As the variety of specific treatments in a disease area increases, there may be a growing interest in employing treatment sequencing within health economic models. The aim of this review was to identify and thematically analyze patterns regarding the approaches to modeling treatment sequencing in National Institute for Health and Care Excellence (NICE) appraisals.

A review of NICE technology appraisals (TAs) published between 1 January 2020 and 13 March 2023 was conducted.

A total of twenty-four TAs incorporating treatment sequencing were included, most commonly in autoimmune and oncology indications. Primary justifications for companies employing treatment sequencing were precedence and alignment with clinical practice, whilst lack of appropriate clinical data was cited to justify its exclusion. Relatedly, External Assessment Groups commonly criticized treatment sequences for oversimplifying clinical practice. Notably, almost half of identified TAs assumed that the relative efficacy of an intervention was maintained regardless of disease severity or position within the treatment sequence.

A substantial proportion of TAs employed treatment sequencing, but it is challenging to determine the impact of current approaches on the overall uncertainty associated with any health economic model. The challenges identified in this review could be used to inform future formal guidance and associated methodology for the implementation of treatment sequencing modeling, which could improve the comparability and reliability of models and their results.