Analysis of the characteristics and the degree of pragmatism exhibited by pragmatic-labelled trials of antineoplastic treatments.

BACKGROUND: Pragmatic clinical trials (PCTs) are designed to reflect how an investigational treatment would be applied in clinical practice. As such, unlike their explanatory counterparts, they measure therapeutic effectiveness and are capable of generating high-quality real-world evidence. However, the conduct of PCTs remains extremely rare. The scarcity of such studies has contributed to the emergence of the efficacy-effectiveness gap and has led to calls for launching more of them, including in the field of oncology. This analysis aimed to identify self-labelled pragmatic trials of antineoplastic interventions and to evaluate whether their use of this label was justified. METHODS: We searched PubMed® and Embase® for publications corresponding with studies that investigated antitumor therapies and that were tagged as pragmatic in their titles, abstracts and/or index terms. Subsequently, we consulted all available source documents for the included trials and extracted relevant information from them. The data collected were then used to appraise the degree of pragmatism displayed by the PCTs with the help of the validated PRECIS-2 tool. RESULTS: The literature search returned 803 unique records, of which 46 were retained upon conclusion of the screening process. This ultimately resulted in the identification of 42 distinct trials that carried the 'pragmatic' label. These studies examined eight different categories of neoplasms and were mostly randomized, open-label, multicentric, single-country trials sponsored by non-commercial parties. On a scale of one (very explanatory) to five (very pragmatic), the median PCT had a PRECIS-2 score per domain of 3.13 (interquartile range: 2.57-3.53). The most and least pragmatic studies in the sample had a score of 4.44 and 1.57, respectively. Only a minority of trials were described in sufficient detail to allow them to be graded across all domains of the PRECIS-2 instrument. Many of the studies examined also had features that arguably precluded them from being pragmatic altogether, such as being monocentric or placebo-controlled in nature. CONCLUSION: PCTs of antineoplastic treatments are generally no more pragmatic than they are explanatory.

The fourth edition of the European Network for Health Technology Assessment Forum: highlights and outcomes.

The European Network for Health Technology Assessment (EUnetHTA) organizes an annual Forum with stakeholders to receive feedback on its activities, processes, and outputs produced. The fourth edition of the EUnetHTA Forum brought together representatives of HTA bodies, patient organizations, healthcare professionals (HCPs), academia, payers, regulators, and industry. The aim of this paper is to provide an overview of the highlights presented at the 2019 EUnetHTA Forum, reporting the main items and themes discussed in the plenary panel and breakout sessions. The leading topic was the concept of unmet medical need seen from different stakeholders' perspectives. Breakout sessions covered the joint production of assessment reports and engagement with payers, patients, and HCPs. Synergies, pragmatism, and inclusiveness across Member States and stakeholders were emphasized as leading factors to put in place a collaboration that serves the interest of patients and public health in a truly European spirit.

Responding to the challenges of international collaborations between the east and the west - report of the first JCOG-EORTC symposium and a perspective from young JCOG and EORTC investigators.

International/intercontinental collaboration is necessary to set up new innovative clinical trials for cancer treatment. However, the infrastructure, especially Asia-Europe academic partnerships, to enable such collaboration has not been fully structured and differences and similarities between the research groups have not been well studied. In 2015, collaboration started between the biggest cancer research organizations in Asia and EU, Japan Clinical Oncology Group (JCOG) and European Organisation for Research and Treatment of Cancer (EORTC). Following the first pilot collaboration study, the first scientific symposium took place in December 2017 in Tokyo. Before the symposium, a working visit for EORTC investigators from the Early Career Investigator initiative (ECI), willing to develop projects within the JCOG-EORTC partnership, was held. In addition to the digest of the working visit and symposium, we aimed to describe the differences and similarities between the two groups and to identify key factors for collaboration from the perspective of the young investigators of the networks. These findings are described in this article.

Collaboration between EORTC and JCOG-how to accelerate global clinical research partnership.

The demand for international collaboration in cancer clinical trials has grown stronger to maximize efficiency, avoid duplication of effort and to achieve effective implementation of research results into medical practice. Infrastructures that could facilitate intercontinental collaboration not only between Europe and United States but also between Europe and Asia are urgently needed. The European Organisation for Research and Treatment of Cancer, one of the major cancer clinical research infrastructure in Europe, initiated collaboration with the Japan Clinical Oncology Group, the largest cancer research cooperative group in Japan. Their first pilot trial on unresectable colorectal liver metastasis will commence on fourth quarter of 2016. With similar goals and strategies as well as with similar structures, the two research organizations have a great potential for efficient collaboration that could deliver faster and global therapeutic improvement to cancer patients. However, international collaboration requires careful and structured approach to harmonize activities to ensure success. This article focuses on specific intercontinental differences and the necessary requirements to ensure a successful partnership between European Organisation for Research and Treatment of Cancer and Japan Clinical Oncology Group. This could serve as a model to build more global international academic trials between the East and the West.

Temozolomide chemotherapy versus radiotherapy in high-risk low-grade glioma (EORTC 22033-26033): a randomised, open-label, phase 3 intergroup study.

BACKGROUND: Outcome of low-grade glioma (WHO grade II) is highly variable, reflecting molecular heterogeneity of the disease. We compared two different, single-modality treatment strategies of standard radiotherapy versus primary temozolomide chemotherapy in patients with low-grade glioma, and assessed progression-free survival outcomes and identified predictive molecular factors. METHODS: For this randomised, open-label, phase 3 intergroup study (EORTC 22033-26033), undertaken in 78 clinical centres in 19 countries, we included patients aged 18 years or older who had a low-grade (WHO grade II) glioma (astrocytoma, oligoastrocytoma, or oligodendroglioma) with at least one high-risk feature (aged >40 years, progressive disease, tumour size >5 cm, tumour crossing the midline, or neurological symptoms), and without known HIV infection, chronic hepatitis B or C virus infection, or any condition that could interfere with oral drug administration. Eligible patients were randomly assigned (1:1) to receive either conformal radiotherapy (up to 50·4 Gy; 28 doses of 1·8 Gy once daily, 5 days per week for up to 6·5 weeks) or dose-dense oral temozolomide (75 mg/m2 once daily for 21 days, repeated every 28 days [one cycle], for a maximum of 12 cycles). Random treatment allocation was done online by a minimisation technique with prospective stratification by institution, 1p deletion (absent vs present vs undetermined), contrast enhancement (yes vs no), age (<40 vs ≥40 years), and WHO performance status (0 vs ≥1). Patients, treating physicians, and researchers were aware of the assigned intervention. A planned analysis was done after 216 progression events occurred. Our primary clinical endpoint was progression-free survival, analysed by intention-to-treat; secondary outcomes were overall survival, adverse events, neurocognitive function (will be reported separately), health-related quality of life and neurological function (reported separately), and correlative analyses of progression-free survival by molecular markers (1p/19q co-deletion, MGMT promoter methylation status, and IDH1/IDH2 mutations). This trial is closed to accrual but continuing for follow-up, and is registered at the European Trials Registry, EudraCT 2004-002714-11, and at ClinicalTrials.gov, NCT00182819. FINDINGS: Between Sept 23, 2005, and March 26, 2010, 707 patients were registered for the study. Between Dec 6, 2005, and Dec 21, 2012, we randomly assigned 477 patients to receive either radiotherapy (n=240) or temozolomide chemotherapy (n=237). At a median follow-up of 48 months (IQR 31-56), median progression-free survival was 39 months (95% CI 35-44) in the temozolomide group and 46 months (40-56) in the radiotherapy group (unadjusted hazard ratio [HR] 1·16, 95% CI 0·9-1·5, p=0·22). Median overall survival has not been reached. Exploratory analyses in 318 molecularly-defined patients confirmed the significantly different prognosis for progression-free survival in the three recently defined molecular low-grade glioma subgroups (IDHmt, with or without 1p/19q co-deletion [IDHmt/codel], or IDH wild type [IDHwt]; p=0·013). Patients with IDHmt/non-codel tumours treated with radiotherapy had a longer progression-free survival than those treated with temozolomide (HR 1·86 [95% CI 1·21-2·87], log-rank p=0·0043), whereas there were no significant treatment-dependent differences in progression-free survival for patients with IDHmt/codel and IDHwt tumours. Grade 3-4 haematological adverse events occurred in 32 (14%) of 236 patients treated with temozolomide and in one (<1%) of 228 patients treated with radiotherapy, and grade 3-4 infections occurred in eight (3%) of 236 patients treated with temozolomide and in two (1%) of 228 patients treated with radiotherapy. Moderate to severe fatigue was recorded in eight (3%) patients in the radiotherapy group (grade 2) and 16 (7%) in the temozolomide group. 119 (25%) of all 477 patients had died at database lock. Four patients died due to treatment-related causes: two in the temozolomide group and two in the radiotherapy group. INTERPRETATION: Overall, there was no significant difference in progression-free survival in patients with low-grade glioma when treated with either radiotherapy alone or temozolomide chemotherapy alone. Further data maturation is needed for overall survival analyses and evaluation of the full predictive effects of different molecular subtypes for future individualised treatment choices. FUNDING: Merck Sharpe & Dohme-Merck & Co, Canadian Cancer Society, Swiss Cancer League, UK National Institutes of Health, Australian National Health and Medical Research Council, US National Cancer Institute, European Organisation for Research and Treatment of Cancer Cancer Research Fund.

EBCC-14 manifesto: Addressing disparities in access to innovation for patients with metastatic breast cancer across Europe.

The European Breast Cancer Council (EBCC) traditionally identifies controversies or major deficiencies in the management of patients with breast cancer and selects a multidisciplinary expert team to collaborate in setting crucial principles and recommendations to improve breast cancer care. The 2024 EBCC manifesto focuses on disparities in the care of patients with metastatic breast cancer. There are several reasons for existing disparities both between and within countries. Our recommendations aim to address the stigma of metastatic disease, which has led to significant disparities in access to innovative care regardless of the gross national income of a country. These recommendations are for different stakeholders to promote the care of patients with metastatic breast cancer across Europe and worldwide.

Defining the role of real-world data in cancer clinical research: The position of the European Organisation for Research and Treatment of Cancer.

The emergence of the precision medicine paradigm in oncology has led to increasing interest in the integration of real-world data (RWD) into cancer clinical research. As sources of real-world evidence (RWE), such data could potentially help address the uncertainties that surround the adoption of novel anticancer therapies into the clinic following their investigation in clinical trials. At present, RWE-generating studies which investigate antitumour interventions seem to primarily focus on collecting and analysing observational RWD, typically forgoing the use of randomisation despite its methodological benefits. This is appropriate in situations where randomised controlled trials (RCTs) are not feasible and non-randomised RWD analyses can offer valuable insights. Nevertheless, depending on how they are designed, RCTs have the potential to produce strong and actionable RWE themselves. The choice of which methodology to employ for RWD studies should be guided by the nature of the research question they are intended to answer. Here, we attempt to define some of the questions that do not necessarily require the conduct of RCTs. Moreover, we outline the strategy of the European Organisation for Research and Treatment of Cancer (EORTC) to contribute to the generation of robust and high-quality RWE by prioritising the execution of pragmatic trials and studies set up according to the trials-within-cohorts approach. If treatment allocation cannot be left up to random chance due to practical or ethical concerns, the EORTC will consider undertaking observational RWD research based on the target trial principle. New EORTC-sponsored RCTs may also feature concurrent prospective cohorts composed of off-trial patients.

Inclusion of functional measures and frailty in the development and evaluation of medicines for older adults.

The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) E7, the guidance for the conduct of clinical trials in people older than age 65 years, dates from 1994. Since then, the inclusion of older people in clinical trials has hardly improved, particularly for the oldest old age group (individuals older than age 75 years), which is the fastest growing demographic bracket in the EU. Even though most medications are taken by this group, relevant endpoints and safety outcomes for this cohort are rarely included and reported, both in clinical trials and regulatory approval documents. To improve the critical appraisal and the regulatory review of medicines taken by frail older adults, eight recommendations are presented and discussed in this Health Policy. These recommendations are brought together from different perspectives and experience of the treatment of older patients. On one side, the perspective of medical practitioners from various clinical disciplines, with their direct experience of clinical decision making; on the other, the perspective of regulators assessing the data submitted in medicine registration dossiers, their relevance to the risk-benefit balance for older patients, and the communication of the findings in the product information. Efforts to improve the participation of older people in clinical trials have been in place for more than a decade, with little success. The recommendations presented here are relevant for stakeholders, authorities, pharmaceutical companies, and researchers alike, as the implementation of these measures is not under the capacity of a single entity. Improving the inclusion of frail older adults requires awareness, focus, and action on the part of those who can effect a much needed change.

MGMT methylation analysis of glioblastoma on the Infinium methylation BeadChip identifies two distinct CpG regions associated with gene silencing and outcome, yielding a prediction model for comparisons across datasets, tumor grades, and CIMP-status.

The methylation status of the O(6)-methylguanine-DNA methyltransferase (MGMT) gene is an important predictive biomarker for benefit from alkylating agent therapy in glioblastoma. Recent studies in anaplastic glioma suggest a prognostic value for MGMT methylation. Investigation of pathogenetic and epigenetic features of this intriguingly distinct behavior requires accurate MGMT classification to assess high throughput molecular databases. Promoter methylation-mediated gene silencing is strongly dependent on the location of the methylated CpGs, complicating classification. Using the HumanMethylation450 (HM-450K) BeadChip interrogating 176 CpGs annotated for the MGMT gene, with 14 located in the promoter, two distinct regions in the CpG island of the promoter were identified with high importance for gene silencing and outcome prediction. A logistic regression model (MGMT-STP27) comprising probes cg12434587 [corrected] and cg12981137 provided good classification properties and prognostic value (kappa = 0.85; log-rank p < 0.001) using a training-set of 63 glioblastomas from homogenously treated patients, for whom MGMT methylation was previously shown to be predictive for outcome based on classification by methylation-specific PCR. MGMT-STP27 was successfully validated in an independent cohort of chemo-radiotherapy-treated glioblastoma patients (n = 50; kappa = 0.88; outcome, log-rank p < 0.001). Lower prevalence of MGMT methylation among CpG island methylator phenotype (CIMP) positive tumors was found in glioblastomas from The Cancer Genome Atlas than in low grade and anaplastic glioma cohorts, while in CIMP-negative gliomas MGMT was classified as methylated in approximately 50 % regardless of tumor grade. The proposed MGMT-STP27 prediction model allows mining of datasets derived on the HM-450K or HM-27K BeadChip to explore effects of distinct epigenetic context of MGMT methylation suspected to modulate treatment resistance in different tumor types.

How do cancer clinicians perceive real-world data and the evidence derived therefrom? Findings from an international survey of the European Organisation for Research and Treatment of Cancer.

Background: The role of real-world evidence (RWE) in the development of anticancer therapies has been gradually growing over time. Regulators, payers and health technology assessment agencies, spurred by the rise of the precision medicine model, are increasingly incorporating RWE into their decision-making regarding the authorization and reimbursement of novel antineoplastic treatments. However, it remains unclear how this trend is viewed by clinicians in the field. This study aimed to investigate the opinions of these stakeholders with respect to RWE and its suitability for informing regulatory, reimbursement-related and clinical decisions in oncology. Methods: An online survey was disseminated to clinicians belonging to the network of the European Organisation for Research and Treatment of Cancer between May and July 2021. Results: In total, 557 clinicians across 30 different countries participated in the survey, representing 13 distinct cancer domains. Despite seeing the methodological challenges associated with its interpretation as difficult to overcome, the respondents mostly (75.0%) perceived RWE positively, and believed such evidence could be relatively strong, depending on the designs and data sources of the studies from which it is produced. Few (4.6%) saw a future expansion of its influence on decision-makers as a negative evolution. Furthermore, nearly all (94.0%) participants were open to the idea of sharing anonymized or pseudonymized electronic health data of their patients with external parties for research purposes. Nevertheless, most clinicians (77.0%) still considered randomized controlled trials (RCTs) to be the gold standard for generating clinical evidence in oncology, and a plurality (49.2%) thought that RWE cannot fully address the knowledge gaps that remain after a new antitumor intervention has entered the market. Moreover, a majority of respondents (50.7%) expressed that they relied more heavily on RCT-derived evidence than on RWE for their own decision-making. Conclusion: While cancer clinicians have positive opinions about RWE and want to contribute to its generation, they also continue to hold RCTs in high regard as sources of actionable evidence.

Joint Final Report of EORTC 26951 and RTOG 9402: Phase III Trials With Procarbazine, Lomustine, and Vincristine Chemotherapy for Anaplastic Oligodendroglial Tumors.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the basis of the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.Anaplastic oligodendroglial tumors (AOTs) are chemotherapy-sensitive brain tumors. We report the final very long-term survival results from European Organization for the Research and Treatment of Cancer 26951 and Radiation Therapy Oncology Group 9402 phase III trials initiated in 1990s, which both studied radiotherapy with/without neo/adjuvant procarbazine, lomustine, and vincristine (PCV) for newly diagnosed anaplastic oligodendroglial tumors. The median follow-up duration in both was 18-19 years. For European Organization for the Research and Treatment of Cancer 26951, median, 14-year, and probable 20-year overall survival rates without versus with PCV were 2.6 years, 13.4%, and 10.1% versus 3.5 years, 25.1%, and 16.8% (N = 368 overall; hazard ratio [HR] 0.78; 95% CI, 0.63 to 0.98; P = .033), with 1p19q codeletion 9.3 years, 26.2%, and 13.6% versus 14.2 years, 51.0%, and 37.1% (n = 80; HR 0.60; 95% CI, 0.35 to 1.03; P = .063), respectively. For Radiation Therapy Oncology Group 9402, analogous results were 4.8 years, 16.5%, and 11.2% versus 4.8 years, 29.1%, and 24.6% (N = 289 overall; HR 0.79; 95% CI, 0.61 to 1.03; P = .08), with codeletion 7.3 years, 25.0%, and 14.9% versus 13.2 years, 46.1%, and 37% (n = 125; HR 0.61; 95% CI, 0.40 to 0.94; P = .02), respectively. With that, the studies show similar long-term survival even without tumor recurrence in a significant proportion of patients after first-line treatment with radiotherapy/PCV.

QUARTET: A SIOP Europe project for quality and excellence in radiotherapy and imaging for children and adolescents with cancer.

The European Society for Paediatric Oncology (SIOPE) Radiation Oncology Working Group presents the QUARTET Project: a centralised quality assurance programme designed to standardise care and improve the quality of radiotherapy and imaging for international clinical trials recruiting children and adolescents with cancer throughout Europe. QUARTET combines the paediatric radiation oncology expertise of SIOPE with the infrastructure and experience of the European Organisation for Research and Treatment of Cancer to deliver radiotherapy quality assurance programmes for large, prospective, international clinical trials. QUARTET-affiliated trials include children and adolescents with brain tumours, neuroblastoma, sarcomas including rhabdomyosarcoma, and renal tumours including Wilms' tumour. With nine prospective clinical trials and two retrospective studies within the active portfolio in March 2022, QUARTET will collect one of the largest repositories of paediatric radiotherapy and imaging data, support the clinical assessment of radiotherapy, and evaluate the role and benefit of radiotherapy quality assurance for this cohort of patients within the context of clinical trials.

Design, organisation and impact of treatment optimisation studies in breast, lung and colorectal cancer: The experience of the European Organisation for Research and Treatment of Cancer.

BACKGROUND: Treatment optimisation studies (TOSs) are clinical trials which aim to tackle research questions that are often left unaddressed within the current drug development paradigm due to a lack of financial and regulatory incentives to undertake them. Examples include comparative effectiveness, therapeutic sequencing and dose de-escalation studies. Trials of this nature have historically been primarily carried out by academic institutions and not-for-profit organisations such as the European Organisation for Research and Treatment of Cancer (EORTC). OBJECTIVES: Our objective was to conduct an in-depth analysis of the breast, lung and colorectal cancer TOSs that have been performed by the EORTC in the past four decades. METHODS: We searched the EORTC clinical trials database for relevant studies and subsequently analysed them based on a number of predefined criteria relating to their design, organisation and scientific impact. RESULTS: The 113 EORTC TOSs examined in this analysis were mainly standard-sized, international, multicentre phase III trials using a relatively simple, randomised, open-label design and comparing pharmacological combination regimens against standard-of-care treatments in terms of their potential to improve overall survival of patients with cancer. Although they were typically financially and/or materially supported by the industry, their legal sponsor was nearly always an independent party that did not benefit monetarily from their outcomes. If meaningful findings were obtained, their results, regardless of whether positive or negative, were published in high-impact journals, and the corresponding articles usually received a considerable number of citations. CONCLUSIONS: Our analysis provides an empirical framework for setting up future TOSs based on the EORTC experience in oncology.

Past, Current, and Future Cancer Clinical Research Collaborations: The Case of the European Organisation for Research and Treatment of Cancer.

Although collaborations between academic institutions and industry have led to important scientific breakthroughs in the discovery stage of the pharmaceutical research and development process, the role of multistakeholder partnerships in the clinical development of anticancer medicines necessitates further clarification. The benefits associated with such cooperation could be undercut by the conflicting goals and motivations of the actors included. The aim of this review was to identify and characterize past, present, and future stakeholder partnership models in cancer clinical research through the lens of the European Organisation for Research and Treatment of Cancer (EORTC). Based on the analysis of several landmark EORTC trials performed across the span of three decades, four existing models of stakeholder cooperation were delineated and characterized. Additionally, a hypothetical fifth model representing a potential future collaborative framework for cancer clinical research was formulated. These models mainly differ in terms of the nature and responsibilities of the partners included and show that clinical research partnerships in oncology have evolved over time from small-scale academia-industry collaborations to complex interdisciplinary cooperation involving many different stakeholders.

The Porto European Cancer Research Summit 2021.

Key stakeholders from the cancer research continuum met in May 2021 at the European Cancer Research Summit in Porto to discuss priorities and specific action points required for the successful implementation of the European Cancer Mission and Europe's Beating Cancer Plan (EBCP). Speakers presented a unified view about the need to establish high-quality, networked infrastructures to decrease cancer incidence, increase the cure rate, improve patient's survival and quality of life, and deal with research and care inequalities across the European Union (EU). These infrastructures, featuring Comprehensive Cancer Centres (CCCs) as key components, will integrate care, prevention and research across the entire cancer continuum to support the development of personalized/precision cancer medicine in Europe. The three pillars of the recommended European infrastructures - namely translational research, clinical/prevention trials and outcomes research - were pondered at length. Speakers addressing the future needs of translational research focused on the prospects of multiomics assisted preclinical research, progress in Molecular and Digital Pathology, immunotherapy, liquid biopsy and science data. The clinical/prevention trial session presented the requirements for next-generation, multicentric trials entailing unified strategies for patient stratification, imaging, and biospecimen acquisition and storage. The third session highlighted the need for establishing outcomes research infrastructures to cover primary prevention, early detection, clinical effectiveness of innovations, health-related quality-of-life assessment, survivorship research and health economics. An important outcome of the Summit was the presentation of the Porto Declaration, which called for a collective and committed action throughout Europe to develop the cancer research infrastructures indispensable for fostering innovation and decreasing inequalities within and between member states. Moreover, the Summit guidelines will assist decision making in the context of a unique EU-wide cancer initiative that, if expertly implemented, will decrease the cancer death toll and improve the quality of life of those confronted with cancer, and this is carried out at an affordable cost.

Effects of radiotherapy with concomitant and adjuvant temozolomide versus radiotherapy alone on survival in glioblastoma in a randomised phase III study: 5-year analysis of the EORTC-NCIC trial.

BACKGROUND: In 2004, a randomised phase III trial by the European Organisation for Research and Treatment of Cancer (EORTC) and National Cancer Institute of Canada Clinical Trials Group (NCIC) reported improved median and 2-year survival for patients with glioblastoma treated with concomitant and adjuvant temozolomide and radiotherapy. We report the final results with a median follow-up of more than 5 years. METHODS: Adult patients with newly diagnosed glioblastoma were randomly assigned to receive either standard radiotherapy or identical radiotherapy with concomitant temozolomide followed by up to six cycles of adjuvant temozolomide. The methylation status of the methyl-guanine methyl transferase gene, MGMT, was determined retrospectively from the tumour tissue of 206 patients. The primary endpoint was overall survival. Analyses were by intention to treat. This trial is registered with Clinicaltrials.gov, number NCT00006353. FINDINGS: Between Aug 17, 2000, and March 22, 2002, 573 patients were assigned to treatment. 278 (97%) of 286 patients in the radiotherapy alone group and 254 (89%) of 287 in the combined-treatment group died during 5 years of follow-up. Overall survival was 27.2% (95% CI 22.2-32.5) at 2 years, 16.0% (12.0-20.6) at 3 years, 12.1% (8.5-16.4) at 4 years, and 9.8% (6.4-14.0) at 5 years with temozolomide, versus 10.9% (7.6-14.8), 4.4% (2.4-7.2), 3.0% (1.4-5.7), and 1.9% (0.6-4.4) with radiotherapy alone (hazard ratio 0.6, 95% CI 0.5-0.7; p<0.0001). A benefit of combined therapy was recorded in all clinical prognostic subgroups, including patients aged 60-70 years. Methylation of the MGMT promoter was the strongest predictor for outcome and benefit from temozolomide chemotherapy. INTERPRETATION: Benefits of adjuvant temozolomide with radiotherapy lasted throughout 5 years of follow-up. A few patients in favourable prognostic categories survive longer than 5 years. MGMT methylation status identifies patients most likely to benefit from the addition of temozolomide. FUNDING: EORTC, NCIC, Nélia and Amadeo Barletta Foundation, Schering-Plough.