Comprehensive Review of Methods to Assess Uncertainty in Health Economic Evaluations

Bring Out Your Dead: A Review of the Cost Minimisation Approach in Health Technology Assessment Submissions to the Australian Pharmaceutical Benefits Advisory Committee

OBJECTIVES

Published literature has levied criticism against the cost-minimisation analysis (CMA) approach to economic evaluation over the past two decades, with multiple papers declaring its 'death'. However, since introducing the requirements for economic evaluations as part of health technology (HTA) decision-making in 1992, the cost-minimisation analysis (CMA) approach has been widely used to inform recommendations about the public subsidy of medicines in Australia. This research aimed to highlight the breadth of use of CMA in Australia and assess the influence of preconditions for the approach on subsidy recommendations METHODS: Relevant information was extracted from Public Summary Documents of Pharmaceutical Benefits Advisory Committee (PBAC) meetings in Australia considering submissions for the subsidy of medicines that included a CMA and were assessed between July 2005 and December 2022. A generalised linear model was used to explore the relationship between whether medicines were recommended and variables that reflected the primary preconditions for using CMA set out in the published PBAC Methodology Guidelines. Other control variables were selected through the Bolasso Method. Subgroup analysis was undertaken which replicated this modelling process.

RESULTS

While the potential for inferior safety or efficacy reduced the likelihood of recommendation (p < 0.01), the effect sizes suggest that the requirements for CMA were not requisite for recommendation.

CONCLUSION

The Australian practice of CMA does not strictly align with the PBAC Methodology Guidelines and the theoretically appropriate application of CMA. However, within the confines of a deliberative HTA decision-making process that balances values and judgement with available evidence, this may be considered acceptable, particularly if stakeholders consider the current approach delivers sufficient clarity of process and enables patients to access medicines at an affordable cost.

Estimating the Potential Benefits of Confirmatory Trials for Drugs with Accelerated Approval: A Comprehensive Value of Information Framework

BACKGROUND

The US Food and Drug Administration's Accelerated Approval (AA) policy provides a pathway for patients to access potentially life-saving drugs rapidly. However, the use of surrogate endpoints, single-arm designs, and small sample sizes in preliminary trials that support AAs can lead to uncertainty regarding the clinical benefits of such drugs. This study aims to develop a comprehensive value of information (VOI) framework for assessing the potential benefits of future confirmatory trials, accounting for the various uncertainties inherent in preliminary trials.

METHODS

I formulated an expected value of information from confirmatory trial (EVICT) metric, which evaluates the potential benefits of a confirmatory trial that would reduce those uncertainties by using a clinically meaningful endpoint, a randomized control, and increased sample size. The EVICT metric can quantify the expected benefits of a well-designed confirmatory trial or an inadequately designed one that continues to use surrogate endpoints or single-arm design. The framework was illustrated using a hypothetical AA drug for metastatic breast cancer.

RESULTS

The case study demonstrates that a highly uncertain preliminary trial of an AA drug was associated with a substantial EVICT. A confirmatory trial with an increased sample size for this AA drug, utilizing a clinically meaningful endpoint and randomized control, yielded a population-level EVICT of $12.6 million. Persistently using a surrogate endpoint and single-arm trial design would reduce the EVICT by 60%.

CONCLUSIONS

This framework can provide accurate VOI estimates to guide coverage policies, value-based pricing, and the design of confirmatory trials for AA drugs.