We have compared the BE evaluations in Japan and the USA for the generic mometasone furoate nasal suspension spray using data available on the package inserts, scientific articles published, and product specific guidance [1, 2, 8]. We have summarized the data package of PK (Table 2) and clinical endpoint studies (Table 3).
Table 2
Comparison of pharmacokinetic studies with mometasone furoate nasal suspension spray between Japan and the USA
JAPAN
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USA
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Purpose: Safety evaluation
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Purpose: Equivalent systemic exposure
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Design
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Criterion
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Design
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Criterion
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Single dose
Dose: 200 µg once daily, administered as two sprays in each nostril
Subjects: Intended patient population
|
Cmax
Equivalent with, less than the exposure of the reference product or below the permissible level
|
Single dose, two-way crossover,
fasting
Dose: 200 µg once daily, administered as two sprays in each nostril
Subjects: Normal healthy adult males and nonpregnant females
|
AUC and Cmax
90% CI within 80.00–125.00%
|
AUC: Area under the curve; CI: Confidence interval |
Table 3
Comparison of clinical endpoint studies with mometasone furoate nasal suspension spray in Japan and the USA
JAPAN
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USA
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Design: Randomized, evaluator-blinded, three-arm, placebo-controlled, parallel group
Subjects: Allergic rhinitis patients
Dose: 200 µg once daily, administered as two sprays into each nostril once daily
Primary endpoint: Change from baseline in TNSS at two weeks
Criterion: 95% CI for treatment differences within ±1.13
|
Design: Randomized, double-blind, three-arm, placebo-controlled, parallel group
Subjects: Allergic rhinitis patients
Dose: 200 µg once daily, administered as two sprays into each nostril once daily
Primary endpoint: Change from the baseline mean rTNSS to the treatment mean rTNSS
Criterion: 90% CI within 80.00–125.00%
|
TNSS: Total nasal symptom score; CI: Confidence interval; rTNSS: reflective TNSS |
Baseline mean rTNSS is the mean of the final seven scores from the placebo run-in period. The final 7 scores from the placebo run-in period consist of the AM and PM scores on Days −3, –2, and –1 and the AM score (prior to drug dosing) on Day 1 of the 14-day randomized treatment period. |
Treatment mean rTNSS is the average of 27 scores from the randomized treatment period which consist of the PM score on Day 1 and the AM and PM scores on Days 2 to 14. |
Table 2 shows the comparison of PK study, and the study purposes are slightly different between Japan and the USA. Japan aims at safety evaluation, and the USA aims at equivalent assessment of systemic exposure. The study designs are also different: Japan evaluates allergic rhinitis patients on day 1 of a multiple dose study, while the USA conducts a single dose two-way crossover study with healthy volunteers under fasting conditions. Japan evaluates the plasma drug concentration at 1 hour after the first administration, while the USA evaluates the area under the curve and Cmax of the drug. The acceptance criteria are also different: Japan requires a concentration that was equivalent with, less than the exposure, or permissible level of the reference product, while the USA requires the results to fall within 90% CI of 80.00–125.00% for the ratios of the generic and innovator products.
In the clinical endpoint studies, the study design, subject, and dosages are the same in the studies from Japan and the USA (Table 3). However, the primary endpoints, 90 or 95% CIs, and therapeutic equivalence criteria are completely different. Japan uses the same primary endpoint as the endpoint for phase III trials for innovator products, while the USA scores the symptoms observed twice daily (AM and PM, 12 hours apart at the same times daily) throughout the 7-day placebo run-in period and the 14-day randomized treatment period. For this study, the scoring is done immediately prior to dosing (and 12 hours after the AM dose for once-daily dosing) to reflect the previous 12 hours (reflective scores). Japan generally adopts 95% CI to evaluate the therapeutic equivalence based on the index of clinical effects in the Q&A 2 section of ICH E9 [9]. On the other hand, the USA accepts the same criterion of 90% CI within 80.00–125.00% for oral solid dosage forms. Japan adopts the half of the change from baseline in TNSS after two weeks based on the data of primary endpoint of phase III study between innovator product and placebo. This concept is mentioned in a domestic article which explain the ICH E10 [10], and in a concept paper from the EU that summarizes the margin of equivalence or noninferiority in comparative clinical trials [11]. Generally, Japan does not require a placebo-arm for BE evaluations. However, in this case, Japan also requires a placebo-arm because the test product has different pharmaceutical properties from the innovator product. It may be advised that a placebo-arm is added to clinical endpoint studies to establish a more sensitive and robust endpoint study in which the test and reference products can be accepted as statistically superior to the placebo.