Elucidating vaccine efficacy using a correlate of protection, demographics, and logistic regression.

BACKGROUND: Vaccine efficacy (VE) assessed in a randomized controlled clinical trial can be affected by demographic, clinical, and other subject-specific characteristics evaluated as baseline covariates. Understanding the effect of covariates on efficacy is key to decisions by vaccine developers and public health authorities. METHODS: This work evaluates the impact of including correlate of protection (CoP) data in logistic regression on its performance in identifying statistically and clinically significant covariates in settings typical for a vaccine phase 3 trial. The proposed approach uses CoP data and covariate data as predictors of clinical outcome (diseased versus non-diseased) and is compared to logistic regression (without CoP data) to relate vaccination status and covariate data to clinical outcome. RESULTS: Clinical trial simulations, in which the true relationship between CoP data and clinical outcome probability is a sigmoid function, show that use of CoP data increases the positive predictive value for detection of a covariate effect. If the true relationship is characterized by a decreasing convex function, use of CoP data does not substantially change positive or negative predictive value. In either scenario, vaccine efficacy is estimated more precisely (i.e., confidence intervals are narrower) in covariate-defined subgroups if CoP data are used, implying that using CoP data increases the ability to determine clinical significance of baseline covariate effects on efficacy. CONCLUSIONS: This study proposes and evaluates a novel approach for assessing baseline demographic covariates potentially affecting VE. Results show that the proposed approach can sensitively and specifically identify potentially important covariates and provides a method for evaluating their likely clinical significance in terms of predicted impact on vaccine efficacy. It shows further that inclusion of CoP data can enable more precise VE estimation, thus enhancing study power and/or efficiency and providing even better information to support health policy and development decisions.

A two-stage group-sequential design for delayed treatment responses with the possibility of trial restart.

Common statistical theory applicable to confirmatory phase III trial designs usually assumes that patients are enrolled simultaneously and there is no time gap between enrollment and outcome observation. However, in practice, patients are enrolled successively and there is a lag between the enrollment of a patient and the measurement of the primary outcome. For single-stage designs, the difference between theory and practice only impacts on the trial duration but not on the statistical analysis and its interpretation. For designs with interim analyses, however, the number of patients already enrolled into the trial and the number of patients with available outcome measurements differ, which can cause issues regarding the statistical analyses of the data. The main issue is that current methodologies either imply that at the time of the interim analysis there are so-called pipeline patients whose data are not used to make a statistical decision (like stopping early for efficacy) or the enrollment into the trial needs to be at least paused for interim analysis to avoid pipeline patients. There are methods for delayed responses available that introduced error-spending stopping boundaries for the enrollment of patients followed by critical values to reject the null hypothesis in case the stopping boundaries have been crossed beforehand. Here, we will discuss other solutions, considering different boundary determination algorithms using conditional power and introducing a design allowing for recruitment restart while keeping the type I error rate controlled.

Single-arm phase 3 designs: An oxymoron?

BACKGROUND: Since the 1950s, randomized clinical trials (RCTs) have served as the gold standard for confirming the benefits of a new drug. Accordingly, phase 3 trials, the last steps in the evaluation process for a new drug, have been recommended to all be RCTs. Nevertheless, single-arm phase 3 trials still appear to be in use. METHODS: We performed a PubMed search to identify the use of a single-arm design in phase 3 trials, excluding only non-English articles. Three categories were distinguished: past use of an RCT, of any other trial design, or no previous trial; and according to diagnosis (oncology, infection, others). RESULTS: A total of 176 single-arm phase 3 trials (19 oncology, 43 infections and 114 others) were identified by the search, with exponential growth since 1994, in parallel with that of RCTs. Among them, 64 (36%) were preceded by an RCT, 58 (33%) by a non-randomized trial, and 54 (31%) had no previous trial, with no main influence of the diagnosis setting. Justification of the design was reported in 30 (18%) of those trials, with ethical concerns comprising one-third of those justifications. This was similar in the 14 single-arm phase 2-3 trials, with about one-third in each group, and 17% justification of a non-comparative design. CONCLUSION: The use of a single-arm phase 3 trial is heterogeneous, ranging from first trials up to confirmatory trials after a previously conducted RCT. Justification for these single-arm designs as confirmatory evidence should be more clearly reported, along with potential sources of bias.

Statistical and practical considerations in planning and conduct of dose-optimization trials.

The U.S. Food and Drug Administration launched Project Optimus with the aim of shifting the paradigm of dose-finding and selection toward identifying the optimal biological dose that offers the best balance between benefit and risk, rather than the maximum tolerated dose. However, achieving dose optimization is a challenging task that involves a variety of factors and is considerably more complicated than identifying the maximum tolerated dose, both in terms of design and implementation. This article provides a comprehensive review of various design strategies for dose-optimization trials, including phase 1/2 and 2/3 designs, and highlights their respective advantages and disadvantages. In addition, practical considerations for selecting an appropriate design and planning and executing the trial are discussed. The article also presents freely available software tools that can be utilized for designing and implementing dose-optimization trials. The approaches and their implementation are illustrated through real-world examples.

Nonalcoholic steatohepatitis (NASH) cirrhosis: a snapshot of therapeutic agents in clinical development and the optimal design for clinical trials.

INTRODUCTION: Patients with nonalcoholic steatohepatitis (NASH)-associated cirrhosis have the highest rates of major adverse liver outcomes (MALO) within the fatty liver disease spectrum and therefore have the highest unmet need for effective therapeutic agents. Several drugs are being tested for patients with NASH cirrhosis with different mechanisms of action and endpoints. AREAS COVERED: This article summarizes the available data on the natural history of NASH cirrhosis and the rates of developing MALO. We provide examples of ongoing clinical trials for NASH cirrhosis including the study design and endpoints. We then discuss the FDA-guidance on acceptable endpoints for NASH cirrhosis trials that will lead to approval. EXPERT OPINION: Metabolic and antifibrotic drugs are currently in phase 2b trials for NASH cirrhosis with outcomes ranging from histologic improvement on liver biopsy to the development of varices or MALO. We provide the readers with pragmatic advice on trial design for phase 2B and 3 NASH cirrhosis trials. The data presented in the article justify further development and investigation of therapeutic agents for the treatment of NASH cirrhosis.

A standardised Phase III clinical trial framework to assess therapeutic interventions for Lassa fever.

BACKGROUND: Only one recommendation currently exists for the treatment of Lassa fever (LF), which is ribavirin administered in conjunction with supportive care. This recommendation is primarily based on evidence generated from a single clinical trial that was conducted more than 30 years ago-the methodology and results of which have recently come under scrutiny. The requirement for novel therapeutics and reassessment of ribavirin is therefore urgent. However, a significant amount of work now needs to be undertaken to ensure that future trials for LF can be conducted consistently and reliably to facilitate the efficient generation of evidence. METHODOLOGY: We convened a consultation group to establish the position of clinicians and researchers on the core components of future trials. A Core Eligibility Criteria (CEC), Core Case Definition (CCD), Core Outcome Set (COS) and Core Data Variables (CDV) were developed through the process of a multi-stakeholder consultation that took place using a modified-Delphi methodology. RESULTS: A consensus position was achieved for each aspect of the framework, which accounts for the inclusion of pregnant women and children in future LF clinical trials. The framework consists of 8 core criteria, as well as additional considerations for trial protocols. CONCLUSIONS: This project represents the first step towards delineating the clinical development pathway for new Lassa fever therapeutics, following a period of 40 years without advancement. Future planned projects will bolster the work initiated here to continue the advancement of LF clinical research through a regionally-centred, collaborative methodology, with the aim of delineating a clear pathway through which LF clinical trials can progress efficiently and ensure sustainable investments are made in research capacity at a regional level.

Melanoma trials that defined surgical management.

Treatment of regional lymph nodes in melanoma has been controversial for more than a century. A series of clinical trials evaluating elective lymph node dissection and then sentinel lymph node biopsy have helped define the current standard of care. These trials resulted in increasingly selective application of surgical intervention for regional lymph nodes in melanoma. First by focusing on optimal candidates for elective lymph node dissection and then by identifying patients through sentinel lymph node biopsy. The current standard of sentinel lymph node biopsy for appropriately selected patients and nodal observation for many patients, even with involved sentinel nodes is both more accurate in staging and much less morbid than what came before.

The evolution of adjuvant/neoadjuvant trials for resectable localized sarcoma.

Soft-tissue sarcomas are rare tumors arising from mesenchymal tissues. As a heterogeneous group comprising more than 50 types, the development of clinical trials remains challenging. Decision-making for neoadjuvant or adjuvant chemotherapy and radiation therapy is based on the available evidence of contemporary trials and multidisciplinary clinical judgment.

Quality-of-life methodology in hormone receptor-positive advanced breast cancer: Current tools and perspectives for the future.

Health-related quality of life (HRQOL) is increasingly recognized as important when evaluating cancer treatments. The use, reporting, and analysis of patient-reported outcome measures (PROMs), however, are not standardized in clinical trials and are often poorly implemented in clinical practice. We report the results of a systematic literature review (PubMed search: January 1, 2000 to August 15, 2020) of PROM use, reporting, and analysis in phase 3 clinical trials of hormone receptor-positive (HR+) advanced breast cancer (ABC). Further inspection of cyclin-dependent kinase 4/6 (CDK4/6) inhibitor publications was performed to examine PROMs in the HR+/human epidermal growth factor receptor 2-negative setting. A total of 88 results were identified in the initial search; 32 were included in the final analysis. Among included studies, most (66%) had been published in the last 5 years (2015 to 2020). CDK4/6 inhibitors (38%) were the most common agents reported. No clear standard for PROM use, reporting, or analysis was found. The most common PROMs were European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30; 59%) and the Functional Assessment of Cancer Therapy-Breast (FACT-B; 34%). Important differences, among studies that reported them, ranged from 5 to 10 points for the EORTC QLQ-C30 and 8 points for the FACT-B total score. This review showed that a lack of clear consistency remains for PROM use, reporting, and analysis in phase 3 clinical trials of HR+ ABC. However, HRQOL is of high interest in the literature, including for CDK4/6 inhibitors.

Evaluating the Role of Ketamine/Esketamine in the Management of Major Depressive Disorder with Suicide Risk.

Nearly 5% of individuals in the USA had serious thoughts of suicide in 2019 and over 30% of individuals suffering with major depressive disorder reported suicidal ideation with 2 million of those reporting suicidal ideation with some level of intent. However, options to treat depressed individuals considered at imminent risk of suicide remain limited. Until the recent approval of esketamine in the treatment of patients with major depressive disorder with serious suicidal thoughts or actions, no medications had been specifically evaluated for use in this population in the acute setting. This review discusses the history and the current understanding of the role of ketamine and esketamine in depression and suicidal ideation and behavior. It covers some of the pivotal studies in this field and provides a summary of their major findings. The trials of esketamine in patients with major depressive disorder with active suicidal ideation or behavior are the first large-scale trials in patients considered at imminent risk of suicide. As such, the design of these studies is by definition novel, a fact that complicates the interpretation of the data and assessment of the true clinical meaningfulness of the findings. Despite this, the findings in toto draw a consistent picture of benefits that appears to outweigh the potential risks of the treatment. The studies also serve to highlight the complexities and limitations associated with clinical trials aiming to test the ability of novel therapeutics to reduce the burden and risks in patients with suicide ideation and behavior.

Neuromyelitis optica spectrum disorders: from pathophysiology to therapeutic strategies.

Neuromyelitis optica (NMO) is a chronic inflammatory autoimmune disease of the central nervous system (CNS) characterized by acute optic neuritis (ON) and transverse myelitis (TM). NMO is caused by a pathogenic serum IgG antibody against the water channel aquoporin 4 (AQP4) in the majority of patients. AQP4-antibody (AQP4-ab) presence is highly specific, and differentiates NMO from multiple sclerosis. It binds to AQP4 channels on astrocytes, triggering activation of the classical complement cascade, causing granulocyte, eosinophil, and lymphocyte infiltration, culminating in injury first to astrocyte, then oligodendrocytes followed by demyelination and neuronal loss. NMO spectrum disorder (NMOSD) has recently been defined and stratified based on AQP4-ab serology status. Most NMOSD patients experience severe relapses leading to permanent neurologic disability, making suppression of relapse frequency and severity, the primary objective in disease management. The most common treatments used for relapses are steroids and plasma exchange.Currently, long-term NMOSD relapse prevention includes off-label use of immunosuppressants, particularly rituximab. In the last 2 years however, three pivotal clinical trials have expanded the spectrum of drugs available for NMOSD patients. Phase III studies have shown significant relapse reduction compared to placebo in AQP4-ab-positive patients treated with satralizumab, an interleukin-6 receptor (IL-6R) inhibitor, inebilizumab, an antibody against CD19+ B cells; and eculizumab, an antibody blocking the C5 component of complement. In light of the new evidence on NMOSD pathophysiology and of preliminary results from ongoing trials with new drugs, we present this descriptive review, highlighting promising treatment modalities as well as auspicious preclinical and clinical studies.

The quality of clinical trials in neuroendocrine tumours; have we learnt from our mistakes? An evaluation of phase II and phase III clinical trials.

The quality and reporting of neuroendocrine tumour (NET) clinical trials has previously been found to be heterogeneous impairing trial interpretability. We aimed to perform an updated review of the quality of phase II/III clinical trials in NET to assess if trial design and reporting have improved since 2011. We performed a PubMed search for phase II/III trials evaluating systemic anticancer therapies or liver-directed therapies published between 2011 and 2018. Data collected comprised administrative data, study population characteristics, endpoints, reporting and statistical design parameters, and results. Sixty studies were included (5218 patients): 50 phase II and 10 phase III trials. Study populations were heterogeneous: 52% of trials allowed tumours from various primary sites, 28% allowed both well- and poorly-differentiated tumour morphology or did not specify, and 57% did not report proliferative indices and/or tumour grade in ≥80% of the study population. Only 36% of trials mandated radiological disease progression on participant enrolment using a validated measure. Statistical design and primary endpoint were clearly defined in 67% and 88% of trials, respectively. Toxicity (88%), radiological response rate (85%) and progression-free survival/time to progression (82%) were well reported in a majority of trials, but health-related quality of life was included in the minority. Of the randomised trials (n = 11), study populations were more homogeneous and study design was more often clearly defined; however, only 45% mandated radiological progression at baseline as measured per Response Evaluation Criteria In Solid Tumours, and reporting of health-related quality of life (55%) remained suboptimal. The design and reporting of NET clinical trials, predominantly of single-arm phase II trials, remains suboptimal and has not considerably improved over time despite the growth in our knowledge of the biology and unique characteristics of NETs. Higher quality is seen in randomised trials, although certain design and reporting elements remain inadequate in some studies. We must prioritise the design and conduct of NET clinical trials to effectively inform future research and guide practice change.

Impact of baseline clinical asthma characteristics on the response to mepolizumab: a post hoc meta-analysis of two Phase III trials.

BACKGROUND: Severe asthma is associated with a broad range of phenotypes and clinical characteristics. This analysis assessed whether select baseline patient characteristics could prognosticate mepolizumab efficacy in severe eosinophilic asthma. METHODS: This was a post hoc meta-analysis of data from the Phase III MENSA (NCT01691521/MEA115588) and MUSCA (NCT02281318/200862) studies. Patients aged ≥ 12 years with severe eosinophilic asthma and a history of exacerbations were randomised to receive placebo (MENSA/MUSCA), mepolizumab 75 mg intravenously (MENSA) or 100 mg subcutaneously (SC) (MENSA/MUSCA) every 4 weeks for 32 (MENSA) or 24 (MUSCA) weeks. The primary endpoint was the annual rate of clinically significant exacerbations; other outcomes included the proportion of patients with no exacerbations and changes from baseline in pre-bronchodilator forced expiratory volume in 1 s (FEV1), St George's Respiratory Questionnaire (SGRQ) total score and Asthma Control Questionnaire (ACQ)-5 score. Analyses were performed by baseline age of asthma onset (< 18 years; 18-40 years; ≥ 40 years); lung function (% predicted FEV1 ≤ 60; 60-80; > 80); airway reversibility (reversible [≥ 12% change in FEV1]; non-reversible [< 12% change in FEV1]); perennial and/or seasonal allergen sensitivity (yes/no); asthma control (uncontrolled [ACQ-5 score ≥ 1.5]; partial/complete control [ACQ-5 score < 1.5]). RESULTS: Overall, 936 patients received mepolizumab 100 mg SC or placebo. Across age at asthma onset, lung function and airway reversibility subgroups, mepolizumab reduced the rate of clinically significant exacerbations by 49-63% versus placebo. Improvements in lung function, SGRQ total score and ACQ-5 score were also seen with mepolizumab versus placebo across most age and lung function subgroups. Clinically significant exacerbations were reduced with mepolizumab versus placebo irrespective of season or allergen sensitivity; SGRQ total and ACQ-5 scores were generally improved across seasons. CONCLUSIONS: Mepolizumab efficacy was consistent for patients with varying age at asthma onset, lung function, airway reversibility and allergen sensitivities at baseline. Our results indicate that mepolizumab is likely to be beneficial for patients with severe eosinophilic asthma with a broad range of baseline clinical characteristics; large-scale real-world studies are needed to confirm the external validity of these findings. Trial registration Post hoc meta-analysis of data from MENSA (NCT01691521/MEA115588) and MUSCA (NCT02281318/200862).

COVID-19 vaccines: concerns beyond protective efficacy and safety.

INTRODUCTION: Several vaccine candidates have been developed using different platforms, including nucleic acids (DNA and RNA), viral vectors (replicating and non-replicating), virus-like particles, peptide-based, recombinant proteins, live attenuated, and inactivated virus modalities. Although many of these vaccines are undergoing pre-clinical trials, several large clinical trials investigating the clinical efficacy and safety of coronavirus disease 2019 (COVID-19) vaccines have produced promising findings. AREAS COVERED: In this review, we provide a status update on COVID-19 vaccines currently undergoing clinical trials and discuss issues of concern beyond vaccine efficacy and safety, including dosing regimens, the mixed vaccine strategy, prior severe acute respiratory syndrome coronavirus-2 infection, antibody levels, cellular immunity and protection, variants of concern, COVID-19 vaccine distribution, vaccination willingness, herd immunity, immunity passports, and vaccine indications. EXPERT OPINION: Four vaccines have obtained emergency use authorization, 87 are at the clinical development stage, and 186 are in pre-clinical development. While the knowledge and development of COVID-19 vaccines is rapidly expanding, the benefits of COVID-19 vaccines must outweigh the potential risks of adverse events. To combat the COVID-19 pandemic, clinicians should consistently update COVID-19-associated information, and healthcare authorities and manufacturers should work together to provide adequate and appropriate vaccinations for the prevention of COVID-19. PLAIN LANGUAGE SUMMARY: What is the context?Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) caused a global pandemic: the coronavirus disease 2019 (COVID-19) outbreak. The development and implementation of the COVID-19 vaccine could be an important measure to control the COVID-19 pandemic.What is new?Several phase 3 clinical trials have demonstrated the effectiveness and safety of COVID-19 vaccines for the prevention of SARS-CoV-2 infections. Several COVID-19 vaccines have obtained emergency use authorization and been implemented in many countries. Although concerns regarding unusual blood clots and low platelet counts have been raised, the benefits of COVID-19 vaccines outweigh the potential risks of adverse events.What is the impact?Except for children, the COVID-19 vaccine is recommended for all people, including those pregnant or immunocompromised. Healthcare authorities should advise people receiving the vaccine that they must seek medical attention if they have associated thromboembolism and thrombocytopenia symptoms. More studies are necessary to determine the appropriate vaccine dose and regimen strategy, as well as the effectiveness of COVID-19 vaccines against variants of concerns. A global effort must be made to achieve widespread vaccination and herd immunity.

Mirabegron: Pediatric First Approval.

Mirabegron (MYRBETRIQ®), a beta-3 adrenergic agonist developed by Astellas Pharma Inc., is well established as a treatment for overactive bladder in adults and is available as extended-release (ER) tablets administered once daily. More recently, mirabegron has been investigated in pediatric patients with neurogenic detrusor overactivity (NDO) and received its first approval in this indication in pediatric patients aged ≥ 3 years on 25 March 2021 in the USA. In addition to mirabegron ER tablets (which can be used in pediatric patients weighing ≥ 35 kg), mirabegron is available as an ER oral suspension (MYRBETRIQ® Granules) for pediatric patients; in those weighing < 35 kg, only the ER oral suspension formulation should be used. The ER tablet and ER oral suspension formulations are not substitutable on a mg-by-mg basis. This article summarizes the milestones in the development of mirabegron for NDO leading to this pediatric first approval.

Viloxazine: Pediatric First Approval.

Viloxazine (QELBREE™), a selective norepinephrine reuptake inhibitor, is being developed by Supernus Pharmaceuticals as a non-stimulant for the treatment of attention-deficit/hyperactivity disorder (ADHD) in pediatric and adult patients. This is a novel formulation of a pharmacological agent formerly marketed in Europe for the treatment of depression in adults. Viloxazine received its first pediatric approval in April 2021 in the USA for the treatment of ADHD in pediatric patients aged 6-17 years. Approval was based on positive results from a series of short-term phase III clinical trials in which viloxazine improved the severity of ADHD symptoms in children and adolescents with diagnosed ADHD. Viloxazine is available as extended-release capsules for once-daily oral administration. This article summarizes the milestones in the development of viloxazine leading to this first pediatric approval for ADHD.

Safety and tolerability of fixed-dose combinations of ibuprofen and acetaminophen: pooled analysis of phase 1-3 clinical trials.

OBJECTIVES: An ibuprofen (IBU)/acetaminophen (APAP) fixed-dose combination (FDC) for over-the-counter (OTC) use was developed with the goal of providing the same effective analgesic activity as full doses of the individual monocomponents, while reducing individual monocomponent drug exposures. Here, the safety and tolerability of the FDC is characterized using pooled safety data from phase 1-3 clinical trials in the FDC development program. METHODS: We conducted a pooled safety analysis of data from 7 clinical trials: three phase 1 pharmacokinetic trials, a phase 2 proof-of-concept trial, and three phase 3 trials (a single- and a multiple-dose trial in a dental pain model and a single-dose trial in an induced-fever model). Safety and tolerability of the FDC were assessed by adverse events (AEs) for the total group and subgroups (age, sex, race). RESULTS: A total of 1,477 participants were enrolled in the 7 trials; 715 were treated with FDC IBU/APAP, 432 with IBU monotherapy, 330 with APAP monotherapy, and 156 with placebo. Most subjects were white (86.5%), and 44% were female. Two trials enrolling 195 adolescents accounted for 13.2% of the overall study population. All-causality treatment-emergent AEs (TEAEs) occurred in 19.7% of the 1477 participants. Nausea (13.5%), vomiting (7.4%), dizziness (4.5%), headache (1.2%), and feeling hot (1.0%) were the only TEAEs reported in ≥1% of subjects. Treatment-related AEs occurred in 1.8% of the subjects in the overall population. The incidence of AEs, including treatment-related AEs, was consistently lower in all active treatment groups than in the placebo group; this also applied to subgroups according to sex, race, and age, including adolescents aged 12-17 years. The higher rate of AEs with placebo was likely due to lack of pain/fever control. CONCLUSION: Single-dose or short-course FDC IBU/APAP OTC use was well tolerated, with an AE profile similar to its IBU and APAP monocomponents. CLINICALTRIALS.GOV REGISTRATION: NCT01559259; NCT02912650; NCT02837952; NCT02761980. The pharmacokinetic studies (n = 3) did not require registration.