Exploring the feasibility of using the ICER Evidence Rating Matrix for Comparative Clinical Effectiveness in assessing treatment benefit and certainty in the clinical evidence on orphan therapies for paediatric indications

Abstract

Background: The evaluation of clinical evidence takes account of health benefit (efficacy and safety) and the degree of certainty in the estimate of benefit. In orphan indications practical and ethical challenges in conducting clinical trials, particularly in paediatric patients, often limit the available evidence, rendering structured evaluation challenging. While acknowledging the paucity of evidence, regulators and reimbursement authorities compare the efficacy and safety of alternative treatments for a given indication, often in the context of the benefits of other treatments for similar or different conditions. This study explores the feasibility of using the Institute for Clinical and Economic Review (ICER) Evidence Rating Matrix for Comparative Clinical Effectiveness in structured assessment of both the magnitude of clinical benefit (net health benefit, NHB) and the certainty of the effect estimate in a sample of orphan therapies for paediatric indications.

Results: Eleven systemic therapies with European Medicines Agency (EMA) orphan medicinal product designation, licensed for 16 paediatric indications between January 2017 and March 2020 were identified using OrphaNet and EMA databases and were selected for evaluation with the ICER Evidence Rating Matrix: burosumab; cannabidiol; cerliponase alfa; chenodeoxycholic acid (CDCA); dinutuximab beta; glibenclamide; metreleptin; nusinersen; tisagenlecleucel; velmanase alfa; and vestronidase alfa. EMA European Public Assessment Reports, PubMed, EMBASE, the Cochrane Library, Clinical Key, and conference presentations from January 2016 to April 2021 were searched for evidence on efficacy and safety. Two of the identified therapies were graded as "substantial" NHB: dinutuximab beta (neuroblastoma maintenance) and nusinersen (Type I SMA), and one as "comparable" NHB (CDCA). The NHB grade of the remaining therapies fell between "comparable" and "substantial". No therapies were graded as having negative NHB. The certainty of the estimate ranged from "high" (dinutuximab beta in neuroblastoma maintenance) to "low" (CDCA, metreleptin and vestronidase alfa). The certainty of the other therapies was graded between "low" and "high". The ICER Evidence Rating Matrix overall rating "A" (the highest) was given to two therapies, "B+" to 6 therapies, "C+" to five therapies, and "I" (the lowest) to three therapies. The scores varied between rating authors with mean agreement over all indications of 71.9% for NHB, 56.3% for certainty and 68.8% for the overall rating.

Conclusions: Using the ICER Matrix to grade orphan therapies according to their treatment benefit and certainty is feasible. However, the assessment involves subjective judgements based on heterogenous evidence. Tools such as the ICER Matrix might aid decision makers to evaluate treatment benefit and its certainty when comparing therapies across indications.

Keywords: Assessment framework; Effect size; Health benefit; Orphan drugs; Paediatric population; Quality of evidence; Rare diseases; Uncertainty of estimate.