Randomized controlled trials in the era of molecular oncology: methodology, biomarkers, and end points

Agnostic drug development revisited

The advent of molecular profiling and the generalization of next generation sequencing in oncology has enabled the identification of patients who could benefit from targeted agents. Since the tumor-agnostic approval of pembrolizumab for patients with MSI-High tumors in 2017, different molecularly-guided therapeutics have been awarded approvals and progressively incorporated in the treatment landscape across multiple tumor types. As the number of tumor-agnostic targets considered druggable expands in the clinic, novel challenges will reshape the drug development field involving all the stakeholders in oncology. In this review, we provide an overview of current tumor-agnostic approvals and discuss promising candidate therapeutics for tumor-agnostic designation and challenges for their broad implementation.

Association of differential censoring with survival and suboptimal control arms among oncology clinical trials

Differential censoring, which refers to censoring imbalance between treatment arms, may bias the interpretation of survival outcomes in clinical trials. In 146 phase III oncology trials with statistically significant time-to-event surrogate primary endpoints, we evaluated the association between differential censoring in the surrogate primary endpoints, control arm adequacy, and the subsequent statistical significance of overall survival results. Twenty-four (16%) trials exhibited differential censoring that favored the control arm, whereas 15 (10%) exhibited differential censoring that favored the experimental arm. Positive overall survival was more common in control arm differential censoring trials (63%) than in trials without differential censoring (37%) or with experimental arm differential censoring (47%; odds ratio = 2.64, 95% confidence interval = 1.10 to 7.20; P = .04). Control arm differential censoring trials more frequently used suboptimal control arms at 46% compared with 20% without differential censoring and 13% with experimental arm differential censoring (odds ratio = 3.60, 95% confidence interval = 1.29 to 10.0; P = .007). The presence of control arm differential censoring in trials with surrogate primary endpoints, especially in those with overall survival conversion, may indicate an inadequate control arm and should be examined and explained.

Allocation of authorship and patient enrollment among global clinical trials in oncology

BACKGROUND

Oncology randomized controlled trials (RCTs) are increasingly global in scope. Whether authorship is equitably shared between investigators from high-income countries (HIC) and low-middle/upper-middle incomes countries (LMIC/UMIC) is not well described. The authors conducted this study to understand the allocation of authorship and patient enrollment across all oncology RCTs conducted globally.

METHODS

A cross-sectional retrospective cohort study of phase 3 RCTs (published 2014-2017) that were led by investigators in HIC and recruited patients in LMIC/UMIC.

FINDINGS

During 2014-2017, 694 oncology RCTs were published; 636 (92%) were led by investigators from HIC. Among these HIC-led trials, 186 (29%) enrolled patients in LMIC/UMIC. One-third (33%, 62 of 186) of RCTs had no authors from LMIC/UMIC. Forty percent (74 of 186) of RCTs reported patient enrollment by country; in 50% (37 of 74) of these trials, LMIC/UMIC contributed <15% of patients. The relationship between enrollment and authorship proportion is very strong and is comparable between LMIC/UMIC and HIC (Spearman's ρ LMIC/UMIC 0.824, p < .001; HIC 0.823, p < .001). Among the 74 trials that report country enrollment, 34% (25 of 74) have no authors from LMIC/UMIC.

CONCLUSIONS

Among trials that enroll patients in HIC and LMIC/UMIC, authorship appears to be proportional to patient enrollment. This finding is limited by the fact that more than half of RCTs do not report enrollment by country. Moreover, there are important outliers as a significant proportion of RCTs had no authors from LMIC/UMIC despite enrolling patients in these countries. The findings in this study reflect a complex global RCT ecosystem that still underserves cancer control outside high-income settings.

Analysis of Efficacy-To-Safety Ratio of Angiogenesis-Inhibitors Based Therapies in Ovarian Cancer: A Systematic Review and Meta-Analysis

(1) Background: Among new anti-angiogenesis agents being developed and ever-changing guidelines indications, the question of the benefits/safety ratio remains unclear. (2) Methods: We performed a systematic review combined with a meta-analysis of 23 randomized controlled trials (12,081 patients), evaluating overall survival (OS), progression free survival (PFS) and toxicity (grade ≥ 3 toxic effects, type, and number of all adverse effects. (3) Results: The analysis showed improvement of pooled-PFS (HR, 0.71; 95% CI, 0.64-0.78; I² = 77%; p < 0.00001) in first-line (HR, 0.85; 95% CI, 0.78-0.93; p = 0.0003) or recurrent cancer (HR, 0.62; 95% CI, 0.56-0.70; p < 0.00001) and regardless of the type of anti-angiogenesis drug used (Vascular endothelial growth factor (VEGF) inhibitors, VEGF-receptors (VEGF-R) inhibitors or angiopoietin inhibitors). Improved OS was also observed (HR, 0.95; 95% CI, 0.90-0.99; p = 0.03). OS benefits were only observed in recurrent neoplasms, both platinum-sensitive and platinum-resistant neoplasms. Grade ≥ 3 adverse effects were increased across all trials. Anti-angiogenetic therapy increased the risk of hypertension, infection, thromboembolic/hemorrhagic events, and gastro-intestinal perforations but not the risk of wound-related issues, anemia or posterior leukoencephalopathy syndrome. (4) Conclusions: Although angiogenesis inhibitors improve PFS, there are little-to-no OS benefits. Given the high risk of severe adverse reactions, a careful selection of patients is required for obtaining the best results possible.

Current Scenario of Clinical Cancer Research in Latin America and the Caribbean

In Latin America and the Caribbean (LAC), progress has been made in some national and regional cancer control initiatives, which have proved useful in reducing diagnostic and treatment initiation delays. However, there are still significant gaps, including a lack of oncology clinical trials. In this article, we will introduce the current status of the region's clinical research in cancer, with a special focus on academic cancer research groups and investigator-initiated research (IIR) initiatives. Investigators in LAC have strived to improve cancer research despite drawbacks and difficulties in funding, regulatory timelines, and a skilled workforce. Progress has been observed in the representation of this region in clinical trial development and conduct, as well as in scientific productivity. However, most oncology trials in the region have been sponsored by pharmaceutical companies, highlighting the need for increased funding from governments and private foundations. Improvements in obtaining and/or strengthening the LAC cancer research group's financing will provide opportunities to address cancer therapies and management shortcomings specific to the region. Furthermore, by including this large, ethnic, and genetically diverse population in the world's research agenda, one may bridge the gap in knowledge regarding the applicability of results of clinical trials now mainly conducted in populations from the Northern Hemisphere.

An Expanded Role for IRBs in the Oversight of Research Biopsies

Research biopsies included in cancer clinical trials have the goal of advancing scientific understanding of the biological bases of cancer and its treatments, but may offer no prospect of direct benefit to participants and often pose more than minimal risk. The research community is examining the ethics of research biopsies increasingly often, especially when they are mandatory for study participation but do not support primary study objectives and thus are "nonintegral" to the study. Ethical concerns center on the limited scientific justification supporting some biopsies, risks to research participants, and the potential for coercion and therapeutic misconception during the informed consent process. There is also a lack of comprehensive oversight of research biopsies by regulatory agencies and institutions. This paper reviews these ethical concerns, discusses the scope of federal oversight, and suggests that institutional review boards (IRBs) should assume a larger role in ensuring the ethical conduct of research biopsies. It concludes with guidance to IRBs on how to weigh the risks, benefits, and acceptability of such biopsies in different contexts that is based on a framework the American Society of Clinical Oncology developed for the inclusion of research biopsies in oncology clinical trials.

A retrospective analysis of changes in distant and breast cancer related disease-free survival events in adjuvant breast cancer trials over time

Disease-free survival (DFS) comprises both breast cancer and non-breast cancer events. DFS has not been validated as a surrogate endpoint for overall survival (OS) in most breast cancer subtypes. We assessed changes to the type of events contributing to DFS over time. We identified adjuvant studies in breast cancer (BC) from 2000 to 2020 where the endpoint was DFS. We examined change in distant DFS events and the BC-related DFS using univariable and multivariable linear regression. Data were reported quantitatively using the Burnand criteria irrespective of statistical significance. We included 84 studies (88 cohorts), comprising 212,191 participants, 41,604 DFS events and 23,205 distant DFS events. The DFS event rate/100 participants/year has declined modestly over time (ß - 0.34, p = 0.001). Start year was negatively associated with distant DFS events (ß - 0.58, p < 0.0001); however, the effect was lost after adjusting for follow-up time (ß - 0.18, p = 0.096). The average number of BC-related events/100 participants/year also declined over time (ß - 0.28, p = 0.009). In multivariable analysis, start year and ER expression were quantitatively associated with distant DFS events and BC-related DFS events. DFS events have declined over time driven by a reduction in BC related events. As DFS events are increasingly defined by non-BC events, there will be limited surrogacy between DFS and OS.

Randomized Controlled Trials in Lung, Gastrointestinal, and Breast Cancers: An Overview of Global Research Activity

Background: In this study, we compared and contrasted design characteristics, results, and publications of randomized controlled trials (RCTs) in gastrointestinal (GI), lung, and breast cancer. Methods: A PUBMED search identified phase III RCTs of anticancer therapy in GI, lung, and breast cancer published globally during the period 2014−2017. Descriptive statistics, chi-square tests, and the Kruskal−Wallis test were used to compare RCT design, results, and output across the cancer sites. Results: A total of 352 RCTs were conducted on GI (36%), lung (29%), and breast (35%) cancer. Surrogate endpoints were used in 55% of trials; this was most common in breast trials (72%) compared to GI (47%) and lung trials (43%, p < 0.001). Breast trials more often met their primary endpoint (54%) than GI (41%) and lung trials (41%) (p = 0.024). When graded with the ESMO-MCBS, lung cancer trials (50%, 15/30) were more likely to meet the threshold for substantial benefit. GI trials were published in journals with a substantially lower impact factor (IF; median IF 13) than lung (median IF 21) and breast cancer trials (median IF 21) (p = 0.038). Conclusions: Important differences in RCT design and output exist between the three major cancer sites. Use of surrogate endpoints and the magnitude of benefit associated with new treatments vary substantially across cancer sites.

A comprehensive systematic review and network meta-analysis: the role of anti-angiogenic agents in advanced epithelial ovarian cancer

The efficacy of anti-angiogenic agents (AAAs) in epithelial ovarian cancer (EOC) remains unclear. Therefore, we conducted a systematic review and network meta-analysis (NMA) to synthesize evidence of their comparative effectiveness for improving overall survival (OS) among EOC patients. We searched six databases for randomized controlled trials (RCTs) from their inception to February 2021. We performed an NMA with hazard ratios (HRs) and 95%-confidence intervals (CIs) to evaluate comparative effectiveness among different AAAs in chemotherapy-naïve and recurrent EOC. P-score was used to provide an effectiveness hierarchy ranking. Sensitivity NMA was carried out by focusing on studies that reported high-risk chemotherapy-naïve, platinum-resistant, and platinum-sensitive EOC. The primary outcome was OS. We identified 23 RCTs that assessed the effectiveness of AAAs. In recurrent EOC, concurrent use of trebananib (10 mg/kg) with chemotherapy was likely to be the best option (P-score: 0.88, HR 1.67, 95% CI 0.94; 2.94). The NMA indicated that bevacizumab plus chemotherapy followed by maintenance bevacizumab (P-score: 0.99) and pazopanib combined with chemotherapy (P-score: 0.79) both had the highest probability of being the best intervention for improving OS in high-risk chemotherapy-naïve and platinum-resistant EOC, respectively. AAAs may not play a significant clinical role in non-high-risk chemotherapy-naïve and platinum-sensitive EOC.

Industry Funding of Oncology Randomised Controlled Trials: Implications for Design, Results and Interpretation

AIMS

Most randomised controlled trials (RCTs) in oncology are now funded by the pharmaceutical industry. We explore the extent to which RCT design, results and interpretation differ between industry-funded and non-industry-funded RCTs.

MATERIALS AND METHODS

In this cross-sectional analysis, a structured literature search was used to identify all oncology RCTs published globally during 2014-2017. Industry funding was identified based on explicit statements in the publication. Descriptive statistics were used to compare elements of trial methodology and output between industry- and non-industry-funded RCTs.

RESULTS

The study sample included 694 RCTs; 71% were funded by industry. Industry-funded trials were more likely to test systemic therapy (97% versus 62%; P < 0.001), palliative-intent therapy (71% versus 41%; P < 0.001) and study breast cancer (20% versus 12%; P < 0.001). Industry-funded trials were larger (median sample size 474 versus 375; P < 0.001) and more likely to meet their primary end point (49% versus 41%; P < 0.001). Among positive trials, there were no differences in the magnitude of benefit between industry- and non-industry-funded RCTs. Trials funded by industry were published in journals that had a significantly higher median impact factor (21, interquartile range 7, 28) than non-industry-funded trials (impact factor 12, interquartile range 5, 24; P = 0.005); this persisted when adjusted for whether a trial was positive or negative.

CONCLUSIONS

The vast majority of oncology RCTs are now funded by industry. Industry-funded trials are larger, more likely to be positive, predominantly test systemic therapies in the palliative setting and are published in higher impact journals than trials without industry support.

The frequency of medical reversals in a cross-sectional analysis of high-impact oncology journals, 2009-2018

Background

Identifying ineffective practices that have been used in oncology is important in reducing wasted resources and harm. We sought to examine the prevalence of practices that are being used but have been shown in RCTs to be ineffective (medical reversals) in published oncology studies.

Methods

We cross-sectionally analyzed studies published in three high-impact oncology medical journals (2009–2018). We abstracted data relating to the frequency and characterization of medical reversals.

Results

Of the 64 oncology reversals, medications (44%) represented the most common intervention type (39% were targeted). Fourteen (22%) were funded by pharmaceutical/industry only and 56% were funded by an organization other than pharmaceutical/industry. The median number of years that the practice had been in use prior to the reversal study was 9 years (range 1–50 years).

Conclusion

Here we show that oncology reversals most often involve the administration of medications, have been practiced for years, and are often identified through studies funded by non-industry organizations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08632-8.

Clinical and cost outcomes following genomics-informed treatment for advanced cancers

BACKGROUND

Single-arm trials are common in precision oncology. Owing to the lack of randomized counterfactual, resultant data are not amenable to comparative outcomes analyses. Difference-in-difference (DID) methods present an opportunity to generate causal estimates of time-varying treatment outcomes. Using DID, our study estimates within-cohort effects of genomics-informed treatment versus standard care on clinical and cost outcomes.

METHODS

We focus on adults with advanced cancers enrolled in the single-arm BC Cancer Personalized OncoGenomics program between 2012 and 2017. All individuals had a minimum of 1-year follow up. Logistic regression explored baseline differences across patients who received a genomics-informed treatment versus a standard care treatment after genomic sequencing. DID estimated the incremental effects of genomics-informed treatment on time to treatment discontinuation (TTD), time to next treatment (TTNT), and costs. TTD and TTNT correlate with improved response and survival.

RESULTS

Our study cohort included 346 patients, of whom 140 (40%) received genomics-informed treatment after sequencing and 206 (60%) received standard care treatment. No significant differences in baseline characteristics were detected across treatment groups. DID estimated that the incremental effect of genomics-informed versus standard care treatment was 102 days (95% CI: 35, 167) on TTD, 91 days (95% CI: -9, 175) on TTNT, and CAD$91,098 (95% CI: $46,848, $176,598) on costs. Effects were most pronounced in gastrointestinal cancer patients.

CONCLUSIONS

Genomics-informed treatment had a statistically significant effect on TTD compared to standard care treatment, but at increased treatment costs. Within-cohort evidence generated through this single-arm study informs the early-stage comparative effectiveness of precision oncology.

Food and Drug Administration approvals in phase 3 Cancer clinical trials

BACKGROUND

Phase 3 oncologic randomized clinical trials (RCTs) can lead to Food and Drug Administration (FDA) approvals. In this study, we aim to identify trial-related factors associated with trials leading to subsequent FDA drug approvals.

METHODS

We performed a database query through the ClinicalTrials.gov registry to search for oncologic phase 3 RCTs on February 2020. We screened all trials for therapeutic, cancer-specific, phase 3, randomized, multi-arm trials. We then identified whether a trial was used for subsequent FDA drug approval through screening of FDA approval announcements.

RESULTS

In total, 790 trials were included in our study, with 225 trials (28.4%) generating data that were subsequently used for FDA approvals. Of the 225 FDA approvals identified, 65 (28.9%) were based on trials assessing overall survival (OS) as a primary endpoint (PEP), two (0.9%) were based on trials with a quality of life (QoL) PEP, and 158 approvals (70.2%) were based on trials with other PEP (P = 0.01). FDA approvals were more common among industry funded-trials (219, 97.3%; P < 0.001), and less common among trials sponsored by national cooperative groups (21, 9.3%; P < 0.001). Finally, increased pre-hoc power and meeting patients' accrual target were associated with FDA approvals (P < 0.001).

CONCLUSIONS

The majority of FDA approvals are based on data generated from trials analyzing surrogate primary endpoints and trials receiving industry funding. Additional studies are required to understand the complexity of FDA approvals.

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.

Evolution of the Randomized Clinical Trial in the Era of Precision Oncology

IMPORTANCE

The randomized clinical trial (RCT) in oncology has evolved since its widespread adoption in the 1970s. In recent years, concerns have emerged regarding the use of putative surrogate end points, such as progression-free survival (PFS), and marginal effect sizes.

OBJECTIVE

To describe contemporary trends in oncology RCTs and compare these findings with earlier eras of RCT design and output.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study of systemic therapy RCTs in breast, colorectal, and non-small cell lung cancer published in 7 major journals between 2010 and 2020. This strategy replicates prior work and allows for comparison of trends with RCTs published between 1995 to 2004 and 2005 to 2009.

MAIN OUTCOMES AND MEASURES

Data on RCT design, funding, results, and reporting were extracted from the published RCT report. Findings from the current period (2010-2020) were compared with data from RCTs published from 1995 to 2004 and 2005 to 2009. Descriptive and bivariate statistics were used to analyze temporal trends.

RESULTS

The cohort included 298 RCTs (132 [44%] breast, 111 [37%] non-small cell lung cancer, 55 [19%] colorectal cancer). Experimental treatment included molecular inhibitor (171 of 298 [57%]), cytotoxic (83 of 298 [28%]), hormone (15 of 298 [5%]), and immune (24 of 298 [8%]) therapies. Sixty-nine percent (206 of 298) of RCTs were of palliative intent. The most common primary end point is now PFS; this has increased substantially over time (from 0% [0 of 167] to 18% [25 of 137] to 42% [125 of 298]; P < .001). Of 298 RCTs, 265 (89%) are now funded by industry (previously 95 of 167 [57%] and 107 of 137 [78%]; P < .001). Fifty-eight percent (173 of 298) of trials met their primary end point. Among positive trials, median improvement in overall survival and PFS was 3.4 and 2.9 months, respectively. More than one-third (117 of 298 [39%]) of reports used a professional medical writer; this increased substantially during the study period (from 3 of 27 [11%] in 2010 to 12 of 18 [67%] in 2020; P < .001).

CONCLUSIONS AND RELEVANCE

This cohort study suggests that contemporary oncology RCTs now largely measure putative surrogate end points and are almost exclusively funded by the pharmaceutical industry. The increasing role of medical writers warrants attention. To demonstrate that new cancer treatments are high value, the oncology community needs to consider the extent to which study end points and target effect size provide meaningful benefit to patients.

An Analysis of Contemporary Oncology Randomized Clinical Trials From Low/Middle-Income vs High-Income Countries

Importance

The burden of cancer falls disproportionally on low-middle-income countries (LMICs). It is not well known how novel therapies are tested in current clinical trials and the extent to which they match global disease burden.

Objectives

To describe the design, results, and publication of oncology randomized clinical trials (RCTs) and examine the extent to which trials match global disease burden and how trial methods and results differ across economic settings.

Design, Setting, and Participants

In this retrospective cohort study, a literature search identified all phase 3 RCTs evaluating anticancer therapies published from 2014 to 2017. Randomized clinical trials were classified based on World Bank economic classification. Descriptive statistics were used to compare RCT design and results from high-income countries (HICs) and low/middle-income countries (LMICs). Statistical analysis was conducted in January 2020.

Main Outcomes and Measures

Differences in the design, results, and output of RCTs between HICs and LMICs.

Results

The study cohort included 694 RCTs: 636 (92%) led by HICs and 58 (8%) led by LMICs. A total of 601 RCTs (87%) tested systemic therapy and 88 RCTs (13%) tested radiotherapy or surgery. The proportion of RCTs relative to global deaths was higher for breast cancer (121 RCTs [17%] and 7% of deaths) but lower for gastroesophageal cancer (38 RCTs [6%] and 14% of deaths), liver cancer (14 RCTs [2%] and 8% of deaths), pancreas cancer (14 RCTs [2%] and 5% of deaths), and cervical cancer (9 RCTs [1%] and 3% of deaths). Randomized clinical trials in HICs were more likely than those in LMICs to be funded by industry (464 [73%] vs 24 [41%]; P < .001). Studies in LMICs were smaller than those in HICs (median, 219 [interquartile range, 137-363] vs 474 [interquartile range, 262-743] participants; P < .001) and more likely to meet their primary end points (39 of 58 [67%] vs 286 of 636 [45%]; P = .001). The observed median effect size among superiority trials was larger in LMICs compared with HICs (hazard ratio, 0.62 [interquartile range, 0.54-0.76] vs 0.84 [interquartile range, 0.67-0.97]; P < .001). Studies from LMICs were published in journals with lower median impact factors than studies from HICs (7 [interquartile range, 4-21] vs 21 [interquartile range, 7-34]; P < .001). Publication bias persisted when adjusted for whether a trial was positive or negative (median impact factor: LMIC negative trial, 5 [interquartile range, 4-6] vs HIC negative trial, 18 [interquartile range, 6-26]; LMIC positive trial, 9 [interquartile range, 5-25] vs HIC positive trial, 25 [interquartile range, 10-48]; P < .001).

Conclusions and Relevance

This study suggests that oncology RCTs are conducted predominantly by HICs and do not match the global burden of cancer. Randomized clinical trials from LMICs are more likely to identify effective therapies and have a larger effect size than RCTs from HICs. This study suggests that there is a funding and publication bias against RCTs led by LMICs. Policy makers, research funders, and journals need to address this issue with a range of measures including building capacity and capability in RCTs.

Ethics of Pharma Clinical Trials in the Era of Precision Oncology

Pharmaceutical industry clinical trials are ethically problematic: human research subjects are being used as a means to the end of demonstrating statistically significant efficacy of novel anticancer agents to achieve regulatory registration and marketing approval. Randomized controlled trial design is inequitable since control arm patients are denied access to the postulated best treatment. Most pharma studies do not provide clinically meaningful benefit of increased overall survival and enhanced quality of life (QOL) to cohorts and are not reliably generalizable to real-world patients. Precision oncology now enables prospective identification of patients expressing a specific cancer biomarker to determine their particular eligibility for evaluation of efficiency of molecular-targeted treatments. A patient-centered approach, collecting prospective real-world data in large populations, could provide real-world evidence of cost-effective, sustained clinical benefits of survival and QOL, while preserving the ethical beneficent compact between patient and doctor.

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.

Progression-free survival is a suboptimal predictor for overall survival among metastatic solid tumour clinical trials

BACKGROUND

The use of overall survival (OS) as the gold standard primary end-point (PEP) in metastatic oncologic randomised controlled trials (RCTs) has declined in favour of progression-free survival (PFS) without a complete understanding of the degree to which PFS reliably predicts for OS.

METHODS

Using ClinicalTrials.gov, we identified 1239 phase III oncologic RCTs, 260 of which were metastatic solid tumour trials with a superiority-design investigating a therapeutic intervention by using either a PFS or OS PEP. Each individual trial was reviewed to quantify RCT design factors and disease-related outcomes.

RESULTS

A total of 172,133 patients were enrolled from the year 1999 to 2015 in RCTs that used PFS (56.2%, 146/260) or OS (43.8%, 114/260) as the PEP. PFS trials were more likely to restrict patient eligibility by using molecular criteria (15.1% versus 4.4%, p = 0.005) use targeted therapy (80.1% versus 67.5%, p = 0.048), accrue fewer patients (median 495 versus 619, p = 0.03), and successfully meet the trial PEP (66.9% versus 33.3%, p < 0.0001). On multiple binary logistic regression analysis, factors that predicted for PFS or OS PEP trial success included choice of PFS PEP (p < 0.0001), molecular profile restriction (p = 0.02) and single agent therapy (p = 0.02). Notably, there was only a 38% (31/82) conversion rate of positive PFS-to-OS benefit; lack of industry sponsorship predicted for PFS-to-OS signal conversion (80.0% without industry sponsorship versus 35.1% with industry sponsorship, p = 0.045).

CONCLUSIONS

A PFS PEP has suboptimal positive predictive value for OS among phase III metastatic solid tumour RCTs. Regulatory agency decisions should be judicious in using PFS results as the primary basis for approval.

The Value of Progression-Free Survival in Metastatic Breast Cancer: Results From a Survey of Patients and Providers

Background. Value assessments and treatment decision making typically focus on clinical endpoints, especially overall survival (OS). However, OS data are not always available, and surrogate markers may also have some value to patients. This study sought to estimate preferences for progression-free survival (PFS) relative to OS in metastatic breast cancer (mBC) among a diverse set of stakeholders—patients, oncologists, and oncology nurses—and estimate the value patients and providers place on other attributes of treatment. Methods. Utilizing a combined conjoint analysis and discrete choice experiment approach, we conducted an online prospective survey of mBC patients and oncology care providers who treat mBC patients across the United States. Results. A total of 299 mBC patients, 100 oncologists, and 99 oncology nurses completed the survey. Virtually all patients preferred health state sequences with contiguous periods of PFS, compared with approximately 85% and 75% of nurses and oncologists, respectively. On average, longer OS was significantly (P < 0.01) preferred by the majority (75%) patients, but only 15% of nurses preferred longer OS, and OS did not significantly affect oncologists’ preferred health state. However, in the context of a treatment decision, whether a treatment offered continuous periods of stable disease holding OS constant significantly affected nurses’ treatment choices. Patients and providers alike valued reductions in adverse event risk and evidence from high-quality randomized controlled clinical trials. Conclusions. The strong preference for observed PFS suggests more research is warranted to better understand the reasons for PFS having positive value to patients. The results also suggest a range of endpoints in clinical trials may have importance to patients.

Attitude and willingness of attendance for participating in or completing acupuncture trials: a cross-sectional study

OBJECTIVE

To explore the influence of patients' participation in and completing the acupuncture clinical trials through a cross-sectional survey. In addition, we explored potential factors involved in improving patient's compliance to treatment, thus enhancing the quality of acupuncture clinical studies.

METHODS

A survey was conducted at outpatient department of acupuncture and metabolic diseases in two hospitals in Beijing. The semi-structured questionnaire was designed based on literature review and Delphi methods. It contains 15 questions related to patients' experience and attitude. SPSS 22.0 was used for analyses. OR and 95% CI were used for dichotomous outcomes. Logistic regression analysis (LRA) and multi-LRA were used to explore the factors influencing patients' participation or completion and the relationship between demographic characteristics and potential factors.

RESULTS

A survey was conducted from April to September 2016. Five hundred patients were consecutively sampled to fill semi-structured questionnaires regardless of their types of disease. The participants (75.2% were female) were in the age range of 15-85 years and all of them completed the survey. The effect and safety of acupuncture therapy were considered to be the deciding factors by 92% and 96% of the respondents, respectively. Only 40 of the surveyed participants (8.0%) had previously participated in the clinical trials. The LRA showed they paid more attention to treatment regimen (frequency and session of treatment) when deciding whether or not to participate in the trials (OR 1.54, 95% CI 1.02-2.34). Multivariate LRA showed that elder people considered cost (OR 1.36, 95% CI 1.09-1.70) to be an important factor, while the participants having medical insurance (OR 1.45, 95% CI -0.20-0.93) thought informed consent was important. Meanwhile, participants with higher education preferred regular follow-up (OR 1.16, 95% CI 0.02-0.28).

CONCLUSION

After providing adequate information regarding the potential benefits and harms of the acupuncture treatment, completion of the treatment within the specific time regimen was found to be the most important factor affecting patient's compliance. Other factors, such as cost and regular follow-up, should also be given special consideration.

Outcome switching in randomized controlled oncology trials reporting on surrogate endpoints: a cross-sectional analysis

Inconsistent reporting of clinical trials is well-known in the literature. Despite this, factors associated with poor practice such as outcome switching in clinical trials are poorly understood. We performed a cross-sectional analysis to evaluate the prevalence of, and the factors associated with outcome switching. PubMed and Embase were searched for pharmaceutical randomized controlled trials (RCTs) in oncology reporting on a surrogate primary outcome published in 2015. Outcome switching was present in 18% (39/216). First-author male sex was significantly more likely associated with outcome switching compared to female sex with an OR of 3.05 (95% CI 1.07-8.64, p = 0.04) after multivariable adjustment. For-profit funded RCTs were less likely associated with outcome switching compared to non-profit funded research with an OR of 0.22 (95% CI 0.07-0.74, p = 0.01). First author male sex was more likely associated with outcome switching compared to female sex in drug oncology RCTs reporting on a primary surrogate endpoint. For-profit funded research was less likely associated with outcome switching compared to research funded by non-profit organizations. Furthermore, 18 percent of drug oncology trials reporting on a surrogate endpoint could have a higher risk of false positive results due to primary outcome switching.

Surrogate endpoints in oncology: when are they acceptable for regulatory and clinical decisions, and are they currently overused?

BACKGROUND

Surrogate outcomes are not intrinsically beneficial to patients, but are designed to be easier and faster to measure than clinically meaningful outcomes. The use of surrogates as an endpoint in clinical trials and basis for regulatory approval is common, and frequently exceeds the guidance given by regulatory bodies.

DISCUSSION

In this article, we demonstrate that the use of surrogates in oncology is widespread and increasing. At the same time, the strength of association between the surrogates used and clinically meaningful outcomes is often unknown or weak. Attempts to validate surrogates are rarely undertaken. When this is done, validation relies on only a fraction of available data, and often concludes that the surrogate is poor. Post-marketing studies, designed to ensure drugs have meaningful benefits, are often not performed. Alternatively, if a drug fails to improve quality of life or overall survival, market authorization is rarely revoked. We suggest this reliance on surrogates, and the imprecision surrounding their acceptable use, means that numerous drugs are now approved based on small yet statistically significant increases in surrogates of questionable reliability. In turn, this means the benefits of many approved drugs are uncertain. This is an unacceptable situation for patients and professionals, as prior experience has shown that such uncertainty can be associated with significant harm.

CONCLUSION

The use of surrogate outcomes should be limited to situations where a surrogate has demonstrated robust ability to predict meaningful benefits, or where cases are dire, rare or with few treatment options. In both cases, surrogates must be used only when continuing studies examining hard endpoints have been fully recruited.

Delivery of meaningful cancer care: a retrospective cohort study assessing cost and benefit with the ASCO and ESMO frameworks

BACKGROUND

The American Society of Clinical Oncology (ASCO) and the European Society for Medical Oncology (ESMO) have developed frameworks that quantify survival gains in light of toxicity and quality of life to assess the benefits of cancer therapies. We applied these frameworks to a cohort of contemporary randomised controlled trials to explore agreement between the two approaches and to assess the relation between treatment benefit and cost.

METHODS

We identified all randomised controlled trials of systemic therapies in non-small-cell lung cancer, breast cancer, colorectal cancer, and pancreatic cancer published between Jan 1, 2011, and Dec 31, 2015, and assessed their abstracts and methods. Trials were eligible for inclusion in our cohort if significant differences favouring the experimental group in a prespecified primary or secondary outcome were reported (secondary outcomes were assessed only if primary outcomes were not significant). We assessed trial endpoints with the ASCO and ESMO frameworks at two timepoints 3 months apart to confirm intra-rater reliability. Cohen's κ statistic was calculated to establish agreement between the two frameworks on the basis of the median ASCO score, which was used as an arbitrary threshold of benefit, and the framework-recommended ESMO threshold. Differences in monthly drug cost between the experimental and control groups of each randomised controlled trial (ie, incremental drug cost) were derived from 2016 average wholesale prices.

FINDINGS

109 randomised controlled trials were eligible for inclusion, 42 (39%) in non-small-cell lung cancer, 36 (33%) in breast cancer, 25 (23%) in colorectal cancer, and six (6%) in pancreatic cancer. ASCO scores ranged from 2 to 77; median score was 25 (IQR 16-35). 41 (38%) trials met the benefit thresholds in the ESMO framework. Agreement between the two frameworks was fair (κ=0·326). Among the 100 randomised controlled trials for which drug costing data were available, ASCO benefit score and monthly incremental drug costs were negatively correlated (ρ=-0·207; p=0·039). Treatments that met ESMO benefit thresholds had a lower median incremental drug cost than did those that did not meet benefit thresholds (US$2981 [IQR 320-9059] vs $8621 [1174-13 930]; p=0·018).

INTERPRETATION

There is only fair correlation between these two major value care frameworks, and negative correlations between framework outputs and drug costs. Delivery of optimal cancer care in a sustainable health system will necessitate future oncologists, investigators, and policy makers to reconcile the disconnect between drug cost and clinical benefit.

FUNDING

None.

Untapped Potential of Observational Research to Inform Clinical Decision Making: American Society of Clinical Oncology Research Statement

ASCO believes that high-quality observational studies can advance evidence-based practice for cancer care and are complementary to randomized controlled trials (RCTs). Observational studies can generate hypotheses by evaluating novel exposures or biomarkers and by revealing patterns of care and relationships that might not otherwise be discovered. Researchers can then test these hypotheses in RCTs. Observational studies can also answer or inform questions that either have not been or cannot be answered by RCTs. In addition, observational studies can be used for postmarketing surveillance of new cancer treatments, particularly in vulnerable populations. The incorporation of observational research as part of clinical decision making is consistent with the position of many leading institutions. ASCO identified five overarching recommendations to enhance the role of observational research in clinical decision making: (1) improve the quality of electronic health data available for research, (2) improve interoperability and the exchange of electronic health information, (3) ensure the use of rigorous observational research methodologies, (4) promote transparent reporting of observational research studies, and (5) protect patient privacy.

Use of Intermediate Endpoints in the Economic Evaluation of New Treatments for Advanced Cancer and Methods Adopted When Suitable Overall Survival Data are Not Available

OBJECTIVES

This study assessed the use of intermediate endpoints in the economic evaluation of new treatments for advanced cancer and the methodological approaches adopted when overall survival (OS) data are unavailable or of limited use.

METHODS

A systematic literature review was conducted to identify economic evaluations of treatments for advanced cancer published between 2003 and 2013. Cost-effectiveness and cost-utility analyses expressed in cost per life-year gained and cost per quality-adjusted life-year using an intermediate endpoint as an outcome measure were eligible. Characteristics of selected studies were extracted and comprised population, treatment of interest, comparator, line of treatment, study perspective, and time horizon. Use of intermediate endpoints and methods adopted when OS data were lacking were analyzed.

RESULTS

In total, 7219 studies were identified and 100 fulfilled the eligibility criteria. Intermediate endpoints mostly used were progression-free survival and time to progression, accounting for 92 % of included studies. OS data were unavailable for analysis in nearly 25 % of economic evaluations. In the absence of OS data, studies most commonly assumed an equal risk of death for all treatment groups. Other methods included use of indirect comparison based on numerous assumptions, use of a proxy for OS, consultation with clinical experts, and use of published external information from different treatment settings.

CONCLUSION

Intermediate endpoints are widely used in the economic evaluation of new treatments for advanced cancer in order to estimate OS. Currently, different methods are used in the absence of suitable OS data and the choice of an appropriate method depends on many factors including the data availability.

Prostate Cancer Registries: Current Status and Future Directions

CONTEXT

Disease-specific registries that enroll a considerable number of patients play a major role in prostate cancer (PCa) research.

OBJECTIVE

To evaluate available registries, describe their strengths and limitations, and discuss the potential future role of PCa registries in outcomes research.

EVIDENCE ACQUISITION

We performed a literature review of the Medline, Embase, and Web of Science databases. The search strategy included the terms prostate cancer, outcomes, statistical approaches, population-based cohorts, registries of outcomes, and epidemiological studies, alone or in combination. We limited our search to studies published between January 2005 and January 2015.

EVIDENCE SYNTHESIS

Several population-based and prospective disease-specific registries are currently available for prostate cancer. Studies performed using these data sources provide important information on incidence and mortality, disease characteristics at presentation, risk factors, trends in utilization of health care services, disparities in access to treatment, quality of care, long-term oncologic and health-related quality of life outcomes, and costs associated with management of the disease. Although data from these registries have some limitations, statistical methods are available that can address certain biases and increase the internal and external validity of such analyses. In the future, improvements in data quality, collection of tissue samples, and the availability of data feedback to health care providers will increase the relevance of studies built on population-based and disease-specific registries.

CONCLUSIONS

The strengths and limitations of PCa registries should be carefully considered when planning studies using these databases. Although randomized controlled trials still provide the highest level of evidence, large registries play an important and growing role in advancing PCa research and care.

PATIENT SUMMARY

Several population-based and prospective disease-specific registries for prostate cancer are currently available. Analyses of data from these registries yield information that is clinically relevant for the management of patients with prostate cancer.

Strength of Validation for Surrogate End Points Used in the US Food and Drug Administration's Approval of Oncology Drugs

OBJECTIVE

To determine the strength of the surrogate-survival correlation for cancer drug approvals based on a surrogate.

PARTICIPANTS AND METHODS

We performed a retrospective study of the US Food and Drug Administration (FDA) database, with focused searches of MEDLINE and Google Scholar. Among cancer drugs approved based on a surrogate end point, we examined previous publications assessing the strength of the surrogate-survival correlation. Specifically, we identified the percentage of surrogate approvals lacking any formal analysis of the strength of the surrogate-survival correlation, and when conducted, the strength of such correlations.

RESULTS

Between January 1, 2009, and December 31, 2014, the FDA approved marketing applications for 55 indications based on a surrogate, of which 25 were accelerated approvals and 30 were traditional approvals. We could not find any formal analyses of the strength of the surrogate-survival correlation in 14 out of 25 accelerated approvals (56%) and 11 out of 30 traditional approvals (37%). For accelerated approvals, just 4 approvals (16%) were made where a level 1 analysis (the most robust way to validate a surrogate) had been performed, with all 4 studies reporting low correlation (r≤0.7). For traditional approvals, a level 1 analysis had been performed for 15 approvals (50%): 8 (53%) reported low correlation (r≤0.7), 4 (27%) medium correlation (r>0.7 to r<0.85), and 3 (20%) high correlation (r≥0.85) with survival.

CONCLUSIONS

The use of surrogate end points for drug approval often lacks formal empirical verification of the strength of the surrogate-survival association.

Patients' willingness to participate in clinical trials and their views on aspects of cancer research: results of a prospective patient survey

Background

Recruitment to clinical trials can be challenging and slower than anticipated. This prospective patient survey aimed to investigate the proportion of patients approached about a trial who agree to participate, their motivations for trial participation and their views on aspects of cancer research.

Methods

Patients who had been approached about participation in any clinical trials in the Gastrointestinal and Lymphoma Unit at the Royal Marsden were invited to complete a questionnaire. The statistical analysis is mainly descriptive, with percentages being reported. Univariate logistic regression analysis was used to determine any associations between patient characteristics and patient responses.

Results

From August 2013–July 2014, 276 patients received 298 clinical trial patient information sheets and were asked to complete the questionnaire. The majority of patients (263 patients, 88 %) consented to a clinical trial and 249 of the 263 patients (95 %) completed the questionnaire. Multiple factors influenced decisions to participate in clinical trials, with patients stating that the most important reasons were that the trial offered the best treatment available and that the trial results could benefit others. Of the 249 questionnaire respondents, 78 % would donate their tissue for genetic research, 75 % would consider participating in studies requiring a research biopsy and 75 % felt that patients should be informed of trial results. Patients treated with palliative intent and those who had received multiple lines of treatment were more willing to consider research biopsies. Of the patients approached about a clinical trial of an investigational medicinal product, 48–50 % would have liked more information on the study drugs/procedures.

Conclusion

The majority of patients approached about a clinical trial consented to one or more trials. Patients’ motivations for trial participation included potential personal benefit and altruistic reasons. A high proportion of patients were willing to donate tissue for research and to consider trials involving repeat biopsies. The majority of patients feel that participants should be informed of trial results and there is a group of patients who would like more detailed trial information.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-015-1105-3) contains supplementary material, which is available to authorized users.

Translation failure and medical reversal: Two sides to the same coin

Translation failure occurs when the results of preclinical, observational and/or early phase studies fail to predict the results of well done (i.e. appropriately controlled, adequately powered, and properly conducted) phase III or randomised clinical trials. Some failures occur when promising basic science findings fail to replicate in human studies, while others happen when promising uncontrolled trial data show an exaggerated effect that vanishes in the setting of a randomised trial. Medical reversals occur when the results of preclinical, observational and/or early phase studies fail to predict the results of subsequent randomized clinical trials, but the practice has already gained widespread acceptance. Oncologic examples include bevacizumab and the use of autologous stem cell transplant in metastatic breast cancer. In a well-intentioned effort to reduce the rate of translation failure, oncologists must be careful that changes to regulatory processes and clinical trial design do not actually work to increase the approval of ineffective compounds. By trying to cure translation failure, we should be careful to avoid medical reversal. The rise of surrogate end-points and role of hard-wired bias in oncology trials suggest that we may be currently ignoring the simple fact that translation failure and medical reversal are two sides to the same coin.

Planning and reporting of quality-of-life outcomes in cancer trials

BACKGROUND

Information about the impact of cancer treatments on patients' quality of life (QoL) is of paramount importance to patients and treating oncologists. Cancer trials that do not specify QoL as an outcome or fail to report collected QoL data, omit crucial information for decision making. To estimate the magnitude of these problems, we investigated how frequently QoL outcomes were specified in protocols of cancer trials and subsequently reported.

DESIGN

Retrospective cohort study of RCT protocols approved by six research ethics committees in Switzerland, Germany, and Canada between 2000 and 2003. We compared protocols to corresponding publications, which were identified through literature searches and investigator surveys.

RESULTS

Of the 173 cancer trials, 90 (52%) specified QoL outcomes in their protocol, 2 (1%) as primary and 88 (51%) as secondary outcome. Of the 173 trials, 35 (20%) reported QoL outcomes in a corresponding publication (4 modified from the protocol), 18 (10%) were published but failed to report QoL outcomes in the primary or a secondary publication, and 37 (21%) were not published at all. Of the 83 (48%) trials that did not specify QoL outcomes in their protocol, none subsequently reported QoL outcomes. Failure to report pre-specified QoL outcomes was not associated with industry sponsorship (versus non-industry), sample size, and multicentre (versus single centre) status but possibly with trial discontinuation.

CONCLUSIONS

About half of cancer trials specified QoL outcomes in their protocols. However, only 20% reported any QoL data in associated publications. Highly relevant information for decision making is often unavailable to patients, oncologists, and health policymakers.

Cardiovascular drug development: is it dead or just hibernating?

Despite the global burden of cardiovascular disease, investment in cardiovascular drug development has stagnated over the past 2 decades, with relative underinvestment compared with other therapeutic areas. The reasons for this trend are multifactorial, but of primary concern is the high cost of conducting cardiovascular outcome trials in the current regulatory environment that demands a direct assessment of risks and benefits, using clinically-evident cardiovascular endpoints. To work toward consensus on improving the environment for cardiovascular drug development, stakeholders from academia, industry, regulatory bodies, and government agencies convened for a think tank meeting in July 2014 in Washington, DC. This paper summarizes the proceedings of the meeting and aims to delineate the current adverse trends in cardiovascular drug development, understand the key issues that underlie these trends within the context of a recognized need for a rigorous regulatory review process, and provide potential solutions to the problems identified.

The clinical viewpoint: definitions, limitations of RECIST, practical considerations of measurement

In selecting an endpoint in clinical trial design, it is important to consider that the endpoint is both reliably measured and clinically meaningful. As such, overall survival (OS) has traditionally been considered the most clinically relevant and convincing endpoint in clinical trial design as long as it is accompanied by preservation in quality of life. However, progression-free survival (PFS) is increasingly more prominent in clinical trial design because of feasibility issues (smaller sample sizes and shorter follow-up). PFS has the advantage of taking into account not only responsive disease, but stable disease as well, an issue of particular importance in the relapsed and refractory setting in which therapies are often associated with a minimal to nil response but may still confer a survival advantage. Finally, PFS has a significant advantage in molecularly selected populations, in whom OS advantages are difficult to detect due to the effects of crossover. With an understanding of the limitations and biases that are introduced with PFS as a primary endpoint, we believe that PFS is not only a viable but also a necessary alternative to OS in assessing the efficacy of selected novel-targeted therapies in molecularly defined cancer populations. Ultimately, the selection of a clinical trial endpoint should not be based on a one-size-fits all approach; rather, it should be based on the specifics of the therapeutic strategy being tested and the population under study.

Overall survival should be the primary endpoint in clinical trials for advanced non-small-cell lung cancer

An article in a recent edition of Current Oncology explored the validation of progression-free survival (pfs) as an endpoint in clinical trials of antineoplastic agents for metastatic colorectal cancer, metastatic renal cell carcinoma, and ovarian cancer. The support for pfs as a surrogate endpoint for overall survival (os) was elucidated. As with the aforementioned tumour types, advanced non-small-cell lung cancer (nsclc) has seen a rise in active agents since the year 2000. Those agents range from improved cytotoxics such as pemetrexed, to targeted therapies such as tyrosine kinase inhibitors of the epidermal growth factor receptor and agents that target the EML4-ALK gene mutation. More recently, it has also become apparent that histology plays an important role in the response to and outcomes of treatment. With the therapeutic options for patients with advanced nsclc increasing, concerns are being raised that the efficacy of drugs measured by os may be diluted in clinical trials, thereby underestimating their true clinical benefit. That possibility, together with the need to have efficacious drugs available to patients earlier, has resulted in the search for a surrogate to the os endpoint in advanced nsclc. The present article follows up the recent article on pfs as a surrogate. Although advances in identifying pfs as a valid surrogate endpoint for os have been made in other tumour types, in advanced nsclc, such surrogacy has not been formally validated. Until it has, os should remain the primary endpoint of clinical trials in advanced nsclc.

Correlation of progression-free and post-progression survival with overall survival in advanced colorectal cancer

BACKGROUND

Polychemotherapy and biological drugs have increased therapeutic options and outcomes of advanced colorectal cancer (CRC). We examined the relation between progression-free survival (PFS), post-progression survival (PPS) and overall survival (OS) in trials of modern (oxaliplatin- and irinotecan-based) chemotherapy alone or with targeted therapies for advanced CRC. We also evaluated surrogacy of PFS and OS.

PATIENTS AND METHODS

A PubMed search identified 34 randomized trials. We split the OS, PFS and PPS and evaluated the correlation between OS and either PFS or PPS.

RESULTS

The median PPS and PFS were 10.75 and 8.4 months, respectively. For all trials, PPS was strongly associated with OS [regression coefficient (R2)=0.8; Spearman's rank correlation coefficient (r)=0.88], whereas PFS was moderately associated with OS (R2)=0.43; r=0.64). In trials with targeted therapies, the correlation of PPS with OS was 0.88. However, across all trials, correlation between differences in median PFS (ΔPFS) and median OS (ΔOS) is 0.59 (P=0.0007), confirming PFS/OS surrogacy.

CONCLUSION

Our findings indicate that in recent first-line, phase III, trials, OS becomes more associated with PPS than PFS. However, improvements in PFS are strongly associated with improvements in OS. In this setting so, PFS may be an appropriate surrogate for OS.