Search

Designing a study for independent confirmation of a treatment effect is sometimes not practical due to required large sample size. Post hoc pooling of studies including those for learning purposes is subject to selection bias and therefore generally not suitable for confirmation of a treatment effect. We propose a Bayesian approach which calibrates the role of prior information from historical studies for learning and confirming purposes. The amount of prior information to be combined with current study data for the purpose of hypothesis confirmation depends on the overall strength of prior information for hypothesis generation. The method is illustrated in the analysis of mortality data for the pirfenidone NDA. The Bayesian analysis provides a formal method to calibrate the role of information from historical evidence in the overall interpretation of results from both historical and concurrent clinical studies. The increased efficiency of using all available data is especially important in drug development for rare diseases with serious consequences, where limited patient source prohibits large trials, and unmet medical needs demand rapid access to treatment options.

Context Serum insulin-like growth factor 1 (IGF-1) levels are relatively constant in somatropin-treated children with growth hormone deficiency (GHD), and guide dose adjustments for clinical efficacy and long-term safety. IGF-1 levels following treatment with long-acting growth hormones such as lonapegsomatropin (lonapegsomatropin-tcgd, TransCon hGH), a once-weekly somatropin prodrug, exhibit a characteristic profile over the dosing interval. Objective This study aimed to develop a method to predict average IGF-1 in lonapegsomatropin-treated GHD children to interpret IGF-1 data based on a single sample obtained any time at steady state. Methods A population nonlinear mixed-effect pharmacodynamic model for IGF-1 was developed based on 2 randomized, open-label trials of TransCon hGh in GHD children and used to develop a linear mixed model with Taylor series to fit simulated IGF-1 profiles of lonapegsomatropin-treated children. A total of 49 896 IGF-1 sample data simulated from 105 lonapegsomatropin-treated GHD children were utilized for the final prediction model. The dosage range of TransCon hGh was 0.14 to 0.30 hGH mg/kg/week, and weekly average IGF-1 was calculated using IGF-1 profiles simulated from the nonlinear pharmacodynamic model. Predicted average IGF-1 was obtained by linear mixed model with Taylor series. Results The nonlinear mixed-effect model provided satisfactory model fit. The linear mixed model with Taylor series fit simulated IGF-1 data well, with a relatively straightforward prediction formula. IGF-1 values sampled at ~4.5 days post-dose coincided with weekly average IGF-1 at steady state. Conclusion A formula to predict average IGF-1 from a single sample of IGF-1 at steady state was established to aid clinicians in interpreting IGF-1 levels in GHD children administered lonapegsomatropin.

Background Hypoparathyroidism (HP) is a rare endocrine disorder characterized by absent or inappropriately low levels of circulating parathyroid hormone with associated significant physical and cognitive symptoms. This study evaluated the psychometric properties of the Hypoparathyroidism Patient Experience Scales (HPES), which were developed as disease-specific, patient-reported outcome (PRO) measures to assess the symptoms and impacts associated with HP in adults. Methods Data from a non-interventional, observational study (N = 300) and a Phase 2 clinical trial (N = 59) were used in the psychometric evaluation. Observational and trial assessments included: an online validation battery (baseline or screening) and retest (approximately 2 weeks after baseline or screening). In the trial, the primary efficacy endpoint was assessed at week 4 through re-administration of the HPES and validation battery subset. The observational study’s larger sample size allowed for evaluation of the HPES descriptive properties, scoring algorithm, test-retest reliability, and construct validity. The trial data examined responsiveness, meaningful within-patient change estimates, and treatment impact on HPES scores. Results Demographic and self-reported medical characteristics results were similar across the 2 studies. Factor analysis confirmed domains in the HPES-Symptom (n = 2) and HPES-Impact (n = 4). For both measures, total and domain scores demonstrated acceptable reliability and validity for both the observational and trial samples. Internal consistency evidence was strong. Test-retest reliability estimates generally approached the recommended 0.70 threshold. The construct validity correlations with other PRO measures were mainly as hypothesized, thus supporting the HPES scores and constructs. Mean scores for both measures also differed as anticipated and significantly across known-groups, thus providing evidence for the scores discriminating between meaningful groups. Trial results supported both HPES total and domain scores’ ability to detect change. The difference in mean total and domain scores for both measures demonstrated statistically significant improvements for TransCon PTH compared to placebo treated subjects despite the small sample and a short 4-week duration on fixed, non-optimized doses. Conclusions The HPES were found to be conceptually sound with adequate evidence supporting their reliability and validity. Incorporation of the HPES into clinical and research settings will help to further elucidate and assess the patient experience of living with HP and identify treatment differences.

Objective This double‐blind, randomized, placebo‐controlled Phase 2 study (NCT01462292) assessed the 24‐week efficacy, safety, tolerability, and pharmacokinetics of two different subcutaneous drisapersen doses, and the 24‐week off‐dose persistent effect, in ambulant Duchenne muscular dystrophy (DMD) patients. Methods Male DMD patients (≥5 years; time to rise from floor ≤15 s) were randomized to drisapersen 3 mg/kg/week, 6 mg/kg/week or placebo. The primary efficacy endpoint was change from baseline in 6‐minute walking distance (6MWD) at week 24. Secondary endpoints included changes in timed function tests, muscle strength, and pulmonary function tests. Results Fifty‐one patients were randomized to placebo (N = 16), drisapersen 3 mg/kg/week (N = 17) or 6 mg/kg/week (N = 18). All but 2 patients had baseline rise from floor time

This 48-week, randomized, placebo-controlled phase 3 study (DMD114044; NCT01254019) evaluated efficacy and safety of subcutaneous drisapersen 6 mg/kg/week in 186 ambulant boys aged >=5 years, with Duchenne muscular dystrophy (DMD) resulting from an exon 51 skipping amenable mutation. Drisapersen was generally well tolerated, with injection-site reactions and renal events as most commonly reported adverse events. A nonsignificant treatment difference (P = 0.415) in the change from baseline in six-minute walk distance (6MWD; primary efficacy endpoint) of 10.3 meters in favor of drisapersen was observed at week 48. Key secondary efficacy endpoints (North Star Ambulatory Assessment, 4-stair climb ascent velocity, and 10-meter walk/run velocity) gave consistent findings. Lack of statistical significance was thought to be largely due to greater data variability and subgroup heterogeneity. The increased standard deviation alone, due to less stringent inclusion/exclusion criteria, reduced the statistical power from pre-specified 90% to actual 53%. Therefore, a post-hoc analysis was performed in 80 subjects with a baseline 6MWD 300-400 meters and ability to rise from floor. A statistically significant improvement in 6MWD of 35.4 meters (P = 0.039) in favor of drisapersen was observed in this subpopulation. Results suggest that drisapersen could have benefit in a less impaired population of DMD subjects.

OBJECTIVE—Insulin glargine (LANTUS) is a once-daily basal insulin analog with a smooth 24-h time-action profile that provides effective glycemic control with reduced hypoglycemia risk (particularly nocturnal) compared with NPH insulin in patients with type 2 diabetes. A recent “treat-to-target” study has shown that more patients on insulin glargine reached HbA1c levels ≤7.0% without confirmed nocturnal hypoglycemia compared with NPH insulin. We further assessed the risk for hypoglycemia in a meta-analysis of controlled trials of a similar design for insulin glargine versus once- or twice-daily NPH insulin in adults with type 2 diabetes. RESEARCH DESIGN AND METHODS—All studies were 24–28 weeks long, except one 52-week study, for which interim 20-week data were used. RESULTS—Patient demographics were similar between the insulin glargine (n = 1,142) and NPH insulin (n = 1,162) groups. The proportion of patients achieving target HbA1c (≤7.0%) was similar between insulin glargine–and NPH insulin–treated patients (30.8 and 32.1%, respectively). There was a consistent significant reduction of hypoglycemia risk associated with insulin glargine, compared with NPH insulin, in terms of overall symptomatic (11%; P = 0.0006) and nocturnal (26%; P < 0.0001) hypoglycemia. Most notably, the risk of severe hypoglycemia and severe nocturnal hypoglycemia were reduced with insulin glargine by 46% (P = 0.0442) and 59% (P = 0.0231), respectively. CONCLUSIONS—These results confirmed that insulin glargine given once daily reduces the risk of hypoglycemia compared with NPH insulin, which can facilitate more aggressive insulin treatment to a HbA1c target of ≤7.0% in patients with type 2 diabetes.

In the pharmaceutical industry it is often important to ensure fast patient enrollment. A common practice to speed up patient enrollment is to use more clinical centers. One of the concerns regarding this practice is that increasing the total number of centers to a certain degree may decrease the statistical efficiency of treatment comparisons. This is mainly because a study with too many clinical centers usually includes quite a few small centers and very often they do not have enough patients to represent all treatment groups. These small centers often carry little information on treatment differences. This paper utilizes a statistical model to quantify the relationship between statistical efficiency and the number of centers under typical clinical trial settings. Results in this paper provide useful statistical knowledge in choosing the number of clinical centers when planning multicenter studies.

Fospropofol is a sedative hypnotic with a slower onset and longer duration of action. Fospropofol has demonstrated successful dose-dependent sedation at 6.5 mg/kg. This study evaluated the efficacy and safety of a lower weight-adjusted dose compared with the approved dose (4.875 or 6.5 mg/kg depending on patient subgroup) in high-risk elderly patients undergoing colonoscopy. In this study, 153 subjects were classified into 3 subgroups based on the following: age, weight, and American Society of Anesthesiologist (ASA) physical status criteria. The patients were randomized to the approved dose or weight-adjusted dose of fospropofol in a 1:1 ratio. Subgroup 1 (n = 50) consisted of patients weighing

Insulin glargine (LANTUS) is a once-daily basal insulin analog with a smooth 24-h time-action profile that provides effective glycemic control with reduced hypoglycemia risk (particularly nocturnal) compared with NPH insulin in patients with type 2 diabetes. A recent "treat-to-target" study has shown that more patients on insulin glargine reached HbA(1c) levelsor =7.0% without confirmed nocturnal hypoglycemia compared with NPH insulin. We further assessed the risk for hypoglycemia in a meta-analysis of controlled trials of a similar design for insulin glargine versus once- or twice-daily NPH insulin in adults with type 2 diabetes.All studies were 24-28 weeks long, except one 52-week study, for which interim 20-week data were used.Patient demographics were similar between the insulin glargine (n = 1,142) and NPH insulin (n = 1,162) groups. The proportion of patients achieving target HbA(1c) (or =7.0%) was similar between insulin glargine-and NPH insulin-treated patients (30.8 and 32.1%, respectively). There was a consistent significant reduction of hypoglycemia risk associated with insulin glargine, compared with NPH insulin, in terms of overall symptomatic (11%; P = 0.0006) and nocturnal (26%; P0.0001) hypoglycemia. Most notably, the risk of severe hypoglycemia and severe nocturnal hypoglycemia were reduced with insulin glargine by 46% (P = 0.0442) and 59% (P = 0.0231), respectively.These results confirmed that insulin glargine given once daily reduces the risk of hypoglycemia compared with NPH insulin, which can facilitate more aggressive insulin treatment to a HbA(1c) target ofor =7.0% in patients with type 2 diabetes.

When analysing data from a controlled multi-centre study, an important issue is how to weight each centre to assess the overall treatment effect. The unweighted analysis, which weights all centres equally, was recommended by many statisticians and the U.S. Food and Drug Administration, and has been routinely utilized as the primary statistical method for many phase III clinical studies in the pharmaceutical industry. The weighted analysis, which weights centres relative to the number of patients in them, was considered not meaningful in the presence of treatment-by-centre interaction. This paper demonstrates why we should hesitate to use the unweighted analysis as the primary statistical method of a study from a statistical power perspective. It also shows that the weighted analysis is meaningful, even in the presence of treatment-by-centre interaction, and that it is generally the preferred approach.