A simple numerical approach towards improving the two one-sided test for average bioequivalence

Performance evaluation and user experience of BT-50 transportation unit with automated and scheduled quality control measurements

OBJECTIVES

Even in the current era of hematology analyzer automation and peripheral equipment, quality control sample measurement remains a manual task, leading to variability in quality control data and increased workload. In this study, we evaluated the performance of quality control measurement using the BT-50 Transportation Unit (BT-50, Sysmex, Kobe, Japan), equipped with a scheduled automatic quality control function, to ensure measurement accuracy and streamline the workflow of hematology testing.

METHODS

We evaluated the automatic measurement performance of quality control samples using the BT-50 for six representative blood test parameters: WBC (white blood cell), RBC (red blood cell), HGB (hemoglobin), HCT (hematocrit), PLT (platelet), and RET% (reticulocyte percent). We evaluated the equivalence and compared measurement accuracy between the BT-50 and the manual method. We then compared the variability to other laboratories and confirmed the stability of quality control samples. We also evaluated changes in workflow and staff resources before and after the introduction of the BT-50.

RESULTS

The quality control measurement results for the BT-50 and the manual method were found to be equivalent for all six parameters. The variability measured by the BT-50 was lower for some parameters compared to the manual method. Furthermore, the workflow was streamlined by reducing manual processes, resulting in increased efficiency.

CONCLUSIONS

We confirmed the performance of quality control measurements using the schedule function of the BT-50. Introducing the BT-50 reduced the operator's workload, improved operational efficiency, and promoted the standardization of quality control measurements.

Finite sample corrections for average equivalence testing

Average (bio)equivalence tests are used to assess if a parameter, like the mean difference in treatment response between two conditions for example, lies within a given equivalence interval, hence allowing to conclude that the conditions have "equivalent" means. The two one-sided tests (TOST) procedure, consisting in testing whether the target parameter is respectively significantly greater and lower than some pre-defined lower and upper equivalence limits, is typically used in this context, usually by checking whether the confidence interval for the target parameter lies within these limits. This intuitive and visual procedure is however known to be conservative, especially in the case of highly variable drugs, where it shows a rapid power loss, often reaching zero, hence making it impossible to conclude for equivalence when it is actually true. Here, we propose a finite sample correction of the TOST procedure, theα $$ \alpha $$ -TOST, which consists in a correction of the significance level of the TOST allowing to guarantee a test size (or type-I error rate) ofα $$ \alpha $$ . This new procedure essentially corresponds to a finite sample and variability correction of the TOST procedure. We show that this procedure is uniformly more powerful than the TOST, easy to compute, and that its operating characteristics outperform the ones of its competitors. A case study about econazole nitrate deposition in porcine skin is used to illustrate the benefits of the proposed method and its advantages compared to other available procedures.

Evaluation of the single-dose pharmacokinetics of bilastine in subjects with various degrees of renal insufficiency

BACKGROUND

Bilastine is a novel second-generation H1 antihistamine, which has not shown sedative or cardiotoxic effects in clinical trials and in post-marketing experience so far, developed for the symptomatic treatment of allergic rhinoconjunctivitis and urticaria. It has recently been granted marketing authorization for these therapeutic indications in adults and adolescents at a once-daily oral dose of 20 mg in several European countries.

OBJECTIVE

This study was conducted to determine the pharmacokinetics of bilastine at a single oral dose of 20 mg in renally impaired subjects. The need for a dose adjustment in patients with renal insufficiency was assessed by comparing the exposure to bilastine in these subjects with the estimated exposure of a dose corresponding to the safety margin.

METHODS

The study was an open-label, single-dose, parallel-group study of the pharmacokinetics and safety of a single dose of bilastine. The study was conducted as an in-patient setting at a clinical pharmacology facility. A total of 24 male or female subjects aged 18-80 years were to be enrolled in four groups of six subjects each. The groups were as follows: (1) healthy [glomerular filtration rate (GFR) >80 mL/min/1.73 m(2)]; (2) mild renal insufficiency (GFR 50-80 mL/min/1.73 m(2)); (3) moderate renal insufficiency (GFR 30-50 mL/min/1.73 m(2)); and (4) severe renal insufficiency (GFR ≤30 mL/min/1.73 m(2)). A single 20 mg bilastine tablet was administered in a fasted state. Blood and urine samples were collected from pre-dose up to 72 h post-dose for bilastine pharmacokinetic analysis. Pharmacokinetic results were summarized using appropriate descriptive statistics.

RESULTS

There was a clear trend of increasing area under the plasma concentration-time curve (AUC) and maximum plasma concentration (C(max)) through the groups 1-4. The mean AUC from time zero to infinity (AUC(∞)) ranged from 737.4 to 1708.5 ng·h/mL in healthy subjects and severely impaired subjects, respectively. No significant differences among groups in median time to reach Cmax (tmax) or in the mean terminal disposition rate constants for bilastine were found. Renal and plasma clearance paralleled GFR. In all groups of renally impaired subjects the corresponding 90 % confidence interval of both AUC(∞) and AUC from time zero to time of last measurable plasma concentration (AUC(last)) were not within the 0.8-1.25 interval, indicating that bioequivalence between groups could not be demonstrated. The majority of bilastine was excreted within the first 12 h, and elimination was essentially complete by 72 h.

CONCLUSION

An oral dose of bilastine (20 mg) was well-tolerated in renal insufficiency, despite the increase in exposure. The oral plasma clearance to renal clearance ratio [(CL(P)/F)/CL(R)] was approximately equal in the different groups, suggesting that renal excretion was the main elimination route for bilastine, and no alternative elimination routes were used even in severe renal insufficiency. Although exposure to bilastine was higher in renally impaired subjects, it remained well within the safety margins, thus allowing the conclusion that a 20-mg daily dose can be safely administered to subjects with different degrees of renal insufficiency without the need for dose adjustments.

Bioequivalence tests based on individual estimates using non-compartmental or model-based analyses: evaluation of estimates of sample means and type I error for different designs

PURPOSE

The main objective of this work is to compare the standard bioequivalence tests based on individual estimates of the area under the curve and the maximal concentration obtained by non-compartmental analysis (NCA) to those based on individual empirical Bayes estimates (EBE) obtained by nonlinear mixed effects models.

METHODS

We evaluate by simulation the precision of sample means estimates and the type I error of bioequivalence tests for both approaches. Crossover trials are simulated under H ( 0 ) using different numbers of subjects (N) and of samples per subject (n). We simulate concentration-time profiles with different variability settings for the between-subject and within-subject variabilities and for the variance of the residual error.

RESULTS

Bioequivalence tests based on NCA show satisfactory properties with low and high variabilities, except when the residual error is high, which leads to a very poor type I error, or when n is small, which leads to biased estimates. Tests based on EBE lead to an increase of the type I error, when the shrinkage is above 20%, which occurs notably when NCA fails.

CONCLUSIONS

For small n or data with high residual error, tests based on a global data analysis should be considered instead of those based on individual estimates.