Intention-to-treat outcomes utilising a stringent event definition in children and young people treated with tisagenlecleucel for r/r ALL through a national access scheme.

CAR T-cell therapy has transformed relapsed/refractory (r/r) B-cell precursor acute lymphoblastic leukaemia (B-ALL) management and outcomes, but following CAR T infusion, interventions are often needed. In a UK multicentre study, we retrospectively evaluated tisagenlecleucel outcomes in all eligible patients, analysing overall survival (OS) and event-free survival (EFS) with standard and stringent definitions, the latter including measurable residual disease (MRD) emergence and further anti-leukaemic therapy. Both intention-to-treat and infused cohorts were considered. We collected data on feasibility of delivery, manufacture, toxicity, cause of therapy failure and followed patients until death from any cause. Of 142 eligible patients, 125 received tisagenlecleucel, 115/125 (92%) achieved complete remission (CR/CRi). Severe cytokine release syndrome and neurotoxicity occurred in 16/123 (13%) and 10/123 (8.1%), procedural mortality was 3/126 (2.4%). The 2-year intent to treat OS and EFS were 65.2% (95%CI 57.2-74.2%) and 46.5% (95%CI 37.6-57.6%), 2-year intent to treat stringent EFS was 35.6% (95%CI 28.1-44.9%). Median OS was not reached. Sixty-two responding patients experienced CAR T failure by the stringent event definition. Post failure, 1-year OS and standard EFS were 61.2% (95%CI 49.3-75.8) and 55.3% (95%CI 43.6-70.2). Investigation of CAR T-cell therapy for B-ALL delivered on a country-wide basis, including following patients beyond therapy failure, provides clinicians with robust outcome measures. Previously, outcomes post CAR T-cell therapy failure were under-reported. Our data show that patients can be successfully salvaged in this context with good short-term survival.

Study Protocol for the Social Interventions for Support During Treatment for Endometrial Cancer and Recurrence (SISTER) study: a community engaged national randomized trial.

Aim: Social isolation in cancer patients is correlated with prognosis and is a potential mediator of treatment completion. Black women with endometrial cancer (EC) are at increased risk for social isolation when compared with White patients. We developed the Social Interventions for Support during Treatment for Endometrial Cancer and Recurrence (SISTER) study to compare and evaluate interventions to address social isolation among Black women with high-risk EC in USA. The primary objective of the SISTER study is to determine whether virtual support interventions improve treatment completion compared with Enhanced Usual Care. Secondary objectives include comparing effectiveness virtual evidence-based interventions and evaluating barriers and facilitators to social support delivery. Patients & methods: This is a multi-site prospective, open-label, community-engaged randomized controlled trial, consisting of three intervention arms: enhanced usual care, facilitated support group and one-to-one peer support. Primary outcome will be measured using relative dose. Qualitative semi-structured interviews will be conducted with a subset of participants to contextualize the relative degree or lack thereof of social isolation, over time. Data analysis: Primary analysis will be based on an intent-to-treat analysis. Multivariable analysis will be performed to determine the effect of the intervention on the primary and secondary outcomes of interest, relative dose and social isolation score. Semi-structured interviews will be qualitatively analyzed using inductive and deductive approaches of content analysis. Discussion/conclusion: Endometrial cancer mortality disproportionately affects Black women, and social isolation contributes to this disparity. The SISTER study aims to identify whether and to what extent differing social support vehicles improve key outcomes for Black women in the United States with high-risk EC. Clinical Trial Registration: NCT04930159 (ClinicalTrials.gov).

Cyclosporine vs. tacrolimus after liver transplantation for primary sclerosing cholangitis - a propensity score-matched intention-to-treat analysis.

BACKGROUND & AIMS: There is controversy regarding the optimal calcineurin inhibitor type after liver transplant(ation) (LT) for primary sclerosing cholangitis (PSC). We compared tacrolimus with cyclosporine in a propensity score-matched intention-to-treat analysis based on registries representing nearly all LTs in Europe and the US. METHODS: From the European Liver Transplant Registry (ELTR) and Scientific Registry of Transplant Recipients (SRTR), we included adult patients with PSC undergoing a primary LT between 2000-2020. Patients initially treated with cyclosporine were propensity score-matched 1:3 with those initially treated with tacrolimus. The primary outcomes were patient and graft survival rates. RESULTS: The propensity score-matched sample comprised 399 cyclosporine-treated and 1,197 tacrolimus-treated patients with PSC. During a median follow-up of 7.4 years (IQR 2.3-12.8, 12,579.2 person-years), there were 480 deaths and 231 re-LTs. The initial tacrolimus treatment was superior to cyclosporine in terms of patient and graft survival, with 10-year patient survival estimates of 72.8% for tacrolimus and 65.2% for cyclosporine (p <0.001) and 10-year graft survival estimates of 62.4% and 53.8% (p <0.001), respectively. These findings were consistent in the subgroups according to age, sex, registry (ELTR vs. SRTR), time period of LT, MELD score, and diabetes status. The acute rejection rates were similar between groups. In the multivariable Cox regression analysis, tacrolimus (hazard ratio 0.72, p <0.001) and mycophenolate use (hazard ratio 0.82, p = 0.03) were associated with a reduced risk of graft loss or death, whereas steroid use was not significant. CONCLUSIONS: Tacrolimus is associated with better patient and graft survival rates than cyclosporine and should be the standard calcineurin inhibitor used after LT for patients with PSC. IMPACT AND IMPLICATIONS: The optimal calcineurin inhibitor to use after liver transplantation in patients with primary sclerosing cholangitis has yet to be firmly established. Since randomized trials with long follow-up are unlikely to be performed, multicontinental long-term registry data are essential in informing clinical practices. Our study supports the practice of using tacrolimus instead of cyclosporine in the initial immunosuppressive regimen after liver transplantation for patients with primary sclerosing cholangitis. The retrospective registry-based design is a limitation.

Resection rates and intention-to-treat outcomes in borderline and locally advanced pancreatic cancer: real-world data from a population-based, prospective cohort study (NORPACT-2).

BACKGROUND: Systemic chemotherapy is the initial treatment strategy for borderline resectable and locally advanced pancreatic cancer to facilitate curative resection. The aim of this study was to investigate the resection rates and overall survival in patients with borderline resectable pancreatic cancer and locally advanced pancreatic cancer. METHODS: Consecutive patients with borderline resectable pancreatic cancer/locally advanced pancreatic cancer discussed by Oslo University Hospital multidisciplinary team between 2018 and 2020, serving a population of 3.1 million within a geographically defined area in south-eastern Norway, were included in this prospective Norwegian Pancreatic Cancer Trial-2 study, according to intention-to-treat principles. The total number of patients with pancreatic cancer was sought from the Cancer Registry of Norway. RESULTS: A total of 1178 patients were diagnosed with pancreatic cancer, of whom 618 were referred to Oslo University Hospital. After multidisciplinary team evaluation, 230 patients were considered to have borderline resectable pancreatic cancer/locally advanced pancreatic cancer. The final study group consisted of 188 patients (borderline resectable pancreatic cancer n = 96, locally advanced pancreatic cancer n = 92) who were fit to receive primary chemotherapy. Resection rates were 46.9% (45 of 96) for borderline resectable pancreatic cancer and 13% (12 of 92) for locally advanced pancreatic cancer (P <0.001). Median overall survival was 14.6 months (borderline resectable pancreatic cancer 16.4 months; locally advanced pancreatic cancer 13.7 months, (P = 0.2)). Adjusted for immortal time bias, median overall survival for patients undergoing resection versus only chemotherapy was 24.4 months versus 10.1 months (P <0.001) for borderline resectable pancreatic cancer and 28.4 months versus 12.6 months for locally advanced pancreatic cancer (P = 0.001). CONCLUSION: Resection rates and survival in patients with borderline resectable pancreatic cancer and locally advanced pancreatic cancer treated at a high-volume centre in a universal healthcare system compare well with those treated at international expert centres.Registration number: NCT04423731 (http://www.clinicaltrials.gov).

Intention-to-treat versus as-treated versus per-protocol approaches to analysis.

Randomized controlled trials (RCTs) are considered the most rigorous study design for testing hypotheses and the gold standard for evaluating intervention effectiveness. However, RCTs are often conducted under the assumption of ideal conditions that may differ from real-world scenarios in which various issues, such as loss to follow-up, mistakes in participant enrollment or intervention, and low subject compliance or adherence, may occur. There are various group-defining strategies for analyzing RCT data, including the intention-to-treat (ITT), as-treated, and per-protocol (PP) approaches. The ITT principle involves analyzing all participants according to their initial group assignments, regardless of study completion and compliance or adherence to treatment protocols. This approach aims to replicate real-world clinical settings in which several anticipated or unexpected conditions may occur with regard to the study protocol. For the PP approach, only participants who meet the inclusion criteria, complete the interventions according to the study protocols, and have primary outcome data available are included. This approach aims to confirm treatment effects under optimal conditions. In general, the ITT principle is preferred for superiority and inequality trials, whereas the PP approach is preferred for equivalence and non-inferiority trials. However, both analytical approaches should be conducted and their results compared to determine whether significant differences exist. Overall, using both the ITT and PP approaches can provide a more complete picture of the treatment effects and ensure the reliability of the trial results.

Antibiotic Prophylaxis in Infants with Grade III, IV, or V Vesicoureteral Reflux.

BACKGROUND: The efficacy of continuous antibiotic prophylaxis in preventing urinary tract infection (UTI) in infants with grade III, IV, or V vesicoureteral reflux is controversial. METHODS: In this investigator-initiated, randomized, open-label trial performed in 39 European centers, we randomly assigned infants 1 to 5 months of age with grade III, IV, or V vesicoureteral reflux and no previous UTIs to receive continuous antibiotic prophylaxis (prophylaxis group) or no treatment (untreated group) for 24 months. The primary outcome was the occurrence of the first UTI during the trial period. Secondary outcomes included new kidney scarring and the estimated glomerular filtration rate (GFR) at 24 months. RESULTS: A total of 292 participants underwent randomization (146 per group). Approximately 75% of the participants were male; the median age was 3 months, and 235 participants (80.5%) had grade IV or V vesicoureteral reflux. In the intention-to-treat analysis, a first UTI occurred in 31 participants (21.2%) in the prophylaxis group and in 52 participants (35.6%) in the untreated group (hazard ratio, 0.55; 95% confidence interval [CI], 0.35 to 0.86; P = 0.008); the number needed to treat for 2 years to prevent one UTI was 7 children (95% CI, 4 to 29). Among untreated participants, 64.4% had no UTI during the trial. The incidence of new kidney scars and the estimated GFR at 24 months did not differ substantially between the two groups. Pseudomonas species, other non-Escherichia coli organisms, and antibiotic resistance were more common in UTI isolates obtained from participants in the prophylaxis group than in isolates obtained from those in the untreated group. Serious adverse events were similar in the two groups. CONCLUSIONS: In infants with grade III, IV, or V vesicoureteral reflux and no previous UTIs, continuous antibiotic prophylaxis provided a small but significant benefit in preventing a first UTI despite an increased occurrence of non-E. coli organisms and antibiotic resistance. (Funded by the Italian Ministry of Health and others; PREDICT ClinicalTrials.gov number, NCT02021006; EudraCT number, 2013-000309-21.).

The Effectiveness of a Parents as Teachers Home Visitation Program on School Readiness: An Application of Complier Average Causal Effect Analysis.

PURPOSE: The purpose of this study is to evaluate an encouragement trial of a Parents as Teachers (PAT) home visitation intervention on the school readiness of preschool children using an innovative analysis to address issues of selective enrollment. METHOD: Families were given the opportunity to enroll in a PAT program through a randomized lottery. The PAT program is assessed using standardized measures of school readiness before and after the two-year program. A comparison of three different analyses is used to evaluate the program - Average Treatment Effect (ATE) analysis, Intent-to-Treat (ITT) analysis, and Complier Average Causal Effect (CACE) analysis. CACE is an innovative analysis developed specifically to diagnose bias arising from selective enrollment in the context of an encouragement trial. RESULT: All three analyses (ATE, ITT, and CACE) provide statistically significant evidence of an effective PAT program. However, the effect sizes for the CACE analysis are over twice as large as the other two analyses. The Cohen's D for CACE is .934 compared to .424 for ATE and .381 for ITT. CONCLUSION: This study provides evidence of an effective PAT program. The comparison of ATE, ITT, and CACE analyses reveals the potential for meaningful under-reporting of the program's impact if selective enrollment is ignored. CACE analysis demonstrates how selective enrollment can bias evaluations of home visitation interventions in general.

Treatment outcome of patients with synchronous oligometastatic non-small cell lung cancer in the immunotherapy era: Analysis of a real-life intention-to-treat population.

The standard first-line treatment for non-oncogene driven metastatic non-small cell lung cancer (NSCLC) is an immune checkpoint inhibitor (ICI) based strategy. Although guidelines increasingly advise adding local radical treatment (LRT) to patients with synchronous oligometastatic (sOMD) NSCLC responding to systemic therapy, this recommendation is based on the studies without ICI. Furthermore, the majority of published oligometastatic studies were not on an intention-to-treat basis, resulting in selection bias. Moreover, staging Positron Emission Tomography-Computed Tomography (PET-CT) and brain imaging were often not mandatory and definitions of oligometastatic were heterogeneous. Therefore, this study focused on a single centre retrospective series, including all adequately staged patients with sOMD NSCLC according to the European Organisation for Research and Treatment of Cancer definition (maximum of 5 metastases in 3 organs) that were treated with induction (chemo)-ICI and compared outcomes to those treated with chemotherapy only, with and without LRT. The primary end-points were median progression-free survival (PFS) and overall survival (OS) for patients treated with induction (chemo)-ICI versus chemotherapy. Out of 68 included patients, 38 (56%) eventually received LRT. With a median follow-up of 26.7 months, the median PFS was 19.0 months for (chemo)-ICI (n = 18) versus 6.8 for chemotherapy-only (n = 50) (HR 0.5, p = 0.03), the median OS was 19.3 versus 15.7 months, respectively (HR 0.8, p = 0.4). In patients having received LRT, median PFS was 19.0 months for (chemo)-ICI versus 8.3 for chemotherapy-only (HR 0.6, p = 0.2). In conclusion, an ICI-based systemic treatment is feasible and may result in superior survival outcomes. This should be investigated in prospective trials. Strategies to improve response rates to systemic treatment are also needed.

Postoperative morbidity after anatomical lung resections by VATS vs thoracotomy: Treatment and intention-to-treat analysis of the Spanish Video-Assisted Thoracic Surgery Group.

OBJECTIVES: In recent years, video-assisted thoracoscopic lung resections (VATS) have been associated with lower morbidity than open surgery. The aim of our study is to compare postoperative morbidity among patients from the national database of the Spanish Group of Video-Assisted Thoracic Surgery (GE-VATS) after open and video-assisted anatomic lung resections using a propensity score analysis. METHODS: From December 2016 to March 2018, a total of 3533 patients underwent anatomical lung resection at 33 centers. Pneumonectomies and extended resections were excluded. A propensity score analysis was performed to compare the morbidity of the thoracotomy group (TG) vs the VATS group (VATSG). Treatment and intention-to-treat (ITT) analyses were conducted. RESULTS: In total, 2981 patients were finally included in the study: 1092 (37%) in the TG and 1889 (63%) in the VATSG for the treatment analysis; and 816 (27.4%) in the TG and 2165 patients (72.6%) in the VATSG for the ITT analysis. After propensity score matching, in the treatment analysis, the VATSG was significantly associated with fewer overall complications than the TG OR 0.680 [95%CI 0.616, 0.750]), fewer respiratory (OR 0.571 [0.529, 0.616]) cardiovascular (OR 0.529 [0.478, 0.609]) and surgical (OR 0.875 [0.802, 0.955]) complications, lower readmission rate (OR 0.669 [0.578, 0.775]) and a reduction of hospital length of stay (-1.741 ([-2.073, -1.410]). Intention-to-treat analysis showed only statistically significant differences in overall complications (OR 0.76 [0.54-0.99]) in favor of the VATSG. CONCLUSION: In this multicenter population, VATS anatomical lung resections have been associated with lower morbidity than those performed by thoracotomy. However, when an intention-to-treat analysis was performed, the benefits of the VATS approach were less prominent.

Intention-to-treat Analysis of Patients Aged 70 Years and Older Awaiting Kidney Transplantation in Post-Kidney Allocation System Era.

BACKGROUND: The US population is aging, and so the number of patients treated for end-stage renal disease is on the rise. In the United States, 38% of people over 65 y old have chronic kidney disease. There continues to be a reluctance of clinicians to consider older candidates for transplant, including early referrals. METHODS: We conducted a retrospective analysis of the Organ Procurement and Transplantation Network database of all adults ≥70 y old undergoing kidney transplants from December 1, 2014, to June 30, 2021. We compared patient and graft survival in candidates who were transplanted while on hemodialysis versus preemptive with a living versus deceased donor kidney transplant. RESULTS: In 2021, only 43% of the candidates listed for transplant were preemptive. In an intention-to-treat analysis from the time of listing, candidate survival was significantly improved for those transplanted preemptively versus being on dialysis (hazard ratio 0.59; confidence interval, 0.56-0.63). All donor types, donor after circulatory death, donor after brain death, and living donor, had a significant decrease in death over remaining on the waiting list. Patients who were on dialysis or transplanted preemptively with a living donor kidney had significantly better survival than those receiving a deceased donor kidney. However, receiving a deceased donor kidney significantly decreased the chance of death over remaining on the waiting list. CONCLUSIONS: Patients ≥70 y old who are transplanted preemptively, whether with a deceased donor or a living donor kidney, have a significantly better survival than those who are transplanted after initiating dialysis. Emphasis on timely referral for a kidney transplant should be placed in this population.

Thoracic epidural analgesia in intensive care unit patients with acute pancreatitis: the EPIPAN multicenter randomized controlled trial.

BACKGROUND: Findings from preclinical studies and one pilot clinical trial suggest potential benefits of epidural analgesia in acute pancreatitis. We aimed to assess the efficacy of thoracic epidural analgesia, in addition to usual care, in improving clinical outcomes of intensive care unit patients with acute pancreatitis. METHODS: A multicenter, open-label, randomized, controlled trial including adult patients with a clinical diagnosis of acute pancreatitis upon admission to the intensive care unit. Participants were randomly assigned (1:1) to a strategy combining thoracic epidural analgesia and usual care (intervention group) or a strategy of usual care alone (control group). The primary outcome was the number of ventilator-free days from randomization until day 30. RESULTS: Between June 2014 and January 2019, 148 patients were enrolled, and 135 patients were included in the intention-to-treat analysis, with 65 patients randomly assigned to the intervention group and 70 to the control group. The number of ventilator-free days did not differ significantly between the intervention and control groups (median [interquartile range], 30 days [15-30] and 30 days [18-30], respectively; median absolute difference of - 0.0 days, 95% CI - 3.3 to 3.3; p = 0.59). Epidural analgesia was significantly associated with longer duration of invasive ventilation (median [interquartile range], 14 days [5-28] versus 6 days [2-13], p = 0.02). CONCLUSIONS: In a population of intensive care unit adults with acute pancreatitis and low requirement for intubation, this first multicenter randomized trial did not show the hypothesized benefit of epidural analgesia in addition to usual care. Safety of epidural analgesia in this setting requires further investigation. TRIAL REGISTRATION: ClinicalTrials.gov registration number NCT02126332 , April 30, 2014.

Surgical Treatment of Hepatocellular Carcinoma: Multicenter Competing-risk Analysis of Tumor-related Death Following Liver Resection and Transplantation Under an Intention-to-treat Perspective.

BACKGROUND: Early-stage hepatocellular carcinoma could benefit from upfront liver resection (LR) or liver transplantation (LT), but the optimal strategy in terms of tumor-related outcomes is still debated. We compared the oncological outcomes of LR and LT for hepatocellular carcinoma, stratifying the study population into a low-, intermediate-, and high-risk class according to the risk of death at 5-y predicted by a previously developed prognostic model. The impact of tumor pathology on oncological outcomes of low- and intermediate-risk patients undergoing LR was investigated as a secondary outcome. METHODS: We performed a retrospective multicentric cohort study involving 2640 patients consecutively treated by LR or LT from 4 tertiary hepatobiliary and transplant centers between 2005 and 2015, focusing on patients amenable to both treatments upfront. Tumor-related survival and overall survival were compared under an intention-to-treat perspective. RESULTS: We identified 468 LR and 579 LT candidates: 512 LT candidates underwent LT, whereas 68 (11.7%) dropped-out for tumor progression. Ninety-nine high-risk patients were selected from each treatment cohort after propensity score matching. Three and 5-y cumulative incidence of tumor-related death were 29.7% and 39.5% versus 17.2% and 18.3% for LR and LT group ( P = 0.039), respectively. Low-risk and intermediate-risk patients treated by LR and presenting satellite nodules and microvascular invasion had a significantly higher 5-y incidence of tumor-related death (29.2% versus 12.5%; P < 0.001). CONCLUSIONS: High-risk patients showed significantly better intention-to-treat tumor-related survival after upfront LT rather than LR. Cancer-specific survival of low- and intermediate-risk LR patients was significantly impaired by unfavorable pathology, suggesting the application of ab-initio salvage LT in such scenarios.

Effectiveness of exercise on fall prevention in community-dwelling older adults: a 2-year randomized controlled study of 914 women.

BACKGROUND: Communal exercise interventions may help prevent falls and injuries. However, pragmatic trials demonstrating the effectiveness of such strategies are sparse. METHODS: We determined whether a cost-free 12-month admission to the city's recreational sports facilities including initial 6 months of supervised weekly gym and Tai Chi sessions decreases the number of falls and related injuries. The mean (SD) follow-up time was 22·6 (4.8) months in 2016-19. A total of 914 women from a population-based sample with a mean age of 76.5 (SD 3.3, range 71.1-84.8) years were randomized into exercise intervention (n = 457) and control (n = 457) groups. Fall information was collected through biweekly short message (SMS) queries and fall diaries. Altogether 1,380 falls were recorded for the intention-to-treat analysis, with 1,281 (92.8%) being verified by telephone. RESULTS: A 14.3% fall rate reduction was detected in the exercise group (Incidence rate ratio (IRR) = 0.86; CI 95% 0.77-0.95) compared with the control group. Approximately half of the falls caused moderate (n = 678, 52.8%) or severe (n = 61, 4.8%) injury. In total, 13.2% (n = 166) of falls (including 73 fractures) required medical consultation with a 38% lower fracture rate in the exercise group (IRR = 0.62; CI 95% 0.39-0.99). Overall, the greatest reduction of 41% (IRR = 0.59; CI 95% 0.36-0.99) was observed in falls with severe injury and pain. CONCLUSIONS: A community-based approach for a 6-month exercise period combined with a 12-month free use of sports premises can reduce falls, fractures and other fall-related injuries in aging women.

Using modified intention-to-treat as a principal stratum estimator for failure to initiate treatment.

BACKGROUND: A common intercurrent event affecting many trials is when some participants do not begin their assigned treatment. For example, in a double-blind drug trial, some participants may not receive any dose of study medication. Many trials use a 'modified intention-to-treat' approach, whereby participants who do not initiate treatment are excluded from the analysis. However, it is not clear (a) the estimand being targeted by such an approach and (b) the assumptions necessary for such an approach to be unbiased. METHODS: Using potential outcome notation, we demonstrate that a modified intention-to-treat analysis which excludes participants who do not begin treatment is estimating a principal stratum estimand (i.e. the treatment effect in the subpopulation of participants who would begin treatment, regardless of which arm they were assigned to). The modified intention-to-treat estimator is unbiased for the principal stratum estimand under the assumption that the intercurrent event is not affected by the assigned treatment arm, that is, participants who initiate treatment in one arm would also do so in the other arm (i.e. if someone began the intervention, they would also have begun the control, and vice versa). RESULTS: We identify two key criteria in determining whether the modified intention-to-treat estimator is likely to be unbiased: first, we must be able to measure the participants in each treatment arm who experience the intercurrent event, and second, the assumption that treatment allocation will not affect whether the participant begins treatment must be reasonable. Most double-blind trials will satisfy these criteria, as the decision to start treatment cannot be influenced by the allocation, and we provide an example of an open-label trial where these criteria are likely to be satisfied as well, implying that a modified intention-to-treat analysis which excludes participants who do not begin treatment is an unbiased estimator for the principal stratum effect in these settings. We also give two examples where these criteria will not be satisfied (one comparing an active intervention vs usual care, where we cannot identify which usual care participants would have initiated the active intervention, and another comparing two active interventions in an unblinded manner, where knowledge of the assigned treatment arm may affect the participant's choice to begin or not), implying that a modified intention-to-treat estimator will be biased in these settings. CONCLUSION: A modified intention-to-treat analysis which excludes participants who do not begin treatment can be an unbiased estimator for the principal stratum estimand. Our framework can help identify when the assumptions for unbiasedness are likely to hold, and thus whether modified intention-to-treat is appropriate or not.

Statistically Adjusting for Wear Time in Randomized Trials of Continuous Glucose Monitors as a Complement to Intent-to-Treat and As-Treated Analyses: Application and Evaluation in Two Trials.

Background: Randomized trials of continuous glucose monitoring (CGM) often estimate treatment effects using standard intent-to-treat (ITT) analyses. We explored how adjusting for CGM-measured wear time could complement existing analyses by estimating the effect of receiving and using CGM 100% of the time. Methods: We analyzed data from two 6-month CGM trials spanning diverse ages, the Wireless Innovation for Seniors with Diabetes Mellitus (WISDM) and CGM Intervention in Teens and Young Adults with Type 1 Diabetes (CITY) Studies. To adjust the ITT estimates for CGM use, as measured by wear time, we used an instrumental variable (IV) approach with the treatment assignment as an instrument. Outcomes included (1) time in range ([TIR] 70-180 mg/dL), time below range ([TBR] ≤70 mg/dL), and time above range ([TAR] ≥250 mg/dL). We estimated outcomes based on CGM use in the last 28 days of the trial and the full trial. Findings: In the WISDM study, the wear time rates over the 28-day window and full trial period were 93.1% (standard deviation [SD]: 20.4) and 94.5% (SD: 11.9), respectively. In the CITY study, the wear time rates over the 28-day window and full trial period were 82.2% (SD: 26.5) and 83.1% (SD: 21.5), respectively. IV-based estimates for the effect of CGM on TIR, TBR, and TAR suggested greater improvements in glycemic management than the ITT counterparts. The magnitude of the differences was proportional to the level of wear time observed in the trials. Interpretation: In trials of CGM use, the effect of variable wear time is non-negligible. By providing adherence-adjusted estimates, the IV approach may have additional utility for individual clinical decision-making.

Power and sample sizes estimation in clinical trials with treatment switching in intention-to-treat analysis: a simulation study.

BACKGROUND: Treatment switching, also called crossover, is common in clinical trials because of ethical concerns or other reasons. When it occurs and the primary objective is to identify treatment effects, the most widely used intention-to-treat analysis may lead to underpowered trials. Here, we presented an approach to preview power reductions and to estimate sample sizes required to achieve the desired power when treatment switching occurs in the intention-to-treat analysis. METHODS: We proposed a simulation-based approach and developed an R package to perform power and sample sizes estimation in clinical trials with treatment switching. RESULTS: We simulated a number of randomized trials incorporating treatment switching and investigated the impact of the relative effectiveness of the experimental treatment to the control, the switching probability, the switching time, and the deviation between the assumed and the real distributions for the survival time on power reductions and sample sizes estimation. The switching probability and the switching time are key determinants for significant power decreasing and thus sample sizes surging to maintain the desired power. The sample sizes required in randomized trials absence of treatment switching vary from around four-fifths to one-seventh of the sample sizes required in randomized trials allowing treatment switching as the switching probability increases. The power reductions and sample sizes increase with the decrease of switching time. CONCLUSIONS: The simulation-based approach not only provides a preview for power declining but also calculates the required sample size to achieve an expected power in the intention-to-treat analysis when treatment switching occurs. It will provide researchers and clinicians with useful information before randomized controlled trials are conducted.