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Zhang Z, Pan Q, Lu M, Zhao B. Intermediate endpoints as surrogates for outcomes in cancer immunotherapy: a systematic review and meta-analysis of phase 3 trials. EClinicalMedicine 2023; 63:102156. [PMID: 37600482 PMCID: PMC10432823 DOI: 10.1016/j.eclinm.2023.102156] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 07/24/2023] [Accepted: 07/26/2023] [Indexed: 08/22/2023] Open
Abstract
Background Cancer immunotherapy shows unique efficacy kinetics that differs from conventional treatment. These characteristics may lead to the prolongation of trial duration, hence reliable surrogate endpoints are urgently needed. We aimed to systematically evaluate the study-level performance of commonly reported intermediate clinical endpoints for surrogacy in cancer immunotherapy. Methods We searched the Embase, PubMed, and Cochrane databases, between database inception and October 18, 2022, for phase 3 randomised trials investigating the efficacy of immunotherapy in patients with advanced solid tumours. An updated search was done on July, 15, 2023. No language restrictions were used. Eligible trials had to set overall survival (OS) as the primary or co-primary endpoint and report at least one intermediate clinical endpoint including objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), and 1-year overall survival. Other key inclusion and exclusion criteria included: (1) adult patients (>18 years old) with advanced solid tumour; (2) no immunotherapy conducted in the control arms; (3) follow-up is long enough to achieve OS; (4) data should be public available. A two-stage meta-analytic approach was conducted to evaluate the magnitude of the association between these intermediate endpoints and OS. A surrogate was identified if the coefficient of determination (R2) was 0.7 or greater. Leave-one-out cross-validation and pre-defined subgroup analysis were conducted to examine the heterogeneity. Potential publication bias was evaluated using the Egger's and Begg's tests. This trial was registered with PROSPERO, number CRD42022381648. Findings 52,342 patients with 15 types of tumours from 77 phase 3 studies were included. ORR (R2 = 0.11; 95% CI, 0.00-0.24), DCR (R2 = 0.01; 95% CI, 0.00-0.01), and PFS (R2 = 0.40; 95% CI, 0.23-0.56) showed weak associations with OS. However, a strong correlation was observed between 1-year survival and clinical outcome (R2 = 0.74; 95% CI, 0.64-0.83). These associations remained relatively consistent across pre-defined subgroups stratified based on tumour types, masking methods, line of treatments, drug targets, treatment strategies, and follow-up durations. No significant heterogeneities or publication bias were identified. Interpretation 1-year milestone survival was the only identified surrogacy endpoint for outcomes in cancer immunotherapy. Ongoing investigations and development of new endpoints and incorporation of biomarkers are needed to identify potential surrogate markers that can be more robust than 1-year survival. This work may provide important references in assisting the design and interpretation of future clinical trials, and constitute complementary information in drafting clinical practice guidelines. Funding None.
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Affiliation(s)
- Zhishan Zhang
- Quanzhou First Hospital Affiliated to Fujian Medical University, Quanzhou, China
| | - Qunxiong Pan
- Quanzhou First Hospital Affiliated to Fujian Medical University, Quanzhou, China
| | - Mingdong Lu
- The Second Affiliated Hospital & Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China
| | - Bin Zhao
- Quanzhou First Hospital Affiliated to Fujian Medical University, Quanzhou, China
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2
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Villacampa G, Cresta Morgado P, Navarro V, Viaplana C, Dienstmann R. Comprehensive evaluation of surrogate endpoints to predict overall survival in trials with PD1/PD-L1 immune checkpoint inhibitors plus chemotherapy. Cancer Treat Rev 2023; 116:102542. [PMID: 37003083 DOI: 10.1016/j.ctrv.2023.102542] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 03/08/2023] [Accepted: 03/10/2023] [Indexed: 03/19/2023]
Abstract
BACKGROUND PD1/PD-L1 immune checkpoint inhibitors (ICI) have revolutionized cancer treatment. Although there is controversy about the accuracy of surrogate endpoints in the ICI setting to predict overall survival (OS), these endpoints are commonly used in confirmatory trials. Here we aimed to explore the validity of classical and novel surrogate endpoints in randomised controlled trials (RCT) that combine ICI plus chemotherapy (CT) in the first-line setting. MATERIAL AND METHODS A systematic review was conducted to identify RCT investigating anti-PD1/PD-L1 drugs plus CT versus CT alone. We performed (i) arm-level analysis to evaluate predictors of median OS (mOS) and (ii) comparison-level analysis for OS hazard ratio (HR) estimations. Linear regression models weighted by trial size were fitted and adjusted R2 values were reported. RESULTS Thirty-nine RCTs involving 22,341 patients met the inclusion criteria (17 non-small cell lung, 9 gastroesophageal and 13 in other cancers) with ten different ICI under study. Overall, ICI plus CT improved OS (HR = 0.76; 95%CI: 0.73-0.80). In the arm-level analysis, the best mOS prediction was obtained with a new endpoint that combines median duration of response and ORR (mDoR-ORR) and with median PFS (R2 = 0.5 both). In the comparison-level analysis, PFS HR showed a moderate association with OS HR (R2 = 0.52). Early OS read-outs were highly associated with final OS outcomes (R2 = 0.80). CONCLUSIONS The association between surrogate endpoints and OS in first-line RCT combining anti-PD1/PD-L1 and CT is moderate-low. Early OS read-outs showed a good association with final OS HR while the mDOR-ORR endpoint could help to better design confirmatory trials after single-arm phase II trials.
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3
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Korn EL, Allegra CJ, Freidlin B. Clinical Benefit Scales and Trial Design: Some Statistical Issues. J Natl Cancer Inst 2022; 114:1222-1227. [PMID: 35583264 DOI: 10.1093/jnci/djac099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/26/2022] [Accepted: 05/04/2022] [Indexed: 11/14/2022] Open
Abstract
Recently developed clinical-benefit outcome scales by the European Society for Medical Oncology (ESMO) and the American Society of Clinical Oncology (ASCO) allow standardized objective evaluation of outcomes of randomized clinical trials. However, incorporation of clinical-benefit outcome scales into trial designs highlights a number of statistical issues: the relationship between minimal clinical benefit and the target treatment-effect alternative used in the trial design, designing trials to assess long-term benefit, potential problems with using a trial endpoint that is not overall survival, and how to incorporate subgroup analyses into the trial design. Using the ESMO Magnitude of Clinical Benefit Scale as a basis for discussion, we review what these issues are and how they can guide the choice of trial-design target effects, appropriate endpoints, and pre-specified subgroup analyses to increase the chances that the resulting trial outcomes can be appropriately evaluated for clinical benefit.
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Affiliation(s)
- Edward L Korn
- Biometric Research Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD, USA
| | - Carmen J Allegra
- Cancer Therapy Evaluation Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD, USA.,Division of Hematology and Oncology, Department of Medicine, University of Florida College of Medicine, Gainesville, FL, USA
| | - Boris Freidlin
- Biometric Research Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD, USA
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4
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Krishnatreya M. Nothing is permanent except for change: Disease-free survival in cancer, time to change? J Cancer Res Ther 2021; 17:1132-1133. [PMID: 34528578 DOI: 10.4103/jcrt.jcrt_318_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Manigreeva Krishnatreya
- Department of Cancer Registry and Epidemiology, Dr. B Borooah Cancer Institute, Guwahati, Assam, India
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5
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Dang A, Dang S, Vallish BN. Efficacy and Safety of EGFR Inhibitors in the Treatment of EGFRPositive NSCLC Patients: A Meta-Analysis. Rev Recent Clin Trials 2021; 16:193-201. [PMID: 33155914 DOI: 10.2174/1574887115999201103200248] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 09/10/2020] [Accepted: 09/26/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND We compared the response rates, survival rates, and safety profile of epidermal growth factor receptor (EGFR) inhibitors with non-targeted chemotherapy and older EGFR inhibitors when used to treat advanced non-small cell lung cancer (NSCLC) patients with activating EGFR mutations. METHODS We searched PubMed, Cochrane Central Register of Controlled Trials, and clinicaltrial.- gov for randomized controlled trials published until 11-Feb-2020. Treatment outcomes were compared between EGFR inhibitor and pooled comparator; a subgroup analysis compared outcomes between EGFR inhibitor and non-targeted chemotherapy, and between newer and older EGFR inhibitors. RESULTS Twenty-one studies with 4,250 unique patients were included. Significantly higher objective response rate (ORR) (odds ratio (OR) 2.28; 95% CI 2.00-2.61), higher disease control rate (DCR) (OR 2.3; 95% CI 1.88-3.06), and longer progression-free survival (PFS) (Hazard ratio (HR) 0.56; 95% CI 0.52-0.60) were observed in the EGFR inhibitor group compared to the pooled comparator group. Subgroup analysis revealed that the ORR, DCR, and PFS were significantly higher with EGFR inhibitors than non-targeted chemotherapy, and only PFS (and not ORR and DCR) was significantly longer with newer EGFR inhibitors than the older EGFR inhibitors. Overall survival (OS) was not significantly different between EGFR inhibitors and pooled comparator (HR 0.91; 95% CI 0.83-1.00) as well as in either of the subgroup analyses. Adverse events ≥ grade 3 and treatment discontinuation were significantly higher with non-targeted chemotherapy compared to the EGFR inhibitors. CONCLUSION The benefits of prolongation of ORR, DCR, and PFS might not imply significantly improved OS after therapy with EGFR inhibitors when compared with non-targeted chemotherapy or older EGFR inhibitors.
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Affiliation(s)
- Amit Dang
- MarksMan Healthcare Communications and KYT Adhere, Hyderabad, Telangana - 500032, India
| | - Sumit Dang
- Department of Pediatrics, University of Kentucky, Lexington, KY 40506, United States
| | - B N Vallish
- Medical Writing and Biostatistics, MarksMan Healthcare Communications, Hyderabad, Telangana - 500032, India
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6
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Gharzai LA, Jiang R, Wallington D, Jones G, Birer S, Jairath N, Jaworski EM, McFarlane MR, Mahal BA, Nguyen PL, Sandler H, Morgan TM, Reichert ZR, Alumkal JJ, Mehra R, Kishan AU, Fizazi K, Halabi S, Schaeffer EM, Feng FY, Elliott D, Dess RT, Jackson WC, Schipper MJ, Spratt DE. Intermediate clinical endpoints for surrogacy in localised prostate cancer: an aggregate meta-analysis. Lancet Oncol 2021; 22:402-410. [PMID: 33662287 PMCID: PMC10949134 DOI: 10.1016/s1470-2045(20)30730-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 10/23/2020] [Accepted: 11/26/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND The international Intermediate Clinical Endpoints in Cancer of the Prostate working group has established metastasis-free survival as a surrogate for overall survival in localised prostate cancer based on the findings of 19 predominantly radiotherapy-based trials. We sought to comprehensively assess aggregate trial-level performance of commonly reported intermediate clinical endpoints across all randomised trials in localised prostate cancer. METHODS For this meta-analysis, we searched PubMed for all trials in localised or biochemically recurrent prostate cancer published between Jan 1, 1970, and Jan 15, 2020. Eligible trials had to be randomised, therapeutic, reporting overall survival and at least one intermediate clinical endpoint, and with a sample size of at least 70 participants. Trials of metastatic disease were excluded. Intermediate clinical endpoints included biochemical failure, local failure, distant metastases, biochemical failure-free survival, progression-free survival, and metastasis-free survival. Candidacy for surrogacy was assessed using the second condition of the meta-analytical approach (ie, correlation of the treatment effect of the intermediate clinical endpoint and overall survival), using R2 weighted by the inverse variance of the log intermediate clinical endpoint hazard ratio. The intermediate clinical endpoint was deemed to be a surrogate for overall survival if R2 was 0·7 or greater. FINDINGS 75 trials (53 631 patients) were included in our analysis. Median follow-up was 9·1 years (IQR 5·7-10·6). Biochemical failure (R2 0·38 [95% CI 0·11-0·64]), biochemical failure-free survival (R2 0·12 [0·0030-0·33]), biochemical failure and clinical failure (R2 0·28 [0·0045-0·65]), and local failure (R2 0·085 [0·00-0·37]) correlated poorly with overall survival. Progression-free survival (R2 0·46 [95% CI 0·22-0·67]) showed moderate correlation with overall survival, and metastasis-free survival (R2 0·78 [0·59-0·89]) correlated strongly. INTERPRETATION Intermediate clinical endpoints based on biochemical and local failure did not meet the second condition of the meta-analytical approach and are not surrogate endpoints for overall survival in localised prostate cancer. Our findings validate metastasis-free survival as the only identified surrogate endpoint for overall survival to date. FUNDING Prostate Cancer Foundation and National Institutes of Health.
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Affiliation(s)
- Laila A Gharzai
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Ralph Jiang
- Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA
| | - David Wallington
- Department of Radiation Oncology, Western Michigan University, Kalamazoo, MI, USA
| | - Gavin Jones
- Department of Radiation Oncology, University of Kentucky, Lexington, KY, USA
| | - Samuel Birer
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Neil Jairath
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | | | - Matthew R McFarlane
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Brandon A Mahal
- Department of Radiation Oncology, University of Miami, Miami, FL, USA
| | - Paul L Nguyen
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Howard Sandler
- Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Todd M Morgan
- Department of Urology, University of Michigan, Ann Arbor, MI, USA
| | - Zachery R Reichert
- Department of Medical Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Joshi J Alumkal
- Department of Medical Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Rohit Mehra
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Amar U Kishan
- Department of Radiation Oncology, University of California Los Angeles, Los Angeles, CA, USA
| | - Karim Fizazi
- Department of Cancer Medicine, Institut Gustave-Roussy, Villejuif, France
| | - Susan Halabi
- Department of Biostatistics and Bioinformatics, Duke University, Durham, NC, USA
| | | | - Felix Y Feng
- Department of Radiation Oncology, University of California San Francisco, San Francisco, CA, USA
| | - David Elliott
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Robert T Dess
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | - William C Jackson
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Matthew J Schipper
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA; Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA
| | - Daniel E Spratt
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA.
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7
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Baker SG, Kramer BS. Simple Methods for Evaluating 4 Types of Biomarkers: Surrogate Endpoint, Prognostic, Predictive, and Cancer Screening. Biomark Insights 2020; 15:1177271920946715. [PMID: 32821082 PMCID: PMC7412628 DOI: 10.1177/1177271920946715] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 07/06/2020] [Indexed: 11/16/2022] Open
Abstract
We review simple methods for evaluating 4 types of biomarkers. First, we discuss the evaluation of surrogate endpoint biomarkers (to shorten a randomized trial) using 2 statistical and 3 biological criteria. Second, we discuss the evaluation of prognostic biomarkers (to predict the risk of disease) by comparing data collection costs with the anticipated net benefit of risk prediction. Third, we discuss the evaluation of predictive markers (to search for a promising subgroup in a randomized trial) using a multivariate subpopulation treatment effect pattern plot involving a risk difference or responders-only benefit function. Fourth, we discuss the evaluation of cancer screening biomarkers (to predict cancer in asymptomatic persons) using methodology to substantially reduce the sample size with stored specimens.
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Affiliation(s)
- Stuart G Baker
- Biometry Research Group, Division of Cancer Prevention, National Cancer Institute, Bethesda, MD, USA
| | - Barnett S Kramer
- Biometry Research Group, Division of Cancer Prevention, National Cancer Institute, Bethesda, MD, USA
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8
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Zhao S, Zhang Z, Zhang Y, Hong S, Zhou T, Yang Y, Fang W, Zhao H, Zhang L. Progression-free survival and one-year milestone survival as surrogates for overall survival in previously treated advanced non-small cell lung cancer. Int J Cancer 2019; 144:2854-2866. [PMID: 30430561 DOI: 10.1002/ijc.31995] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 10/06/2018] [Accepted: 11/06/2018] [Indexed: 12/24/2022]
Abstract
The advent of immunotherapy leads to greater availability of effective subsequent treatments and extended survival in previously treated advanced non-small cell lung cancer (NSCLC), complicating the evaluation of overall survival (OS) in second-line NSCLC trials. Here, we aimed to assess the surrogacy of progression-free survival (PFS) and milestone survival for OS in second-line NSCLC trials investigating chemotherapy, targeted therapy and immunotherapy, respectively. We systemically searched for active-controlled, second-line NSCLC trials. The milestone time point was set at one-year based on pre-analysis. A two-stage meta-analytic validation model was adopted to assess associations between surrogate endpoint (SE) and OS and associations between treatment effects on SE and OS. Treatment effects on SE and OS were expressed as PFS hazard ratios (HRPFS ), 1 yr-milestone ratio (Ratio1y-SUR ) and HROS . Subgroup analyses stratified by treatment types and trial publication years evaluated the surrogacy in different clinical contexts. The study included 50 trials with 22,804 patients. One-year survival strongly correlated with OS (R2 [95% confidence interval]: one-year survival -median OS = 0.707 [0.704-0.708]; Ratio1y-SUR -HROS = 0.829 [0.828-0.831]). No correlation was established between PFS and OS (median PFS-median OS = 0.100 [0.098-0.101]; HRPFS -HROS = 0.064 [0.059-0.069]), except in immunotherapy subgroup (HRPFS -HROS = 0.835 [0.791-0.918]). In subgroup analyses, surrogacy of one-year survival persisted in different clinical contexts, and the disassociation between PFS and OS persisted in recent trials. One-year milestone survival showed strong surrogacy for OS in second-line NSCLC trials. Although no association was identified between PFS and OS, the strong HRPFS -HROS correlation in immunotherapy trials indicates the potential of PFS as a SE in NSCLC trials involving immunotherapies.
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Affiliation(s)
- Shen Zhao
- Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China.,State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.,Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Zhonghan Zhang
- Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China.,State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.,Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Yaxiong Zhang
- Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China.,State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Shaodong Hong
- Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China.,State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Ting Zhou
- Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China.,State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Yunpeng Yang
- Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China.,State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Wenfeng Fang
- Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China.,State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Hongyun Zhao
- Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China.,State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Li Zhang
- Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China.,State Key Laboratory of Oncology in South China, Guangzhou, China.,Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
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9
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Chen EY, Joshi SK, Tran A, Prasad V. Estimation of Study Time Reduction Using Surrogate End Points Rather Than Overall Survival in Oncology Clinical Trials. JAMA Intern Med 2019; 179:642-647. [PMID: 30933235 PMCID: PMC6503556 DOI: 10.1001/jamainternmed.2018.8351] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
IMPORTANCE Surrogate end points in oncology trade the advantage of reducing the time needed to conduct clinical trials for the disadvantage of greater uncertainty regarding the treatment effect on patient-centered end points, such as overall survival (OS) and quality of life. OBJECTIVE To quantify the amount of time saved through the acceptance of surrogate end points, including response rate (RR) and progression-free survival (PFS). DESIGN, SETTING, AND PARTICIPANTS This retrospective study of US Food and Drug Administration (FDA) oncology approvals and their drug registration trials based on actual publication analyzed the original and updated clinical trials data that led to FDA-approved drug indications in oncology from 2006 to 2017 by using existing publications, conference abstracts, and package inserts from the FDA. Data related to cancer type, line of therapy (first-line, second-line, and third- or later-line treatment of advanced or metastatic disease), FDA approval type, end point basis for approval (RR, PFS, or OS/quality of life), sample size, accrual rate, and drug RR were extracted by March 23, 2018. All data were analyzed by July 13, 2018. MAIN OUTCOMES AND MEASURES The main outcome was the study duration needed to complete the primary end point analysis used for each drug indication approval. This was estimated from reported enrollment dates, analysis cutoff dates, time to response, median duration of response, median PFS, and median OS. RESULTS In total, 188 distinct indications among 107 cancer drugs were identified. The RR was more often used for FDA approval in subsequent lines of therapy (17 of 71 drug indications [24%] in first-line therapy vs 34 of 77 drug indications [44%] in second-line therapy vs 19 of 24 drug indications [79%] in third- or later-line therapy, P < .001). Study duration for PFS (median, 31 [range, 10-104] months) was similar to that for OS (median, 33 [range, 12-117] months; P = .31), whereas study duration for RR (median, 25 [range, 11-54] months) was shorter than that for OS (P = .001). In multivariate analysis, compared with using OS, use of PFS as the end point was associated with study durations that were shorter by a mean of 11 months (95% CI, 5-17 months), and the use of RR as the end point was associated with study durations that were shorter by a mean of 19 months (95% CI, 13-25 months). CONCLUSIONS AND RELEVANCE From the findings of this study, an estimated 11 months appeared to be needed (ie, approximately 12% longer in the drug development cycle) to assess the OS benefit of a cancer drug. This study's findings suggest that this must be weighed against the downside of increased uncertainty of clinical benefit arising from using surrogate end points.
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Affiliation(s)
- Emerson Y Chen
- Division of Hematology Oncology, Knight Cancer Institute, Oregon Health & Science University, Portland
| | - Sunil K Joshi
- Division of Hematology Oncology, Knight Cancer Institute, Oregon Health & Science University, Portland.,School of Medicine, Oregon Health & Science University, Portland
| | - Audrey Tran
- School of Medicine, Oregon Health & Science University, Portland
| | - Vinay Prasad
- Division of Hematology Oncology, Knight Cancer Institute, Oregon Health & Science University, Portland.,Department of Public Health and Preventive Medicine, Oregon Health & Science University, Portland.,Center for Health Care Ethics, Oregon Health & Science University, Portland
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10
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Affiliation(s)
- Catalin Tufanaru
- Research Fellow, The Joanna Briggs Institute, Peer Reviewer, JBI Database of Systematic Reviews and Implementation Reports
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11
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Hettle R, Corbett M, Hinde S, Hodgson R, Jones-Diette J, Woolacott N, Palmer S. The assessment and appraisal of regenerative medicines and cell therapy products: an exploration of methods for review, economic evaluation and appraisal. Health Technol Assess 2018; 21:1-204. [PMID: 28244858 DOI: 10.3310/hta21070] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The National Institute for Health and Care Excellence (NICE) commissioned a 'mock technology appraisal' to assess whether changes to its methods and processes are needed. This report presents the findings of independent research commissioned to inform this appraisal and the deliberations of a panel convened by NICE to evaluate the mock appraisal. METHODS Our research included reviews to identify issues, analysis methods and conceptual differences and the relevance of alternative decision frameworks, alongside the development of an exemplar case study of chimeric antigen receptor (CAR) T-cell therapy for treating acute lymphoblastic leukaemia. RESULTS An assessment of previous evaluations of regenerative medicines found that, although there were a number of evidential challenges, none was unique to regenerative medicines or was beyond the scope of existing methods used to conceptualise decision uncertainty. Regarding the clinical evidence for regenerative medicines, the issues were those associated with a limited evidence base but were not unique to regenerative medicines: small non-randomised studies, high variation in response and the intervention subject to continuing development. The relative treatment effects generated from single-arm trials are likely to be optimistic unless it is certain that the historical data have accurately estimated the efficacy of the control agent. Pivotal trials may use surrogate end points, which, on average, overestimate treatment effects. To reduce overall uncertainty, multivariate meta-analysis of all available data should be considered. Incorporating indirectly relevant but more reliable (more mature) data into the analysis can also be considered; such data may become available as a result of the evolving regulatory pathways being developed by the European Medicines Agency. For the exemplar case of CAR T-cell therapy, target product profiles (TPPs) were developed, which considered the 'curative' and 'bridging to stem-cell transplantation' treatment approaches separately. Within each TPP, three 'hypothetical' evidence sets (minimum, intermediate and mature) were generated to simulate the impact of alternative levels of precision and maturity in the clinical evidence. Subsequent assessments of cost-effectiveness were undertaken, employing the existing NICE reference case alongside additional analyses suggested within alternative frameworks. The additional exploratory analyses were undertaken to demonstrate how assessments of cost-effectiveness and uncertainty could be impacted by alternative managed entry agreements (MEAs), including price discounts, performance-related schemes and technology leasing. The panel deliberated on the range of TPPs, evidence sets and MEAs, commenting on the likely recommendations for each scenario. The panel discussed the challenges associated with the exemplar and regenerative medicines more broadly, focusing on the need for a robust quantification of the level of uncertainty in the cost-effective estimates and the potential value of MEAs in limiting the exposure of the NHS to high upfront costs and loss associated with a wrong decision. CONCLUSIONS It is to be expected that there will be a significant level of uncertainty in determining the clinical effectiveness of regenerative medicines and their long-term costs and benefits, but the existing methods available to estimate the implications of this uncertainty are sufficient. The use of risk sharing and MEAs between the NHS and manufacturers of regenerative medicines should be investigated further. FUNDING The National Institute for Health Research Health Technology Assessment programme.
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Affiliation(s)
- Robert Hettle
- Centre for Health Economics, University of York, York, UK
| | - Mark Corbett
- Centre for Reviews and Dissemination, University of York, York, UK
| | | | - Robert Hodgson
- Centre for Reviews and Dissemination, University of York, York, UK
| | | | - Nerys Woolacott
- Centre for Reviews and Dissemination, University of York, York, UK
| | - Stephen Palmer
- Centre for Health Economics, University of York, York, UK
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12
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Baker SG. Five criteria for using a surrogate endpoint to predict treatment effect based on data from multiple previous trials. Stat Med 2018; 37:507-518. [PMID: 29164641 DOI: 10.1002/sim.7561] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 10/20/2017] [Accepted: 10/23/2017] [Indexed: 11/08/2022]
Abstract
A surrogate endpoint in a randomized clinical trial is an endpoint that occurs after randomization and before the true, clinically meaningful, endpoint that yields conclusions about the effect of treatment on true endpoint. A surrogate endpoint can accelerate the evaluation of new treatments but at the risk of misleading conclusions. Therefore, criteria are needed for deciding whether to use a surrogate endpoint in a new trial. For the meta-analytic setting of multiple previous trials, each with the same pair of surrogate and true endpoints, this article formulates 5 criteria for using a surrogate endpoint in a new trial to predict the effect of treatment on the true endpoint in the new trial. The first 2 criteria, which are easily computed from a zero-intercept linear random effects model, involve statistical considerations: an acceptable sample size multiplier and an acceptable prediction separation score. The remaining 3 criteria involve clinical and biological considerations: similarity of biological mechanisms of treatments between the new trial and previous trials, similarity of secondary treatments following the surrogate endpoint between the new trial and previous trials, and a negligible risk of harmful side effects arising after the observation of the surrogate endpoint in the new trial. These 5 criteria constitute an appropriately high bar for using a surrogate endpoint to make a definitive treatment recommendation.
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Affiliation(s)
- Stuart G Baker
- Division of Cancer Prevention, National Cancer Institute, 9609 Medical Center Dr, Room 5E606, MSC 9789, Bethesda, MD, 20892-9789, USA
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Abstract
Transfusion decision making (TDM) in the critically ill requires consideration of: (1) anemia tolerance, which is linked to active pathology and to physiologic reserve, (2) differences in donor RBC physiology from that of native RBCs, and (3) relative risk from anemia-attributable oxygen delivery failure vs hazards of transfusion, itself. Current approaches to TDM (e.g. hemoglobin thresholds) do not: (1) differentiate between patients with similar anemia, but dissimilar pathology/physiology, and (2) guide transfusion timing and amount to efficacy-based goals (other than resolution of hemoglobin thresholds). Here, we explore approaches to TDM that address the above gaps.
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Affiliation(s)
- Chris Markham
- Division of Critical Care Medicine, Department of Pediatrics, Washington University School of Medicine, McDonnell Pediatric Research Building, Campus Box 8208, 660 South Euclid Avenue, St Louis, MO 63110-1093, USA
| | - Sara Small
- Social Systems Design Laboratory, Brown School of Social Work, Washington University, Campus Box 1196, 1 Brookings Drive, St Louis, MO 63130, USA
| | - Peter Hovmand
- Social Systems Design Laboratory, Brown School of Social Work, Washington University, Campus Box 1196, 1 Brookings Drive, St Louis, MO 63130, USA
| | - Allan Doctor
- Division of Critical Care Medicine, Department of Pediatrics, Washington University School of Medicine, McDonnell Pediatric Research Building, Campus Box 8208, 660 South Euclid Avenue, St Louis, MO 63110-1093, USA.
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Woolacott N, Corbett M, Jones-Diette J, Hodgson R. Methodological challenges for the evaluation of clinical effectiveness in the context of accelerated regulatory approval: an overview. J Clin Epidemiol 2017; 90:108-118. [DOI: 10.1016/j.jclinepi.2017.07.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 06/22/2017] [Accepted: 07/07/2017] [Indexed: 12/25/2022]
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15
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Siddiqui MK, Tyczynski J, Pahwa A, Fernandes AW. Objective response rate is a possible surrogate endpoint for survival in patients with advanced, recurrent ovarian cancer. Gynecol Oncol 2017; 146:44-51. [PMID: 28395896 DOI: 10.1016/j.ygyno.2017.03.515] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 03/29/2017] [Accepted: 03/31/2017] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Evaluate literature to assess response rate as a surrogate endpoint of survival in ovarian cancer (OC). METHODS Systematic review consistent with PRISMA criteria, identified randomized, controlled trials reporting overall survival (OS), progression-free survival (PFS), and objective response rate (ORR) in recurrent OC. MEDLINE® and Embase® searches (year 2000-March 23, 2015) were augmented by bibliographic screening. Proposed surrogate measures (independent variables) were ORR and disease control rate. True clinical outcomes (dependent variables) were median OS and PFS. Analyses were performed on unweighted and weighted data using correlation analysis, linear regression, and surrogate threshold effect (STE). Smaller STE indicates greater predictive precision with magnitude of STE dependent on variance of prediction. RESULTS Thirty-nine studies were included for review, representing 9223 platinum-sensitive and resistant patients. Objective response rate (r=0.82; P<0.001) was a better predictor than disease control rate (r=0.58; P<0.001) and strongly correlated with PFS (r=0.85; P<0.0001). Weighted-regression analysis demonstrated that for each 10% increase in ORR, PFS increased by 1.20months and OS by 2.83months. Regression analysis of treatment effects (odds ratio of response, hazard ratio of survival) suggests that a 10% increase in odds ratio of ORR would result in 2.5% reduction in the hazard ratio of OS. Based on weighted data, STE indicated that an ORR of ≥1% is needed to achieve nonzero OS benefit. CONCLUSION This systematic review supports ORR as a possible surrogate clinical trial endpoint for OS in recurrent OC with at least second-line therapy.
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Affiliation(s)
| | - Jerzy Tyczynski
- Global Medical Evidence and Outcomes Research, AstraZeneca, Gaithersburg, MD, USA
| | - Ankit Pahwa
- PAREXEL International, Chandigarh, Chandigarh, India
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Yu T, Hsu YJ, Fain KM, Boyd CM, Holbrook JT, Puhan MA. Use of surrogate outcomes in US FDA drug approvals, 2003-2012: a survey. BMJ Open 2015; 5:e007960. [PMID: 26614616 PMCID: PMC4663404 DOI: 10.1136/bmjopen-2015-007960] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 10/03/2015] [Accepted: 10/26/2015] [Indexed: 01/12/2023] Open
Abstract
OBJECTIVE To evaluate, across a spectrum of diseases, how often surrogate outcomes are used as a basis for drug approvals by the US Food and Drug Administration (FDA), and whether and how the rationale for using treatment effects on surrogates as predictors of treatment effects on patient-centred outcomes is discussed. STUDY DESIGN AND SETTING We used the Drugs@FDA website to identify drug approvals produced from 2003 to 2012 by the FDA. We focused on four diseases (chronic obstructive pulmonary disease (COPD), type 1 or 2 diabetes, glaucoma and osteoporosis) for which surrogates are commonly used in trials. We reviewed the drug labels and medical reviews to provide empirical evidence on how surrogate outcomes are handled by the FDA. RESULTS Of 1043 approvals screened, 58 (6%) were for the four diseases of interest. Most drugs for COPD (7/9, 78%), diabetes (26/26, 100%) and glaucoma (9/9, 100%) were approved based on surrogates while for osteoporosis, most drugs (10/14, 71%) were also approved for patient-centred outcomes (fractures). The rationale for using surrogates was discussed in 11 of the 43 (26%) drug approvals based on surrogates. In these drug approvals, we found drug approvals for diabetes are more likely than the other examined conditions to contain a discussion of trial evidence demonstrating that treatment effects on surrogate outcomes predict treatment effects on patient-centred outcomes. CONCLUSIONS Our results suggest that the FDA did not use a consistent approach to address surrogates in assessing the benefits and harms of drugs for COPD, type 1 or 2 diabetes, glaucoma and osteoporosis. For evaluating new drugs, patient-centred outcomes should be chosen whenever possible. If the use of surrogate outcomes is necessary, then a consistent approach is important to review the evidence for surrogacy and consider surrogate's usage in the treatment and population under study.
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Affiliation(s)
- Tsung Yu
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA
- Epidemiology, Biostatistics, and Prevention Institute, University of Zurich, Zurich, Switzerland
| | - Yea-Jen Hsu
- Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Kevin M Fain
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA
| | - Cynthia M Boyd
- School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Janet T Holbrook
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA
| | - Milo A Puhan
- Epidemiology, Biostatistics, and Prevention Institute, University of Zurich, Zurich, Switzerland
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Christensen TD, Skjøth F, Nielsen PB, Maegaard M, Grove EL, Larsen TB. Self-Management of Anticoagulant Therapy in Mechanical Heart Valve Patients: A Matched Cohort Study. Ann Thorac Surg 2015; 101:1494-9. [PMID: 26572254 DOI: 10.1016/j.athoracsur.2015.09.084] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 09/19/2015] [Accepted: 09/28/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND Patient-self-management (PSM) of oral anticoagulant therapy with vitamin K antagonists for mechanical heart valves has demonstrated efficacy in randomized controlled trials. However, the effectiveness of PSM in clinical practice has only been investigated in small trials. Our aim was to evaluate the effectiveness of PSM of oral anticoagulant therapy in mechanical heart valve patients. METHODS We conducted a matched cohort study: cases were patients with a mechanical heart valve performing PSM affiliated with Aarhus University Hospital or Aalborg University Hospital, Denmark, in the period 1996 to 2012 (n = 615). Prospectively registered patient data were obtained from databases at two hospitals, and cross linkage between these databases and national patient registries provided detailed information on comorbidities and events. Control patients were matched (on sex, date of birth, year of first valve surgery, and grouped valve position) in a ratio of 5:1 (n = 3,075) with patients receiving conventional management who were randomly selected within the match group. The effectiveness and safety was estimated using major bleeding and thromboembolic events and death as outcomes. RESULTS We observed low event rates in the PSM group. After 5 years, PSM was associated with a lower risk of all-cause mortality compared with conventional management (adjusted hazard ratio of 0.49, 95% confidence interval: 0.34 to 0.71). The hazard ratios for thromboembolism and major bleeding were 0.91 (95% confidence interval: 0.66 to 1.24) and 0.83 (95% confidence interval: 0.56 to 1.22). CONCLUSIONS Owing to superior clinical effectiveness, self-managed oral anticoagulant therapy may potentially improve the standard of care for patients with mechanical heart valves.
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Affiliation(s)
- Thomas Decker Christensen
- Department of Cardiothoracic and Vascular Surgery and Institute of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.
| | - Flemming Skjøth
- Aalborg Thrombosis Research Unit, Department of Clinical Medicine, Faculty of Medicine, Aalborg University, Aalborg, Denmark; Unit of Clinical Biostatistics and Bioinformatics, Aalborg University Hospital, Aalborg, Denmark
| | - Peter Brønnum Nielsen
- Aalborg Thrombosis Research Unit, Department of Clinical Medicine, Faculty of Medicine, Aalborg University, Aalborg, Denmark; Unit of Clinical Biostatistics and Bioinformatics, Aalborg University Hospital, Aalborg, Denmark
| | - Marianne Maegaard
- Department of Cardiothoracic and Vascular Surgery and Institute of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | | | - Torben Bjerregaard Larsen
- Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark; Department of Cardiology, AF Study Group, Aalborg University Hospital, Aalborg, Denmark
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Baker SG, Kramer BS. Evaluating surrogate endpoints, prognostic markers, and predictive markers: Some simple themes. Clin Trials 2015; 12:299-308. [PMID: 25385934 PMCID: PMC4451440 DOI: 10.1177/1740774514557725] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND A surrogate endpoint is an endpoint observed earlier than the true endpoint (a health outcome) that is used to draw conclusions about the effect of treatment on the unobserved true endpoint. A prognostic marker is a marker for predicting the risk of an event given a control treatment; it informs treatment decisions when there is information on anticipated benefits and harms of a new treatment applied to persons at high risk. A predictive marker is a marker for predicting the effect of treatment on outcome in a subgroup of patients or study participants; it provides more rigorous information for treatment selection than a prognostic marker when it is based on estimated treatment effects in a randomized trial. METHODS We organized our discussion around a different theme for each topic. RESULTS "Fundamentally an extrapolation" refers to the non-statistical considerations and assumptions needed when using surrogate endpoints to evaluate a new treatment. "Decision analysis to the rescue" refers to use the use of decision analysis to evaluate an additional prognostic marker because it is not possible to choose between purely statistical measures of marker performance. "The appeal of simplicity" refers to a straightforward and efficient use of a single randomized trial to evaluate overall treatment effect and treatment effect within subgroups using predictive markers. CONCLUSION The simple themes provide a general guideline for evaluation of surrogate endpoints, prognostic markers, and predictive markers.
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Affiliation(s)
- Stuart G Baker
- Division of Cancer Prevention, National Cancer Institute, Bethesda MD, USA
| | - Barnett S Kramer
- Division of Cancer Prevention, National Cancer Institute, Bethesda MD, USA
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Wilson MK, Karakasis K, Oza AM. Outcomes and endpoints in trials of cancer treatment: the past, present, and future. Lancet Oncol 2014; 16:e32-42. [PMID: 25638553 DOI: 10.1016/s1470-2045(14)70375-4] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Cancer treatment should allow patients to live better or longer lives, and ideally, both. Trial endpoints should show clinically meaningful improvements in patient survival or quality of life. Alternative endpoints such as progression-free survival, disease-free survival, and objective response rate have been used to identify benefit earlier, but their true validity as surrogate endpoints is controversial. In this Review we discuss the measurement, assessment, and benefits and limitations of trial endpoints in use for cancer treatment. Many stakeholders are affected, including regulatory agencies, industry partners, clinicians, and most importantly, patients. In an accompanying Review, reflections from individual stakeholders are incorporated into a discussion of what the future holds for clinical trial endpoints and design.
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Affiliation(s)
| | | | - Amit M Oza
- Princess Margaret Cancer Centre, Toronto, Canada.
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Serrano D, Lazzeroni M, Bonanni B. Cancer chemoprevention: Much has been done, but there is still much to do. State of the art and possible new approaches. Mol Oncol 2014; 9:1008-17. [PMID: 25556583 DOI: 10.1016/j.molonc.2014.12.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 12/15/2014] [Indexed: 12/14/2022] Open
Abstract
Over the past three decades great efforts have been made in search of cancer chemoprevention strategies. The increase in knowledge of the long process from normal to cancer cell has enabled interventions in terms of lifestyle modifications, natural compounds or drugs to block or reverse the process. Great successes have been achieved, especially for breast and colorectal cancer. However, these strategies have yet to find clinical application on a large scale. In this article we identify the achievements, the pitfalls and the next steps to be taken to improve the efficacy and applicability of chemoprevention strategies. Among the crucial key points to be implemented are educational activities for physicians to appropriately disseminate the aim and indeed the culture of chemoprevention. It is essential to improve the risk-benefit balance, seeking the minimal active doses, intermittent schedules, a better characterization of the risk categories via a more personalized intervention based on individual characteristics, and ensure the containment of costs of public and private health prevention programs.
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Affiliation(s)
- Davide Serrano
- Division of Cancer Prevention and Genetics, European Institute of Oncology, Milan, Italy
| | - Matteo Lazzeroni
- Division of Cancer Prevention and Genetics, European Institute of Oncology, Milan, Italy
| | - Bernardo Bonanni
- Division of Cancer Prevention and Genetics, European Institute of Oncology, Milan, Italy.
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Abstract
Antibody-based tests are the primary technology used for clinical measurement of cardiac biomarkers in peripheral circulation. This article focuses on the principles of immunometric methods that have been applied to cardiac biomarkers of widespread clinical utility (CKMB, Troponins, and B-type natriuretic proteins) and of more recent clinical testing (ST2, Galectin-2, and myosin binding protein C). How these principles are applied in the design of immunometric assays and how they influence assay performance in quantifying cardiac biomarkers in biologic fluids (serum or plasma) is discussed.
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Affiliation(s)
- Patrick M Sluss
- Pathology Service, Clinical Pathology Core Laboratories (Special Chemistry), Pathology, Massachusetts General Hospital, Harvard Medical School, GRB554, 55 Fruit Street, Boston, MA 02114, USA.
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Abstract
Effective chemoprevention of oestrogen receptor (ER)-positive breast cancer has been shown convincingly using several selective ER modulators and the aromatase inhibitor exemestane. Although these agents are well tolerated and the numbers needed-to-treat in the prevention setting are similar to other established preventive interventions, uptake has been poor in clinical practice because of difficulties in visualizing risk, predicting individual outcomes and measuring treatment benefit. In addition, new agents targeting ER-negative breast cancer are urgently needed. The development of new agents is hampered by the lack of suitable biomarkers and targets, as well as regulatory and financial considerations. Establishing breast cancer chemoprevention in standard clinical practice will require advances in many different fields, including biomarker research, the development of more powerful tools to predict and communicate the risks and benefits of treatments and establishing innovative trial designs. Furthermore, changes in regulatory procedures could reduce the size and cost of trials needed in the prevention setting. Identification of biomarkers for risk and efficacy that are easily accessible, such as blood-based biomarkers, will be key to future chemoprevention strategies.
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Baker SG. Causal inference, probability theory, and graphical insights. Stat Med 2013; 32:4319-30. [PMID: 23661231 DOI: 10.1002/sim.5828] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 01/15/2013] [Accepted: 03/26/2013] [Indexed: 11/09/2022]
Abstract
Causal inference from observational studies is a fundamental topic in biostatistics. The causal graph literature typically views probability theory as insufficient to express causal concepts in observational studies. In contrast, the view here is that probability theory is a desirable and sufficient basis for many topics in causal inference for the following two reasons. First, probability theory is generally more flexible than causal graphs: Besides explaining such causal graph topics as M-bias (adjusting for a collider) and bias amplification and attenuation (when adjusting for instrumental variable), probability theory is also the foundation of the paired availability design for historical controls, which does not fit into a causal graph framework. Second, probability theory is the basis for insightful graphical displays including the BK-Plot for understanding Simpson's paradox with a binary confounder, the BK2-Plot for understanding bias amplification and attenuation in the presence of an unobserved binary confounder, and the PAD-Plot for understanding the principal stratification component of the paired availability design.
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Affiliation(s)
- Stuart G Baker
- Biometry Research Group, National Cancer Institute, Bethesda, MD 20892, USA.
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