Comparison of Bayesian and frequentist monitoring boundaries motivated by the Multiplatform Randomized Clinical Trial.

BACKGROUND: The coronavirus disease 2019 pandemic highlighted the need to conduct efficient randomized clinical trials with interim monitoring guidelines for efficacy and futility. Several randomized coronavirus disease 2019 trials, including the Multiplatform Randomized Clinical Trial (mpRCT), used Bayesian guidelines with the belief that they would lead to quicker efficacy or futility decisions than traditional "frequentist" guidelines, such as spending functions and conditional power. We explore this belief using an intuitive interpretation of Bayesian methods as translating prior opinion about the treatment effect into imaginary prior data. These imaginary observations are then combined with actual observations from the trial to make conclusions. Using this approach, we show that the Bayesian efficacy boundary used in mpRCT is actually quite similar to the frequentist Pocock boundary. METHODS: The mpRCT's efficacy monitoring guideline considered stopping if, given the observed data, there was greater than 99% probability that the treatment was effective (odds ratio greater than 1). The mpRCT's futility monitoring guideline considered stopping if, given the observed data, there was greater than 95% probability that the treatment was less than 20% effective (odds ratio less than 1.2). The mpRCT used a normal prior distribution that can be thought of as supplementing the actual patients' data with imaginary patients' data. We explore the effects of varying probability thresholds and the prior-to-actual patient ratio in the mpRCT and compare the resulting Bayesian efficacy monitoring guidelines to the well-known frequentist Pocock and O'Brien-Fleming efficacy guidelines. We also contrast Bayesian futility guidelines with a more traditional 20% conditional power futility guideline. RESULTS: A Bayesian efficacy and futility monitoring boundary using a neutral, weakly informative prior distribution and a fixed probability threshold at all interim analyses is more aggressive than the commonly used O'Brien-Fleming efficacy boundary coupled with a 20% conditional power threshold for futility. The trade-off is that more aggressive boundaries tend to stop trials earlier, but incur a loss of power. Interestingly, the Bayesian efficacy boundary with 99% probability threshold is very similar to the classic Pocock efficacy boundary. CONCLUSIONS: In a pandemic where quickly weeding out ineffective treatments and identifying effective treatments is paramount, aggressive monitoring may be preferred to conservative approaches, such as the O'Brien-Fleming boundary. This can be accomplished with either Bayesian or frequentist methods.

Gilteritinib as Post-Transplant Maintenance for AML With Internal Tandem Duplication Mutation of FLT3.

PURPOSE: Allogeneic hematopoietic cell transplantation (HCT) improves outcomes for patients with AML harboring an internal tandem duplication mutation of FLT3 (FLT3-ITD) AML. These patients are routinely treated with a FLT3 inhibitor after HCT, but there is limited evidence to support this. Accordingly, we conducted a randomized trial of post-HCT maintenance with the FLT3 inhibitor gilteritinib (ClinicalTrials.gov identifier: NCT02997202) to determine if all such patients benefit or if detection of measurable residual disease (MRD) could identify those who might benefit. METHODS: Adults with FLT3-ITD AML in first remission underwent HCT and were randomly assigned to placebo or 120 mg once daily gilteritinib for 24 months after HCT. The primary end point was relapse-free survival (RFS). Secondary end points included overall survival (OS) and the effect of MRD pre- and post-HCT on RFS and OS. RESULTS: Three hundred fifty-six participants were randomly assigned post-HCT to receive gilteritinib or placebo. Although RFS was higher in the gilteritinib arm, the difference was not statistically significant (hazard ratio [HR], 0.679 [95% CI, 0.459 to 1.005]; two-sided P = .0518). However, 50.5% of participants had MRD detectable pre- or post-HCT, and, in a prespecified subgroup analysis, gilteritinib was beneficial in this population (HR, 0.515 [95% CI, 0.316 to 0.838]; P = .0065). Those without detectable MRD showed no benefit (HR, 1.213 [95% CI, 0.616 to 2.387]; P = .575). CONCLUSION: Although the overall improvement in RFS was not statistically significant, RFS was higher for participants with detectable FLT3-ITD MRD pre- or post-HCT who received gilteritinib treatment. To our knowledge, these data are among the first to support the effectiveness of MRD-based post-HCT therapy.

Evaluating treatment effects in group sequential multivariate longitudinal studies with covariate adjustment.

Jeffries et al. (2018) investigated testing for a treatment difference in the setting of a randomized clinical trial with a single outcome measured longitudinally over a series of common follow-up times while adjusting for covariates. That paper examined the null hypothesis of no difference at any follow-up time versus the alternative of a difference for at least one follow-up time. We extend those results here by considering multivariate outcome measurements, where each individual outcome is examined at common follow-up times. We consider the case where there is interest in first testing for a treatment difference in a global function of the outcomes (e.g., weighted average or sum) with subsequent interest in examining the individual outcomes, should the global function show a treatment difference. Testing is conducted for each follow-up time and may be performed in the setting of a group sequential trial. Testing procedures are developed to determine follow-up times for which a global treatment difference exists and which individual combinations of outcome and follow-up time show evidence of a difference while controlling for multiplicity in outcomes, follow-up, and interim analyses. These approaches are examined in a study evaluating the effects of tissue plasminogen activator on longitudinally obtained stroke severity measurements.

Treatment for Mild Chronic Hypertension during Pregnancy.

BACKGROUND: The benefits and safety of the treatment of mild chronic hypertension (blood pressure, <160/100 mm Hg) during pregnancy are uncertain. Data are needed on whether a strategy of targeting a blood pressure of less than 140/90 mm Hg reduces the incidence of adverse pregnancy outcomes without compromising fetal growth. METHODS: In this open-label, multicenter, randomized trial, we assigned pregnant women with mild chronic hypertension and singleton fetuses at a gestational age of less than 23 weeks to receive antihypertensive medications recommended for use in pregnancy (active-treatment group) or to receive no such treatment unless severe hypertension (systolic pressure, ≥160 mm Hg; or diastolic pressure, ≥105 mm Hg) developed (control group). The primary outcome was a composite of preeclampsia with severe features, medically indicated preterm birth at less than 35 weeks' gestation, placental abruption, or fetal or neonatal death. The safety outcome was small-for-gestational-age birth weight below the 10th percentile for gestational age. Secondary outcomes included composites of serious neonatal or maternal complications, preeclampsia, and preterm birth. RESULTS: A total of 2408 women were enrolled in the trial. The incidence of a primary-outcome event was lower in the active-treatment group than in the control group (30.2% vs. 37.0%), for an adjusted risk ratio of 0.82 (95% confidence interval [CI], 0.74 to 0.92; P<0.001). The percentage of small-for-gestational-age birth weights below the 10th percentile was 11.2% in the active-treatment group and 10.4% in the control group (adjusted risk ratio, 1.04; 95% CI, 0.82 to 1.31; P = 0.76). The incidence of serious maternal complications was 2.1% and 2.8%, respectively (risk ratio, 0.75; 95% CI, 0.45 to 1.26), and the incidence of severe neonatal complications was 2.0% and 2.6% (risk ratio, 0.77; 95% CI, 0.45 to 1.30). The incidence of any preeclampsia in the two groups was 24.4% and 31.1%, respectively (risk ratio, 0.79; 95% CI, 0.69 to 0.89), and the incidence of preterm birth was 27.5% and 31.4% (risk ratio, 0.87; 95% CI, 0.77 to 0.99). CONCLUSIONS: In pregnant women with mild chronic hypertension, a strategy of targeting a blood pressure of less than 140/90 mm Hg was associated with better pregnancy outcomes than a strategy of reserving treatment only for severe hypertension, with no increase in the risk of small-for-gestational-age birth weight. (Funded by the National Heart, Lung, and Blood Institute; CHAP ClinicalTrials.gov number, NCT02299414.).

Combined haploidentical and cord blood transplantation for refractory severe aplastic anaemia and hypoplastic myelodysplastic syndrome.

Umbilical cord blood (UCB) transplantation is a potentially curative treatment for patients with refractory severe aplastic anaemia (SAA), but has historically been associated with delayed engraftment and high graft failure and mortality rates. We conducted a prospective phase 2 trial to assess outcome of an allogeneic transplant regimen that co-infused a single UCB unit with CD34+ -selected cells from a haploidentical relative. Among 29 SAA patients [including 10 evolved to myelodysplastic syndrome (MDS)] who underwent the haplo cord transplantation (median age 20 years), 97% had neutrophil recovery (median 10 days), and 93% had platelet recovery (median 32 days). Early myeloid engraftment was from the haplo donor and was gradually replaced by durable engraftment from UCB in most patients. The cumulative incidences of grade II-IV acute and chronic graft-versus-host disease (GVHD) were 21% and 41%, respectively. With a median follow-up of 7·5 years, overall survival was 83% and GVHD/relapse-free survival was 69%. Patient- and transplant-related factors had no impact on engraftment and survival although transplants with haplo-versus-cord killer-cell immunoglobulin-like receptor (KIR) ligand incompatibility had delayed cord engraftment. Our study shows haplo cord transplantation is associated with excellent engraftment and long-term outcome, providing an alternative option for patients with refractory SAA and hypoplastic MDS who lack human leucocyte antigen (HLA)-matched donors.

Myeloablative versus Reduced-Intensity Conditioning for Hematopoietic Cell Transplantation in Acute Myelogenous Leukemia and Myelodysplastic Syndromes-Long-Term Follow-Up of the BMT CTN 0901 Clinical Trial.

Several prospective randomized trials comparing conditioning intensity before allogeneic hematopoietic cell transplantation (HCT) have been performed, with conflicting results. Although reduced-intensity conditioning (RIC) leads to lower treatment-related mortality (TRM), this is offset by higher rates of relapse. Long-term follow-up of randomized comparative trials are limited. Here we present long-term follow-up of a randomized comparison of myeloablative conditioning (MAC) compared with RIC before HCT for acute myelogenous leukemia (AML) or myelodysplasia (MDS). Long-term comparative analyses of overall survival, relapse, and relapse-free survival were performed. Patients age 18 to 65 years with <5% marrow myeloblasts were randomized to receive MAC (n = 135) or RIC (n = 137), followed by HCT from an HLA-matched donor. The primary endpoint of the trial was an 18-month pointwise comparison of overall survival. The analyses were performed using a proportional hazards model. The median follow-up of the entire cohort was 51 months. At 4 years, the transplant-related mortality (TRM) was 25.1% for MAC, compared with 9.9% for RIC (P < .001). Patients who received RIC had a significantly higher risk of relapse compared to those who received MAC (hazard ratio [HR], 4.06; 95% CI, 2.59 to 6.35; P < 0.001). Among the patients who relapsed after HCT, postrelapse survival was similar at 3 years (24% for MAC and 26% for RIC). Overall survival was superior for patients who received MAC compared to those who received RIC (HR, 1.54; 95% CI, 1.07 to 2.2; P = .03). Our data show that patients who received MAC were at higher risk of late TRM compared with those who received RIC; however, because of the exceedingly high rates of relapse in the RIC arm, overall survival remained significantly better for patients who received MAC. Among patients with MDS or AML eligible for either MAC or RIC regimens, long-term follow up demonstrates a survival advantage for patients who received MAC.

Three prophylaxis regimens (tacrolimus, mycophenolate mofetil, and cyclophosphamide; tacrolimus, methotrexate, and bortezomib; or tacrolimus, methotrexate, and maraviroc) versus tacrolimus and methotrexate for prevention of graft-versus-host disease with haemopoietic cell transplantation with reduced-intensity conditioning: a randomised phase 2 trial with a non-randomised contemporaneous control group (BMT CTN 1203).

BACKGROUND: Prevention of graft-versus-host disease (GvHD) without malignant relapse is the overall goal of allogeneic haemopoietic cell transplantation (HCT). We aimed to evaluate regimens using either maraviroc, bortezomib, or post-transplantation cyclophosphamide for GvHD prophylaxis compared with controls receiving the combination of tacrolimus and methotrexate using a novel composite primary endpoint to identify the most promising intervention to be further tested in a phase 3 trial. METHODS: In this prospective multicentre phase 2 trial, adult patients aged 18-75 years who received reduced-intensity conditioning HCT were randomly assigned (1:1:1) by random block sizes to tacrolimus, mycophenolate mofetil, and post-transplantation cyclophosphamide (cyclophosphamide 50 mg/kg on days 3 and 4, followed by tacrolimus starting on day 5 and mycophenolate mofetil starting on day 5 at 15 mg/kg three times daily not to exceed 1 g from day 5 to day 35); tacrolimus, methotrexate, and bortezomib (bortezomib 1·3 mg/m2 intravenously on days 1, 4, and 7 after HCT); or tacrolimus, methotrexate, and maraviroc (maraviroc 300 mg orally twice daily from day -3 to day 30 after HCT). Methotrexate was administered as a 15 mg/m2 intravenous bolus on day 1 and 10 mg/m2 intravenous bolus on days 3, 6, and 11 after HCT; tacrolimus was given intravenously at a dose of 0·05 mg/kg twice daily (or oral equivalent) starting on day -3 (except the post-transplantation cyclophosphamide, as indicated), with a target level of 5-15 ng/mL. Tacrolimus was continued at least until day 90 and was tapered off by day 180. Each study group was compared separately to a contemporary non-randomised prospective cohort of patients (control group) who fulfilled the same eligibility criteria as the trial, but who were treated with tacrolimus and methotrexate at centres not participating in the trial. The primary endpoint (GvHD-free, relapse-free survival [GRFS]) was defined as the time from HCT to onset of grade 3-4 acute GvHD, chronic GvHD requiring systemic immunosuppression, disease relapse, or death. The study was analysed by modified intention to treat. The study is closed to accrual and this is the planned analysis. This trial is registered with ClinicalTrials.gov, number NCT02208037. FINDINGS: Between Nov 17, 2014, and May 18, 2016, 273 patients from 31 US centres were randomly assigned to the three study arms: 89 to tacrolimus, methotrexate, and bortezomib; 92 to tacrolimus, methotrexate, and maraviroc; 92 to tacrolimus, mycophenolate mofetil, and post-transplantation cyclophosphamide; and six were excluded. Between Aug 1, 2014, and Sept 14, 2016, 224 controls received tacrolimus and methotrexate. Controls were generally well matched except for more frequent comorbidities than the intervention groups and a different distribution of types of conditioning regimens used. Compared with controls, the hazard ratio for GRFS was 0·72 (90% CI 0·54-0·94; p=0·044) for tacrolimus, mycophenolate mofetil, and post-transplantation cyclophosphamide, 0·98 (0·76-1·27; p=0·92) for tacrolimus, methotrexate, and bortezomib, and 1·10 (0·86-1·41; p=0·49) for tacrolimus, methotrexate, and maraviroc. 238 patients experienced grade 3 or 4 toxicities: 12 (13%) had grade 3 and 67 (73%) grade 4 events with tacrolimus, mycophenolate mofetil, and post-transplantation cyclophosphamide; ten (11%) had grade 3 and 68 (76%) had grade 4 events with tacrolimus, methotrexate, and bortezomib; and 18 (20%) had grade 3 and 63 (68%) had grade 4 events with tacrolimus, methotrexate, and maraviroc. The most common toxicities were haematological (77 [84%] for tacrolimus, mycophenolate mofetil, and post-transplantation cyclophosphamide; 73 [82%] for tacrolimus, methotrexate, and bortezomib; and 78 [85%] for tacrolimus, methotrexate, and maraviroc) and cardiac (43 [47%], 44 [49%], and 43 [47%], respectively). INTERPRETATION: Tacrolimus, mycophenolate mofetil, and post-transplantation cyclophosphamide was the most promising intervention, yielding the best GRFS; this regimen is thus being prospectively compared with tacrolimus and methotrexate in a phase 3 randomised trial. FUNDING: US National Health, Lung, and Blood Institute; National Cancer Institute; National Institute of Allergy and Infectious Disease; and Millennium Pharmaceuticals.

Detecting treatment differences in group sequential longitudinal studies with covariate adjustment.

In longitudinal studies comparing two treatments over a series of common follow-up measurements, there may be interest in determining if there is a treatment difference at any follow-up period when there may be a non-monotone treatment effect over time. To evaluate this question, Jeffries and Geller (2015) examined a number of clinical trial designs that allowed adaptive choice of the follow-up time exhibiting the greatest evidence of treatment difference in a group sequential testing setting with Gaussian data. The methods are applicable when a few measurements were taken at prespecified follow-up periods. Here, we test the intersection null hypothesis of no difference at any follow-up time versus the alternative that there is a difference for at least one follow-up time. Results of Jeffries and Geller (2015) are extended by considering a broader range of modeled data and the inclusion of covariates using generalized estimating equations. Testing procedures are developed to determine a set of follow-up times that exhibit a treatment difference that accounts for multiplicity in follow-up times and interim analyses.

Myeloablative Versus Reduced-Intensity Hematopoietic Cell Transplantation for Acute Myeloid Leukemia and Myelodysplastic Syndromes.

Purpose The optimal regimen intensity before allogeneic hematopoietic cell transplantation (HCT) is unknown. We hypothesized that lower treatment-related mortality (TRM) with reduced-intensity conditioning (RIC) would result in improved overall survival (OS) compared with myeloablative conditioning (MAC). To test this hypothesis, we performed a phase III randomized trial comparing MAC with RIC in patients with acute myeloid leukemia or myelodysplastic syndromes. Patients and Methods Patients age 18 to 65 years with HCT comorbidity index ≤ 4 and < 5% marrow myeloblasts pre-HCT were randomly assigned to receive MAC (n = 135) or RIC (n = 137) followed by HCT from HLA-matched related or unrelated donors. The primary end point was OS 18 months post-random assignment based on an intent-to-treat analysis. Secondary end points included relapse-free survival (RFS) and TRM. Results Planned enrollment was 356 patients; accrual ceased at 272 because of high relapse incidence with RIC versus MAC (48.3%; 95% CI, 39.6% to 56.4% and 13.5%; 95% CI, 8.3% to 19.8%, respectively; P < .001). At 18 months, OS for patients in the RIC arm was 67.7% (95% CI, 59.1% to 74.9%) versus 77.5% (95% CI, 69.4% to 83.7%) for those in the MAC arm (difference, 9.8%; 95% CI, -0.8% to 20.3%; P = .07). TRM with RIC was 4.4% (95% CI, 1.8% to 8.9%) versus 15.8% (95% CI, 10.2% to 22.5%) with MAC ( P = .002). RFS with RIC was 47.3% (95% CI, 38.7% to 55.4%) versus 67.8% (95% CI, 59.1% to 75%) with MAC ( P < .01). Conclusion OS was higher with MAC, but this was not statistically significant. RIC resulted in lower TRM but higher relapse rates compared with MAC, with a statistically significant advantage in RFS with MAC. These data support the use of MAC as the standard of care for fit patients with acute myeloid leukemia or myelodysplastic syndromes.

Effect of high-dose plerixafor on CD34+ cell mobilization in healthy stem cell donors: results of a randomized crossover trial.

Hematopoietic stem cells can be mobilized from healthy donors using single-agent plerixafor without granulocyte colony-stimulating factor and, following allogeneic transplantation, can result in sustained donor-derived hematopoiesis. However, when a single dose of plerixafor is administered at a conventional 240 µg/kg dose, approximately one-third of donors will fail to mobilize the minimally acceptable dose of CD34+ cells needed for allogeneic transplantation. We conducted an open-label, randomized trial to assess the safety and activity of high-dose (480 µg/kg) plerixafor in CD34+ cell mobilization in healthy donors. Subjects were randomly assigned to receive either a high dose or a conventional dose (240 µg/kg) of plerixafor, given as a single subcutaneous injection, in a two-sequence, two-period, crossover design. Each treatment period was separated by a 2-week minimum washout period. The primary endpoint was the peak CD34+ count in the blood, with secondary endpoints of CD34+ cell area under the curve (AUC), CD34+ count at 24 hours, and time to peak CD34+ following the administration of plerixafor. We randomized 23 subjects to the two treatment sequences and 20 subjects received both doses of plerixafor. Peak CD34+ count in the blood was significantly increased (mean 32.2 versus 27.8 cells/µL, P=0.0009) and CD34+ cell AUC over 24 hours was significantly increased (mean 553 versus 446 h cells/µL, P<0.0001) following the administration of the 480 µg/kg dose of plerixafor compared with the 240 µg/kg dose. Remarkably, of seven subjects who mobilized poorly (peak CD34+ ≤20 cells/µL) after the 240 µg/kg dose of plerixafor, six achieved higher peak CD34+ cell numbers and all achieved higher CD34+ AUC over 24 hours after the 480 µg/kg dose. No grade 3 or worse drug-related adverse events were observed. This study establishes that high-dose plerixafor can be safely administered in healthy donors and mobilizes greater numbers of CD34+ cells than conventional-dose plerixafor, which may improve CD34+ graft yields and reduce the number of apheresis procedures needed to collect sufficient stem cells for allogeneic transplantation. (ClinicalTrials.gov, identifier: NCT00322127).

Two-Year Outcomes of Surgical Treatment of Severe Ischemic Mitral Regurgitation.

BACKGROUND: In a randomized trial comparing mitral-valve repair with mitral-valve replacement in patients with severe ischemic mitral regurgitation, we found no significant difference in the left ventricular end-systolic volume index (LVESVI), survival, or adverse events at 1 year after surgery. However, patients in the repair group had significantly more recurrences of moderate or severe mitral regurgitation. We now report the 2-year outcomes of this trial. METHODS: We randomly assigned 251 patients to mitral-valve repair or replacement. Patients were followed for 2 years, and clinical and echocardiographic outcomes were assessed. RESULTS: Among surviving patients, the mean (±SD) 2-year LVESVI was 52.6±27.7 ml per square meter of body-surface area with mitral-valve repair and 60.6±39.0 ml per square meter with mitral-valve replacement (mean changes from baseline, -9.0 ml per square meter and -6.5 ml per square meter, respectively). Two-year mortality was 19.0% in the repair group and 23.2% in the replacement group (hazard ratio in the repair group, 0.79; 95% confidence interval, 0.46 to 1.35; P=0.39). The rank-based assessment of LVESVI at 2 years (incorporating deaths) showed no significant between-group difference (z score=-1.32, P=0.19). The rate of recurrence of moderate or severe mitral regurgitation over 2 years was higher in the repair group than in the replacement group (58.8% vs. 3.8%, P<0.001). There were no significant between-group differences in rates of serious adverse events and overall readmissions, but patients in the repair group had more serious adverse events related to heart failure (P=0.05) and cardiovascular readmissions (P=0.01). On the Minnesota Living with Heart Failure questionnaire, there was a trend toward greater improvement in the replacement group (P=0.07). CONCLUSIONS: In patients undergoing mitral-valve repair or replacement for severe ischemic mitral regurgitation, we observed no significant between-group difference in left ventricular reverse remodeling or survival at 2 years. Mitral regurgitation recurred more frequently in the repair group, resulting in more heart-failure-related adverse events and cardiovascular admissions. (Funded by the National Institutes of Health and Canadian Institutes of Health Research; ClinicalTrials.gov number, NCT00807040.).

Smart Technology in Lung Disease Clinical Trials.

This article describes the use of smart technology by investigators and patients to facilitate lung disease clinical trials and make them less costly and more efficient. By "smart technology" we include various electronic media, such as computer databases, the Internet, and mobile devices. We first describe the use of electronic health records for identifying potential subjects and then discuss electronic informed consent. We give several examples of using the Internet and mobile technology in clinical trials. Interventions have been delivered via the World Wide Web or via mobile devices, and both have been used to collect outcome data. We discuss examples of new electronic devices that recently have been introduced to collect health data. While use of smart technology in clinical trials is an exciting development, comparison with similar interventions applied in a conventional manner is still in its infancy. We discuss advantages and disadvantages of using this omnipresent, powerful tool in clinical trials, as well as directions for future research.

Patient-reported physical functioning predicts the success of hematopoietic cell transplantation (BMT CTN 0902).

BACKGROUND: In hematopoietic cell transplantation (HCT), current risk adjustment strategies are based on clinical and disease-related variables. Although patient-reported outcomes (PROs) predict mortality in multiple cancers, they have been less well studied within HCT. Improvements in risk adjustment strategies in HCT would inform patient selection, patient counseling, and quality reporting. The objective of the current study was to determine whether pre-HCT PROs, in particular physical health, predict survival among patients undergoing autologous or allogeneic transplantation. METHODS: In this secondary analysis, the authors studied pre-HCT PROs that were reported by 336 allogeneic and 310 autologous HCT recipients enrolled in the Blood and Marrow Transplant Clinical Trials Network (BMT CTN) 0902 protocol, a study with broad representation of patients who underwent transplantation in the United States. RESULTS: Among allogeneic HCT recipients, the pre-HCT Medical Outcomes Study Short Form-36 Health Survey (SF-36) physical component summary (PCS) scale independently predicted overall mortality (hazards ratio, 1.40 per 10-point decrease; P<.001) and performed at least as well as currently used, non-PRO risk indices. Survival probability estimates at 1 year for the first, second, third, and fourth quartiles of the baseline PCS were 50%, 65%, 75%, and 83%, respectively. Early post-HCT decreases in PCS were associated with higher overall and treatment-related mortality. When adjusted for patient variables included in the US Stem Cell Therapeutic Outcomes Database model for transplant center-specific reporting, the SF-36 PCS retained independent prognostic value. CONCLUSIONS: PROs have the potential to improve prognostication in HCT. The authors recommend the routine collection of PROs before HCT, and consideration of the incorporation of PROs into risk adjustment for quality reporting.

Robust Association Tests for the Replication of Genome-Wide Association Studies.

In genome-wide association study (GWAS), robust genetic association tests such as maximum of three CATTs (MAX3), each corresponding to recessive, additive, and dominant genetic models, the minimum p value of Pearson's Chi-square test with 2 degrees of freedom, and CATT based on additive genetic model (MIN2), genetic model selection (GMS), and genetic model exclusion (GME) methods have been shown to provide better power performance under wide range of underlying genetic models. In this paper, we demonstrate how these robust tests can be applied to the replication study of GWAS and how the overall statistical significance can be evaluated using the combined test formed by p values of the discovery and replication studies.

Negative Epistasis between Sickle and Foetal Haemoglobin Suggests a Reduction in Protection against Malaria.

BACKGROUND: Haemoglobin variants, Sickle (HbS) and foetal (HbF) have been associated with malaria protection. This study explores epistatic interactions between HbS and HbF on malaria infection. METHODS: The study was conducted between March 2004 and December 2013 within the sickle cell disease (SCD) programme at Muhimbili National Hospital, Tanzania. SCD status was categorized into HbAA, HbAS and HbSS using hemoglobin electrophoresis and High Performance Liquid Chromatography (HPLC). HbF levels were determined by HPLC. Malaria was diagnosed using rapid diagnostic test and/or blood film. Logistic regression and generalized estimating equations models were used to evaluate associations between SCD status, HbF and malaria. FINDINGS: 2,049 individuals with age range 0-70 years, HbAA 311(15.2%), HbAS 241(11.8%) and HbSS 1,497(73.1%) were analysed. At enrolment, malaria prevalence was significantly higher in HbAA 13.2% compared to HbAS 1.24% and HbSS 1.34% (p<0.001). Mean HbF was lower in those with malaria compared to those without malaria in HbAA (0.43% vs 0.82%) but was the reverse in HbSS (8.10% vs 5.59%). An increase in HbF was associated with a decrease in risk of malaria OR=0.50 (95%CI: 0.28, 0.90; p=0.021) in HbAA, whereas for HbSS the risk of malaria increased OR=2.94 (1.44, 5.98; p=0.003). A similar pattern was seen during multiple visits; HbAA OR=0.52 (0.34, 0.80; p=0.003) vs HbSS OR=2.01 (1.27, 3.23; p=0.003). CONCLUSION: Higher prevalence of malaria in HbAA compared to HbAS and HbSS confirmed the protective effect of HbS. Lower prevalence of malaria in HbAA with high HbF supports a protective effect of HbF. However, in HbSS, the higher prevalence of malaria with high levels of HbF suggests loss of malaria protection. This is the first epidemiological study to suggest a negative epistasis between HbF and HbS on malaria.

Surgical ablation of atrial fibrillation during mitral-valve surgery.

BACKGROUND: Among patients undergoing mitral-valve surgery, 30 to 50% present with atrial fibrillation, which is associated with reduced survival and increased risk of stroke. Surgical ablation of atrial fibrillation has been widely adopted, but evidence regarding its safety and effectiveness is limited. METHODS: We randomly assigned 260 patients with persistent or long-standing persistent atrial fibrillation who required mitral-valve surgery to undergo either surgical ablation (ablation group) or no ablation (control group) during the mitral-valve operation. Patients in the ablation group underwent further randomization to pulmonary-vein isolation or a biatrial maze procedure. All patients underwent closure of the left atrial appendage. The primary end point was freedom from atrial fibrillation at both 6 months and 12 months (as assessed by means of 3-day Holter monitoring). RESULTS: More patients in the ablation group than in the control group were free from atrial fibrillation at both 6 and 12 months (63.2% vs. 29.4%, P<0.001). There was no significant difference in the rate of freedom from atrial fibrillation between patients who underwent pulmonary-vein isolation and those who underwent the biatrial maze procedure (61.0% and 66.0%, respectively; P=0.60). One-year mortality was 6.8% in the ablation group and 8.7% in the control group (hazard ratio with ablation, 0.76; 95% confidence interval, 0.32 to 1.84; P=0.55). Ablation was associated with more implantations of a permanent pacemaker than was no ablation (21.5 vs. 8.1 per 100 patient-years, P=0.01). There were no significant between-group differences in major cardiac or cerebrovascular adverse events, overall serious adverse events, or hospital readmissions. CONCLUSIONS: The addition of atrial fibrillation ablation to mitral-valve surgery significantly increased the rate of freedom from atrial fibrillation at 1 year among patients with persistent or long-standing persistent atrial fibrillation, but the risk of implantation of a permanent pacemaker was also increased. (Funded by the National Institutes of Health and the Canadian Institutes of Health Research; ClinicalTrials.gov number, NCT00903370.).

Longitudinal clinical trials with adaptive choice of follow-up time.

In longitudinal studies comparing two treatments with a maximum follow-up time there may be interest in examining treatment effects for intermediate follow-up times. One motivation may be to identify the time period with greatest treatment difference when there is a non-monotone treatment effect over time; another motivation may be to make the trial more efficient in terms of time to reach a decision on whether a new treatment is efficacious or not. Here, we test the composite null hypothesis of no difference at any follow-up time versus the alternative that there is a difference at at least one follow-up time. The methods are applicable when a few measurements are taken over time, such as in early longitudinal trials or in ancillary studies. Suppose the test statistic Z(t(k)) will be used to test the hypothesis of no treatment effect at a fixed follow-up time t(k). In this context a common approach is to perform a pilot study on N1 subjects, and evaluate the treatment effect at the fixed time points t1,…,t(K) and choose t* as the value of t(k) for which Z(t(k)) is maximized. Having chosen t* a second trial can be designed. In a setting with group sequential testing we consider several adaptive alternatives to this approach that treat the pilot and second trial as a seamless, combined entity and evaluate Type I error and power characteristics. The adaptive designs we consider typically have improved power over the common, separate trial approach.

Management practices and major infections after cardiac surgery.

BACKGROUND: Infections are the most common noncardiac complication after cardiac surgery, but their incidence across a broad range of operations, as well as the management factors that shape infection risk, remain unknown. OBJECTIVES: This study sought to prospectively examine the frequency of post-operative infections and associated mortality, and modifiable management practices predictive of infections within 65 days from cardiac surgery. METHODS: This study enrolled 5,158 patients and analyzed independently adjudicated infections using a competing risk model (with death as the competing event). RESULTS: Nearly 5% of patients experienced major infections. Baseline characteristics associated with increased infection risk included chronic lung disease (hazard ratio [HR]: 1.66; 95% confidence interval [CI]: 1.21 to 2.26), heart failure (HR: 1.47; 95% CI: 1.11 to 1.95), and longer surgery (HR: 1.31; 95% CI: 1.21 to 1.41). Practices associated with reduced infection risk included prophylaxis with second-generation cephalosporins (HR: 0.70; 95% CI: 0.52 to 0.94), whereas post-operative antibiotic duration >48 h (HR: 1.92; 95% CI: 1.28 to 2.88), stress hyperglycemia (HR: 1.32; 95% CI: 1.01 to 1.73); intubation time of 24 to 48 h (HR: 1.49; 95% CI: 1.04 to 2.14); and ventilation >48 h (HR: 2.45; 95% CI: 1.66 to 3.63) were associated with increased risk. HRs for infection were similar with either <24 h or <48 h of antibiotic prophylaxis. There was a significant but differential effect of transfusion by surgery type (excluding left ventricular assist device procedures/transplant) (HR: 1.13; 95% CI: 1.07 to 1.20). Major infections substantially increased mortality (HR: 10.02; 95% CI: 6.12 to 16.39). CONCLUSIONS: Major infections dramatically affect survival and readmissions. Second-generation cephalosporins were strongly associated with reduced major infection risk, but optimal duration of antibiotic prophylaxis requires further study. Given practice variations, considerable opportunities exist for improving outcomes and preventing readmissions. (Management Practices and Risk of Infection Following Cardiac Surgery; NCT01089712).