A causal roadmap for generating high-quality real-world evidence

Increasing emphasis on the use of real-world evidence (RWE) to support clinical policy and regulatory decision-making has led to a proliferation of guidance, advice, and frameworks from regulatory agencies, academia, professional societies, and industry. A broad spectrum of studies use real-world data (RWD) to produce RWE, ranging from randomized trials with outcomes assessed using RWD to fully observational studies. Yet, many proposals for generating RWE lack sufficient detail, and many analyses of RWD suffer from implausible assumptions, other methodological flaws, or inappropriate interpretations. The Causal Roadmap is an explicit, itemized, iterative process that guides investigators to prespecify study design and analysis plans; it addresses a wide range of guidance within a single framework. By supporting the transparent evaluation of causal assumptions and facilitating objective comparisons of design and analysis choices based on prespecified criteria, the Roadmap can help investigators to evaluate the quality of evidence that a given study is likely to produce, specify a study to generate high-quality RWE, and communicate effectively with regulatory agencies and other stakeholders. This paper aims to disseminate and extend the Causal Roadmap framework for use by clinical and translational researchers; three companion papers demonstrate applications of the Causal Roadmap for specific use cases

GSTT1 and GSTM1 polymorphisms and myelodysplastic syndrome risk: A systematic review and meta-analysis

Glutathione-S-transferace polymorphisms may make hematopoietic lineage cells susceptible to genotoxicity following exposure to heavy metals or benzene. We conducted a systematic review and meta-analysis to define the effect of GSTM1 and GSTT1 null polymorphisms on MDS risk. We searched the PubMed and SCOPUS databases to identify peer-reviewed published case-control studies investigating the association between GSTT1 and/or GSTM1 null genotypes and development of MDS. Between-study heterogeneity was assessed using Cochran's Q statistic and the I2 statistic. Odds ratios from individual studies were pooled using fixed and random effects models. Thirteen studies were considered eligible for the GSTT1 metaanalysis (1471 cases, 1907 controls) and 10 were considered eligible for the GSTM1 meta-analysis (1161 cases, 1668 controls). For the GSTT1 polymorphism, there was moderate between study heterogeneity (pQ = 0.01; I2 = 52.3%) and the null genotype was significantly associated with increased risk of MDS development, random effects OR = 1.43 (95% CI, 1.09-1.89); p = 0.01. For the GSTM1 polymorphisms there was moderate between-study heterogeneity (p = 0.07; I 2 = 43.1%) and the random effects OR = 1.02 (95% CI, 0.82-1.28) was non-significant (p = 0.85). The GSTT1 null genotype is a significant risk factor for MDS development. Gene-environment interactions need to be further explored. © 2009 UICC

Hematologic manifestations and predictors of lymphoma development in primary sjögren syndrome: Clinical and pathophysiologic aspects

The diverse hematologic manifestations of primary Sjögren syndrome (pSS) have not been systematically investigated, and their prognostic relevance remains unclear. We conducted a retrospective study of 536 consecutive patients followed in our institution to assess the prevalence of hematologic abnormalities and their associations with various disease manifestations in pSS. We also aimed to identify risk factors for the development of non-Hodgkin lymphoma (NHL) overall and by subtype.Anemia of chronic disease and hypergammaglobulinemia were the most prevalent hematologic manifestations encountered at diagnosis and during the course of pSS. Univariate analysis between cytopenias and glandular manifestations revealed a statistically significant correlation between lymphocytopenia and parotid gland enlargement (p = 0.002), as well as between neutropenia and xerostomia (p = 0.019). Anemia, lymphocytopenia, thrombocytopenia, hypergammaglobulinemia, the presence of monoclonal serum proteins, and cryoglobulinemia correlated significantly with the presence of extraglandular symptoms such as palpable purpura, lymphadenopathy, and splenomegaly.Lymphoma was diagnosed in 7.5% (95% confidence interval [CI], 5.4%-10%) of patients. Marginal zone B-cell lymphomas (MZBCLs) were the predominant histologic type (65%; 95% CI, 48.3%-79.4%), while diffuse large B-cell lymphomas (DLBCLs) accounted for 17.5% (95% CI, 7.3%-32.8%) of all cases. The development of NHL in patients with pSS could be predicted by the presence of simple clinical and laboratory factors at diagnosis: neutropenia (p = 0.041), cryoglobulinemia (p = 0.008), splenomegaly (p = 0.006), lymphadenopathy (p = 0.021), and low C4 levels (p = 0.009). Patients carrying any of these factors had a more than 5-fold increased risk of NHL compared to patients with no risk factors at all. The above set of disease characteristics could predict subsequent development of MZBCL; the presence of lymphocytopenia (p = 0.044) at diagnosis served as a risk factor for the development of a non-MZBCL, most commonly DLBCL.Anemia of chronic disease and hypergammaglobulinemia are common hematologic manifestations at diagnosis and during the course of pSS. Neutropenia and cryoglobulinemia at diagnosis are significantly associated with an increased risk of lymphoma development. Copyright © 2009 by Lippincott Williams & Wilkins

Infliximab and methotrexate in the treatment of rheumatoid arthritis: A systematic review and meta-analysis of dosage regimens

Background: Because of its long-term effectiveness in clinical practice, methotrexate (MTX) is currently the preferred disease-modifying antirheumatic drug (DMARD) for patients with active rheumatoid arthritis (RRA). However, many patients do not experience remission and continue to have signs and symptoms of active disease while receiving a maximally tolerated dose. Objectives: The aims of this meta-analysis were to estimate the efficacy and tolerability of the various dosage schemes of infliximab versus MTX for the treatment of active RA, to eliminate size-related uncertainty of effects, and to identify subgroups of patients who benefit most from infliximab + MTX therapy. Methods: Using the MEDLINE online database (inception through November 2006) and the Cochrane Database of Systematic Reviews (Issue 4, 2006), we identified English-language articles on randomized controlled clinical trials. Studies investigating infliximab + MTX regimens versus a control group receiving MTX alone to assess efficacy in active RA, usinng the American College of Rheumatology (A criteria for 20% improvement (AA, 50% improvement (ACR50), and 70% improvement (AA, were considered eligible for the meta-aanalysis. Pooled odds ratios (ORs) and 95% CIs were calculated to compare the relative risks and benefits of adding infliximab to MTX. Results: From a total of 78 initially identified studies, 42 were considered potentially eligible for this review and 12 were considered eligible for the meta-analysis. Overall, 4899 patients were randomized to either infliximab + MTX (3919 patients) or MTX alone (980 patients). Mean patient age ranged from 44.6 to 56 years in the MTX-only arms and from 45.8 to 56 years in the infliximab + MTX arms. The proportion of female patients ranged from 66.6% to 100% in the MTX arms and from 68% to 100% in the infliximab arms. Infliximab 3 mg/kkg + MTX was moreeffective than MTX alone (OR = 3.52 [2.14-5.79] for reaching ACR20; 2.87 [2.228-3.61] for ACR50; and 2.42 [1.87-3.13] for ACR70). Infliximab 10 mg/kkg + MTX was also more effective than MTX alone (OR = 5.06 [3.88-6.59] for reaching ACR20; 5.72 [4.05-8.08] for ACR50; and 7.32 [2.28-23.50] for ACR70). Infliximab 10-mm/kg regimens appeared to be more effective than infliximab 3-mg/kg regimens (P = NS, P = 0.001, and P = NS for reaching ACR20, ACR50, and ACR70, respectively), without being associated with an increased risk for adverse events. Infliximab 10 mg/kg appeared to be more effective in trials of longer duration (≥54 weeks) compared with those of shorter duration (P = 0.03, P = 0.02, and P = 0.01 for reaching ACR20, ACR50, and ACR70, respectively) and in those that enrolled patients with severe disease activity (P = 0.05, P = 0.05, and P = NS for reaching ACR20, ACR50, and ACR70, respectively). Steroid coadministration (P < 0.001, P < 0.001, and P = NS for reaching ACR20, ACR50, and ACR70, respectively), previous DMARD exposure (P < 0.001, P < 0.001, and P = 0.04 for reaching ACR20, ACR50, and ACR70, respectively), and MTX naivete (P = NS, P < 0.001, and P =0.013 for reaching ACR20, ACR50, and ACR70, respectively) correlated with higher infliximab efficacy. Conclusions: Based on this meta-aanalysis, higher dose infliximab (10 mg/kg) in combination with MTX appeared to be more effective than the standard 3 mg/kg dose, particularly for patients with severe disease activity.The benefits of high-dose treatment appeared to accrue over time, and patients who received higher doses of infliximab did not experience a higher incidence of severe adverse events. The addition of oral low-dose steroids significantly enhanced infliximab efficacy. © 2008 Excerpta Medica Inc. All rights reserved

Somatic EGFR mutations and efficacy of tyrosine kinase inhibitors in NSCLC

Early clinical studies of tyrosine kinase inhibitors (TKIs) that target the EGFR in patients with advanced non-small-cell lung cancer (NSCLC) showed that some patients experienced rapid, durable, complete or partial responses. These data were the basis for attempts to identify specific subgroups of patients who would further benefit from these agents. The discovery of somatic mutations in EGFR that correlated with sensitivity to TKIs identified a plausible explanation for these observations. Clinical and pathological factors such as female sex, never having smoked, Asian origin and adenocarcinoma histology correlate with the presence of EGFR mutations and objective responses to TKIs in patients with NSCLC. Recent studies in metastatic colorectal cancer highlighted that somatic mutations in KRAS represent a negative predictor of response to anti-EGFR monoclonal antibodies; KRAS mutations also represent an important mechanism of resistance to TKIs in NSCLC. Many large clinical studies are currently investigating the predictive and prognostic value of EGFR mutational status and other candidate biomarkers. We summarize the literature and present an overview of the field of anti-EGFR therapy in NSCLC, focusing on the influence of somatic EGFR mutations on selection of patients for TKI therapy and the influence of EGFR pathway regulation

Somatic EGFR mutation and gene copy gain as predictive biomarkers for response to tyrosine kinase inhibitors in non-small cell lung cancer

Purpose: The aim of this systematic review and meta-analysis was to characterize common EGFR molecular aberrations as potential predictive biomarkers for response to monotherapy with tyrosine kinase inhibitors (TKI) in non-small cell lung cancer (NSCLC). Experimental Design: We systematically identified articles investigating EGFR status [somatic mutational and gene copy aberrations (copy number)] in patients with NSCLC treated with TKIs. Eligible studies had to report complete and partial response rates stratified by EGFR status. We used random effects models for bivariable meta-analysis of sensitivity and specificity; positive and negative likelihood ratios (+LR and -LR, respectively) were also calculated and were considered as secondary end points. Results: Among 222 retrieved articles, 59 were considered eligible for the somatic EGFR mutation meta-analysis (1,020 mutations among 3,101 patients) and 21 were considered eligible for the EGFR gene copy number meta-analysis (542 gene gain among 1,539 patients). EGFR mutations were predictive of response to single-agent TKIs [sensitivity, 0.78; 95% confidence interval (95% CI), 0.74-0.82; specificity, 0.86; 95% CI, 0.82-0.89; +LR, 5.6; -LR, 0.25]. EGFR gene gain was also associated with response to TKIs, albeit with lower sensitivity and specificity. In subgroup analysis, the only recognized trend was for a higher predictive value in Whites compared with East Asians for both mutation and gene copy number. Conclusion: This analysis provides empirical evidence that EGFR mutations are sensitive and specific predictors of response to single-agent epidermal growth factor receptor TKIs in advanced NSCLC. The diagnostic performance of mutations seems better than that of EGFR gene gain. ©2010 AACR

Is JAK2 V617F mutation more than a diagnostic index?. A meta-analysis of clinical outcomes in essential thrombocythemia

A systematic review and meta-analysis was carried out to compare the frequency of clinically significant outcomes between JAK2 V617F positive and wild type patients with essential thrombocythemia (ET). JAK2 V617F positivity in patients with ET was associated with a clear increase in the odds of thrombosis [OR = 1.83 (95% CI, 1.32-2.53), p < 0.0001], and much higher odds of transformation to polycythemia vera [OR = 7.67 (95% CI, 2.04-28.87), p = 0.0009]. The mean difference of the white blood cell count between JAK2 positive and negative patients was associated with an increased odds ratio for thrombosis (p = 0.02). The JAK2 V617F mutation in patients with ET is associated with an increased risk of adverse cardiovascular outcomes via an increase in the leukocyte count. © 2008 Elsevier Ltd. All rights reserved