Trial Emulation Research Articles

Comparative effectiveness of combination therapy with nirmatrelvir–ritonavir and remdesivir versus monotherapy with remdesivir or nirmatrelvir–ritonavir in patients hospitalised with COVID-19: a target trial emulation study

Remdesivir (Veklury, Gilead Sciences, Foster City, CA, USA) and nirmatrelvir-ritonavir (Paxlovid, Pfizer, New York, NY, USA) were reported to improve the outcome of patients with mild-to-moderate COVID-19 symptoms. Preclinical data suggest that nirmatrelvir-ritonavir might be more effective than remdesivir alone or in combination with nirmatrelvir-ritonavir for people at high risk of severe COVID-19. We aimed to assess the safety and effectiveness of combining remdesivir and nirmatrelvir-ritonavir compared with using each drug alone for adults hospitalised with COVID-19. In this target trial emulation study, we used electronic health records of patients aged 18 years or older who received either combination treatment of nirmatrelvir-ritonavir and remdesivir or monotherapy of either drug between March 16 and Dec 31, 2022, within 5 days of hospitalisation for COVID-19 in Hong Kong. Inverse probability of treatment weighting was applied to balance baseline patient characteristics across the treatment groups. The primary outcome was all-cause mortality. Cox proportional hazards regression adjusting weighting was used to compare the risk of all-cause mortality, intensive care unit (ICU) admission, or ventilatory support for 90 days of follow-up between groups. Between March 16 and Dec 31, 2022, 18 196 participants were identified from electronic health records and assigned to receive remdesivir (n=4232), nirmatrelvir-ritonavir (n=13 656), or nirmatrelvir-ritonavir and remdesivir (n=308). By applying an inverse probability of treatment weighting, a weighted sample composed of 18 410 recipients of nirmatrelvir-ritonavir and remdesivir combination treatment, 18 178 recipients of remdesivir monotherapy, and 18 287 recipients of nirmatrelvir-ritonavir monotherapy was obtained. After a median follow-up of 84 days (IQR 45-90), risk of mortality was lower in patients who received nirmatrelvir-ritonavir monotherapy (hazard ratio [HR] 0·18 [95% CI 0·15 to 0·20]; absolute risk reduction [ARR] -16·33% [95% CI -16·98 to -15·68]) or remdesivir and nirmatrelvir-ritonavir combination therapy (HR 0·66 [95% CI 0·49 to 0·89]; ARR -6·52% [95% CI -7·29 to -5·74]) than in patients who received remdesivir monotherapy. Similar results were observed for ICU admission or ventilatory support (nirmatrelvir-ritonavir monotherapy: HR 0·09 [95% CI 0·07 to 0·11]; ARR -10·04% [95% CI -10·53 to -9·56]; combination therapy: HR 0·68 [95% CI 0·42 to 1·12]; ARR -3·24% [95% CI -3·84 to -2·64]). Compared with combination therapy, nirmatrelvir-ritonavir monotherapy was associated with lower risk of mortality (HR 0·27 [95% CI 0·20 to 0·37]; ARR -9·81% [95% CI -10·39 to -9·24]) and ICU admission or ventilatory support (HR 0·13 [95% CI 0·08 to 0·22]; ARR -6·80% [95% CI -7·22 to -6·39]). Our study highlighted the potential for reduced risk of mortality, ICU admission, or the need for ventilatory support in patients hospitalised with COVID-19 treated with nirmatrelvir-ritonavir as a monotherapy compared with treatment regimens based on nirmatrelvir-ritonavir and remdesivir combination therapy or remdesivir monotherapy. Further randomised controlled trials are needed to support the validity of the current results. The Health and Medical Research Fund Commissioned Research on COVID-19. For the Chinese translation of the abstract see Supplementary Materials section.

Real-World Effectiveness and Safety of Tixagevimab-Cilgavimab: A Target Trial Emulation Study.

Immunocompromised individuals are at high risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and subsequent severe or fatal coronavirus disease 2019 (COVID-19), yet they have suboptimal responses to mRNA and inactivated COVID-19 vaccines. The efficacy of tixagevimab-cilgavimab in reducing symptomatic SARS-CoV-2 infection was demonstrated in phase III clinical trials. Nevertheless, real-world data on the effectiveness and safety of tixagevimab-cilgavimab remain limited. The aim was to evaluate the effectiveness and safety of tixagevimab-cilgavimab among immunocompromised individuals. Adults who were immunocompromised or receiving immunosuppressive therapies were included in this target trial emulation using territory-wide electronic health records in Hong Kong. A sequential trial emulation approach was adopted to compare effectiveness and safety outcomes between individuals who received tixagevimab-cilgavimab and individuals who did not. A total of 746 tixagevimab-cilgavimab recipients and 2980 controls were included from 1 May 2022 to 30 November 2022. Tixagevimab-cilgavimab significantly reduced the risk of COVID-19 infection (hazard ratio [HR] 0.708, 95% confidence interval [CI] 0.527-0.951) during a median follow-up of 60 days. No significant difference was observed in the risk of COVID-19-related hospitalisation. Zero versus eight COVID-19 mortality cases and zero versus two severe COVID-19 cases were observed in tixagevimab-cilgavimab recipients and controls, respectively. Notably, significant risk reduction in COVID-19 infection was also observed among immunocompromised individuals who had been previously vaccinated with three or more doses of COVID-19 vaccine, or had no prior COVID-19 infection history. Tixagevimab-cilgavimab was effective in reducing COVID-19 infection among immunocompromised patients during the Omicron wave. Findings were consistent among individuals who previously received three or more doses of COVID-19 vaccine, or had no previous history of COVID-19 infection.

Replacement Strategies for Tunneled Hemodialysis Catheters with Complications: A Nationwide Cohort Study.

Tunneled hemodialysis catheters often have infectious or mechanical complications that require unplanned removal and replacement, but the optimal replacement strategy is unknown. This study described the real-world use of two strategies in Australia and compared the survival of replacement catheters inserted by either strategy. Observational data from the REDUCCTION trial, which enrolled a nationwide cohort of 6400 adults who received an incident hemodialysis catheter (2016-2020) was used for this secondary analysis. Tunneled catheters were replaced by either catheter exchange through the existing tunnel tract or removal and replacement through a new tract. The effect of the replacement strategy on the time to catheter removal due to infection or dysfunction was estimated by emulating a hypothetical pragmatic randomized trial among a subset of 434 patients with mechanical tunneled catheter failure. Out of 9974 tunneled hemodialysis catheters inserted during the trial, 380 had infectious and 945 had mechanical complications that required replacement. Almost all infected hemodialysis catheters (97%) were removed and separately replaced through a new tunnel tract, whereas nephrology services differed widely in their replacement practices for catheters with mechanical failure (median = 50% guidewire exchanged, interquartile range= 30%-67%). Service-level differences accounted for 29% of the residual variation after adjusting for patient factors. In the target trial emulation cohort of mechanical failure (N=434 patients), catheter exchange was not associated with lower complication-free survival at one, six, or 12 months (counterfactual survival difference at one month = 5.9%, 95% CI = -2%, 14%). Guidewire exchange for mechanical failure of catheter was not associated with lower catheter survival and may be preferable for patients.

Comparative effectiveness of treatment approaches for early invasive breast cancer

BackgroundRandomized controlled trials (RCTs) suggested breast conserving therapy (BCT) and mastectomy have similar survival for early-stage breast cancer, whereas observational studies reported survival advantage for BCT. We aimed to address biases in observational studies to compare the effect of BCT and mastectomy on survival. MethodsWe emulated a target trial using institutional cancer registry. We included adult women diagnosed with early invasive first primary breast tumors ≤ 5 cm between July 2011 and December 2017. We used cloning, censoring, and weighting to estimate risk differences (RDs) and risk ratios (RRs) for all-cause mortality and recurrence or all-cause mortality between BCT and mastectomy (reference). ResultsOur study population comprised 534 observations with breast cancer. Median age was 56 years and 65 % were racial/ethnic minorities. The 8-year RD was 1.5 % (95 % confidence limits [CL]: −7.0 %, 9.8 %) and RR was 1.1 (95 % CL: 0.57, 2.2) for all-cause mortality. Results for recurrence or mortality were similar. ConclusionsOur results suggest that target trial emulation to mitigate selection and immortal-time biases in observational studies may generate estimates that are more compatible with RCTs when comparing the effects of BCT and mastectomy on survival. Studies with longer follow-up and more events are needed to confirm our findings.

Comparative effectiveness and safety of BNT162b2 and CoronaVac in Hong Kong: A target trial emulation

ObjectivesTo evaluate the difference between BNT162b2 and CoronaVac in vaccine effectiveness and safety. MethodsThis target trial emulation study included individuals aged ≥12 during 2022. Propensity score matching was applied to ensure group balance. The Cox proportional hazard model was used to compare the effectiveness outcomes including COVID-19 infection, severity, 28-day hospitalization, and 28-day mortality after infection. Poisson regression was used for safety outcomes including 32 adverse events of special interests between groups. ResultsA total of 639,818 and 1804,388 individuals were identified for the 2-dose and 3-dose comparison, respectively. In 2-dose and 3-dose comparison, the hazard ratios (95% confidence intervals [CI]) were 0.844 [0.833-0.856] and 0.749 [0.743-0.755] for COVID-19 infection, 0.692 [0.656-0.731] and 0.582 [0.559-0.605] for hospitalization, 0.566 [0.417-0.769] and 0.590 [0.458-0.76] for severe COVID-19, and 0.563 [0.456-0.697] and 0.457 [0.372-0.561] for mortality for BNT162b2 recipients versus CoronaVac recipients, respectively. Regarding safety, 2-dose BNT162b2 recipients had a significantly higher incidence of myocarditis (incidence rate ratio [IRR] [95% CI]: 8.999 [1.14-71.017]) versus CoronaVac recipients, but the difference was insignificant in 3-dose comparison (IRR [95% CI]: 2.000 [0.500-7.996]). ConclusionBNT162b2 has higher effectiveness among individuals aged ≥12 against COVID-19-related outcomes for SARS-CoV-2 omicron compared to CoronaVac, with almost 50% lower mortality risk.

Real-World Effectiveness of Nirmatrelvir in Protecting Long COVID for Outpatient Adult Patients - A Large-Scale Observational Cohort Study from the RECOVER Initiative.

Paxlovid has been approved for use in patients who are at high risk for severe acute COVID-19 illness. Evidence regarding whether Paxlovid protects against Post-Acute Sequelae of SARS-CoV-2 infection (PASC), or Long COVID, is mixed in high-risk patients and lacking in low-risk patients. With a target trial emulation framework, we evaluated the association of Paxlovid treatment within 5 days of SARS-CoV-2 infection with incident Long COVID and hospitalization or death from any cause in the post-acute period (30-180 days after infection) using electronic health records from the Patient-Centered Clinical Research Networks (PCORnet) RECOVER repository. The study population included 497,499 SARS-CoV-2 positive patients between March 1, 2022, to February 1, 2023, and among which 165,256 were treated with Paxlovid within 5 days since infection and 307,922 were not treated with Paxlovid or other COVID-19 treatments. Compared with the non-treated group, Paxlovid treatment was associated with reduced risk of Long COVID with a Hazard Ratio (HR) of 0.88 (95% CI, 0.87 to 0.89) and absolute risk reduction of 2.99 events per 100 persons (95% CI, 2.65 to 3.32). Paxlovid treatment was associated with reduced risk of all-cause death (HR, 0.53, 95% CI 0.46 to 0.60; risk reduction 0.23 events per 100 persons, 95% CI 0.19 to 0.28) and hospitalization (HR, 0.70, 95% CI 0.68 to 0.73; risk reduction 2.37 events per 100 persons, 95% CI 2.19 to 2.56) in the post-acute phase. For those without documented risk factors, the associations (HR, 1.03, 95% CI 0.95 to 1.11; risk increase 0.80 events per 100 persons, 95% CI -0.84 to 2.45) were inconclusive. Overall, high-risk, nonhospitalized adult patients with COVID-19 who were treated with Paxlovid within 5 days of SARS-CoV-2 infection had a lower risk of Long COVID and all-cause hospitalization or death in the post-acute period. However, Long COVID risk reduction with Paxlovid was not observed in low-risk patients.

Comparative effectiveness of glucagon-like peptide-1 agonists, dipeptidyl peptidase-4 inhibitors, and sulfonylureas on the risk of dementia in older individuals with type 2 diabetes in Sweden: an emulated trial study

The comparative effectiveness of glucagon-like peptide-1 (GLP-1) agonists, dipeptidyl peptidase-4 (DPP-4) inhibitors, and sulfonylureas on the risk of dementia in older individuals with type 2 diabetes mellitus (T2DM) is unknown. We conducted a sequential trial emulation from 1st January 2010 to 30th June 2020 using data from Swedish national registers. Swedish residents who were aged 65 or older, had type 2 diabetes (T2DM), and initiated GLP-1 agonists, DPP-4 inhibitors, or sulfonylureas were followed for up to 10 years to assess the risk of dementia. Participants who had dementia, used the three drug classes, or had contraindications were excluded from enrollment. The characteristics between arms were balanced through the application of propensity scores estimated from predefined covariates. Intention-to-treat effects were analysed with all enrolled participants, while the per-protocol effects were analysed with participants who adhered to the assigned treatment. The pooled trial included 88,381 participants who received prescriptions for GLP-1 agonists (n=12,351), DPP-4 inhibitors (n=43,850), or sulfonylureas (n=32,216) at baseline and were followed for an average of 4.3 years. A total of 4607 dementia cases developed during follow-up: 278 for the GLP-1 agonist initiators (incidence rate: 6.7 per 1000 person years), 1849 for DPP-4 inhibitor initiators (IR: 11.8), and 2480 for sulfonylurea initiators (IR: 13.7). In an intention-to-treat analysis, GLP-1 agonist initiation was associated with a reduced risk of dementia compared to sulfonylureas (hazard ratio: 0.69, 95% CI: 0.60-0.79, p<0.0001) and DPP-4 inhibitors (HR: 0.77, 95% CI: 0.68-0.88, p<0.0001), after adjusting for age, enrollment year, sex, socioeconomic factors, health conditions, and past medication uses. These findings were consistent in several sensitivity analyses, including a per-protocol analysis (HR for sulfonylureas: 0.41, 95% CI: 0.32-0.53, p<0.0001; HR for DPP-4 inhibitors: 0.38, 95% CI: 0.30-0.49, p<0.0001). Our research suggested that GLP-1 agonists were associated with a lower risk of dementia compared to sulfonylureas and DPP-4 inhibitors in older individuals with T2DM. Further clinical trials are needed to validate these findings. Swedish Research Council, Karolinska Institutet, the National Institute on Aging, the National Institutes of Health, and Riksbankens Jubileumsfond.

Cardiorenal effects of Angiotensin-converting enzyme inhibitors and Angiotensin receptor blockers in people underrepresented in trials: analysis of routinely collected data with emulation of a reference trial (ONTARGET).

Cardiovascular disease (CVD) is a leading cause of death globally. Angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB), compared in the ONTARGET trial, each prevent CVD. However, trial results may not be generalisable and their effectiveness in underrepresented groups is unclear. Using trial emulation methods within routine-care data to validate findings, we explored generalisability of ONTARGET results. For people prescribed an ACEi/ARB in the UK Clinical Practice Research Datalink GOLD from 1/1/2001-31/7/2019, we applied trial criteria and propensity-score methods to create an ONTARGET trial-eligible cohort. Comparing ARB to ACEi, we estimated hazard ratios for the primary composite trial outcome (cardiovascular death, myocardial infarction, stroke, or hospitalisation for heart failure), and secondary outcomes. As the pre-specified criteria were met confirming trial emulation, we then explored treatment heterogeneity among three trial-underrepresented subgroups: females, those aged ≥75 years and those with chronic kidney disease (CKD). In the trial-eligible population (n=137,155), results for the primary outcome demonstrated similar effects of ARB and ACEi, (HR 0.97 [95% CI: 0.93, 1.01]), meeting the pre-specified validation criteria. When extending this outcome to trial-underrepresented groups, similar treatment effects were observed by sex, age and CKD. This suggests that ONTARGET trial findings are generalisable to trial-underrepresented subgroups.

Estimated Effect of Restarting Renin-Angiotensin System Inhibitors after Discontinuation on Kidney Outcomes and Mortality.

While renin-angiotensin system inhibitors (RASi) have been the mainstream treatment for patients with CKD, they are often discontinued due to adverse effects such as hyperkalemia and acute kidney injury. It is unknown whether restarting RASi after discontinuation improves clinical outcomes. Using the OCKR (Osaka Consortium for Kidney disease Research) database, we performed a target trial emulation study including 6,065 patients with an eGFR of 10-60 mL/min/1.73m2 who were followed up by nephrologists and discontinued RASi between 2005 and 2021. With a clone-censor-weight approach, we compared a treatment strategy for restarting RASi within a year after discontinuation with that for not restarting RASi. Patients were followed up for five years at maximum after RASi discontinuation. The primary outcome was a composite kidney outcome (initiation of kidney replacement therapy, a ≥50% decline in eGFR, or kidney failure [eGFR <5 mL/min/1.73m2]). Secondary outcomes were all-cause death and incidence of hyperkalemia (serum potassium levels ≥5.5 mEq/L). Among those who discontinued RASi (mean [standard deviation (SD)] age 66 [15] years, 62% male, mean [SD] eGFR 40 [26] ml/min/1.73m2), 2,262 (37%) restarted RASi within a year. Restarting RASi was associated with a lower hazard of the composite kidney outcome (hazard ratio 0.85 [95% confidence intervals (CIs) 0.78 to 0.93]) and all-cause death (hazard ratio 0.70 [95% CI 0.61 to 0.80]) compared with not restarting RASi. The incidence of hyperkalemia did not differ significantly between the two strategies (hazard ratio 1.11 [95% CI 0.96 to 1.27]). Restarting RASi after discontinuation was associated with a lower risk of kidney outcomes and mortality but not related to the incidence of hyperkalemia.

Emulating randomised clinical trials in relapsing-remitting multiple sclerosis with non-randomised real-world evidence: an application using data from the MSBase Registry

BackgroundTo mimic as closely as possible a randomised controlled trial (RCT) and calibrate the real-world evidence (RWE) studies against a known treatment effect would be helpful to understand if RWE...

CO5 Effectiveness and Safety of Direct Oral Anticoagulants Versus Warfarin in Patients With Atrial Fibrillation and Cancer: A Target Trial Emulation From SEER-Medicare Database

CO5 Effectiveness and Safety of Direct Oral Anticoagulants Versus Warfarin in Patients With Atrial Fibrillation and Cancer: A Target Trial Emulation From SEER-Medicare Database

EE444 Target Trial Emulation with Real-World Data to Determine the Population-Level Cost-Effectiveness of Multi-Gene Panel Sequencing for Advanced Melanoma

EE444 Target Trial Emulation with Real-World Data to Determine the Population-Level Cost-Effectiveness of Multi-Gene Panel Sequencing for Advanced Melanoma

Long-term statin use and risk of cancers: a target trial emulation study

Background and ObjectivesControversy exists regarding potential cancer risks associated with long-term statin use. This study aimed to use real-world data to investigate the association between cancer incidence and sustained statin use over a 10-year period. MethodsUsing territory-wide public electronic medical records in Hong Kong, we emulated a sequence of nested target trials on patients who met indications for statin initiation in each calendar month from January 2009 to December 2011. Statin initiators and noninitiators were matched in a 1:1 ratio to mimic the randomization of eligible person-trials at baseline. Pooled logistic regression was applied to obtain the hazard ratios for the cancer incidence of statin initiation in intention-to-treat analysis, with the adjustment of baseline confounders and the inverse probability weighting accounting for the postbaseline confounders in per-protocol analysis. ResultsAmong 8,560,051 eligible person-trials, 119,715 noninitiators were matched to 119,715 initiators for analysis. Over the 10-year study period, the estimated hazard ratio of overall cancer incidence was 0.96 (0.87, 1.05), and the standardized 10-year risk difference was −0.4% (−1.3%, 0.4%) in the per-protocol analysis. For the cancer subtypes of interest (ie, breast cancer, colorectal cancer, hematological cancer, pancreatic cancer, prostate cancer, urothelial carcinoma, and lung cancer), the 10-year risk differences ranged from −0.3% to 0.2% in the per-protocol analysis. No observable risk change for cancer was found in all patient subgroups with regards to their sex, age (<70/≥70 years), Charlson Comorbidity Index (≤4/>4), and statin indication. ConclusionStatin use has no impact on cancer incidence over a 10-year follow-up period, including all cancer subtypes of interest and patient subgroups with regards to sex, age, comorbidities, and statin indications.

Use of Sodium-Glucose Co-Transporter 2 Inhibitors in Patients With Type 2 Diabetes and the Incidence of Retinal Vein Occlusion in Taiwan.

The purpose of this study was to evaluate the risk of newly diagnosed retinal vein occlusion (RVO) in patients with type 2 diabetes (T2D) using sodium-glucose cotransporter-2 inhibitors (SGLT-2i) compared to dipeptidyl peptidase-4 inhibitors (DPP-4i). Claims data from the National Health Insurance Research Database of Taiwan were used in this nationwide retrospective cohort study. A target trial emulation framework was applied. Patients with T2D with no prior diagnosis of RVO who had newly commenced treatment with SGLT-2i or DPP-4i between May 1, 2016, and December 31, 2020, were included. Potential systematic differences in baseline characteristics between the paired groups were controlled using stabilized inverse probability of treatment weighting. The outcome of interest was incident RVO. The hazard ratio (HR) for SGLT-2i compared with that of DPP-4i was estimated using a Cox regression model. Data from 123,567 and 578,665 patients receiving SGLT-2i and DPP-4i, respectively, were analyzed. The incidence of RVO was lower in patients newly receiving SGLT-2i (0.59 events per 1000 person-years) compared to those receiving DPP-4i (0.77 events per 1000 person-years) over a mean follow-up of 1.61years. SGLT-2i users had a significantly lower risk of developing RVO compared with DPP-4i users (HR = 0.76, 95% confidence interval [CI] = 0.59-0.98). In the individual outcome analysis, SGLT-2i use was significantly associated with a lower risk of branch RVO (HR = 0.71, 95% CI = 0.52-0.96), but not central RVO (HR = 0.84, 95% CI = 0.57-1.24). The risk of developing RVO was lower in patients with T2D receiving SGLT-2i compared with that in those receiving DPP-4i.

Target Trial Emulation: Improving the Quality of Observational Studies in Inflammatory Bowel Disease Using the Principles of Randomized Trials.

The past decade has seen a substantial increase in the number of randomized controlled trials (RCTs) conducted in inflammatory bowel disease (IBD). Randomized controlled trials are the gold standard method for generating robust evidence of drug safety and efficacy but are expensive, time-consuming, and may have ethical implications. Observational studies in IBD are often used to fill the gaps in evidence but are typically hindered by significant bias. There are several approaches for making statistical inferences from observational data with some that focus on study design and others on statistical techniques. Target trial emulation is an emerging methodological process that aims to bridge this gap and improve the quality of observational studies by applying the principles of an ideal, or "target," randomized trial to routinely collected clinical data. There has been a rapid expansion of observational studies that have emulated trials over the past 5 years in other medical fields, but this has yet to be adopted in gastroenterology and IBD. The wealth of nonrandomized clinical data available through electronic health records, patient registries, and administrative health databases afford innumerable hypothesis-generating opportunities for IBD research. This review outlines the principles of target trial emulation, discusses the merits to IBD observational studies in reducing the most common biases and improving confidence in causality, and details the caveats of using this approach.

Impact of ibrutinib dose adjustment on TTNT in first-line CLL/SLL: a real-world analysis using target trial emulation

AbstractIbrutinib, a once-daily Bruton tyrosine kinase inhibitor, is a standard-of-care first-line (1L) treatment for patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). Dosing flexibility (adjustment to daily dose of <420 mg/d) with ibrutinib can help prevent recurrence or worsening of adverse events while maintaining long-term efficacy. This study compared time to next treatment among patients with CLL/SLL in the United States initiating 1L single-agent ibrutinib at 420 mg/d (index date) and staying on this dose vs patients with dose adjustment (DA) within 3 to 12 months. Two databases were used: Komodo claims (a majority from community practices) and Acentrus electronic medical records (from academic and nonteaching hospital systems). To account for immortal time bias (patients with DA survived on 1L therapy until DA) and overlap between follow-up time and definition of treatment strategies, a target trial emulation approach was used, in which patients were cloned at index date and contributed follow-up to both treatment strategy arms until deviation from the strategy. Among 3343 patients in Komodo (mean age: 67.5 years; 37.6% female) and 1171 patients in Acentrus (mean age: 70.4 years; 34.6% female) who initiated 1L single-agent ibrutinib 420 mg/d, 18.0% and 19.6%, respectively, had a DA. DA was not associated with an increased risk of having a next treatment in both databases (adjusted hazard ratio [95% confidence interval]: Komodo: 0.95 [0.80-1.14], Acentrus: 1.14 [0.80-1.62]). These findings suggest that a flexible dosing approach with ibrutinib may be effective in allowing patients to achieve optimal outcomes while remaining on long-term continuous 1L treatment.

Effectiveness of nirmatrelvir/ritonavir in children and adolescents aged 12–17 years following SARS-CoV-2 Omicron infection: A target trial emulation

Currently there is a lack of randomized trial data examining the use of the antiviral nirmatrelvir/ritonavir in paediatric patients with SARS-CoV-2 infection. This target trial emulation study aims to address this gap by evaluating the use of nirmatrelvir/ritonavir in non-hospitalized paediatric patients aged 12–17 years with SARS-CoV-2 Omicron variant infection. Among paediatric patients diagnosed between 16th March 2022 and 5th February 2023, exposure was defined as outpatient nirmatrelvir/ritonavir treatment within 5 days of symptom onset or COVID-19 diagnosis. Primary outcome was 28 day all-cause mortality or all-cause hospitalization, while secondary outcomes were 28 day in-hospital disease progression, 28 day COVID-19-specific hospitalization, multisystem inflammatory syndrome in children (MIS-C), acute liver injury, acute renal failure, and acute respiratory distress syndrome. Overall, 49,378 eligible paediatric patients were included. Nirmatrelvir/ritonavir treatment was associated with reduced 28 day all-cause hospitalization (absolute risk reduction = 0.23%, 95%CI = 0.19%–0.31%; relative risk = 0.66, 95%CI = 0.56–0.71). No events of mortality, in-hospital disease progression, or adverse clinical outcomes were observed among nirmatrelvir/ritonavir users. The findings confirmed the effectiveness of nirmatrelvir/ritonavir in reducing all-cause hospitalization risk among non-hospitalized pediatric patients with SARS-CoV-2 Omicron variant infection.

Effectiveness and Safety of Direct Oral Anticoagulants Versus Warfarin in Patients with Atrial Fibrillation and Cancer: A Target Trial Emulation from SEER-Medicare Database

Effectiveness and Safety of Direct Oral Anticoagulants Versus Warfarin in Patients with Atrial Fibrillation and Cancer: A Target Trial Emulation from SEER-Medicare Database

Medication use evaluation of tocilizumab implementation in COVID-19 treatment guidelines: A causal inference approach.

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. Introduction of new medications to health-system formularies is often not accompanied by assessments of their clinical impact on the local patient population. The growing availability of electronic health record (EHR) data and advancements in pharmacoepidemiology methods offer institutions the opportunity to monitor the medication implementation process and assess clinical effectiveness in the local clinical context. In this study, we applied novel causal inference methods to evaluate the effects of a formulary policy introducing tocilizumab therapy for critically ill patients with coronavirus disease 2019 (COVID-19). We conducted a medication use evaluation utilizing EHR data from patients admitted to a large medical center during the 6 months before and after implementation of a formulary policy endorsing the use of tocilizumab for treatment of COVID-19. The impact of tocilizumab on 28-day all-cause mortality was assessed using a difference-in-differences analysis, with ineligible patients serving as a nonequivalent control group, and a matched analysis guided by a target trial emulation framework. Safety endpoints assessed included the incidence of secondary infections and liver enzyme elevations. Our findings were benchmarked against clinical trials, an observational study, and a meta-analysis. Following guideline modification, tocilizumab was administered to 69% of eligible patients. This implementation was associated with a 3.1% absolute risk reduction in 28-day mortality (odds ratio, 0.86; number needed to treat to prevent one death, 32) attributable to the inclusion of tocilizumab in the guidelines and an additional 8.6% absolute risk reduction (odds ratio, 0.65; number needed to treat to prevent one death, 12) linked to its administration. These findings were consistent with estimates from published literature, although the effect estimates from the difference-in-differences analysis exhibited imprecision. Evaluating formulary management decisions through novel causal inference approaches offers valuable estimates of clinical effectiveness and the potential to optimize the impact of new medications on population outcomes.

Risk of SARS-CoV-2 infection and severe COVID-19 in hematological patients who received or not pre-exposure prophylaxis with tixagevimab/cilgavimab: a target trial emulation

We emulated a hypothetical target trial in which hematological subjects cared at the University Hospital of Pisa (Italy) received or not SARS-CoV-2 prophylaxis with tixagevimab/cilgavimab. Subjects who received prophylaxis (cases) were compared to those who did not (controls). The main outcome was SARS-CoV-2 infection in the subsequent 6 months. Inverse probability weighting (IPW) was used to adjust for confounders. A multivariable analysis was performed to identify variables associated with SARS-CoV-2 infection. We recruited 462 patients: 228 received prophylaxis, 234 were controls. COVID-19 was lower in cases compared to controls (16.7% vs 24.8%, p = 0.03, after IPW 14.3% vs 24.6%, p = 0.01). On multivariable analysis, B-cell depleting therapies (HR 2.09, 95%CI 1.05-4.18, p = 0.037) were associated with increased risk of COVID-19, while tixagevimab/cilgavimab prophylaxis (HR 0.45, 95%CI 0.27-0.73, p = 0.001) and previous SARS-CoV-2 infection (HR 0.27, 95%CI 0.14-0.51, p < 0.001) were protective. In conclusion, prophylaxis with monoclonal antibodies may reduce the risk of COVID-19 in hematological patients.