonstrated efficacy in the treatment of psoriasis. A population pharmacokinetics–pharmacodynamics model was developed using NONMEM 7.2 to describe the temporal relationship between ixekizumab concentrations and absolute Psoriasis Area and Severity Index (PASI) scores from a phase 2 dose‐finding study in chronic plaque psoriasis. The objective was to inform dose‐selection for further development. The primary endpoint, PASI 75 (75% or greater improvement from baseline PASI score) was then derived from each individuals absolute PASI score. The population pharmacokinetics of ixekizumab was characterized by a two‐compartment model, while the exposure–response relationship was characterized using an indirect response model that described the pharmacological effects of ixekizumab and placebo in the form of inhibition of the formation of psoriatic skin lesions. PASI 75 responder status at the Week 12 primary endpoint was found to be a significant covariate on the concentration producing half maximal effect (EC50). While the results suggested patient may have different levels of sensitivity to ixekizumab, it is possible that nonresponder patients assigned to lower doses of ixekizumab may potentially become responders to ixekizumab if given doses that yield adequate exposures.