Analysis of two binomial proportions in noninferiority confirmatory trials.

In this article, we propose considering an approximate exact score (AES) test for noninferiority comparisons and we derive its test-based confidence interval for the difference between two independent binomial proportions. This test was published in the literature, but not its associated confidence interval. The p-value for this test is obtained by using exact binomial probabilities with the nuisance parameter being replaced by its restricted maximum likelihood estimate. Calculated type I errors revealed that the AES method has important advantages for noninferiority comparisons over popular asymptotic methods for adequately powered confirmatory clinical trials, at 80% or 90% statistical power. For unbalanced sample sizes of the compared groups, type I errors for the asymptotic score method were shown to be higher than the nominal level in a systematic pattern over a range of true proportions, but the AES method did not suffer from such a problem. On average, the true type I error of the AES method was closer to the nominal level than all considered methods in the empirical comparisons. In rare cases, type I errors of the AES test exceeded the nominal level, but only by a small amount. Presented examples showed that the AES method can be more attractive in practice than practical exact methods. In addition, p-value and confidence interval of the AES method can be obtained in <30 s of computer time for most confirmatory trials. Theoretical arguments, combined with empirical evidence and fast computation time should make the AES method attractive in statistical practice.

Adjunctive lumateperone (ITI-007) in the treatment of bipolar depression: Results from a randomized placebo-controlled clinical trial.

OBJECTIVE: This phase 3, randomized, double-blind, placebo-controlled study (NCT02600507) evaluated the efficacy and safety of lumateperone adjunctive therapy to lithium or valproate in patients with bipolar depression. METHODS: Patients (18-75 years) with bipolar I or bipolar II disorder experiencing a major depressive episode (MDE), with inadequate therapeutic response to lithium or valproate, were randomized 1:1:1 to 6 weeks adjunctive therapy with lumateperone 28 mg (n = 176), lumateperone 42 mg (n = 177), or placebo (n = 176). The primary and key secondary efficacy endpoints were change from baseline to Day 43 in Montgomery-Åsberg Depression Rating Scale (MADRS) Total score and the Clinical Global Impression Scale-Bipolar Version-Severity Scale (CGI-BP-S) depression subscore. Safety assessments included adverse events, laboratory evaluations, vital signs, extrapyramidal symptoms (EPS), and suicidality. RESULTS: Patients treated with adjunctive lumateperone 42 mg showed significantly greater improvement compared with adjunctive placebo in MADRS Total score (LS mean difference vs placebo [LSMD], -2.4; p = 0.02) and CGI-BP-S depression subscore (LSMD, -0.3; p = 0.01), while adjunctive lumateperone 28 mg showed numerical improvement in MADRS Total score (LSMD, -1.7; p = 0.10) and improvement in the CGI-BP-S depression subscore (LSMD, -0.3; p = 0.04). Adjunctive lumateperone treatment was well tolerated; treatment-emergent adverse events reported at rates >5% and twice placebo for lumateperone 42 mg were somnolence (11.3%), dizziness (10.7%), and nausea (8.5%), with minimal risk of EPS, metabolic abnormalities, or increased prolactin. CONCLUSIONS: Lumateperone 42-mg treatment adjunctive to lithium or valproate significantly improved depression symptoms and was generally well tolerated in patients with MDEs associated with either bipolar I or bipolar II disorder.

Randomized Trial of Ceftazidime-Avibactam vs Meropenem for Treatment of Hospital-Acquired and Ventilator-Associated Bacterial Pneumonia (REPROVE): Analyses per US FDA-Specified End Points.

BACKGROUND: Hospital-acquired and ventilator-associated pneumonia (HAP/VAP; nosocomial pneumonia) due to Gram-negative pathogens are associated with significant morbidity and mortality; treatment options for multidrug-resistant infections are limited. The pivotal phase III REPROVE trial evaluated the efficacy of ceftazidime-avibactam (CAZ-AVI) vs meropenem in the treatment of patients with HAP/VAP. Study results for prespecified analyses per US Food and Drug Administration-recommended trial end points are reported here. METHODS: Hospitalized adults with HAP/VAP proven or suspected to be caused by a Gram-negative pathogen were randomized 1:1 to receive CAZ-AVI or meropenem for 7 to 14 days. The primary outcome was 28-day all-cause mortality in the intent-to-treat (ITT) population. Secondary outcomes included clinical cure at test of cure (TOC) in the ITT and microbiological ITT (micro-ITT) populations, and safety and tolerability throughout the study. RESULTS: hundred seventy randomized patients received treatment and were included in the ITT population (CAZ-AVI, n = 436; meropenem, n = 434). CAZ-AVI was noninferior to meropenem for the primary end point (28-day all-cause mortality; ITT) based on the prespecified 10% noninferiority margin (CAZ-AVI, 9.6%; meropenem, 8.3%; difference, 1.5%; 95% confidence interval [CI], -2.4% to 5.3%) and for the clinical cure end point in the ITT population based on a prespecified -10% noninferiority margin (CAZ-AVI, 67.2%; meropenem, 69.1%; difference, -1.9%; 95% CI, -8.1% to 4.3%). Clinical cure rates at TOC for patients infected with CAZ-nonsusceptible pathogens were similar (CAZ-AVI, 75.5%; meropenem, 71.2%; micro-ITT). Safety data were consistent with established safety profiles for both agents. CONCLUSIONS: CAZ-AVI provides an important new treatment option for HAP/VAP due to Gram-negative pathogens, including CAZ-nonsusceptible strains.

Sample size calculation for comparing two negative binomial rates.

Negative binomial model has been increasingly used to model the count data in recent clinical trials. It is frequently chosen over Poisson model in cases of overdispersed count data that are commonly seen in clinical trials. One of the challenges of applying negative binomial model in clinical trial design is the sample size estimation. In practice, simulation methods have been frequently used for sample size estimation. In this paper, an explicit formula is developed to calculate sample size based on the negative binomial model. Depending on different approaches to estimate the variance under null hypothesis, three variations of the sample size formula are proposed and discussed. Important characteristics of the formula include its accuracy and its ability to explicitly incorporate dispersion parameter and exposure time. The performance of the formula with each variation is assessed using simulations.

Cardiovascular safety in patients receiving roflumilast for the treatment of COPD.

BACKGROUND: Evaluation of cardiovascular safety for new therapies for COPD is important because of a high prevalence of cardiac comorbidities in the COPD population. Hence, we evaluated the effects of roflumilast, a novel oral phosphodiesterase 4 inhibitor developed for the treatment and prevention of COPD exacerbations, on major adverse cardiovascular events (MACEs). METHODS: Intermediate- and long-term placebo-controlled clinical trials of roflumilast in COPD were pooled and assessed for potential cardiovascular events. Studies comprised 14 12- to 52-week placebo-controlled trials in patients with moderate to very severe COPD. All deaths and serious nonfatal cardiovascular events were evaluated by an independent adjudication committee blinded to study and treatment. The MACE composite of cardiovascular death, nonfatal myocardial infarction, and stroke was analyzed according to treatment group. RESULTS: Of 6,563 patients receiving roflumilast, 52 experienced MACEs (14.3 per 1,000 patient-years), and of 5,491 patients receiving placebo, 76 experienced MACEs (22.3 per 1,000 patient-years). The MACE composite rate was significantly lower for roflumilast compared with placebo (hazard ratio, 0.65; 95% CI, 0.45-0.93; P = .019). CONCLUSIONS: A lower rate of cardiovascular events was observed with roflumilast than with placebo in patients with COPD, indicating the lack of a cardiovascular safety signal when treating patients with COPD. Potential cardiovascular benefits of roflumilast should be evaluated in future controlled clinical trials.

Efficacy and safety of a 12-week treatment with twice-daily aclidinium bromide in COPD patients (ACCORD COPD I).

BACKGROUND: This Phase III study evaluated the efficacy and safety of twice-daily aclidinium 200 µg and 400 µg versus placebo in the treatment of moderate-to-severe COPD. METHODS: In this 12-week, double-blind, multicenter trial, patients were randomized (1:1:1) to inhaled twice-daily aclidinium 200 µg, aclidinium 400 µg, or placebo. Primary and secondary endpoints were changes from baseline in trough FEV1 and peak FEV1 at Week 12, respectively. Health status (St. George's Respiratory Questionnaire [SGRQ]), COPD symptoms (Transitional Dyspnea Index [TDI], night and early morning symptoms), and safety were also assessed. RESULTS: A total of 561 patients (mean age, 64 ± 9 years) with a mean baseline FEV1 of 1.36 ± 0.54 L (47.2% of predicted value) were randomized. At Week 12, aclidinium 200 µg and 400 µg showed significant improvements from baseline in mean (95% CI) trough FEV1 compared with placebo by 86 (45, 127) mL and 124 (83,164) mL, respectively, and in peak FEV1 by 146 (101, 190) mL and 192 (148, 236) mL, respectively (p ≤ 0.0001 for all). Both aclidinium doses also provided significant improvements in SGRQ, TDI and almost all COPD symptom scores compared with placebo (p < 0.05 for all). Incidences of adverse events (AEs) were similar across treatment groups. The incidence of anticholinergic AEs was low and similar across groups (dry mouth: 0.5%-1.6%; constipation: 0%-1.1%). CONCLUSIONS: Treatment of moderate-to-severe COPD patients with twice-daily aclidinium 200 µg and 400 µg was associated with significant improvements in bronchodilation, health status, and COPD symptoms. Both doses were well tolerated and had safety profiles similar to placebo. TRIAL REGISTRATION: This ACCORD I study (AClidinium in Chronic Obstructive Respiratory Disease I) was registered on clinicaltrials.gov (NCT00891462) as "Efficacy and Safety of Aclidinium Bromide for Treatment of Moderate to Severe Chronic Obstructive Pulmonary Disease (COPD)".

Effectiveness of a bivalent Haemophilus influenzae type B-hepatitis B vaccine in preventing hepatitis B virus infection among children born to hepatitis B e antigen-positive carrier mothers.

BACKGROUND: This observational study evaluated a modified immunoprophylactic regimen (hepatitis B immune globulin [HBIG]) and a dose of thimerosal-free monovalent hepatitis B (HB) vaccine shortly after birth followed by doses of thimerosal-free bivalent Haemophilus influenzae type b (Hib)-HB vaccine at 2 and 4 months of age, and a booster at 12 months of age) in infants at high risk of hepatitis B virus (HBV) infection (mothers HBeAg+). METHODS: Children >or=6 months of age vaccinated in routine clinical practice were tested twice (>or=6 months apart) for HBV antigens surface antigen (HBsAg) and "e" antigen, and for antibody to HBsAg. Partial nucleotide sequence analysis was performed on HBV DNA isolated from infants identified with a breakthrough chronic HBV infection. A fully sequential statistical design was used to maximize patient safety and study efficiency. RESULTS: Four of 60 children developed chronic HBV infection despite vaccination, but at no point did the cumulative number of cases reach the boundary of statistical significance. Overall, the analysis adjusted for sequential testing yielded an estimated breakthrough rate of 6.7% (90% CI: 2.3%-14.6%). In a subset of uninfected children tested for antibody to HBsAg 1 to 4 months after the second dose of Hib-HB vaccine, 90% (9/10) had >or=10 milli-International Units per milliliter (mIU/mL). The third dose of Hib-HB vaccine induced a secondary increase in the level of antibody; 94.7% (18/19) of a second group developed >or=100 mIU/mL, with a geometric mean concentration of 771 mIU/mL (95% CI: 351.4-1692.1 mIU/mL). CONCLUSION: The tested regimen is comparably effective to historical experience with a standard one employing HBIG plus monovalent thimerosal-containing HB vaccine given at 0, 1, and 6 months of age.

Safety, tolerability and immunogenicity of VAQTA given concomitantly versus nonconcomitantly with other pediatric vaccines in healthy 12-month-old children.

BACKGROUND: The objective of this study is to assess whether hepatitis A vaccine is immunogenic and well tolerated when administered to 12-month-old children alone or concomitantly with other routinely administered pediatric vaccines. METHODS: Six hundred seventeen healthy 12-month-old children were randomized to receive dose 1 of hepatitis A vaccine given alone or concomitantly with measles-mumps-rubella vaccine and varicella vaccine and dose 2 of hepatitis A vaccine given alone or concomitantly with diphtheria-tetanus-acellular pertussis vaccine and optionally with oral or inactivated poliovirus vaccine. Participants were followed for clinical adverse experiences and serologic responses to all vaccine antigens. Antibody responses were compared with historical controls for some indices. RESULTS: The safety profile was generally comparable whether hepatitis A vaccine was administered alone or concomitantly with other vaccines. When administered alone, the hepatitis A seropositivity rate was 98.3% and 100% for dose 1 and dose 2, respectively, and after dose 2 was similar to historical rates and the geometric mean titers were similar between initially seropositive and initially seronegative subjects (6207 and 6810 mIU/mL, respectively). After concomitant administration with hepatitis A vaccine, antibody responses to measles, mumps, rubella, diphtheria, tetanus and filamentous hemagglutinin (98.8%, 99.6%, 100%, 98.6%, 100% and 83.3%, respectively) were similar to historical controls and response to poliovirus was demonstrated, but immune responses to varicella zoster virus (79%) and pertussis toxoid (76%) were inferior to historical controls. CONCLUSIONS: Hepatitis A vaccine is highly immunogenic and generally well tolerated when administered to healthy children as young as 12 months of age regardless of initial hepatitis A serostatus and can be administered concomitantly with measles-mumps-rubella vaccine and oral or inactivated poliovirus vaccine.

large-scale serologic testing program to assess the immunogenicity of inactivated hepatitis a vaccine (VAQTA) in prefilled syringes following product recall in Germany.

A voluntary recall of VAQTA in prefilled syringes was implemented in Europe in late 2001 after the manufacturer noted a slight decrease in the antigen content of a small percentage of the syringes manufactured over a particular time frame. In Germany, a large-scale serologic testing program was implemented. The assay results were conveyed to the subject's physician, and free vaccine was provided for anyone requesting revaccination. An analysis was performed on a subset of 58,546 vaccine recipients with hepatitis A antibody results. Of the 28,681 persons who received either two 25 units (25 U) or two 50 units (50 U) doses of VAQTA, the seropositivity rate (SPR) was 99.5% after receipt of 2 doses, similar to the results in prelicensure clinical trials. The SPR was similar among recipients of lots that had been manufactured over the time frame associated with the recalled lots versus those receiving lots not associated with the recalled lots (25U: 99.7% versus 99,7%; 50U: 98.6% versus 99.6%, respectively). There were less recipients of 25U doses of the affected lots, who had high hepatitis A antibody titers (> or =100 mIU/mL), compared to recipients of unaffected lots.

Safety and immunogenicity of an inactivated hepatitis A vaccine among HIV-infected subjects.

BACKGROUND: Hepatitis A is a major health risk for many human immunodeficiency virus (HIV)-infected individuals. Vaccination is a potentially attractive measure to reduce the incidence of hepatitis A among this population, but data on its safety and immunogenicity are incomplete. METHODS: Ninety HIV-uninfected adults received an inactivated hepatitis A vaccine (VAQTA; Merck), and 90 HIV-infected subjects were randomized, in double-blind fashion, to receive either the vaccine or placebo. The HIV-infected subjects were stratified by CD4 cell count, with 45 subjects having CD4 cell counts of > or =300 cells/mm3 and 45 subjects having CD4 cell counts of <300 cells/mm3. Vaccine was given at weeks 0 and 24 of the study.Results. Seroconversion rates at week 28 of the study were 94% among the HIV-infected subjects and 100% among the HIV-uninfected control subjects. HIV-infected subjects with CD4 cell counts of <300 cells/mm3 had a seroconversion rate of 87%, and HIV-infected subjects with CD4 cell counts of > or =300 cells/mm3 had a seroconversion rate of 100%. The vaccine was generally well tolerated, and no adverse effect on either HIV load or CD4 cell count was found. CONCLUSION: Hepatitis A vaccine was both immunogenic and safe among HIV-infected subjects.

Post-licensure comparative study of unusual high-pitched crying and prolonged crying following COMVAX and placebo versus PedvaxHIB and RECOMBIVAX HB in healthy infants.

BACKGROUND: In a previous clinical trial comparing COMVAX with its monovalent components, PedvaxHIB and RECOMBIVAX HB, one of 92 comparisons of post-vaccination adverse experiences revealed a higher rate of unusual, high-pitched crying following the second, but not the first or third doses of COMVAX compared with two monovalent control vaccines. Rates of prolonged crying were similar between groups at each visit. OBJECTIVES: To compare the frequencies of unusual, high-pitched crying between recipients of COMVAX plus placebo and recipients of PedvaxHIB plus RECOMBIVAX HB following the second vaccine doses (primary) and to summarize the frequency of unusual, high-pitched crying and prolonged crying after each vaccination visit. DESIGN: We enrolled 1215 healthy infants in a randomized, double blind, placebo-controlled study. Participating infants received study vaccines at 2 and 4 months of age and other routine childhood vaccines at 6-7 weeks and 3 months of age. Crying was evaluated via questionnaire at the time of enrollment (baseline) and daily from days 0 to 2 after each injection. RESULTS: Reports of unusual, high-pitched crying and prolonged crying were uncommon (<1%) prior to the first vaccination visit and were comparable in both treatment groups. After each injection, rates of unusual, high-pitched crying (range: 4.26-6.96%) and prolonged crying (range: 0-1.36%) appeared similar between treatment groups and for each vaccination visit. Crying resolved in all infants; no neurological impairment was reported. CONCLUSION: This study found no statistically significant differences in rates of unusual, high-pitched crying and prolonged crying in infants vaccinated with COMVAX plus placebo compared with infants vaccinated with its monovalent components, PedvaxHIB and RECOMBIVAX HB.

An open randomized study of inactivated hepatitis A vaccine administered concomitantly with typhoid fever and yellow fever vaccines.

BACKGROUND: Concomitant administration of several vaccines is a common practice when travel clinics prepare persons for international travel. The purpose of the study was to compare the immunogenicity and safety of hepatitis A, typhoid fever, and yellow fever vaccines administered concomitantly with hepatitis A vaccine administered alone and typhoid fever and yellow fever vaccines administered alone. METHODS: Healthy adults 18 to 55 years of age were randomized to receive either VAQTA, TyphimVi, and YF-VAX on day 0 and VAQTA at week 24 (Group 1); TyphimVi and YF-VAX on day 0 and an optional dose of VAQTA 1 month later (Group 2); or VAQTA at day 0 and week 24 (Group 3). RESULTS: From March to December 1997, a total of 240 subjects were enrolled, 80 in each treatment group. Most were female and Caucasian, and the mean age was 29.4 years. Four weeks after vaccine dose 1, seroconversion to protective antibody levels against hepatitis A was 95.9% in Group 1 and 100% in Group 3. In Group 1, 93.4% of subjects demonstrated at least a 4-fold rise in neutralizing antibody levels against typhoid, compared with 90% in Group 2. Serum neutralizing antibody against yellow fever developed in 98.6% of subjects in Group 1 compared with 100% in Group 2. CONCLUSIONS: These findings were consistent with similarity in the immune responses between treatment groups as defined a priori. The adverse experience (AE) profile did not appear to be substantially affected by concomitant administration of all three vaccines. Providing these three vaccines concomitantly can simplify the process of obtaining pretravel prophylaxis and may help ensure that all needed vaccines are administered.