How Have Canada's Drug Agency Guidelines Impacted Choice of Model Structure and Use of Partitioned Survival Models in Oncology Submissions?
Author(s)
Chloi Theriou, MSc1, Eesha Kodi, MPH2, Alicia N. Pepper, PhD2;
1Precision AQ, London, United Kingdom, 2Precision AQ, Vancouver, BC, Canada
1Precision AQ, London, United Kingdom, 2Precision AQ, Vancouver, BC, Canada
Presentation Documents
OBJECTIVES: In May 2023 Canada’s Drug Agency (CDA) issued methods guidelines for extrapolating clinical evidence within economic evaluations. Within these guidelines, CDA stated that partitioned survival models (PSMs) were not recommended given the assumption of independence between progression-free survival (PFS) and overall survival (OS). The objective of this study was to assess the impact of these guidelines on choice of model structure submitted, acceptance and critiques from CDA, and the impact of reimbursement recommendations.
METHODS: We reviewed all sponsored submissions to CDA across oncology indications submitted after May 2023. Only submissions with a recommendation available were reviewed. Data were extracted for the intervention, indication, line of therapy, model type, CDA’s assessment of model structure including noted limitations, and the reimbursement recommendation.
RESULTS: Twenty-seven oncology submissions with recommendations were identified (December 2024). Of these, 19 were PSMs, 5 were Markov/semi-Markov, and 3 were cost-minimization analyses. For adjuvant indications (N=3), PSM was not used; however, for other indications, including first or later lines for advanced disease, the PSM was predominantly used. Among PSMs with completed reports, the structure was deemed adequate in over half the submissions, suggesting variability across reviewers. In those submissions where the PSM structure was deemed inadequate, reviewers noted limitations such as structural assumptions about the relationship between PFS/OS, inability to capture causal relationships between patient characteristics and probability of events, and not capturing response to subsequent lines of therapy. All submissions received positive recommendations with clinical criteria and/or conditions.
CONCLUSIONS: To date, the new guidance has not impacted the manufacturer’s choice of model structure or CDA’s recommendations in oncology. PSM continues to be the model structure of choice outside of adjuvant indications. Even when the choice of PSM was critiqued by reviewers, it was not associated with any negative recommendations.
METHODS: We reviewed all sponsored submissions to CDA across oncology indications submitted after May 2023. Only submissions with a recommendation available were reviewed. Data were extracted for the intervention, indication, line of therapy, model type, CDA’s assessment of model structure including noted limitations, and the reimbursement recommendation.
RESULTS: Twenty-seven oncology submissions with recommendations were identified (December 2024). Of these, 19 were PSMs, 5 were Markov/semi-Markov, and 3 were cost-minimization analyses. For adjuvant indications (N=3), PSM was not used; however, for other indications, including first or later lines for advanced disease, the PSM was predominantly used. Among PSMs with completed reports, the structure was deemed adequate in over half the submissions, suggesting variability across reviewers. In those submissions where the PSM structure was deemed inadequate, reviewers noted limitations such as structural assumptions about the relationship between PFS/OS, inability to capture causal relationships between patient characteristics and probability of events, and not capturing response to subsequent lines of therapy. All submissions received positive recommendations with clinical criteria and/or conditions.
CONCLUSIONS: To date, the new guidance has not impacted the manufacturer’s choice of model structure or CDA’s recommendations in oncology. PSM continues to be the model structure of choice outside of adjuvant indications. Even when the choice of PSM was critiqued by reviewers, it was not associated with any negative recommendations.
Conference/Value in Health Info
2025-05, ISPOR 2025, Montréal, Quebec, CA
Value in Health, Volume 28, Issue S1
Code
HTA27
Topic
Health Technology Assessment
Topic Subcategory
Systems & Structure
Disease
No Additional Disease & Conditions/Specialized Treatment Areas, SDC: Oncology