Statistical considerations in model-based dose finding for binary responses under model uncertainty.

The statistical methodology for model-based dose finding under model uncertainty has attracted increasing attention in recent years. While the underlying principles are simple and easy to understand, developing and implementing an efficient approach for binary responses can be a formidable task in practice. Motivated by the statistical challenges encountered in a phase II dose finding study, we explore several key design and analysis issues related to the hybrid testing-modeling approaches for binary responses. The issues include candidate model selection and specifications, optimal design and efficient sample size allocations, and, notably, the methods for dose-response testing and estimation. Specifically, we consider a class of generalized linear models suited for the candidate set and establish D-optimal designs for these models. Additionally, we propose using permutation-based tests for dose-response testing to avoid asymptotic normality assumptions typically required for contrast-based tests. We perform trial simulations to enhance our understanding of these issues.

Improved mortality analysis in early-phase dose-ranging clinical trials for emergency medical diseases using Bayesian time-to-event models with active comparators.

Emergency medical diseases (EMDs) are the leading cause of death worldwide. A time-to-death analysis is needed to accurately identify the risks and describe the pattern of an EMD because the mortality rate can peak early and then decline. Dose-ranging Phase II clinical trials are essential for developing new therapies for EMDs. However, most dose-finding trials do not analyze mortality as a time-to-event endpoint. We propose three Bayesian dose-response time-to-event models for a secondary mortality analysis of a clinical trial: a two-group (active treatment vs control) model, a three-parameter sigmoid EMAX model, and a hierarchical EMAX model. The study also incorporates one specific active treatment as an active comparator in constructing three new models. We evaluated the performance of these six models and a very popular independent model using simulated data motivated by a randomized Phase II clinical trial focused on identifying the most effective hyperbaric oxygen dose to achieve favorable functional outcomes in patients with severe traumatic brain injury. The results show that the three-group, EMAX, and EMAX model with an active comparator produce the smallest averaged mean squared errors and smallest mean absolute biases. We provide a new approach for time-to-event analysis in early-phase dose-ranging clinical trials for EMDs. The EMAX model with an active comparator can provide valuable insights into the mortality analysis of new EMDs or other conditions that have changing risks over time. The restricted mean survival time, a function of the model's hazards, is recommended for displaying treatment effects for EMD research.

Confidence intervals for odds ratio from multistage randomized phase II trials.

A multi-stage randomized trial design can significantly improve efficiency by allowing early termination of the trial when the experimental arm exhibits either low or high efficacy compared to the control arm during the study. However, proper inference methods are necessary because the underlying distribution of the target statistic changes due to the multi-stage structure. This article focuses on multi-stage randomized phase II trials with a dichotomous outcome, such as treatment response, and proposes exact conditional confidence intervals for the odds ratio. The usual single-stage confidence intervals are invalid when used in multi-stage trials. To address this issue, we propose a linear ordering of all possible outcomes. This ordering is conditioned on the total number of responders in each stage and utilizes the exact conditional distribution function of the outcomes. This approach enables the estimation of an exact confidence interval accounting for the multi-stage designs.

Adaptive designs were primarily used but inadequately reported in early phase drug trials.

BACKGROUND: Faced with the high cost and limited efficiency of classical randomized controlled trials, researchers are increasingly applying adaptive designs to speed up the development of new drugs. However, the application of adaptive design to drug randomized controlled trials (RCTs) and whether the reporting is adequate are unclear. Thus, this study aimed to summarize the epidemiological characteristics of the relevant trials and assess their reporting quality by the Adaptive designs CONSORT Extension (ACE) checklist. METHODS: We searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL) and ClinicalTrials.gov from inception to January 2020. We included drug RCTs that explicitly claimed to be adaptive trials or used any type of adaptative design. We extracted the epidemiological characteristics of included studies to summarize their adaptive design application. We assessed the reporting quality of the trials by Adaptive designs CONSORT Extension (ACE) checklist. Univariable and multivariable linear regression models were used to the association of four prespecified factors with the quality of reporting. RESULTS: Our survey included 108 adaptive trials. We found that adaptive design has been increasingly applied over the years, and was commonly used in phase II trials (n = 45, 41.7%). The primary reasons for using adaptive design were to speed the trial and facilitate decision-making (n = 24, 22.2%), maximize the benefit of participants (n = 21, 19.4%), and reduce the total sample size (n = 15, 13.9%). Group sequential design (n = 63, 58.3%) was the most frequently applied method, followed by adaptive randomization design (n = 26, 24.1%), and adaptive dose-finding design (n = 24, 22.2%). The proportion of adherence to the ACE checklist of 26 topics ranged from 7.4 to 99.1%, with eight topics being adequately reported (i.e., level of adherence ≥ 80%), and eight others being poorly reported (i.e., level of adherence ≤ 30%). In addition, among the seven items specific for adaptive trials, three were poorly reported: accessibility to statistical analysis plan (n = 8, 7.4%), measures for confidentiality (n = 14, 13.0%), and assessments of similarity between interim stages (n = 25, 23.1%). The mean score of the ACE checklist was 13.9 (standard deviation [SD], 3.5) out of 26. According to our multivariable regression analysis, later published trials (estimated ß = 0.14, p < 0.01) and the multicenter trials (estimated ß = 2.22, p < 0.01) were associated with better reporting. CONCLUSION: Adaptive design has shown an increasing use over the years, and was primarily applied to early phase drug trials. However, the reporting quality of adaptive trials is suboptimal, and substantial efforts are needed to improve the reporting.

Race and Ethnicity Representation in Phase 2/3 Oncology Clinical Trial Publications: A Systematic Review.

Importance: The five 1997 Office of Management and Budget races in the US include American Indian or Alaska Native, Asian, Black or African American, Native Hawaiian or Other Pacific Islander, and White, with Hispanic ethnicity. Despite the Affordable Care Act mandating Office of Management and Budget-based collecting and reporting standards, race and ethnicity publishing in medical journals is inconsistent, despite being necessary to achieve health equity. Objective: To quantify race and ethnicity reporting rates and calculate representation quotients (RQs) in published oncology clinical trials. Evidence Review: In this systematic review, PubMed and Embase were queried for phase 2/3 clinical trials of the 6 most common noncutaneous solid cancers, published between January 1, 2012, and December 31, 2022, in 4 high-impact journals. Trial characteristics were recorded. The RQs for each race and ethnicity were calculated by dividing the percent of representation in each clinical trial publication by the percent of year-matched, site-specific incident cancers in the US, compared with Kruskal-Wallis tests with Bonferroni correction (BC). Reporting was compared between journal publications and ClinicalTrials.gov. Findings: Among 1202 publications evaluated, 364 met inclusion criteria: 16 JAMA, 241 Journal of Clinical Oncology, 19 Lancet, and 88 New England Journal of Medicine. Publications included 268 209 patients (171 132 women [64%]), with a median of 356 (IQR, 131-800) patients per publication. Reported race and ethnicity included American Indian or Alaska Native in 52 (14%) publications, Asian in 196 (54%), Black or African American in 215 (59%), Hispanic in 67 (18%), Native Hawaiian or Other Pacific Islander in 28 (8%), and White in 254 (70%). Median RQ varied across race (P < .001 BC), with 1.04 (IQR, 0.09-4.77) for Asian, 0.98 (IQR, 0.86-1.06) for White, 0.42 (IQR, 0.12-0.75) for Black or African American, and 0.00 (IQR, 0.00-0.00) for both American Indian or Alaska Native and Native Hawaiian or Other Pacific Islander patients. Sensitivity analyses showed similar findings on subset analysis for US-only clinical trials. There was significantly less race and ethnicity reporting in the clinical trial publications compared with ClinicalTrials.gov documentation for American Indian or Alaska Native (14% vs 45%; P < .001 per McNemar χ2 test with continuity correction [MC]) and Native Hawaiian or Other Pacific Islander (8% vs 43%; P < .001 MC). Conclusions and Relevance: While most phase 2/3 oncology clinical trials published in high-impact journals report race and ethnicity, most did not report American Indian or Alaska Native and Native Hawaiian or Other Pacific Islander racial categories. Our findings support a call to action for consistent journal policies and transparent race and ethnicity reporting, in alignment with Affordable Care Act-concordant race and ethnicity federal reporting requirements.

Datos de rilpivirina en pacientes naïve. Lecciones de los estudios ECHO, THRIVE y STaR / Data on rilpivirine in treatment-naïve patients. Lessons from ECHO, THRIVE and STaR

Rilpivirina (RPV) es un nuevo inhibidor de la transcriptasa inversa no análogo de nucleósidos de segunda generación, aprobado recientemente para el tratamiento de pacientes con infección por el virus de la inmunodeficiencia humana a dosis de 25mg, administrado 1 vez al día con alimentos. En pacientes que inician tratamiento, RPV se ha evaluado en 1 estudio fase IIb (TMC278-C204) y en 3 estudios fase III (ECHO, THRIVE y STaR). En todos ellos, RPV se compara con el gold standard (efavirenz [EFV]), incluyendo un considerable número de pacientes tratados con el nuevo fármaco (n=1.349). La eficacia terapéutica ha resultado elevada y similar con ambos tratamientos, demostrándose que RPV es no inferior a EFV a las 48 y 96 semanas. En todos los estudios y en todos los subgrupos analizados, RPV ha mostrado una mejor tolerabilidad que EFV, especialmente en lo referido a efectos adversos del área neuropsiquiátrica, exantema cutáneo y de la esfera lipídica. En el análisis conjunto de los estudios ECHO y THRIVE se observaron diferencias notables en función de la carga viral (CV) basal. Así, la eficacia terapéutica de RPV resultó superior a la de EFV en pacientes con CV basal ≤ 100.000 copias/ml, con similar eficacia virológica y, además, una mejor tolerabilidad de RPV. Por el contrario, en los pacientes con CV basal ≥ 100.000 copias/ml se observó una mayor incidencia de fallos virológicos en el grupo de RPV, especialmente con CV basal ≥ 500.000 copias/ml. La aparición de mutaciones de resistencia en los pacientes con fallo virológico resultó superior a la esperada, especialmente en los pacientes con CV basal elevada. Según estos resultados, las agencias del medicamento europeo (EMA) y americana (FDA) han aprobado el uso de RPV en pacientes naïve con CV basal ≤ 100.000 copias/ml. Algunas guías terapéuticas ya incorporan RPV en sus recomendaciones. Así, las americanas (DHHS e IAS-USA), en espera de datos adicionales, la consideran todavía como un régimen alternativo, mientras que las europeas y la reciente actualización de las Guías de GeSIDA la consideran entre los regímenes preferidos en pacientes con CV ≤ 100.000 copias/ml. Los datos recientes del estudio STaR, en el que se utilizan combinaciones a dosis fijas de los 3 fármacos, muestran no inferioridad de RPV frente a EFV, independientemente de la CV basal, con menos fallos virológicos y una menor selección de resistencias que en los estudios ECHO y THRIVE. En definitiva, los datos de eficacia y seguridad del fármaco indican que los regímenes basados en RPV con 2 inhibidores de la transcriptasa inversa análogos de nucleósidos son eficaces y seguros en el tratamiento antirretroviral de inicio

Rilpivirine (RPV) is a new, second-generation nonnucleoside reverse transcriptase inhibitor (NNRTI) that has been recently approved for use in the initial antiretroviral therapy (ART) of treatment-naïve HIV-infected patients, combined with two nucleoside/nucleotide reverse transcriptase inhibitors (NRTI). The approved dose is 25mg once daily with food. RPV has been assessed in a phase IIb study (TMC278-C204) and in three phase III trials (ECHO, THRIVE and STaR). In all of them, RPV was compared with the gold standard, efavirenz (EFV); these studies enrolled a large number of patients (n=1,349 on RPV). RPV was non-inferior to EFV at 48 and 96 weeks. In all the studies and study arms, the tolerability of RPV was better than that of EFV, especially for neuropsychiatric adverse effects, rash, and lipid profile. An analysis of the combined data from the ECHO and THRIVE trials showed marked differences, depending on baseline viral load. The therapeutic efficacy of RPV was superior to that of EFV in patients with a baseline viral load ≤100,000 copies/mL, due to a similar virological efficacy and a better tolerability profile. However, in patients with a baseline viral load ≥100,000 copies/mL, virological failure was more frequent in the RPV arm, especially in patients with a viral load ≥500,000 copies/mL. Emerging resistance mutations to RPV were commonly detected in patients with virological failure, especially in those with a higher baseline viral load. In view of these results, the European Medications Agency and the US Food and Drug Administration have approved the use of RPV in treatment-naïve patients with a baseline viral load ≤100,000 copies/mL. Some treatment guidelines have already included RPV among their recommendations. The guidelines of the US Department of Health and Human Services (DHSS) and the International Antiviral Society-USA ((IAS-USA), while awaiting additional data, consider RPV-based regimens as an alternative regimen. The Gesida guidelines consider RPV to be among the preferred regimens in patients with a viral load ≤100,000 copies/mL. Recent data from the STaR trial, which used fixed drug combinations, have shown the non-inferiority of RPV with respect to EFV, less virological failure and less emergence of resistance mutations with RPV use, irrespective of baseline viral load. In summary, efficacy and safety data suggest that RPV plus 2 NRTI is an effective and safe initial antiretroviral regime