Are Surrogate Endpoints Unbiased Metrics in Clinical Benefit Scores of the ASCO Value Framework?

BACKGROUND: Clinical benefit scores (CBS) are key elements of the ASCO Value Framework (ASCO-VF) and are weighted based on a hierarchy of efficacy endpoints: hazard ratio for death (HR OS), median overall survival (mOS), HR for disease progression (HR PFS), median progression-free survival (mPFS), and response rate (RR). When HR OS is unavailable, the other endpoints serve as "surrogates" to calculate CBS. CBS are computed from PFS or RR in 39.6% of randomized controlled trials. This study examined whether surrogate-derived CBS offer unbiased scoring compared with HR OS-derived CBS. METHODS: Using the ASCO-VF, CBS for advanced disease settings were computed for randomized controlled trials of oncology drug approvals by the FDA, European Medicines Agency, and Health Canada in January 2006 through December 2017. Mean differences of surrogate-derived CBS minus HR OS-derived CBS assessed the tendency of surrogate-derived CBS to overestimate or underestimate clinical benefit. Spearman's correlation evaluated the association between surrogate- and HR OS-derived CBS. Mean absolute error assessed the average difference between surrogate-derived CBS relative to HR OS-derived CBS. RESULTS: CBS derived from mOS, HR PFS, mPFS, and RR overestimated HR OS-derived CBS in 58%, 68%, 77%, and 55% of pairs and overall by an average of 5.62 (n=90), 6.86 (n=110), 29.81 (n=101), and 3.58 (n=108), respectively. Correlation coefficients were 0.80 (95% CI, 0.70-0.86), 0.38 (0.20-0.53), 0.20 (0.00-0.38), and 0.01 (-0.18 to 0.19) for mOS-, HR PFS-, mPFS-, and RR-derived CBS, respectively, and mean absolute errors were 11.32, 12.34, 40.40, and 18.63, respectively. CONCLUSIONS: Based on the ASCO-VF algorithm, HR PFS-, mPFS-, and RR-derived CBS are suboptimal surrogates, because they were shown to be biased and poorly correlated to HR OS-derived CBS. Despite lower weighting than OS in the ASCO-VF algorithm, PFS still overestimated CBS. Simple rescaling of surrogate endpoints may not improve their validity within the ASCO-VF given their poor correlations with HR OS-derived CBS.

Do older and younger patients derive similar survival benefits from novel oncology drugs? A systematic review and meta-analysis.

Background: older patients are commonly believed to derive less benefit from cancer drugs, even if they fulfil clinical trial eligibility [Talarico et al. (2004, J Clin Oncol, 22(22):4626-31)]. We aim to examine if novel oncology drugs provide differential age-based treatment outcomes for patients on clinical trials. Methods: a systematic review of randomised control trials (RCTs) cited for clinical efficacy evidence in novel oncology drug approvals by the Food and Drug Administration, European Medicines Agency and Health Canada between 2006 and 2017 was conducted. Studies reporting age-based subgroup analyses for overall or progression-free survival (OS/PFS) were included. Hazard ratios (HRs) and confidence intervals (CIs) for age-based subgroups were extracted. Meta-analyses with random effects were conducted, examining patient subgroups <65 and ≥65 years separately and pooled HRs of studies primary endpoints (OS or PFS) compared to examine if differences existed between age-based subgroups. Sensitivity analyses were conducted for cancer type, primary endpoint and systemic treatment. Results: one-hundred-two RCTs, including 65,122 patients, met the inclusion criteria. One study reported age-based toxicity and none reported age-based quality of life (QOL) results. Pooled HRs [95% CIs] for patients <65 and ≥65 years were 0.61 [0.57-0.65] and 0.65 [0.61-0.70], respectively, with no difference between them (P = 0.14). Sensitivity analyses revealed similar results. Conclusion: our results suggest that older and young patients, who fulfil clinical trial eligibility, may derive similar relative survival benefits from novel oncology drugs. There is, however, a need to report age-based toxicity and QOL results to support patient discussions regarding the balance of treatment benefit and harm, to encourage informed decision-making.

Pembrolizumab alone or with chemotherapy for metastatic non-small-cell lung cancer: A systematic review and network meta-analysis.

Pembrolizumab monotherapy has replaced chemotherapy as first-line treatment for patients with metastatic non-small-cell lung cancer with tumor programmed death-ligand 1 expression ≥ 50%. The benefit of chemotherapy combined with pembrolizumab, as compared to pembrolizumab monotherapy, remains uncertain. This systematic review and network meta-analysis aimed to compare these therapies through a network of randomized controlled trials. Endpoints evaluated were progression-free survival (PFS) and overall survival (OS) expressed as hazard ratio (HR) and restricted mean survival time (RMST) through reconstruction of individual patient data from Kaplan-Meier curves, and objective response rate and adverse events. Four trials were included. Through HR and RMST, combination therapy demonstrated longer PFS and similar OS as compared to pembrolizumab monotherapy. Combination therapy was associated with an increase in response rate and adverse events. Thus, combination therapy can be considered when rapid response or prevention of rapid progression is needed. Further evidence to directly compare these therapies is required.

Examining Trends in Cost and Clinical Benefit of Novel Anticancer Drugs Over Time.

PURPOSE: The purpose of this study was to determine if clinical benefits of novel anticancer drugs, measured by the ASCO Value Framework and European Society of Medical Oncology (ESMO) Magnitude of Clinical Benefit Scale, have increased over time in parallel with increasing costs. METHODS: Anticancer drugs from phase III randomized controlled trials cited for clinical efficacy evidence in drug approvals between January 2006 to December 2015 were identified and scored using both frameworks. For each drug, the monthly price and incremental anticancer drug costs were calculated. Relationships between cost and year of approval were examined using generalized linear regressions models. Ordinary least square models were used to evaluate relationships between ASCO and ESMO scores and year of approval. Spearman correlation coefficients between costs and clinical benefit scores were calculated. RESULTS: In total, 42 randomized controlled trials were included. Both monthly prices and incremental anticancer drug costs were significantly associated with year of approval and showed an average annual increase of 9% and 21%, respectively. The predicted mean incremental anticancer drug cost increased from $30,447 in 2006 to $161,141 in 2015 (greater than five-fold increase). Both ASCO and ESMO scores were not statistically associated with year of approval or correlated with monthly prices or incremental anticancer drug costs. CONCLUSION: Over the past decade, costs of novel oncology drugs have increased, while clinical benefits of these medications have not experienced a proportional positive change. The incremental anticancer drug costs have increased at a much greater rate than monthly prices, indicating that the increase in anticancer drug costs may be higher than commonly reported.

Do the American Society of Clinical Oncology Value Framework and the European Society of Medical Oncology Magnitude of Clinical Benefit Scale Measure the Same Construct of Clinical Benefit?

Purpose Whether the ASCO Value Framework and the European Society for Medical Oncology (ESMO) Magnitude of Clinical Benefit Scale (MCBS) measure similar constructs of clinical benefit is unclear. It is also unclear how they relate to quality-adjusted life-years (QALYs) and funding recommendations in the United Kingdom and Canada. Methods Randomized clinical trials of oncology drug approvals by the US Food and Drug Administration, European Medicines Agency, and Health Canada between 2006 and August 2015 were identified and scored using the ASCO version 1 (v1) framework, ASCO version 2 (v2) framework, and ESMO-MCBS by at least two independent reviewers. Spearman correlation coefficients were calculated to assess construct (between frameworks) and criterion validity (against QALYs from the National Institute for Health and Care Excellence [NICE] and the pan-Canadian Oncology Drug Review [pCODR]). Associations between scores and NICE/pCODR recommendations were examined. Inter-rater reliability was assessed using intraclass correlation coefficients. Results From 109 included randomized clinical trials, 108 ASCOv1, 111 ASCOv2, and 83 ESMO scores were determined. Correlation coefficients for ASCOv1 versus ESMO, ASCOv2 versus ESMO, and ASCOv1 versus ASCOv2 were 0.36 (95% CI, 0.15 to 0.54), 0.17 (95% CI, -0.06 to 0.37), and 0.50 (95% CI, 0.35 to 0.63), respectively. Compared with NICE QALYs, correlation coefficients were 0.45 (ASCOv1), 0.53 (ASCOv2), and 0.46 (ESMO); with pCODR QALYs, coefficients were 0.19 (ASCOv1), 0.20 (ASCOv2), and 0.36 (ESMO). None of the frameworks were significantly associated with NICE/pCODR recommendations. Inter-rater reliability was good for all frameworks. Conclusion The weak-to-moderate correlations of the ASCO frameworks with the ESMO-MCBS, as well as their correlations with QALYs and with NICE/pCODR funding recommendations, suggest different constructs of clinical benefit measured. Construct convergent validity with the ESMO-MCBS did not increase with the updated ASCO framework.