MRI outcomes with cladribine tablets for multiple sclerosis in the CLARITY study.

We herein provide a comprehensive assessment of magnetic resonance imaging (MRI) outcomes from CLARITY, a 96-week, double-blind study demonstrating significant clinical and MRI improvements in patients with relapsing-remitting multiple sclerosis (RRMS) treated with cladribine tablets. Patients with RRMS were randomized 1:1:1 to annual short-course therapy with cladribine tablets cumulative dose 3.5 or 5.25 mg/kg or placebo. MRI endpoints included mean number of T1 gadolinium-enhancing (Gd+), active T2 and combined unique (CU) lesions/patient/scan. MRI-measured disease activity was significantly reduced in both cladribine tablets groups versus placebo. The proportion of patients with no active lesions at study end was: T1 Gd+ lesions: 86.8 and 91.0 versus 48.3 % (p < 0.001); active T2 lesions: 61.7 and 62.5 versus 28.4 % (p < 0.001); CU lesions: 59.6 and 60.7 versus 26.1 % (p < 0.001). Clinically meaningful and significant reductions in active lesion counts and increases in proportions of active lesion-free patients were achieved consistently in cladribine tablet groups when data were stratified by baseline disease characteristics. For example, the percentage of patients who remained lesion-free over the study was significantly greater in cladribine tablet groups than in the placebo group for all lesion types regardless of relapse category at baseline (p < 0.001 for all analyses of patients with ≤1 or 2 relapses; p ≤ 0.022 for analyses of patients with ≥3 relapses). MRI-measured disease activity was greatly reduced by both doses of cladribine tablets, with consistent effect across clinically relevant patient populations. These findings add to our scientific understanding of the neurological impact of this therapeutic modality in patients with RRMS.

Cladribine tablets for relapsing-remitting multiple sclerosis: Efficacy across patient subgroups from the phase III CLARITY study.

BACKGROUND: In the phase III CLARITY study, treatment with cladribine tablets at cumulative doses of 3.5 or 5.25mg/kg over 96 weeks led to significant reductions in annualized relapse rates (ARR) versus placebo in patients with relapsing-remitting multiple sclerosis. Further post hoc analyses of CLARITY study data were conducted to determine the efficacy of cladribine tablets across patient subgroups stratified by baseline characteristics. METHODS: Relapse rates over the 96-week CLARITY study were analyzed in cohorts stratified by demographics; disease duration; treatment history and disease activity at baseline. RESULTS: In the intent-to-treat population (n=437, 433 and 456 in the placebo, cladribine 3.5 and 5.25mg/kg groups, respectively), treatment with cladribine tablets 3.5 and 5.25mg/kg led to consistent improvements in ARR versus placebo in patients stratified by gender; age (≤40/>40 years); disease duration (<3/3-10/>10 years); prior disease-modifying drug treatment (treated/naïve); relapses in the prior year (≤1/2/≥3); Expanded Disability Status Scale score (<3.5/≥3.5); T1 gadolinium-enhancing lesions (presence, absence); and T2 lesion volume (≤median/>median) at baseline (all P≤0.05 for reduction in the relative risk of relapse [cladribine tablets versus placebo]). Significant effects were also observed in patients who had only one relapse in the year prior to study entry (n=306, 303 and 323 in the placebo, cladribine 3.5 and 5.25mg/kg groups, respectively) and who were further stratified according to other measures of disease activity at baseline. CONCLUSIONS: Treatment with cladribine tablets provides consistent reductions in ARR compared with placebo across the spectrum of baseline demographics and disease characteristics represented in the CLARITY study.

Sustained disease-activity-free status in patients with relapsing-remitting multiple sclerosis treated with cladribine tablets in the CLARITY study: a post-hoc and subgroup analysis.

BACKGROUND: On the basis of various clinical and MRI measurements, the phase 3 Cladribine Tablets Treating Multiple Sclerosis Orally (CLARITY) study in patients with relapsing-remitting multiple sclerosis (RRMS) showed that short-course oral treatment with cladribine at cumulative doses of 3·5 and 5·25 mg/kg over 96 weeks was more effective than placebo. Achieving sustained freedom from disease activity is becoming a viable treatment goal in RRMS; we therefore aimed to assess the effects of cladribine on this composite outcome measure by doing a post-hoc analysis of data from the CLARITY study. METHODS: Freedom from disease activity is composed of three components that are commonly used individually as endpoints in clinical trials; it is defined as the patient having no relapse, no 3-month sustained change in expanded disability status scale (EDSS) score, and no new MRI lesions (no T1 gadolinium-enhancing or active T2 lesions) over a specified period. We assessed the effect of two doses of cladribine tablets versus placebo on the proportion of patients who were free from disease activity based on the individual components, all pair-wise combinations, and the composite of the three components (freedom from disease activity). Freedom from disease activity was analysed at 24, 48, and 96 weeks, and in subgroups of patients stratified according to baseline demographic and disease characteristics (age, disease duration, previous treatment with disease-modifying therapy, T1 gadolinium-enhancing lesion number, T2 lesion volume, EDSS score, number of previous relapses, and highly active disease). FINDINGS: Of the 1326 patients randomly assigned to treatment in the CLARITY study, 1192 were assessable for freedom from disease activity at 96 weeks. Over 24 weeks, 266 (67%) of 395 patients in the cladribine 3·5 mg/kg group and 283 (70%) of 406 in the cladribine 5·25 mg/kg group were free from disease activity, versus 145 (39%) of 373 in the placebo group (odds ratio [OR] 3·31, 95% CI 2·46-4·46 for the 3·5 mg/kg group; and 3·68, 2·73-4·97 for the 5·25 mg/kg group; both p<0·0001). Over 48 weeks, 208 (54%) of 384 patients in the cladribine 3·5 mg/kg group and 222 (56%) of 396 patients in the cladribine 5·25 mg/kg group were free from disease activity, versus 86 (24%) of 360 patients in the placebo group (OR 3·80, 2·77-5·22 for the 3·5 mg/kg group; 4·13, 3·02-5·66 for the 5·25 mg/kg group; both p<0·0001). Over 96 weeks, 178 (44%) of 402 patients in the cladribine 3·5 mg/kg group and 189 (46%) of 411 patients in the cladribine 5·25 mg/kg group were free from disease activity, versus 60 (16%) of 379 patients in the placebo group (OR 4·28, 3·05-6·02 for the 3·5 mg/kg group; 4·62, 3·29-6·48 for the 5·25 mg/kg group; both p<0·0001). The effects of cladribine tablets on freedom from disease activity were significant across all patient subgroups. INTERPRETATION: Treatment with cladribine tablets significantly increased the proportion of patients with sustained freedom from disease activity over 96 weeks compared with placebo. Sustained freedom from disease activity could become an important measure of therapeutic response in RRMS. FUNDING: Merck Serono SA-Geneva, Switzerland; an affiliate of Merck, Darmstadt, Germany.

A placebo-controlled trial of oral cladribine for relapsing multiple sclerosis.

BACKGROUND: Cladribine provides immunomodulation through selective targeting of lymphocyte subtypes. We report the results of a 96-week phase 3 trial of a short-course oral tablet therapy in patients with relapsing-remitting multiple sclerosis. METHODS: We randomly assigned 1326 patients in an approximate 1:1:1 ratio to receive one of two cumulative doses of cladribine tablets (either 3.5 mg or 5.25 mg per kilogram of body weight) or matching placebo, given in two or four short courses for the first 48 weeks, then in two short courses starting at week 48 and week 52 (for a total of 8 to 20 days per year). The primary end point was the rate of relapse at 96 weeks. RESULTS: Among patients who received cladribine tablets (either 3.5 mg or 5.25 mg per kilogram), there was a significantly lower annualized rate of relapse than in the placebo group (0.14 and 0.15, respectively, vs. 0.33; P<0.001 for both comparisons), a higher relapse-free rate (79.7% and 78.9%, respectively, vs. 60.9%; P<0.001 for both comparisons), a lower risk of 3-month sustained progression of disability (hazard ratio for the 3.5-mg group, 0.67; 95% confidence interval [CI], 0.48 to 0.93; P=0.02; and hazard ratio for the 5.25-mg group, 0.69; 95% CI, 0.49 to 0.96; P=0.03), and significant reductions in the brain lesion count on magnetic resonance imaging (MRI) (P<0.001 for all comparisons). Adverse events that were more frequent in the cladribine groups included lymphocytopenia (21.6% in the 3.5-mg group and 31.5% in the 5.25-mg group, vs. 1.8%) and herpes zoster (8 patients and 12 patients, respectively, vs. no patients). CONCLUSIONS: Treatment with cladribine tablets significantly reduced relapse rates, the risk of disability progression, and MRI measures of disease activity at 96 weeks. The benefits need to be weighed against the risks. (ClinicalTrials.gov number, NCT00213135.)

Issues and trends in pediatric growth hormone therapy--an update from the GHMonitor observational registry.

The GHMonitor observational registry collates data on pediatric subjects receiving Saizen (recombinant human growth hormone (GH)) therapy. From January 2003 through August 2006, 1335 subjects were enrolled in the registry, approximately two-thirds of whom are male. The most common diagnosis in the registry is idiopathic growth hormone deficiency (58%). Most subjects in GHMonitor are receiving Saizen doses using a needle-free delivery device, the cool.click (73%). Mean height standard deviation scores show an improvement from -2.1 at screening to -1.1 following 3 years of Saizen therapy. To date, adverse events have been reported in 4% of subjects. Three serious adverse events were identified to be related to Saizen by the primary investigator: cellulitis at the injection site, behavioral problems/suicidal ideation, and enlargement of a craniopharyngioma. This article provides an update on data from the registry and briefly discusses topical and controversial issues in the treatment of pediatric patients requiring GH therapy.

Mixed models for assessing correlation in the presence of replication.

The need to assess correlation in settings where multiple measurements are available on each of the variables of interest often arises in environmental science. However, this topic is not covered in introductory statistics texts. Although several ad hoc approaches can be used, they can easily lead to invalid conclusions and to a difficult choice of an appropriate measure of the correlation. Lam et al. approached this problem by using maximum likelihood estimation in cases where the replicate measurements are linked over time, but the method requires specialized software. We reanalyze the data of Lam et al. using PROC MIXED in SAS and show how to obtain the parameter estimates of interest with just a few lines of code. We then extend Lam et al.'s method to settings where the replicate measurements are not linked. Analysis of the unlinked case is illustrated with data from a study designed to assess correlations between indoor and outdoor measurements of benzene concentration in the air.