Overall survival: still the gold standard: why overall survival remains the definitive end point in cancer clinical trials.
ABSTRACT Overall survival (OS) is the gold standard primary end point to evaluate the outcome of any drug, biologic, intervention, or procedure that is assessed in oncologic clinical trials. OS is universally recognized as being unambiguous, unbiased, with a defined end point of paramount clinical relevance, and positive results provide confirmatory evidence that a given treatment extends the life of a patient. Clinical trialists relentlessly attempt to devise more easily measured, cost-effective, and readily available event-driven end points as predictive surrogates of a definitive outcome, such as OS, and reduce the time with which clinical trials deliver definitive results. For some treatment modalities used in a limited number of cancer types, certain event-driven surrogates, eg, progression-free survival or time-to-progression may predict OS benefit. Biologic, cell-based, and vaccine-generated treatments are rapidly expanding the oncologist's armamentarium to combat cancers and pose a dilemma in that response may not be reflected by progression-free survival, time-to-progression, or other surrogates? As targeted therapies march forward, will each new therapy require a unique biomarker validated for every disease indication? Moreover, adjuvant treatments have demonstrated efficacy and given the current limited possibility of cure in the metastatic setting, should other end points, eg, quality-of-life, emerge as valid outcomes to demonstrate benefit. Clinical trials must continue to assess OS until biologically plausible measures are developed and emerge as valid early end point surrogates to replace the gold standard.
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ABSTRACT: Progression-free survival (PFS) and time to progression (TTP) are frequently used to establish the clinical efficacy of anti-cancer drugs. However, the surrogacy of PFS/TTP for overall survival (OS) remains a matter of uncertainty in metastatic breast cancer (mBC). This study assessed the relationship between PFS/TTP and OS in mBC using a trial-based approach.OncoTargets and Therapy 01/2014; 7:1101-10. DOI:10.2147/OTT.S63302 · 1.34 Impact Factor
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ABSTRACT: The tumor burden (TB) process is postulated to be the primary mechanism through which most anticancer treatments provide benefit. In phase II oncology trials, the biologic effects of a therapeutic agent are often analyzed using conventional endpoints for best response, such as objective response rate and progression-free survival, both of which causes loss of information. On the other hand, graphical methods including spider plot and waterfall plot lack any statistical inference when there is more than one treatment arm. Therefore, longitudinal analysis of TB data is well recognized as a better approach for treatment evaluation. However, longitudinal TB process suffers from informative missingness because of progression or death. We propose to analyze the treatment effect on tumor growth kinetics using a joint modeling framework accounting for the informative missing mechanism. Our approach is illustrated by multisetting simulation studies and an application to a nonsmall-cell lung cancer data set. The proposed analyses can be performed in early-phase clinical trials to better characterize treatment effect and thereby inform decision-making. Copyright © 2014 John Wiley & Sons, Ltd.Pharmaceutical Statistics 09/2014; 13(5). DOI:10.1002/pst.1629 · 1.10 Impact Factor
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ABSTRACT: Non-small-cell lung cancer (NSCLC) represents approximately 80% of all lung cancers. Unfortunately, at their time of diagnosis, most patients have advanced to unresectable disease with a very poor prognosis. The oriental herbal medicine HangAm-Plus(HAP) has been developed for antitumor purposes, and several previous studies have reported its therapeutic effects. In this study, the efficacy of HAP was evaluated as a third-line treatment for advanced-stage IIIb/IV NSCLC. The study involved six patients treated at the East- West Cancer Center (EWCC) from April 2010 to October 2011. Inoperable advanced-stage IIIb/IV NSCLC patients received 3,000 or 6,000 mg of HAP on a daily basis over a 12-week period. Computed tomography (CT) scans were obtained from the patients at the time of the initial administration and after 12 weeks of treatment. We observed and analyzed the patients overall survival (OS) and progression-free survival (PFS). Of the six patients, three expired during the study, and the three remaining patients were alive as of October 31, 2011. The OS ranged from 234 to 512 days, with a median survival of 397 days and a one-year survival rate of 66.7%. In the 12-week-interval chest CT assessment, three patients showed stable disease (SD), and the other three showed progressive disease (PD). The PFS of patients ranged from 88 to 512 days, the median PFS being 96 days. Longer OS and PFS were correlated with SD. Although not directly comparable, the OS and the PFS of this study were greater than those of the docetaxel or the best supportive care group in other studies. HAP may prolong the OS and the PFS of inoperable stage IIIb/IV NSCLC patients without significant adverse effects. In the future, more controlled clinical trials with larger samples from multi-centers should be conducted to evaluate the efficacy and the safety of HAP.06/2012; 15(2). DOI:10.3831/KPI.2012.15.2.031