Optimal timing for an accelerated interim futility analysis incorporating real world data.

BACKGROUND: Randomized controlled trials include interim monitoring guidelines to stop early for safety, efficacy, or futility. Futility monitoring facilitates re-allocation of limited resources. However, conventional methods for interim futility monitoring require a trial to accrue nearly half of the outcome data to make a reliable early stopping decision, limiting its benefit. As early stopping for futility will not inflate type-I error, these analyses are an appealing venue for incorporating external data to improve efficiency. METHODS: We propose a Bayesian approach to futility monitoring leveraging real world data using Semi-Supervised MIXture Multi-source Exchangeability Models, which accounts for both measured and unmeasured differences between data sources. We implement futility monitoring using predictive probabilities and investigate the optimal timing with respect to the expected sample size under the null hypothesis. Because we only incorporate external data during the interim futility analysis the proposed design is not limited by type-I error inflation. RESULTS: When the external and trial data are exchangeable, the proposed method provides a roughly 70 person reduction in expected sample size under the null. Under scenarios where exchangeability does not hold, our approach still provides a 10-20 person reduction in expected sample size under the null with about 80% power. CONCLUSIONS: External data borrowing in interim futility monitoring is a promising venue to improve trial efficiency without type-I error inflation. Approaches that are acceptable to regulatory authorities and leverage the complementary strengths of real world and trial data are vital to more efficiently allocate limited resources amongst clinical trials.

FDA's dilemma with the aducanumab approval: public pressure and hope, surrogate markers and efficacy, and possible next steps.

Accelerating Food and Drug Administration (FDA) product approval to market based on surrogate markers in the absence of proven efficacy creates a risk of adverse outcomes for affected patients, even in response to a life-threatening condition, such as in this case, Alzheimer's disease. FDA's recent unexpected approval of aducanumab, despite the unified opposition of its own highly respected advisory committee after the early termination of two efficacy trials, creates the potential risk of adverse effects and lack of clinical efficacy at very high costs. In view of these concerns, a thorough review of the issues and pressures that led to this decision is worth the careful consideration of the clinical and scientific communities with regard to whether this approval represents a calculated and balanced compassionate decision versus a disturbing precedent.

Induction of CD73 prevents death after emergency open aortic surgery for a ruptured abdominal aortic aneurysm: a randomized, double-blind, placebo-controlled study.

Mortality remains high after emergency open surgery for a ruptured abdominal aortic aneurysm (RAAA). The aim of the present study was to assess, if intravenous (IV) Interferon (IFN) beta-1a improve survival after surgery by up-regulating Cluster of differentiation (CD73). This is a multi-center phase II double-blind, 2:1 randomized, parallel group comparison of the efficacy and safety of IV IFN beta-1a vs. placebo for the prevention of death after open surgery for an infra-renal RAAA. All study patients presented a confirmed infra-renal RAAA, survived the primary emergency surgery and were treated with IFN beta-1a (10 µg) or matching placebo for 6 days after surgery. Major exclusion criteria included fatal hemorrhagic shock, chronic renal replacement therapy, diagnosed liver cirrhosis, severe congestive heart failure, advanced malignant disease, primary attempt of endovascular aortic repair (EVAR), and per-operative suprarenal clamping over 30 min. Main outcome measure was all-cause mortality at day 30 (D30) from initial emergency aortic reconstruction. The study was pre-maturely stopped due to a reported drug-drug interaction and was left under-powered. Out of 40 randomized patients 38 were included in the outcome analyses (27 IFN beta-1a and 11 placebo). There was no statistically significant difference between treatment groups at baseline except more open-abdomen and intestinal ischemia was present in the IFN beta-1a arm. D30 all-cause mortality was 22.2% (6/27) in the IFN beta-1a arm and 18.2% (2/11) in the placebo arm (OR 1.30; 95% CI 0.21-8.19). The most common adverse event relating to the IFN beta-1a was pyrexia (20.7% in the IFN beta-1a arm vs. 9.1% in the placebo arm). Patients with high level of serum CD73 associated with survival (P = 0.001) whereas the use of glucocorticoids and the presence of IFN beta-1a neutralizing antibodies associated with a poor CD73 response and survival. The initial aim of the trial, if postoperative INF beta-1a treatment results on better RAAA survival, could not be demonstrated. Nonetheless the anticipated target mechanism up-regulation of CD73 was associated with 100% survival. According to present results the INF beta-1a induced up-regulation of serum CD73 was blocked with both use of glucocorticoids and serum IFN beta-1a neutralizing antibodies. The study was pre-maturely stopped due to interim analysis after a study concerning the use if IV IFN beta-1a in ARDS suggested that the concomitant use of glucocorticoids and IFN beta-1a block the CD73 induction. Trial registration: ClinicalTrials.gov NCT03119701. Registered 19/04/2017 (retrospectively registered).

Safety, Tolerability, and Pharmacokinetics of FAAH Inhibitor BIA 10-2474: A Double-Blind, Randomized, Placebo-Controlled Study in Healthy Volunteers.

This study evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of BIA 10-2474, a fatty acid amide hydrolase (FAAH) inhibitor, after first administration to healthy male and female participants. Participants (n = 116) were recruited into this phase I, double-blind, randomized, placebo-controlled, single ascending dose and multiple ascending dose (10-day) study. The primary outcome was the safety and tolerability of BIA 10-2474. Secondary outcomes were pharmacokinetics of BIA 10-2474 and pharmacodynamics, considering plasma concentrations of anandamide and three other fatty acid amides (FAAs) and leukocyte FAAH activity. Single oral doses of 0.25-100 mg and repeated oral doses of 2.5-50 mg were evaluated. BIA 10-2474 was well tolerated up to 100 mg as a single dose and up to 20 mg once daily for 10 days. In the cohort receiving repeated administrations of 50 mg, there were central nervous system adverse events in five of six participants, one with fatal outcome, which led to early termination of the study. BIA 10-2474 showed a linear relationship between dose and area under plasma concentration-time curve (AUC) across the entire dose range and reached steady state within 5-6 days of administration, with an accumulation ratio, based on AUC0-24h , of <2 on Day 10. BIA 10-2474 was rapidly absorbed with a mean terminal elimination half-life of 8-10 hours (Day 10). BIA 10-2474 caused reversible, dose-related increases in plasma FAAs. In conclusion, we propose that these data, as well as the additional data generated since the clinical trial was stopped, do not provide a complete mechanistic explanation for the tragic fatality.

Clinical Competence and Perception of Medical Students after Early Clinical Exposure through Pre-clerckship Education at an Ethiopian Medical School: A Cross-sectional Study

BACKGROUND: Conventional medical curriculum is the mainstay in the long history of modern medical education. Innovative integrated medical curriculum attracted significant attention in improving conventional curriculum. In the integrated curriculum, basic sciences are incorporated horizontally with each other, and students are exposed early to clinical settings. This is expected to improve students' knowledge and skills in clinical medicine by the time they start their clerkship rotation. METHOD: the study aims to make a baseline assessment on the overall knowledge and skills of medical students towards clinical medicine. An institution-based cross-sectional study was conducted from March to April of 2020 using 91 third year medical students (convenience sampling). A threesection selfadministered survey instrument, short written MCQ exam, and practical (OSCE) students' examination were used for this survey. RESULT: participants tend to exhibit better knowledge on basics of history taking and physical examination with an average score of 79%. Comparatively, the score for average physical examination skill was low (56.3%). Students' perception on ECE showed, over 50% of participants believe ECE increases burden on their overall workload. Even then, the majority (92.3%) still think that ECE has positive impact on their clerkship education. Taken together, it appears more hands-on interventions is needed to further improve skills of medical students in physical examination with particular emphasis on the clinical examination of breast, thyroid, musculoskeletal, and neurologic systems

Fractional Flow Reserve to Guide Treatment of Patients With Multivessel Coronary Artery Disease.

BACKGROUND: There is limited evidence that fractional flow reserve (FFR) is effective in guiding therapeutic strategy in multivessel coronary artery disease (CAD) beyond prespecified percutaneous coronary intervention or coronary graft surgery candidates. OBJECTIVES: The FUTURE (FUnctional Testing Underlying coronary REvascularization) trial aimed to evaluate whether a treatment strategy based on FFR was superior to a traditional strategy without FFR in the treatment of multivessel CAD. METHODS: The FUTURE trial is a prospective, randomized, open-label superiority trial. Multivessel CAD candidates were randomly assigned (1:1) to treatment strategy based on FFR in all stenotic (≥50%) coronary arteries or to a traditional strategy without FFR. In the FFR group, revascularization (percutaneous coronary intervention or surgery) was indicated for FFR ≤0.80 lesions. The primary endpoint was a composite of major adverse cardiac or cerebrovascular events at 1 year. RESULTS: The trial was stopped prematurely by the data safety and monitoring board after a safety analysis and 927 patients were enrolled. At 1-year follow-up, by intention to treat, there were no significant differences in major adverse cardiac or cerebrovascular events rates between groups (14.6% in the FFR group vs 14.4% in the control group; hazard ratio: 0.97; 95% confidence interval: 0.69-1.36; P = 0.85). The difference in all-cause mortality was nonsignificant, 3.7% in the FFR group versus 1.5% in the control group (hazard ratio: 2.34; 95% confidence interval: 0.97-5.18; P = 0.06), and this was confirmed with a 24 months' extended follow-up. FFR significantly reduced the proportion of revascularized patients, with more patients referred to exclusively medical treatment (P = 0.02). CONCLUSIONS: In patients with multivessel CAD, we did not find evidence that an FFR-guided treatment strategy reduced the risk of ischemic cardiovascular events or death at 1-year follow-up. (Functional Testing Underlying Coronary Revascularisation; NCT01881555).

Effect of Antithrombotic Therapy on Clinical Outcomes in Outpatients With Clinically Stable Symptomatic COVID-19: The ACTIV-4B Randomized Clinical Trial.

Importance: Acutely ill inpatients with COVID-19 typically receive antithrombotic therapy, although the risks and benefits of this intervention among outpatients with COVID-19 have not been established. Objective: To assess whether anticoagulant or antiplatelet therapy can safely reduce major adverse cardiopulmonary outcomes among symptomatic but clinically stable outpatients with COVID-19. Design, Setting, and Participants: The ACTIV-4B Outpatient Thrombosis Prevention Trial was designed as a minimal-contact, adaptive, randomized, double-blind, placebo-controlled trial to compare anticoagulant and antiplatelet therapy among 7000 symptomatic but clinically stable outpatients with COVID-19. The trial was conducted at 52 US sites between September 2020 and June 2021; final follow-up was August 5, 2021. Prior to initiating treatment, participants were required to have platelet count greater than 100 000/mm3 and estimated glomerular filtration rate greater than 30 mL/min/1.73 m2. Interventions: Random allocation in a 1:1:1:1 ratio to aspirin (81 mg orally once daily; n = 164), prophylactic-dose apixaban (2.5 mg orally twice daily; n = 165), therapeutic-dose apixaban (5 mg orally twice daily; n = 164), or placebo (n = 164) for 45 days. Main Outcomes and Measures: The primary end point was a composite of all-cause mortality, symptomatic venous or arterial thromboembolism, myocardial infarction, stroke, or hospitalization for cardiovascular or pulmonary cause. The primary analyses for efficacy and bleeding events were limited to participants who took at least 1 dose of trial medication. Results: On June 18, 2021, the trial data and safety monitoring board recommended early termination because of lower than anticipated event rates; at that time, 657 symptomatic outpatients with COVID-19 had been randomized (median age, 54 years [IQR, 46-59]; 59% women). The median times from diagnosis to randomization and from randomization to initiation of study treatment were 7 days and 3 days, respectively. Twenty-two randomized participants (3.3%) were hospitalized for COVID-19 prior to initiating treatment. Among the 558 patients who initiated treatment, the adjudicated primary composite end point occurred in 1 patient (0.7%) in the aspirin group, 1 patient (0.7%) in the 2.5-mg apixaban group, 2 patients (1.4%) in the 5-mg apixaban group, and 1 patient (0.7%) in the placebo group. The risk differences compared with placebo for the primary end point were 0.0% (95% CI not calculable) in the aspirin group, 0.7% (95% CI, -2.1% to 4.1%) in the 2.5-mg apixaban group, and 1.4% (95% CI, -1.5% to 5.0%) in the 5-mg apixaban group. Risk differences compared with placebo for bleeding events were 2.0% (95% CI, -2.7% to 6.8%), 4.5% (95% CI, -0.7% to 10.2%), and 6.9% (95% CI, 1.4% to 12.9%) among participants who initiated therapy in the aspirin, prophylactic apixaban, and therapeutic apixaban groups, respectively, although none were major. Findings inclusive of all randomized patients were similar. Conclusions and Relevance: Among symptomatic clinically stable outpatients with COVID-19, treatment with aspirin or apixaban compared with placebo did not reduce the rate of a composite clinical outcome. However, the study was terminated after enrollment of 9% of participants because of an event rate lower than anticipated. Trial Registration: ClinicalTrials.gov Identifier: NCT04498273.

Effect of Lower Tidal Volume Ventilation Facilitated by Extracorporeal Carbon Dioxide Removal vs Standard Care Ventilation on 90-Day Mortality in Patients With Acute Hypoxemic Respiratory Failure: The REST Randomized Clinical Trial.

Importance: In patients who require mechanical ventilation for acute hypoxemic respiratory failure, further reduction in tidal volumes, compared with conventional low tidal volume ventilation, may improve outcomes. Objective: To determine whether lower tidal volume mechanical ventilation using extracorporeal carbon dioxide removal improves outcomes in patients with acute hypoxemic respiratory failure. Design, Setting, and Participants: This multicenter, randomized, allocation-concealed, open-label, pragmatic clinical trial enrolled 412 adult patients receiving mechanical ventilation for acute hypoxemic respiratory failure, of a planned sample size of 1120, between May 2016 and December 2019 from 51 intensive care units in the UK. Follow-up ended on March 11, 2020. Interventions: Participants were randomized to receive lower tidal volume ventilation facilitated by extracorporeal carbon dioxide removal for at least 48 hours (n = 202) or standard care with conventional low tidal volume ventilation (n = 210). Main Outcomes and Measures: The primary outcome was all-cause mortality 90 days after randomization. Prespecified secondary outcomes included ventilator-free days at day 28 and adverse event rates. Results: Among 412 patients who were randomized (mean age, 59 years; 143 [35%] women), 405 (98%) completed the trial. The trial was stopped early because of futility and feasibility following recommendations from the data monitoring and ethics committee. The 90-day mortality rate was 41.5% in the lower tidal volume ventilation with extracorporeal carbon dioxide removal group vs 39.5% in the standard care group (risk ratio, 1.05 [95% CI, 0.83-1.33]; difference, 2.0% [95% CI, -7.6% to 11.5%]; P = .68). There were significantly fewer mean ventilator-free days in the extracorporeal carbon dioxide removal group compared with the standard care group (7.1 [95% CI, 5.9-8.3] vs 9.2 [95% CI, 7.9-10.4] days; mean difference, -2.1 [95% CI, -3.8 to -0.3]; P = .02). Serious adverse events were reported for 62 patients (31%) in the extracorporeal carbon dioxide removal group and 18 (9%) in the standard care group, including intracranial hemorrhage in 9 patients (4.5%) vs 0 (0%) and bleeding at other sites in 6 (3.0%) vs 1 (0.5%) in the extracorporeal carbon dioxide removal group vs the control group. Overall, 21 patients experienced 22 serious adverse events related to the study device. Conclusions and Relevance: Among patients with acute hypoxemic respiratory failure, the use of extracorporeal carbon dioxide removal to facilitate lower tidal volume mechanical ventilation, compared with conventional low tidal volume mechanical ventilation, did not significantly reduce 90-day mortality. However, due to early termination, the study may have been underpowered to detect a clinically important difference. Trial Registration: ClinicalTrials.gov Identifier: NCT02654327.

Assessing the efficacy and safety of hydroxychloroquine as outpatient treatment of COVID-19: a randomized controlled trial.

BACKGROUND: Identification of therapies to prevent severe COVID-19 remains a priority. We sought to determine whether hydroxychloroquine treatment for outpatients with SARS-CoV-2 infection could prevent hospitalization, mechanical ventilation or death. METHODS: This randomized controlled trial was conducted in Alberta during the first wave of the COVID-19 pandemic without direct contact with participants. Community-dwelling individuals with confirmed SARS-CoV-2 infection (by reverse transcription polymerase chain reaction [RT-PCR] viral ribonucleic acid test) within the previous 4 days, and symptom onset within the previous 12 days, were randomly assigned to oral hydroxychloroquine or matching placebo for 5 days. Enrolment began Apr. 15, 2020. The primary outcome was the composite of hospitalization, invasive mechanical ventilation or death within 30 days. Secondary outcomes included symptom duration and disposition at 30 days. Safety outcomes, such as serious adverse events and mortality, were also ascertained. Outcomes were determined by telephone follow-up and administrative data. RESULTS: Among 4919 individuals with a positive RT-PCR test, 148 (10.2% of a planned 1446 patients) were randomly assigned, 111 to hydroxychloroquine and 37 to placebo. Of the 148 participants, 24 (16.2%) did not start the study drug. Four participants in the hydroxychloroquine group met the primary outcome (4 hospitalizations, 0 mechanical ventilation, 4 survived to 30 days) and none in the placebo group. Hydroxychloroquine did not reduce symptom duration (hazard ratio 0.77, 95% confidence interval 0.49-1.21). Recruitment was paused on May 22, 2020, when a since-retracted publication raised concerns about the safety of hydroxychloroquine for hospitalized patients with COVID-19. Although we had not identified concerns in a safety review, enrolment was slower than expected among those eligible for the study, and cases within the community were decreasing. Recruitment goals were deemed to be unattainable and the trial was not resumed, resulting in a study underpowered to assess the effect of treatment with hydroxychloroquine and safety. INTERPRETATION: There was no evidence that hydroxychloroquine reduced symptom duration or prevented severe outcomes among outpatients with proven COVID-19, but the early termination of our study meant that it was underpowered. TRIAL REGISTRATION: ClinicalTrials.gov, no. NCT04329611.

A Single-Blind Randomized Comparison of Lithium and Lamotrigine as Maintenance Treatments for Managing Bipolar II Disorder.

PURPOSE/BACKGROUND: No study to date has compared lithium and lamotrigine as maintenance mood stabilizers for bipolar II disorder. The aim of this study was to evaluate and compare these two medications in terms of their maintenance efficacy and side effect profile, thus evaluating their comparative cost/benefit profile. METHODS/PROCEDURES: Forty-four subjects with a newly diagnosed bipolar II disorder were randomly assigned to receive either lithium or lamotrigine treatment in a 20-week single-blinded study. Subjects received either slow-release lithium progressively up-titrated to achieve a serum level of 0.8 mEq/L, or lamotrigine increased progressively to a maintenance dose of 200 mg/d. Our primary outcome measure examined daily data on hypomanic and depressive symptoms. Secondary measures evaluated hypomanic and depressive symptom severity, global functioning, and global improvement in hypomanic and depressive symptoms. FINDINGS/RESULTS: We terminated the trial principally because of severe ongoing side effects experienced by many of those receiving lithium, and with additional concerns about initial severe side effects (including psychosis) experienced by several assigned to lamotrigine. Analyses of study completer data for 28 participants suggested comparable efficacy of both medications; however, lamotrigine had a distinctly lower rate of severe side effects across the study. We calculated that if study trends on outcome measures were valid, then an extremely large sample would be required to demonstrate superiority of either drug, thus making it unlikely that any such adequately powered study will be mounted in the future. IMPLICATIONS/CONCLUSIONS: The small sample size limits any definitive conclusions, but our data suggest that lithium and lamotrigine are likely to have equal efficacy as mood stabilizers for those with a bipolar II condition but that, as maintenance treatments, lithium has more distinctive side effects.

Treatments for unruptured intracranial aneurysms.

BACKGROUND: Unruptured intracranial aneurysms are relatively common lesions in the general population, with a prevalence of 3.2%, and are being diagnosed with greater frequency as non-invasive techniques for imaging of intracranial vessels have become increasingly available and used. If not treated, an intracranial aneurysm can be catastrophic. Morbidity and mortality in aneurysmal subarachnoid hemorrhage are substantial: in people with subarachnoid hemorrhage, 12% die immediately, more than 30% die within one month, 25% to 50% die within six months, and 30% of survivors remain dependent. However, most intracranial aneurysms do not bleed, and the best treatment approach is still a matter of debate. OBJECTIVES: To assess the risks and benefits of interventions for people with unruptured intracranial aneurysms. SEARCH METHODS: We searched CENTRAL (Cochrane Library 2020, Issue 5), MEDLINE Ovid, Embase Ovid, and Latin American and Caribbean Health Science Information database (LILACS). We also searched ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform from inception to 25 May 2020. There were no language restrictions. We contacted experts in the field to identify further studies and unpublished trials. SELECTION CRITERIA: Unconfounded, truly randomized trials comparing conservative treatment versus interventional treatments (microsurgical clipping or endovascular coiling) and microsurgical clipping versus endovascular coiling for individuals with unruptured intracranial aneurysms. DATA COLLECTION AND ANALYSIS: Two review authors independently selected trials for inclusion according to the above criteria, assessed trial quality and risk of bias, performed data extraction, and applied the GRADE approach to the evidence. We used an intention-to-treat analysis strategy. MAIN RESULTS: We included two trials in the review: one prospective randomized trial involving 80 participants that compared conservative treatment to endovascular coiling, and one randomized controlled trial involving 136 participants that compared microsurgical clipping to endovascular coiling for unruptured intracranial aneurysms. There was no difference in outcome events between conservative treatment and endovascular coiling groups. New perioperative neurological deficits were more common in participants treated surgically (16/65, 24.6%; 15.8% to 36.3%) versus 7/69 (10.1%; 5.0% to 19.5%); odds ratio (OR) 2.87 (95% confidence interval (CI) 1.02 to 8.93; P = 0.038). Hospitalization for more than five days was more common in surgical participants (30/65, 46.2%; 34.6% to 58.1%) versus 6/69 (8.7%; 4.0% to 17.7%); OR 8.85 (95% CI 3.22 to 28.59; P < 0.001). Clinical follow-up to one year showed 1/48 clipped versus 1/58 coiled participants had died, and 1/48 clipped versus 1/58 coiled participants had become disabled (modified Rankin Scale > 2). All the evidence is of very low quality. AUTHORS' CONCLUSIONS: There is currently insufficient good-quality evidence to support either conservative treatment or interventional treatments (microsurgical clipping or endovascular coiling) for individuals with unruptured intracranial aneurysms. Further randomized trials are required to establish if surgery is a better option than conservative management, and if so, which surgical approach is preferred for which patients. Future studies should include consideration of important characteristics such as participant age, gender, aneurysm size, aneurysm location (anterior circulation and posterior circulation), grade of ischemia (major stroke), and duration of hospitalizations.

Endobronchial Coil System versus Standard-of-Care Medical Management in the Treatment of Subjects with Severe Emphysema.

BACKGROUND: Bronchoscopic lung volume reduction using endobronchial coils is a new treatment for patients with severe emphysema. To date, the benefits have been modest and have been suggested to be much larger in patients with severe hyperinflation and nonmulti-comorbidity. OBJECTIVE: We aimed to evaluate the efficacy and safety of endobronchial coil treatment in a randomized multicenter clinical trial using optimized patient selection. METHOD: Patients with severe emphysema on HRCT scan with severe hyperinflation (residual volume [RV] ≥200% predicted and RV/total lung capacity [TLC] >55%) were randomized to coil treatment or control. Primary outcome measures were differences in the forced expiratory volume in 1 s (FEV1) and St George's Respiratory Questionnaire (SGRQ) total score at 6 months. RESULTS: Due to premature study termination, a total of 120 patients (age 63 ± 7 years, FEV1 29 ± 7% predicted, RV 251 ± 41% predicted, RV/TLC 67 ± 6%, and SGRQ 58 ± 13 points), instead of 210 patients, were randomized. At study termination, 91 patients (57 coil and 34 control) had 6-month results available. Analyses showed significantly greater improvements in favor of the coil group. The increase in FEV1 was greater in the coil group than that in the control group by + 10.3 [+4.7 to +16.0] % and in SGRQ by -10.6 [-15.9 to -5.4] points. At study termination, there were 5 (6.8%) deaths in the coil cohort reported. CONCLUSION: Despite early study termination, coil treatment compared to control results in a significant improvement in the lung function and quality of life benefits for up to 6 months in patients with emphysema and severe hyperinflation. These improvements were of clinical importance but were associated with a higher likelihood of serious adverse events.

Early stopping in clinical PET studies: How to reduce expense and exposure.

Clinical positron emission tomography (PET) research is costly and entails exposing participants to radioactivity. Researchers should therefore aim to include just the number of subjects needed to fulfill the purpose of the study. In this tutorial we show how to apply sequential Bayes Factor testing in order to stop the recruitment of subjects in a clinical PET study as soon as enough data have been collected to make a conclusion. By using simulations, we demonstrate that it is possible to stop a study early, while keeping the number of erroneous conclusions low. We then apply sequential Bayes Factor testing to a real PET data set and show that it is possible to obtain support in favor of an effect while simultaneously reducing the sample size with 30%. Using this procedure allows researchers to reduce expense and radioactivity exposure for a range of effect sizes relevant for PET research.

Sequential chemotherapy regimen of induction with panitumumab and paclitaxel followed by radiotherapy and panitumumab in patients with locally advanced head and neck cancer unfit for platinum derivatives. The phase II, PANTERA/TTCC-2010-06 study.

BACKGROUND: Sequential treatment of Panitumumab (Pb) plus Paclitaxel (Px) as induction treatment (IT) followed by concurrent bioradiotherapy (Bio-RT) with Pb may be an alternative for locally advanced squamous cell carcinoma of the head and neck (LA-SCCHN) in patients ineligible for high-dose cisplatin therapy. METHODS: Phase II, single-arm, multicentre study, with two-stage design, in patients ≥ 18 years with stage III-IVa-b LA-SCCHN unfit for platinum. Patients received Px + Pb (9 weeks) as IT followed by Bio-RT + Pb. Primary endpoint: overall response rate (ORR) after IT, defined as: more than 70% of patients achieving complete response (CR) or partial response (PR) to IT. Secondary end-points: progression-free survival, organ preservation rate, safety profile. RESULTS: Study ended prematurely (51 patients) due to slow recruitment. ORR: 66.7% (95% CI: 53.7-79.6), 8 (15.7%) CR and 26 (51.0%) PR. 39 patients (76%) completed radiotherapy (RT). Pb and/or Px-related adverse events (AEs) grade 3-4: 56.9% during IT and 63.4% during the concomitant phase, of which most common were skin toxicity (33.3%). Five deaths occurred during treatment, two of them (3.9%) were Pb and/or Px-related. CONCLUSIONS: Although underpowered, ORR was higher than the pre-specified boundary for considering the treatment active. Although Px + Pb as IT provides some benefit, the safety profile is worse than expected. To consider Pb + Px as IT as an alternative for platinum-unsuitable LA-SCCHN, further research/investigation would be needed.