Why We Need a New Outcomes-Based Value Attribution Framework for Combination Regimens in Oncology.

Background: Novel oncology treatment strategies increasingly use medicines with distinct but complementary mechanisms of action in combination or in close sequence. Payers, when confronted with higher total cost of providing combination regimens involving multiple therapies and usually longer treatment durations, are reluctant to reimburse them, particularly when they perceive the expected incremental benefits from adding a new medicine (the add-on) to a currently reimbursed medicine (the backbone) not to represent value for money to the health system. Nevertheless, depending on how value is attributed to the add-on versus the backbone, a clinically effective medicine used as part of a regimen that increases treatment duration might be found "not cost-effective at zero price." This phenomenon, signaling a policy problem not a pricing issue, first needs to be better understood before a generalizable and transparent solution can be presented.

Objective: This article sets out when this policy challenge arises and describes general principles that any proposed solution to the value attribution problem must satisfy.

Methods: We develop a simplified conceptual framework and use this to address 2 topics. The first is to understand the origin of problems posed by the current approach for attributing value in incremental cost-effectiveness analyses of combination regimens. The second is to discuss 2 new approaches in the literature designed to address the challenge.

Findings: We find that neither meets our criteria, meaning that further work is needed to resolve the issue. Finally, we briefly discuss the implications of relaxing the simplifying assumptions in our conceptual framework.