Zuranolone in Major Depressive Disorder: Results From MOUNTAIN-A Phase 3, Multicenter, Double-Blind, Randomized, Placebo-Controlled Trial.

Objective: To evaluate the efficacy and safety of zuranolone, an investigational neuroactive steroid and GABAA receptor positive allosteric modulator, in major depressive disorder (MDD).Methods: The phase 3, double-blind, randomized, placebo-controlled MOUNTAIN study enrolled adult outpatients with DSM-5-diagnosed MDD, 17-item Hamilton Depression Rating Scale total score (HDRS-17) ≥ 22, and Montgomery-Asberg Depression Rating Scale total score ≥ 32. Patients were randomized to treatment with zuranolone 20 mg, zuranolone 30 mg, or placebo for 14 days, followed by an observation period (days 15-42) and an extended follow-up (days 43-182). The primary endpoint was change from baseline (CFB) in HDRS-17 at day 15.Results: 581 patients were randomized to receive zuranolone (20 mg, n = 194; 30 mg, n = 194) or placebo (n = 193). Day 15 HDRS-17 least-squares mean (LSM) CFB was -12.5 (zuranolone 30 mg) vs -11.1 (placebo; P = .116). Improvement vs placebo was significant at days 3, 8, and 12 (all P < .05). LSM CFB (zuranolone 20 mg vs placebo) was not significant at any measured time point. Post hoc analyses of zuranolone 30 mg in patients with measurable plasma zuranolone concentration and/or severe disease (baseline HDRS-17 ≥ 24) showed significant improvement vs placebo at days 3, 8, 12, and 15 (all P < .05). Incidence of treatment-emergent adverse events was similar between zuranolone and placebo groups; the most common (≥ 5%) were fatigue, somnolence, headache, dizziness, diarrhea, sedation, and nausea.Conclusions: MOUNTAIN did not meet its primary endpoint. Significant rapid improvements in depressive symptoms were observed with zuranolone 30 mg at days 3, 8, and 12. Zuranolone was generally well tolerated in patients with MDD.Trial Registration: ClinicalTrials.gov identifier: NCT03672175.

Patient-reported health-related quality of life from a randomized, placebo-controlled phase 2 trial of zuranolone in adults with major depressive disorder.

BACKGROUND: Major depressive disorder (MDD), a disabling, potentially life-threatening condition, negatively affects health-related quality of life (HRQoL). This secondary analysis aimed to understand the impact of the neuroactive steroid zuranolone on HRQoL using the Short Form-36v2 Health Survey (SF-36v2). METHODS: Adult patients with MDD and 17-item Hamilton Rating Scale for Depression total score ≥22 were randomized 1:1 to receive zuranolone 30 mg or placebo for 2 weeks, with 4 weeks follow-up. SF-36v2 scores were assessed at Day 15 across 8 domains (Physical Functioning, Role Physical, Bodily Pain, General Health, Vitality, Social Functioning, Role Emotional, and Mental Health) and 2 summary scores (Physical and Mental Component), using a mixed-effects model for repeated measures. Correlations between SF-36v2 scores and clinician-reported efficacy endpoints were assessed using Pearson's correlation. RESULTS: Eighty-nine patients were treated with zuranolone 30 mg (n = 45) or placebo (n = 44). In zuranolone-treated patients, HRQoL improved across all SF-36v2 domains and summary scores at Day 15. Improvements exceeding established minimally important difference thresholds were observed in Bodily Pain, General Health, Vitality, Social Functioning, Role Emotional, and Mental Health scores. Improvements in General Health, Vitality, Mental Health, and Mental Component Summary were statistically significant versus placebo (p ≤ 0.025). Clinician-rated endpoints negatively correlated with SF-36v2 scores. LIMITATIONS: The small unipolar depression sample may not be representative of all US MDD patients. HRQoL measures could be impacted by factors unrelated to depression. CONCLUSIONS: Zuranolone-treated patients reported rapid and significant improvements in HRQoL versus placebo at Day 15. HRQoL improvements correlated with improvements in clinician-rated assessments. TRIAL REGISTRATION: clinicaltrials.gov:NCT03000530; https://clinicaltrials.gov/ct2/show/NCT03000530.

A phase 1 double-blind, placebo-controlled study of zuranolone (SAGE-217) in a phase advance model of insomnia in healthy adults.

OBJECTIVE: To evaluate single zuranolone (SAGE-217) 30 or 45 mg doses in a 5-h phase advance insomnia model. METHODS: In this double-blind, three-way crossover study, healthy adults received placebo (n = 41), zuranolone 30 mg (n = 44), and zuranolone 45 mg (n = 42) across three treatment periods. Sleep was assessed by polysomnography and a postsleep questionnaire. Next-day residual effects and safety/tolerability were evaluated. RESULTS: Compared with placebo, zuranolone resulted in significant improvements in median sleep efficiency (30 mg, 84.6%; 45 mg, 87.6%; placebo, 72.9%; p < 0.001 for both doses), wake after sleep onset (WASO; 30 mg, 55.0 min; 45 mg, 42.5 min; placebo, 113.0 min; p < 0.001 for both doses), duration of awakenings (30 mg, 4.2 min, p < 0.001; 45 mg, 3.7 min, p = 0.001; placebo, 7.4 min), and total sleep time (TST; 30 mg, 406.3 min; 45 mg, 420.3 min; placebo, 350.0 min; p < 0.001 for both doses). Subjective endpoints (WASO, TST, sleep latency, sleep quality) also improved relative to placebo. Zuranolone was generally well tolerated, and the most common adverse events (≥2 participants, any period) were headache and fatigue. CONCLUSION: Zuranolone improved sleep measures versus placebo in a phase advance model of insomnia in healthy adults, supporting future studies in patients with insomnia disorder.

Effect of Zuranolone vs Placebo in Postpartum Depression: A Randomized Clinical Trial.

Importance: Postpartum depression (PPD) is one of the most common medical complications during and after pregnancy, negatively affecting both mother and child. Objective: To demonstrate the efficacy and safety of zuranolone, a neuroactive steroid γ-aminobutyric acid receptor-positive allosteric modulator, in PPD. Design, Setting, and Participants: This phase 3, double-blind, randomized, outpatient, placebo-controlled clinical trial was conducted between January 2017 and December 2018 in 27 enrolling US sites. Participant were women aged 18 to 45 years, 6 months or fewer post partum, with PPD (major depressive episode beginning third trimester or ≤4 weeks postdelivery), and baseline 17-item Hamilton Rating Scale for Depression (HAMD-17) score of 26 or higher. Analysis was intention to treat and began December 2018 and ended March 2019. Interventions: Randomization 1:1 to placebo:zuranolone, 30 mg, administered orally each evening for 2 weeks. Main Outcomes and Measures: Primary end point was change from baseline in HAMD-17 score for zuranolone vs placebo at day 15. Secondary end points included changes from baseline in HAMD-17 total score at other time points, HAMD-17 response (≥50% score reduction) and remission (score ≤7) rates, Montgomery-Åsberg Depression Rating Scale score, and Hamilton Rating Scale for Anxiety score. Safety was assessed by adverse events and clinical assessments. Results: Of 153 randomized patients, the efficacy set comprised 150 patients (mean [SD] age, 28.3 [5.4] years), and 148 (98.7%) completed treatment. A total of 76 patients were randomized to placebo, and 77 were randomized to zuranolone, 30 mg. Zuranolone demonstrated significant day 15 HAMD-17 score improvements from baseline vs placebo (-17.8 vs -13.6; difference, -4.2; 95% CI, -6.9 to -1.5; P = .003). Sustained differences in HAMD-17 scores favoring zuranolone were observed from day 3 (difference, -2.7; 95% CI, -5.1 to -0.3; P = .03) through day 45 (difference, -4.1; 95% CI, -6.7 to -1.4; P = .003). Sustained differences at day 15 favoring zuranolone were observed in HAMD-17 response (odds ratio, 2.63; 95% CI, 1.34-5.16; P = .005), HAMD-17 score remission (odds ratio, 2.53; 95% CI, 1.24-5.17; P = .01), change from baseline for Montgomery-Åsberg Depression Rating Scale score (difference, -4.6; 95% CI, -8.3 to -0.8; P = .02), and Hamilton Rating Scale for Anxiety score (difference, -3.9; 95% CI, -6.7 to -1.1; P = .006). One patient per group experienced a serious adverse event (confusional state in the zuranolone group and pancreatitis in the placebo group). One patient in the zuranolone group discontinued because of an adverse event vs none for placebo. Conclusions and Relevance: In this randomized clinical trial, zuranolone improved the core symptoms of depression as measured by HAMD-17 scores in women with PPD and was generally well tolerated, supporting further development of zuranolone in the treatment of PPD. Trial Registration: ClinicalTrials.gov Identifier: NCT02978326.

SAGE-217, A Novel GABAA Receptor Positive Allosteric Modulator: Clinical Pharmacology and Tolerability in Randomized Phase I Dose-Finding Studies.

BACKGROUND: SAGE-217, a novel γ-aminobutyric acid A (GABAA) receptor positive allosteric modulator, was evaluated in phase I, double-blind, placebo-controlled, single ascending dose (SAD) and multiple ascending dose (MAD) studies to assess the safety and pharmacokinetics (PK) of SAGE-217 following administration as an oral solution. METHODS: In the SAD study, subjects were randomized 6:2 to a single dose of SAGE-217 or placebo. Doses ranged from 0.25 to 66 mg across nine cohorts. In the MAD study, subjects were randomized 9:3 and received SAGE-217 (15, 30, or 35 mg) or placebo once daily for 7 days. In both studies, PK, maximum tolerated dose (MTD; against predetermined criteria), safety, and tolerability were assessed. RESULTS: A total of 108 healthy volunteers enrolled in the studies-72 subjects in the SAD study and 36 subjects in the MAD study. SAGE-217 was orally bioavailable, with a terminal-phase half-life of 16-23 h and a tmax of approximately 1 h. The MTDs for the oral solution of SAGE-217 in the SAD and MAD studies were determined to be 55 and 30 mg daily, respectively. In both studies, SAGE-217 was generally well tolerated, and no serious adverse events (SAEs) were reported. Most AEs were mild, dose-dependent, transient, occurred around the tmax, and related to drug pharmacology. CONCLUSIONS: SAGE-217 was generally well tolerated, and its PK profile was well characterized. Based on this profile, SAGE-217 has been advanced into multiple phase II clinical programs and pivotal studies of major depressive disorder and postpartum depression.

Trial of SAGE-217 in Patients with Major Depressive Disorder.

BACKGROUND: Altered neurotransmission of γ-aminobutyric acid (GABA) has been implicated in the pathogenesis of depression. Whether SAGE-217, an oral, positive allosteric modulator of GABA type A receptors, is effective and safe for the treatment of major depressive disorder is unknown. METHODS: In this double-blind, phase 2 trial, we enrolled patients with major depression and randomly assigned them in a 1:1 ratio to receive 30 mg of SAGE-217 or placebo once daily. The primary end point was the change from baseline to day 15 in the score on the 17-item Hamilton Depression Rating Scale (HAM-D; scores range from 0 to 52, with higher scores indicating more severe depression). Secondary efficacy end points, which were assessed on days 2 through 8 and on days 15, 21, 28, 35, and 42, included changes from baseline in scores on additional depression and anxiety scales, a reduction from baseline of more than 50% in the HAM-D score, a HAM-D score of 7 or lower, and a Clinical Global Impression of Improvement score of 1 (very much improved) or 2 (much improved) (on a scale of 1 to 7, with a score of 7 indicating that symptoms are very much worse). RESULTS: A total of 89 patients underwent randomization: 45 patients were assigned to the SAGE-217 group, and 44 to the placebo group. The mean baseline HAM-D score was 25.2 in the SAGE-217 group and 25.7 in the placebo group. The least-squares mean (±SE) change in the HAM-D score from baseline to day 15 was -17.4±1.3 points in the SAGE-217 group and -10.3±1.3 points in the placebo group (least-squares mean difference in change, -7.0 points; 95% confidence interval, -10.2 to -3.9; P<0.001). The differences in secondary end points were generally in the same direction as those of the primary end point. There were no serious adverse events. The most common adverse events in the SAGE-217 group were headache, dizziness, nausea, and somnolence. CONCLUSIONS: Administration of SAGE-217 daily for 14 days resulted in a reduction in depressive symptoms at day 15. Adverse events were more common in the SAGE-217 group than in the placebo group. Further trials are needed to determine the durability and safety of SAGE-217 in major depressive disorder and to compare SAGE-217 with available treatments. (Funded by Sage Therapeutics; ClinicalTrials.gov number, NCT03000530.).

Brexanolone injection in post-partum depression: two multicentre, double-blind, randomised, placebo-controlled, phase 3 trials.

BACKGROUND: Post-partum depression is associated with substantial morbidity, and improved pharmacological treatment options are urgently needed. We assessed brexanolone injection (formerly SAGE-547 injection), a positive allosteric modulator of γ-aminobutyric-acid type A (GABAA) receptors, for the treatment of moderate to severe post-partum depression. METHODS: We did two double-blind, randomised, placebo-controlled, phase 3 trials, at 30 clinical research centres and specialised psychiatric units in the USA. Eligible women were aged 18-45 years, 6 months post partum or less at screening, with post-partum depression and a qualifying 17-item Hamilton Rating Scale for Depression (HAM-D) score (≥26 for study 1; 20-25 for study 2). Women with renal failure requiring dialysis, anaemia, known allergy to allopregnanolone or to progesterone, or medical history of schizophrenia, bipolar disorder, or schizoaffective disorder were excluded. Patients were randomly assigned (1:1:1) to receive a single intravenous injection of either brexanolone 90 µg/kg per h (BRX90), brexanolone 60 µg/kg per h (BRX60), or matching placebo for 60 h in study 1, or (1:1) BRX90 or matching placebo for 60 h in study 2. Patients, the study team, site staff, and the principal investigator were masked to treatment allocation. The primary efficacy endpoint was the change from baseline in the 17-item HAM-D total score at 60 h, assessed in all patients who started infusion of study drug or placebo, had a valid HAM-D baseline assessment, and had at least one post-baseline HAM-D assessment. The safety population included all randomised patients who started infusion of study drug or placebo. Patients were followed up until day 30. The trials have been completed and are registered with ClinicalTrials.gov, numbers NCT02942004 (study 1) and NCT02942017 (study 2). FINDINGS: Participants were enrolled between Aug 1, 2016, and Oct 19, 2017, in study 1, and between July 25, 2016, and Oct 11, 2017, in study 2. We screened 375 women simultaneously across both studies, of whom 138 were randomly assigned to receive either BRX90 (n=45), BRX60 (n=47), or placebo (n=46) in study 1, and 108 were randomly assigned to receive BRX90 (n=54) or placebo (n=54) in study 2. In study 1, at 60 h, the least-squares (LS) mean reduction in HAM-D total score from baseline was 19·5 points (SE 1·2) in the BRX60 group and 17·7 points (1·2) in the BRX90 group compared with 14·0 points (1·1) in the placebo group (difference -5·5 [95% CI -8·8 to -2·2], p=0·0013 for the BRX60 group; -3·7 [95% CI -6·9 to -0·5], p=0·0252 for the BRX90 group). In study 2, at 60 h, the LS mean reduction in HAM-D total score from baseline was 14·6 points (SE 0·8) in the BRX90 group compared with 12·1 points (SE 0·8) for the placebo group (difference -2·5 [95% CI -4·5 to -0·5], p=0·0160). In study 1, 19 patients in the BRX60 group and 22 patients in the BRX90 group had adverse events compared with 22 patients in the placebo group. In study 2, 25 patients in the BRX90 group had adverse events compared with 24 patients in the placebo group. The most common treatment-emergent adverse events in the brexanolone groups were headache (n=7 BRX60 group and n=6 BRX90 group vs n=7 placebo group for study 1; n=9 BRX90 group vs n=6 placebo group for study 2), dizziness (n=6 BRX60 group and n=6 BRX90 group vs n=1 placebo group for study 1; n=5 BRX90 group vs n=4 placebo group for study 2), and somnolence (n=7 BRX60 group and n=2 BRX90 group vs n=3 placebo group for study 1; n=4 BRX90 group vs n=2 placebo group for study 2). In study 1, one patient in the BRX60 group had two serious adverse events (suicidal ideation and intentional overdose attempt during follow-up). In study 2, one patient in the BRX90 group had two serious adverse events (altered state of consciousness and syncope), which were considered to be treatment related. INTERPRETATION: Administration of brexanolone injection for post-partum depression resulted in significant and clinically meaningful reductions in HAM-D total score at 60 h compared with placebo, with rapid onset of action and durable treatment response during the study period. Our results suggest that brexanolone injection is a novel therapeutic drug for post-partum depression that has the potential to improve treatment options for women with this disorder. FUNDING: Sage Therapeutics, Inc.

Composite and multicomponent end points in clinical trials.

In January 2017, the FDA released the draft guidance to industry on multiple end points in clinical trials. A class of multiplicity problems arise from the testing of individual or subset of components of a composite or multicomponent end point. This commentary attempts to further clarify these problems. Discussions include general consideration on the use of the composite and multicomponent end points, situations when multiplicity adjustments are needed, and the relevant multiple testing methods. Copyright © 2017 John Wiley & Sons, Ltd.

Use of composite endpoints in clinical trials.

The success of a confirmatory clinical trial designed to demonstrate the efficacy of a new treatment is highly dependent on the choice of valid primary efficacy endpoint(s). The optimal clinical and statistical situation for the design of such a trial is one that starts with the selection of a single primary efficacy endpoint that completely characterizes the disease under study, admits the most efficient clinical and statistical evaluation of treatment effect, and provides clear and broad interpretation of drug effect. For diseases with multidimensional presentations, however, the selection of such an endpoint may not be possible, and so drug effectiveness is often characterized by the use of composite or multiple efficacy endpoint(s). The use of a composite endpoint with components that are only slightly correlated but not quite dissimilar in their recognized clinical relevance could lead to a more sensitive statistical test and thus, adequately powered trials with smaller sample size. This note discusses the utility of composite endpoints in clinical trials and some of the common approaches for dealing with multiplicity arising from their use.

Evaluation of overall treatment effect in MMRM.

In longitudinal clinical trials for drug development, the study objective is often to evaluate overall treatment effect across all visits. Despite careful planning and study conduct, the occurrence of incomplete data cannot be completely eliminated. As a direct likelihood method, the mixed-effects model for repeated measures (MMRM) has become one of the preferred approaches for handling missing data in such designs. MMRM is a full multivariate model in nature, which avoids potential bias as a predetermined model, and operates in a more general missing-at-random (MAR) framework. However, if treatment effect is constant over time, overparameterization of treatment by time interaction in MMRM could result in loss of power. In this article, we utilize MMRM estimates and propose an optimal weighting method for combining visit-specific estimates to maximize the power under MAR mechanism. For a special case where the underlying covariance is compound symmetry, we show that the optimal weighting method is asymptotically equal to MMRM. In other words, MMRM has optimal power under this special case. When the underlying covariance is of an unstructured pattern, the optimal weighting method has increased power under MAR and missing-not-at-random (MNAR) mechanisms, and can lead to bias reduction under MNAR. This is especially true when the variance is greater at later time point, which could lead to a smaller weight. We present practical examples using the optimal weighting method to analyze two cystic fibrosis clinical trial data sets.

Extension of adaptive alpha allocation methods for strong control of the family-wise error rate.

With recent advancements in clinical trial design and the availability of rigorous statistical methods that provide strong control of the family-wise type I error rate for multiple testing of hypotheses, it is now common for sponsors to design clinical trials with prospectively specified multiple testing of hypotheses of both primary and secondary endpoints and with the intent to obtain labeling claims for secondary endpoints. One of these recent advancements in multiple testing techniques is the adaptive alpha allocation approach (4A) proposed by Li and Mehrotra (Statistics in Medicine 2008; 27:5377-5391), which groups the hypotheses into two families on the basis of perceived trial power and allows the significance level for the second family to be set adaptively on the basis of the largest observed p-value in the first family. We introduce a class of flexible functions that generalize the 4A procedure and can lead to relatively more powerful test statistics. In the case when the test statistics are correlated, we introduce well-defined functions to calculate the significance level for the second family. The numerical computation for our methods is straightforward, making application in practice easy.

Response-guided telaprevir combination treatment for hepatitis C virus infection.

BACKGROUND: Patients with chronic infection with hepatitis C virus (HCV) genotype 1 often need 48 weeks of peginterferon-ribavirin treatment for a sustained virologic response. We designed a noninferiority trial (noninferiority margin, -10.5%) to compare rates of sustained virologic response among patients receiving two treatment durations. METHODS: We enrolled patients with chronic infection with HCV genotype 1 who had not previously received treatment. All patients received telaprevir at a dose of 750 mg every 8 hours, peginterferon alfa-2a at a dose of 180 µg per week, and ribavirin at a dose of 1000 to 1200 mg per day, for 12 weeks (T12PR12), followed by peginterferon-ribavirin. Patients who had an extended rapid virologic response (undetectable HCV RNA levels at weeks 4 and 12) were randomly assigned after week 20 to receive the dual therapy for 4 more weeks (T12PR24) or 28 more weeks (T12PR48). Patients without an extended rapid virologic response were assigned to T12PR48. RESULTS: Of the 540 patients, a total of 352 (65%) had an extended rapid virologic response. The overall rate of sustained virologic response was 72%. Among the 322 patients with an extended rapid virologic response who were randomly assigned to a study group, 149 (92%) in the T12PR24 group and 140 (88%) in the T12PR48 group had a sustained virologic response (absolute difference, 4 percentage points; 95% confidence interval, -2 to 11), establishing noninferiority. Adverse events included rash (in 37% of patients, severe in 5%) and anemia (in 39%, severe in 6%). Discontinuation of all the study drugs was based on adverse events in 18% of patients overall, as well as in 1% of patients (all of whom were randomly assigned) in the T12PR24 group and 12% of the patients randomly assigned to the T12PR48 group (P<0.001). CONCLUSIONS: In this study, among patients with chronic HCV infection who had not received treatment previously, a regimen of peginterferon-ribavirin for 24 weeks, with telaprevir for the first 12 weeks, was noninferior to the same regimen for 48 weeks in patients with undetectable HCV RNA at weeks 4 and 12, with an extended rapid virologic response achieved in nearly two thirds of patients. (Funded by Vertex Pharmaceuticals and Tibotec; ILLUMINATE ClinicalTrials.gov number, NCT00758043.).

Telaprevir for previously untreated chronic hepatitis C virus infection.

BACKGROUND: In phase 2 trials, telaprevir, a hepatitis C virus (HCV) genotype 1 protease inhibitor, in combination with peginterferon-ribavirin, as compared with peginterferon-ribavirin alone, has shown improved efficacy, with potential for shortening the duration of treatment in a majority of patients. METHODS: In this international, phase 3, randomized, double-blind, placebo-controlled trial, we assigned 1088 patients with HCV genotype 1 infection who had not received previous treatment for the infection to one of three groups: a group receiving telaprevir combined with peginterferon alfa-2a and ribavirin for 12 weeks (T12PR group), followed by peginterferon-ribavirin alone for 12 weeks if HCV RNA was undetectable at weeks 4 and 12 or for 36 weeks if HCV RNA was detectable at either time point; a group receiving telaprevir with peginterferon-ribavirin for 8 weeks and placebo with peginterferon-ribavirin for 4 weeks (T8PR group), followed by 12 or 36 weeks of peginterferon-ribavirin on the basis of the same HCV RNA criteria; or a group receiving placebo with peginterferon-ribavirin for 12 weeks, followed by 36 weeks of peginterferon-ribavirin (PR group). The primary end point was the proportion of patients who had undetectable plasma HCV RNA 24 weeks after the last planned dose of study treatment (sustained virologic response). RESULTS: Significantly more patients in the T12PR or T8PR group than in the PR group had a sustained virologic response (75% and 69%, respectively, vs. 44%; P<0.001 for the comparison of the T12PR or T8PR group with the PR group). A total of 58% of the patients treated with telaprevir were eligible to receive 24 weeks of total treatment. Anemia, gastrointestinal side effects, and skin rashes occurred at a higher incidence among patients receiving telaprevir than among those receiving peginterferon-ribavirin alone. The overall rate of discontinuation of the treatment regimen owing to adverse events was 10% in the T12PR and T8PR groups and 7% in the PR group. CONCLUSIONS: Telaprevir with peginterferon-ribavirin, as compared with peginterferon-ribavirin alone, was associated with significantly improved rates of sustained virologic response in patients with HCV genotype 1 infection who had not received previous treatment, with only 24 weeks of therapy administered in the majority of patients. (Funded by Vertex Pharmaceuticals and Tibotec; ADVANCE ClinicalTrials.gov number, NCT00627926.).

An overview of practical approaches for handling missing data in clinical trials.

For a variety of reasons including poorly designed case report forms (CRFs), incomplete or invalid CRF data entries, and premature treatment or study discontinuations, missing data is a common phenomenon in controlled clinical trials. With the widely accepted use of the intent-to-treat (ITT) analysis dataset as the primary analysis dataset for the analysis of controlled clinical trial data, the presence of missing data could lead to complicated data analysis strategies and subsequently to controversy in the interpretation of trial results. In this article, we review the mechanisms of missing data and some common approaches to analyzing missing data with an emphasis on study dropouts. We discuss the importance of understanding the reasons for study dropouts with ways to assess the mechanisms of missingness. Finally, we discuss the results of a comparative Monte Carlo investigation of the performance characteristics of commonly utilized statistical methods for the analysis of clinical trial data with dropouts. The methods investigated include the mixed effects model for repeated measurements (MMRM), weighted and unweighted generalized estimating equations (GEE) method for the available case data, multiple-imputation-based GEE (MI-GEE), complete case (CC) analysis of covariance (ANCOVA), and last observation carried forward (LOCF) ANCOVA. Simulation experiments for the repeated measures model with missing at random (MAR) dropout, under varying dropout rates and intrasubject correlation, show that the LOCF, ANCOVA, and weighted GEE methods perform poorly in terms of percent relative bias for estimating a difference in means effect, while the MI-GEE and weighted GEE methods both have less power for rejecting a zero difference in means hypothesis.

A note on the conservativeness of the confidence interval approach for the selection of non-inferiority margin in the two-arm active-control trial.

Compared with placebo-control clinical trials, the interpretation of efficacy results from active-control trials requires more caution. This is because efficacy results from such trials cannot be reliably interpreted without a thorough understanding of the efficacy evidence that formed the basis for the approval of the active control, especially when such drug efficacy is to be established on the basis of clinical evidence from the traditional two-arm active-control clinical equivalence studies as opposed to the multi-arm active control. This is because in addition to over-reliance on the quantification of a clinically irrelevant acceptable margin of inferiority from historical data, such interpretation also depends on cross-trial inference for demonstration of experimental drug effect. We provide a brief overview of some design issues with the traditional two-arm active-control clinical trial and discuss regulators' concern regarding Type I error rate control (with the two most popular methods for the quantification of the non-inferiority margin) in cross-trial demonstration of experimental drug effect. Simulation results are presented to show that the point estimate method provides adequate control of the Type I error rate with > or =75 per cent retention of known active-control effect and that the confidence interval approach is uniformly ultra-conservative. We also report (via a numerical example from real clinical trial data) a couple of potentially less stringent alternative approaches for establishing the non-inferiority of a test drug over a control, which have been used in the past to provide additional efficacy evidence in NDA submission.

The utility of mixed-effects covariate analysis in rapid selection of doses in pediatric subjects: a case study with fexofenadine hydrochloride.

Fexofenadine hydrochloride is a non-sedating antihistamine that is used in the treatment of symptoms associated with seasonal allergic rhinitis and chronic idiopathic urticaria. A pooled analysis of pharmacokinetic data from children 6 months to 12 years of age and adults was conducted to identify the dose(s) in children that produce exposures comparable to those in adults for the treatment of seasonal allergic rhinitis. The pharmacokinetic parameter database included peak and overall exposure data from 269 treatment exposures from 136 adult subjects, and 90 treatment exposures from 77 pediatric allergic rhinitis patients. The data were pooled and analysed using NONMEM software, version 5.0. A covariate model based on body weight and age and a power function model based on body weight were identified as appropriate models to describe the variability in fexofenadine oral clearance and peak concentration, respectively. Individual oral clearance estimates were on average 44%, 36% and 61% lower in children 6 to 12 years (n=14), 2 to 5 years (n=21), and 6 months to 2 years (n=42), respectively, compared with adults. Trial simulations (n=100) were carried out based on the final pharmacostatistical models and parameter estimates to identify the appropriate dose(s) in children relative to the marketed dose of 60 mg fexofenadine hydrochloride in adults. The trials were designed as crossover studies in 18 subjects comprising various potential dosing regimens with and without weight stratification. Pharmacokinetic parameter variability was assumed to have a log-normal distribution. Individual weights and ages were simulated using mean (SD) estimates derived from the studies used in this analysis and proportional measurement/model mis-specification errors derived from the analysis were incorporated into the simulation. The results indicated that a 30 mg dose of fexofenadine hydrochloride administered to children 1 to 12 years of age and weighing >10.5 kg and a 15 mg dose administered to children 6 months and older and weighing

Efficacy endpoint selection and multiplicity adjustment methods in clinical trials with inherent multiple endpoint issues.

The ideal approach for the design and analysis of clinical trials is to select a single primary endpoint that provides a complete characterization of the disease under study and permits an efficient evaluation of the effect of a test drug. However, this is often not possible for a number of diseases or clinical trials. This paper examines some practical clinical decision-making scenarios for the selection and analysis of efficacy outcome measures in clinical trials with inherent multiplicity components.