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There is an urgent need to improve the infrastructure supporting the reuse of scholarly data. A diverse set of stakeholders-representing academia, industry, funding agencies, and scholarly publishers-have come together to design and jointly endorse a concise and measureable set of principles that we refer to as the FAIR Data Principles. The intent is that these may act as a guideline for those wishing to enhance the reusability of their data holdings. Distinct from peer initiatives that focus on the human scholar, the FAIR Principles put specific emphasis on enhancing the ability of machines to automatically find and use the data, in addition to supporting its reuse by individuals. This Comment is the first formal publication of the FAIR Principles, and includes the rationale behind them, and some exemplar implementations in the community.

Studies of the human microbiome have revealed that even healthy individuals differ remarkably in the microbes that occupy habitats such as the gut, skin and vagina. Much of this diversity remains unexplained, although diet, environment, host genetics and early microbial exposure have all been implicated. Accordingly, to characterize the ecology of human-associated microbial communities, the Human Microbiome Project has analysed the largest cohort and set of distinct, clinically relevant body habitats so far. We found the diversity and abundance of each habitat’s signature microbes to vary widely even among healthy subjects, with strong niche specialization both within and among individuals. The project encountered an estimated 81–99% of the genera, enzyme families and community configurations occupied by the healthy Western microbiome. Metagenomic carriage of metabolic pathways was stable among individuals despite variation in community structure, and ethnic/racial background proved to be one of the strongest associations of both pathways and microbes with clinical metadata. These results thus delineate the range of structural and functional configurations normal in the microbial communities of a healthy population, enabling future characterization of the epidemiology, ecology and translational applications of the human microbiome. The Human Microbiome Project Consortium reports the first results of their analysis of microbial communities from distinct, clinically relevant body habitats in a human cohort; the insights into the microbial communities of a healthy population lay foundations for future exploration of the epidemiology, ecology and translational applications of the human microbiome. The Human Microbiome Project (HMP), supported by the National Institutes of Health Common Fund, has the goal of characterizing the microbial communities that inhabit and interact with the human body in sickness and in health. In two Articles in this issue of Nature, the HMP Consortium presents the first population-scale details of the organismal and functional composition of the microbiota across five areas of the body. An associated News & Views discusses the initial results — which, along with those of a series of co-publications, already constitute the most extensive catalogue of organisms and genes related to the human microbiome yet published — and highlights some of the major questions that the project will tackle in the next few years.

The number of cancer survivors continues to increase because of both advances in early detection and treatment and the aging and growth of the population. For the public health community to better serve these survivors, the American Cancer Society and the National Cancer Institute collaborate to estimate the number of current and future cancer survivors using data from the Surveillance, Epidemiology, and End Results cancer registries. In addition, current treatment patterns for the most prevalent cancer types are presented based on information in the National Cancer Data Base and treatment-related side effects are briefly described. More than 15.5 million Americans with a history of cancer were alive on January 1, 2016, and this number is projected to reach more than 20 million by January 1, 2026. The 3 most prevalent cancers are prostate (3,306,760), colon and rectum (724,690), and melanoma (614,460) among males and breast (3,560,570), uterine corpus (757,190), and colon and rectum (727,350) among females. More than one-half (56%) of survivors were diagnosed within the past 10 years, and almost one-half (47%) are aged 70 years or older. People with a history of cancer have unique medical and psychosocial needs that require proactive assessment and management by primary care providers. Although there are a growing number of tools that can assist patients, caregivers, and clinicians in navigating the various phases of cancer survivorship, further evidence-based resources are needed to optimize care. CA Cancer J Clin 2016;66:271-289. © 2016 American Cancer Society.

Lung squamous cell carcinoma is a common type of lung cancer, causing approximately 400,000 deaths per year worldwide. Genomic alterations in squamous cell lung cancers have not been comprehensively characterized, and no molecularly targeted agents have been specifically developed for its treatment. As part of The Cancer Genome Atlas, here we profile 178 lung squamous cell carcinomas to provide a comprehensive landscape of genomic and epigenomic alterations. We show that the tumour type is characterized by complex genomic alterations, with a mean of 360 exonic mutations, 165 genomic rearrangements, and 323 segments of copy number alteration per tumour. We find statistically recurrent mutations in 11 genes, including mutation of TP53 in nearly all specimens. Previously unreported loss-of-function mutations are seen in the HLA-A class I major histocompatibility gene. Significantly altered pathways included NFE2L2 and KEAP1 in 34%, squamous differentiation genes in 44%, phosphatidylinositol-3-OH kinase pathway genes in 47%, and CDKN2A and RB1 in 72% of tumours. We identified a potential therapeutic target in most tumours, offering new avenues of investigation for the treatment of squamous cell lung cancers. Comprehensive analyses of 178 lung squamous cell carcinomas by The Cancer Genome Atlas project show that the tumour type is characterized by complex genomic alterations, with statistically recurrent mutations in 11 genes, including TP53 in nearly all samples; a potential therapeutic target is identified in most of the samples studied. The Cancer Genome Atlas consortium has analysed 178 lung squamous cell carcinomas, a common type of lung cancer for which comprehensive genomic analyses have not previously been available. The researchers report that this tumour type is characterized by complex genomic alterations, with recurrent mutations in 18 genes, including TP53 in nearly all samples. They also report frequent mutations in squamous differentiation genes. Collectively, these analyses identify potential therapeutic targets worthy of further investigation.

<h3>Background</h3> Uncertainties exist about the prevalence and comorbidity of substance use disorders and independent mood and anxiety disorders. <h3>Objective</h3> To present nationally representative data on the prevalence and comorbidity of<i>DSM-IV</i>alcohol and drug use disorders and independent mood and anxiety disorders (including only those that are not substance induced and that are not due to a general medical condition). <h3>Design</h3> Face-to-face survey. <h3>Setting</h3> The United States. <h3>Participants</h3> Household and group quarters' residents. <h3>Main Outcome Measures</h3> Prevalence and associations of substance use disorders and independent mood and anxiety disorders. <h3>Results</h3> The prevalences of 12-month<i>DSM-IV</i>independent mood and anxiety disorders in the US population were 9.21% (95% confidence interval [CI], 8.78%-9.64%) and 11.08% (95% CI, 10.43%-11.73%), respectively. The rate of substance use disorders was 9.35% (95% CI, 8.86%-9.84%). Only a few individuals with mood or anxiety disorders were classified as having only substance-induced disorders. Associations between most substance use disorders and independent mood and anxiety disorders were positive and significant (<i>P</i>&lt;.05). <h3>Conclusions</h3> Substance use disorders and mood and anxiety disorders that develop independently of intoxication and withdrawal are among the most prevalent psychiatric disorders in the United States. Associations between most substance use disorders and independent mood and anxiety disorders were overwhelmingly positive and significant, suggesting that treatment for a comorbid mood or anxiety disorder should not be withheld from individuals with substance use disorders.

A variety of microbial communities and their genes (the microbiome) exist throughout the human body, with fundamental roles in human health and disease. The National Institutes of Health (NIH)-funded Human Microbiome Project Consortium has established a population-scale framework to develop metagenomic protocols, resulting in a broad range of quality-controlled resources and data including standardized methods for creating, processing and interpreting distinct types of high-throughput metagenomic data available to the scientific community. Here we present resources from a population of 242 healthy adults sampled at 15 or 18 body sites up to three times, which have generated 5,177 microbial taxonomic profiles from 16S ribosomal RNA genes and over 3.5 terabases of metagenomic sequence so far. In parallel, approximately 800 reference strains isolated from the human body have been sequenced. Collectively, these data represent the largest resource describing the abundance and variety of the human microbiome, while providing a framework for current and future studies. The Human Microbiome Project Consortium has established a population-scale framework to study a variety of microbial communities that exist throughout the human body, enabling the generation of a range of quality-controlled data as well as community resources. The Human Microbiome Project (HMP), supported by the National Institutes of Health Common Fund, has the goal of characterizing the microbial communities that inhabit and interact with the human body in sickness and in health. In two Articles in this issue of Nature, the HMP Consortium presents the first population-scale details of the organismal and functional composition of the microbiota across five areas of the body. An associated News & Views discusses the initial results — which, along with those of a series of co-publications, already constitute the most extensive catalogue of organisms and genes related to the human microbiome yet published — and highlights some of the major questions that the project will tackle in the next few years.

The Human Microbiome Project (HMP), funded as an initiative of the NIH Roadmap for Biomedical Research (http://nihroadmap.nih.gov), is a multi-component community resource. The goals of the HMP are: (1) to take advantage of new, high-throughput technologies to characterize the human microbiome more fully by studying samples from multiple body sites from each of at least 250 "normal" volunteers; (2) to determine whether there are associations between changes in the microbiome and health/disease by studying several different medical conditions; and (3) to provide both a standardized data resource and new technological approaches to enable such studies to be undertaken broadly in the scientific community. The ethical, legal, and social implications of such research are being systematically studied as well. The ultimate objective of the HMP is to demonstrate that there are opportunities to improve human health through monitoring or manipulation of the human microbiome. The history and implementation of this new program are described here.

BACKGROUND: Lung cancer is made up of distinct subtypes, including non-small-cell lung cancer (NSCLC) and small-cell lung cancer (SCLC). Although overall mortality from lung cancer has been declining in the United States, little is known about mortality trends according to cancer subtype at the population level because death certificates do not record subtype information. METHODS: Using data from Surveillance, Epidemiology, and End Results (SEER) areas, we assessed lung-cancer mortality and linked deaths from lung cancer to incident cases in SEER cancer registries. This allowed us to evaluate population-level mortality trends attributed to specific subtypes (incidence-based mortality). We also evaluated lung-cancer incidence and survival according to cancer subtype, sex, and calendar year. Joinpoint software was used to assess changes in incidence and trends in incidence-based mortality. RESULTS: Mortality from NSCLC decreased even faster than the incidence of this subtype, and this decrease was associated with a substantial improvement in survival over time that corresponded to the timing of approval of targeted therapy. Among men, incidence-based mortality from NSCLC decreased 6.3% annually from 2013 through 2016, whereas the incidence decreased 3.1% annually from 2008 through 2016. Corresponding lung cancer-specific survival improved from 26% among men with NSCLC that was diagnosed in 2001 to 35% among those in whom it was diagnosed in 2014. This improvement in survival was found across all races and ethnic groups. Similar patterns were found among women with NSCLC. In contrast, mortality from SCLC declined almost entirely as a result of declining incidence, with no improvement in survival. This result correlates with limited treatment advances for SCLC in the time frame we examined. CONCLUSIONS: Population-level mortality from NSCLC in the United States fell sharply from 2013 to 2016, and survival after diagnosis improved substantially. Our analysis suggests that a reduction in incidence along with treatment advances - particularly approvals for and use of targeted therapies - is likely to explain the reduction in mortality observed during this period.

PURPOSE: Adoptive immunotherapy using tumor-infiltrating lymphocytes represents an effective cancer treatment for patients with metastatic melanoma. The NY-ESO-1 cancer/testis antigen, which is expressed in 80% of patients with synovial cell sarcoma and approximately 25% of patients with melanoma and common epithelial tumors, represents an attractive target for immune-based therapies. The current trial was carried out to evaluate the ability of adoptively transferred autologous T cells transduced with a T-cell receptor (TCR) directed against NY-ESO-1 to mediate tumor regression in patients with metastatic melanoma and synovial cell sarcoma. PATIENTS AND METHODS: A clinical trial was performed in patients with metastatic melanoma or metastatic synovial cell sarcoma refractory to all standard treatments. Patients with NY-ESO-1-positive tumors were treated with autologous TCR-transduced T cells plus 720,000 iU/kg of interleukin-2 to tolerance after preparative chemotherapy. Objective clinical responses were evaluated using Response Evaluation Criteria in Solid Tumors (RECIST). RESULTS: Objective clinical responses were observed in four of six patients with synovial cell sarcoma and five of 11 patients with melanoma bearing tumors expressing NY-ESO-1. Two of 11 patients with melanoma demonstrated complete regressions that persisted after 1 year. A partial response lasting 18 months was observed in one patient with synovial cell sarcoma. CONCLUSION: These observations indicate that TCR-based gene therapies directed against NY-ESO-1 represent a new and effective therapeutic approach for patients with melanoma and synovial cell sarcoma. To our knowledge, this represents the first demonstration of the successful treatment of a nonmelanoma tumor using TCR-transduced T cells.

This article proposes several conceptual perspectives designed to advance our understanding of the material and experiential conditions contributing to persistent disparities in rates of morbidity and mortality among groups unequal in their social and economic statuses. An underlying assumption is that these disparities, which are in clear evidence at mid- and late life, may be anchored to earlier circumstances of the life course. Of particular interest are those circumstances resulting in people with the least privileged statuses having the greatest chances of exposure to health-related stressors. Among the stressors closely linked to status and status attainment are those that continue or are repeated across the life course, such as enduring economic strain and discriminatory experiences. Also taking a long-range toll on health are circumstances of stress proliferation, a process that places people exposed to a serious adversity at risk for later exposure to additional adversities. We suggest that this process can be observed in instances of trauma, in early out-of-sequence transitions, and in the case of undesired changes that disrupt behaviors and relationships in established roles. Effective effort to close the systemic health gaps must recognize their structural underpinnings.

OBJECTIVES: This study examined age-, sex-, and race-specific gradients in US mortality by area deprivation between 1969 and 1998. METHODS: A census-based area deprivation index was linked to county mortality data. RESULTS: Area deprivation gradients in US mortality increased substantially during 1969 through 1998. The gradients were steepest for men and women aged 25 to 44 years and those younger than 25 years, with higher mortality rates observed in more deprived areas. Although area gradients were less pronounced for women in each age group, they rose sharply for women aged 25 to 44 and 45 to 64 years. CONCLUSIONS: Areal inequalities in mortality widened because of slower mortality declines in more deprived areas. Future research needs to examine population-level social, behavioral, and medical care factors that may account for the increasing gradient.

BACKGROUND: Despite advances in treatments for Hodgkin's lymphoma, about 20% of patients still die from progressive disease. Current prognostic models predict the outcome of treatment with imperfect accuracy, and clinically relevant biomarkers have not been established to improve on the International Prognostic Score. METHODS: Using gene-expression profiling, we analyzed 130 frozen samples obtained from patients with classic Hodgkin's lymphoma during diagnostic lymph-node biopsy to determine which cellular signatures were correlated with treatment outcome. We confirmed our findings in an independent cohort of 166 patients, using immunohistochemical analysis. RESULTS: Gene-expression profiling identified a gene signature of tumor-associated macrophages that was significantly associated with primary treatment failure (P=0.02). In an independent cohort of patients, we found that an increased number of CD68+ macrophages was correlated with a shortened progression-free survival (P=0.03) and with an increased likelihood of relapse after autologous hematopoietic stem-cell transplantation (P=0.008), resulting in shortened disease-specific survival (P=0.003). In multivariate analysis, this adverse prognostic factor outperformed the International Prognostic Score for disease-specific survival (P=0.003 vs. P=0.03). The absence of an elevated number of CD68+ cells in patients with limited-stage disease defined a subgroup of patients with a long-term disease-specific survival of 100% with the use of current treatment strategies. CONCLUSIONS: An increased number of tumor-associated macrophages was strongly associated with shortened survival in patients with classic Hodgkin's lymphoma and provides a new biomarker for risk stratification.

Viral clearance during hepatitis B virus (HBV) infection has been thought to reflect the destruction of infected hepatocytes by CD8(+) T lymphocytes. However, in this study, HBV DNA was shown to largely disappear from the liver and the blood of acutely infected chimpanzees long before the peak of T cell infiltration and most of the liver disease. These results demonstrate that noncytopathic antiviral mechanisms contribute to viral clearance during acute viral hepatitis by purging HBV replicative intermediates from the cytoplasm and covalently closed circular viral DNA from the nucleus of infected cells.

Scalable, integrative methods to understand mechanisms that link genetic variants with phenotypes are needed. Here we derive a mathematical expression to compute PrediXcan (a gene mapping approach) results using summary data (S-PrediXcan) and show its accuracy and general robustness to misspecified reference sets. We apply this framework to 44 GTEx tissues and 100+ phenotypes from GWAS and meta-analysis studies, creating a growing public catalog of associations that seeks to capture the effects of gene expression variation on human phenotypes. Replication in an independent cohort is shown. Most of the associations are tissue specific, suggesting context specificity of the trait etiology. Colocalized significant associations in unexpected tissues underscore the need for an agnostic scanning of multiple contexts to improve our ability to detect causal regulatory mechanisms. Monogenic disease genes are enriched among significant associations for related traits, suggesting that smaller alterations of these genes may cause a spectrum of milder phenotypes.

PURPOSE: Physical activity (PA) is known to improve cognitive and brain function, but debate continues regarding the consistency and magnitude of its effects, populations and cognitive domains most affected, and parameters necessary to achieve the greatest improvements (e.g., dose). METHODS: In this umbrella review conducted in part for the 2018 Health and Human Services Physical Activity Guidelines for Americans Advisory Committee, we examined whether PA interventions enhance cognitive and brain outcomes across the life span, as well as in populations experiencing cognitive dysfunction (e.g., schizophrenia). Systematic reviews, meta-analyses, and pooled analyses were used. We further examined whether engaging in greater amounts of PA is associated with a reduced risk of developing cognitive impairment and dementia in late adulthood. RESULTS: Moderate evidence from randomized controlled trials indicates an association between moderate- to vigorous-intensity PA and improvements in cognition, including performance on academic achievement and neuropsychological tests, such as those measuring processing speed, memory, and executive function. Strong evidence demonstrates that acute bouts of moderate- to vigorous-intensity PA have transient benefits for cognition during the postrecovery period after exercise. Strong evidence demonstrates that greater amounts of PA are associated with a reduced risk of developing cognitive impairment, including Alzheimer's disease. The strength of the findings varies across the life span and in individuals with medical conditions influencing cognition. CONCLUSIONS: There is moderate-to-strong support that PA benefits cognitive functioning during early and late periods of the life span and in certain populations characterized by cognitive deficits.

BACKGROUND: Adult-onset inflammatory syndromes often manifest with overlapping clinical features. Variants in ubiquitin-related genes, previously implicated in autoinflammatory disease, may define new disorders. METHODS: We analyzed peripheral-blood exome sequence data independent of clinical phenotype and inheritance pattern to identify deleterious mutations in ubiquitin-related genes. Sanger sequencing, immunoblotting, immunohistochemical testing, flow cytometry, and transcriptome and cytokine profiling were performed. CRISPR-Cas9-edited zebrafish were used as an in vivo model to assess gene function. RESULTS: lies on the X chromosome.) In such patients, an often fatal, treatment-refractory inflammatory syndrome develops in late adulthood, with fevers, cytopenias, characteristic vacuoles in myeloid and erythroid precursor cells, dysplastic bone marrow, neutrophilic cutaneous and pulmonary inflammation, chondritis, and vasculitis. Most of these 25 patients met clinical criteria for an inflammatory syndrome (relapsing polychondritis, Sweet's syndrome, polyarteritis nodosa, or giant-cell arteritis) or a hematologic condition (myelodysplastic syndrome or multiple myeloma) or both. Mutations were found in more than half the hematopoietic stem cells, including peripheral-blood myeloid cells but not lymphocytes or fibroblasts. Mutations affecting p.Met41 resulted in loss of the canonical cytoplasmic isoform of UBA1 and in expression of a novel, catalytically impaired isoform initiated at p.Met67. Mutant peripheral-blood cells showed decreased ubiquitylation and activated innate immune pathways. Knockout of the cytoplasmic UBA1 isoform homologue in zebrafish caused systemic inflammation. CONCLUSIONS: Using a genotype-driven approach, we identified a disorder that connects seemingly unrelated adult-onset inflammatory syndromes. We named this disorder the VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome. (Funded by the NIH Intramural Research Programs and the EU Horizon 2020 Research and Innovation Program.).

The numerous functions of the liver are controlled primarily at the transcriptional level by the concerted actions of a limited number of hepatocyte-enriched transcription factors (hepatocyte nuclear factor 1alpha [HNF1alpha], -1beta, -3alpha, -3beta, -3gamma, -4alpha, and -6 and members of the c/ebp family). Of these, only HNF4alpha (nuclear receptor 2A1) and HNF1alpha appear to be correlated with the differentiated phenotype of cultured hepatoma cells. HNF1alpha-null mice are viable, indicating that this factor is not an absolute requirement for the formation of an active hepatic parenchyma. In contrast, HNF4alpha-null mice die during embryogenesis. Moreover, recent in vitro experiments using tetraploid aggregation suggest that HNF4alpha is indispensable for hepatocyte differentiation. However, the function of HNF4alpha in the maintenance of hepatocyte differentiation and function is less well understood. To address the function of HNF4alpha in the mature hepatocyte, a conditional gene knockout was produced using the Cre-loxP system. Mice lacking hepatic HNF4alpha expression accumulated lipid in the liver and exhibited greatly reduced serum cholesterol and triglyceride levels and increased serum bile acid concentrations. The observed phenotypes may be explained by (i) a selective disruption of very-low-density lipoprotein secretion due to decreased expression of genes encoding apolipoprotein B and microsomal triglyceride transfer protein, (ii) an increase in hepatic cholesterol uptake due to increased expression of the major high-density lipoprotein receptor, scavenger receptor BI, and (iii) a decrease in bile acid uptake to the liver due to down-regulation of the major basolateral bile acid transporters sodium taurocholate cotransporter protein and organic anion transporter protein 1. These data indicate that HNF4alpha is central to the maintenance of hepatocyte differentiation and is a major in vivo regulator of genes involved in the control of lipid homeostasis.

BACKGROUND: Given the rapid changes in the communication landscape brought about by participative Internet use and social media, it is important to develop a better understanding of these technologies and their impact on health communication. The first step in this effort is to identify the characteristics of current social media users. Up-to-date reporting of current social media use will help monitor the growth of social media and inform health promotion/communication efforts aiming to effectively utilize social media. OBJECTIVE: The purpose of the study is to identify the sociodemographic and health-related factors associated with current adult social media users in the United States. METHODS: Data came from the 2007 iteration of the Health Information National Trends Study (HINTS, N = 7674). HINTS is a nationally representative cross-sectional survey on health-related communication trends and practices. Survey respondents who reported having accessed the Internet (N = 5078) were asked whether, over the past year, they had (1) participated in an online support group, (2) written in a blog, (3) visited a social networking site. Bivariate and multivariate logistic regression analyses were conducted to identify predictors of each type of social media use. RESULTS: Approximately 69% of US adults reported having access to the Internet in 2007. Among Internet users, 5% participated in an online support group, 7% reported blogging, and 23% used a social networking site. Multivariate analysis found that younger age was the only significant predictor of blogging and social networking site participation; a statistically significant linear relationship was observed, with younger categories reporting more frequent use. Younger age, poorer subjective health, and a personal cancer experience predicted support group participation. In general, social media are penetrating the US population independent of education, race/ethnicity, or health care access. CONCLUSIONS: Recent growth of social media is not uniformly distributed across age groups; therefore, health communication programs utilizing social media must first consider the age of the targeted population to help ensure that messages reach the intended audience. While racial/ethnic and health status-related disparities exist in Internet access, among those with Internet access, these characteristics do not affect social media use. This finding suggests that the new technologies, represented by social media, may be changing the communication pattern throughout the United States.

Abstract Analytic expressions for mean squared positions and velocities of a harmonic oscillator are derived for Langevin dynamics algorithms valid in the high and low friction limits, and for the Verlet algorithm. For typical values of the parameters, errors in the positions are small. However, if the velocity is defined by the usual Verlet form, kinetic energies (and therefore calculated temperatures) can be in error by several per cent for the Langevin algorithms. If the Bunger-Brooks-Karplus algorithm is used to calculate positions, a simple redefinition of the velocity results greatly in improved kinetic energies. In addition, due to cancellation of errors in the velocities and the positions, the correct virial is obtained. The effect of including the force derivative in diffusive algorithms is examined. Positional and velocity averages are calculated for the Verlet algorithm for arbitrary initial conditions, and errors in the total energy and virial are analysed. Connection is made with the Langevin algorithms, and it is shown for harmonic oscillators that different definitions of the velocity are required to optimally calculate the temperature, pressure, and total energy, respectively.

BACKGROUND: Fludarabine is an effective treatment for chronic lymphocytic leukemia that does not respond to initial treatment with chlorambucil. We compared the efficacy of fludarabine with that of chlorambucil in the primary treatment of chronic lymphocytic leukemia. METHODS: Between 1990 and 1994, we randomly assigned 509 previously untreated patients with chronic lymphocytic leukemia to one of the following treatments: fludarabine (25 mg per square meter of body-surface area, administered intravenously daily for 5 days every 28 days), chlorambucil (40 mg per square meter, given orally every 28 days), or fludarabine (20 mg per square meter per day for 5 days every 28 days) plus chlorambucil (20 mg per square meter every 28 days). Patients with an additional response at each monthly evaluation continued to receive the assigned treatment for a maximum of 12 cycles. RESULTS: Assignment of patients to the fludarabine-plus-chlorambucil group was stopped when a planned interim analysis revealed excessive toxicity and a response rate that was not better than the rate with fludarabine alone. Among the other two groups, the response rate was significantly higher for fludarabine alone than for chlorambucil alone. Among 170 patients treated with fludarabine, 20 percent had a complete remission, and 43 percent had a partial remission. The corresponding values for 181 patients treated with chlorambucil were 4 percent and 33 percent (P< 0.001 for both comparisons). The median duration of remission and the median progression-free survival in the fludarabine group were 25 months and 20 months, respectively, whereas both values were 14 months in the chlorambucil group (P<0.001 for both comparisons). The median overall survival among patients treated with fludarabine was 66 months, which was not significantly different from the overall survival in the other two groups (56 months with chlorambucil and 55 months with combined treatment). Severe infections and neutropenia were more frequent with fludarabine than with chlorambucil (P=0.08), although, overall, toxic effects were tolerable with the two single-drug regimens. CONCLUSIONS: When used as the initial treatment for chronic lymphocytic leukemia, fludarabine yields higher response rates and a longer duration of remission and progression-free survival than chlorambucil.