Onwards and Upwards: A Systematic Survey of Economic Evaluation Methods in Oncology

A Systematic Review of Modeling Approaches to Evaluate Treatments for Relapsed Refractory Multiple Myeloma: Critical Review and Considerations for Future Health Economic Models

BACKGROUND AND OBJECTIVE

Multiple myeloma is a rare incurable hematological cancer in which most patients relapse or become refractory to treatment. This systematic literature review aimed to critically review the existing economic models used in economic evaluations of systemic treatments for relapsed/refractory multiple myeloma and to summarize how the models addressed differences in the line of therapy and exposure to prior treatment.

METHODS

Following a pre-approved protocol, literature searches were conducted on 17 February, 2023, in relevant databases for models published since 2014. Additionally, key health technology assessment agency websites were manually searched for models published as part of submission dossiers since 2018. Reported information related to model conceptualization, structure, uncertainty, validation, and transparency were extracted into a pre-defined extraction sheet.

RESULTS

In total, 49 models assessing a wide range of interventions across multiple lines of therapy were included. Only five models specific to heavily pre-treated patients and/or those who were refractory to multiple treatment classes were identified. Most models followed a conventional simple methodology, such as partitioned survival (n = 28) or Markov models (n = 9). All included models evaluated specific interventions rather than the whole treatment sequence. Where subsequent therapies were included in the model, these were generally only considered from a cost and resource use perspective. The models generally used overall and progression-free survival as model inputs, although data were often immature. Sensitivity analyses were frequently reported (n = 41) whereas validation was only considered in less than half (n = 19) of the models.

CONCLUSIONS

Published economic models in relapsed/refractory multiple myeloma rarely followed an individual patient approach, mainly owing to the higher need for complex data assumptions compared with simpler modeling approaches. As many patients experience disease progression on multiple treatment lines, there is a growing need for modeling complex treatment strategies, leading to more sophisticated approaches in the future. Maintaining transparency, high reporting standards, and thorough analyses of uncertainty are crucial to support these advancements.

Cost-effectiveness analysis of 7 treatments in metastatic hormone-sensitive prostate cancer: a public-payer perspective

BACKGROUND

Recently, several new treatment regimens have been approved for treating metastatic hormone-sensitive prostate cancer, building on androgen deprivation therapy alone. These include docetaxel androgen deprivation therapy, abiraterone acetate-prednisone androgen deprivation therapy, apalutamide androgen deprivation therapy, enzalutamide androgen deprivation therapy, darolutamide-docetaxel androgen deprivation therapy, and abiraterone-prednisone androgen deprivation therapy with docetaxel. There are no validated predictive biomarkers for choosing a specific regimen. The goal of this study was to conduct a health economic outcome evaluation to determine the optimal treatment from the US public sector (Veterans Affairs).

METHODS

We developed a partitioned survival model in which metastatic hormone-sensitive prostate cancer patients transitioned between 3 health states (progression free, progressive disease to castrate resistance state, and death) at monthly intervals based on Weibull survival model estimated from published Kaplan-Meier curves using a Bayesian network meta-analysis of 7 clinical trials (7208 patients). The effectiveness outcome in our model was quality-adjusted life-years (QALYs). Cost input parameters included initial and subsequent treatment costs and costs for terminal care and for managing grade 3 or higher drug-related adverse events and were obtained from the Federal Supply Schedule and published literature.

RESULTS

Average 10-year costs ranged from $34 349 (androgen deprivation therapy) to $658 928 (darolutamide-docetaxel androgen deprivation therapy) and mean QALYs ranged from 3.25 (androgen deprivation therapy) to 4.57 (enzalutamide androgen deprivation therapy). Treatment strategies docetaxel androgen deprivation therapy, enzalutamide androgen deprivation therapy docetaxel, apalutamide androgen deprivation therapy, and darolutamide-docetaxel androgen deprivation therapy were eliminated because of dominance (ie, they were more costly and less effective than other strategies). Of the remaining strategies, abiraterone acetate-prednisone androgen deprivation therapy was the most cost-effective strategy at a willingness-to-pay threshold of $100 000/QALY (incremental cost-effectiveness ratios = $21 247/QALY).

CONCLUSIONS

Our simulation model found abiraterone acetate-prednisone androgen deprivation therapy to be an optimal first-line treatment for metastatic hormone-sensitive prostate cancer from a public (Veterans Affairs) payer perspective.

Blended Survival Curves: A New Approach to Extrapolation for Time-to-Event Outcomes from Clinical Trials in Health Technology Assessment

BACKGROUND

Survival extrapolation is essential in cost-effectiveness analysis to quantify the lifetime survival benefit associated with a new intervention, due to the restricted duration of randomized controlled trials (RCTs). Current approaches of extrapolation often assume that the treatment effect observed in the trial can continue indefinitely, which is unrealistic and may have a huge impact on decisions for resource allocation.

OBJECTIVE

We introduce a novel methodology as a possible solution to alleviate the problem of survival extrapolation with heavily censored data from clinical trials.

METHOD

The main idea is to mix a flexible model (e.g., Cox semiparametric) to fit as well as possible the observed data and a parametric model encoding assumptions on the expected behavior of underlying long-term survival. The two are "blended" into a single survival curve that is identical with the Cox model over the range of observed times and gradually approaching the parametric model over the extrapolation period based on a weight function. The weight function regulates the way two survival curves are blended, determining how the internal and external sources contribute to the estimated survival over time.

RESULTS

A 4-y follow-up RCT of rituximab in combination with fludarabine and cyclophosphamide versus fludarabine and cyclophosphamide alone for the first-line treatment of chronic lymphocytic leukemia is used to illustrate the method.

CONCLUSION

Long-term extrapolation from immature trial data may lead to significantly different estimates with various modelling assumptions. The blending approach provides sufficient flexibility, allowing a wide range of plausible scenarios to be considered as well as the inclusion of external information, based, for example, on hard data or expert opinion. Both internal and external validity can be carefully examined.

HIGHLIGHTS

Interim analyses of trials with limited follow-up are often subject to high degrees of administrative censoring, which may result in implausible long-term extrapolations using standard approaches.In this article, we present an innovative methodology based on "blending" survival curves to relax the traditional proportional hazard assumption and simultaneously incorporate external information to guide the extrapolation.The blended method provides a simple and powerful framework to allow a careful consideration of a wide range of plausible scenarios, accounting for model fit to the short-term data as well as the plausibility of long-term extrapolations.

Cost-Effectiveness Analysis of Six Immunotherapy-Based Regimens and Sunitinib in Metastatic Renal Cell Carcinoma: A Public Payer Perspective

PURPOSE

Several new treatment combinations have been approved in metastatic renal cell carcinoma (mRCC). To determine the optimal therapy on the basis of cost and health outcomes, we performed a cost-effectiveness analysis of approved immunotherapy-tyrosine kinase inhibitor/immunotherapy drug combinations and sunitinib using public payer acquisition costs in the United States.

METHODS

We constructed a decision model with a 10-year time horizon. The seven treatment drug strategies included atezolizumab + bevacizumab, avelumab + axitinib, pembrolizumab + axitinib, nivolumab + ipilimumab (NI), nivolumab + cabozantinib, lenvatinib + pembrolizumab, and sunitinib. The effectiveness outcome in our model was quality-adjusted life-years (QALYs) with utility values on the basis of the published literature. Costs included drug acquisition costs and costs for management of grade 3-4 drug-related adverse events. We used a partitioned survival model in which patients with mRCC transitioned between three health states (progression-free, progressive disease, and death) at monthly intervals on the basis of parametric survival function estimated from published survival curves. To determine cost-effectiveness, we constructed incremental cost-effectiveness ratios (ICERs) by dividing the difference in cost by the difference in effectiveness between nondominated treatments.

RESULTS

The least expensive treatment was sunitinib ($357,948 US dollars [USD]-$656,100 USD), whereas the most expensive was either lenvatinib + pembrolizumab or pembrolizumab + axitinib ($959,302 USD-$1,403,671 USD). NI yielded the most QALYs (3.6), whereas avelumab + axitinib yielded the least (2.5). NI had an incremental ICER of $297,465 USD-$348,516 USD compared with sunitinib. In sensitivity analyses, this ICER fell below $150,000 USD/QALY if the initial 4-month cost of NI decreased by 22%-38%.

CONCLUSION

NI was the most effective combination for mRCC, but at a willingness-to-pay threshold of $150,000 USD/QALY, sunitinib was the most cost-effective approach.

Appraisals by Health Technology Assessment Agencies of Economic Evaluations Submitted as Part of Reimbursement Dossiers for Oncology Treatments: Evidence from Canada, the UK, and Australia

Publicly funded healthcare systems, including those in Canada, the United Kingdom (UK), and Australia, often use health technology assessment (HTA) to inform drug reimbursement decision-making, based on dossiers submitted by manufacturers, and HTA agencies issue publicly available reports to support funding recommendations. However, the level of information reported by HTA agencies in these reports may vary. To provide insights on this issue, we describe and assess the reporting of economic methods in recent oncology HTA recommendations from the Canadian Agency for Drugs and Technologies in Health (CADTH), National Institute for Health and Care Excellence (NICE), and Pharmaceutical Benefits Advisory Committee (PBAC). Publicly available HTA recommendations and reports for oncology drugs issued by CADTH over a 2-year period, 2019-2020, were identified and compared with the corresponding HTA documents from NICE and the PBAC. Reporting of key model characteristics and attributes, survival analysis methods, methodological criticisms, and re-assessment of the economic results were characterized using descriptive statistics. Dichotomous differences in the methodological criticisms observed between the three agencies were assessed using Cochran's Q tests and substantiated using pairwise McNemar tests. Chi-squared tests were used to assess the dichotomous differences in the reporting of methods and explore the potential relationships between categorical variables, where appropriate. HTAs published by CADTH, NICE, and the PBAC consistently reported a broad spectrum of descriptive information on the economic models submitted by manufacturers. While common economic evaluation attributes were well-reported across the three HTA agencies, significant differences in the reporting of survival analysis methods and methodological criticisms were observed. NICE consistently reported more comprehensive information, compared to either CADTH or PBAC. Despite these differences, broadly similar recommendation rates were observed between CADTH and NICE. The PBAC was found to be more restrictive. Based on our 2-year sample of oncology, the HTAs published by CADTH matched with the corresponding HTAs from NICE and PBAC; we observed important variations in the reporting of economic evidence, especially technical aspects, such as survival analysis, across the three agencies. In addition to guidelines for HTA submissions by manufacturers, the community of HTA agencies should also have common standards for reporting the results of their assessments, though the information and opinions reported may differ.

Cost-effectiveness analysis of nivolumab combination therapy in the first-line treatment for advanced esophageal squamous-cell carcinoma

Objective

We aimed to investigate the cost-effectiveness of nivolumab plus chemotherapy and nivolumab plus ipilimumab versus chemotherapy in the first-line treatment for advanced esophageal squamous-cell carcinoma (ESCC) patients from a healthcare system perspective in China.

Methods

On the basis of the CheckMate 648 trial, a partitioned survival model was constructed to estimate economic costs and health outcomes among overall and PD-L1-positive advanced ESCC patients over a 10-year lifetime horizon. The health-related costs and utilities were obtained from the local charges and published literature. The lifetime costs, life-years, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER) were measured. One-way and probabilistic sensitivity analyses (PSA) were performed to assess the robustness of the model.

Results

In the base-case analysis, in overall and PD-L1-positive advanced ESCC patients, the ICERs were $415,163.81/QALY and $216,628.00/QALY for nivolumab plus chemotherapy, and$430,704.11/QALY and $185,483.94/QALY for nivolumab plus ipilimumab, respectively, compared with chemotherapy. One-way sensitivity analyses revealed that patients’ weight was the most influential parameter on ICER. The PSA demonstrated that the probability of nivolumab combination therapy being cost-effective was 0% over chemotherapy at the current price and willingness-to-pay threshold ($38,351.20/QALY). When the price of nivolumab and ipilimumab decreased 80%, the cost-effective probability of nivolumab plus ipilimumab increased to 40.44% and 86.38% in overall and PD-L1-positive advanced ESCC patients, respectively.

Conclusion

Nivolumab combination therapy could improve survival time and health benefits over chemotherapy for advanced ESCC patients, but it is unlikely to be a cost-effective treatment option in China.