The Impact of Family Spillover Effects in Economic Evaluation for SMA Type 1 Treatments in the United States
Author(s)
Stacey Kowal, BS, MSc1, Alexandra Paffrath, MSc, PharmD2, Benjamin Cohen, MPH, PhD3, Sheila Shapouri, MS, PharmD4, Robert Brett McQueen, BA, MA, PhD5.
1Principal, Genentech, Alameda, CA, USA, 2Lumanity, St Paul, MN, USA, 3Stage Analytics, Denver, CO, USA, 4Genentech, Inc, South San Francisco, CA, USA, 5University of Colorado, Denver, CO, USA.
1Principal, Genentech, Alameda, CA, USA, 2Lumanity, St Paul, MN, USA, 3Stage Analytics, Denver, CO, USA, 4Genentech, Inc, South San Francisco, CA, USA, 5University of Colorado, Denver, CO, USA.
Presentation Documents
OBJECTIVES: Family spillover effects (FSE) are an important component of economic evaluations that are not routinely included. We evaluated the impact of including FSE for informal caregivers in a cost-effectiveness analysis (CEA) of treatments for spinal muscular atrophy (SMA) Type 1.
METHODS: A lifetime CEA, aligned to a published 2019 SMA assessment, was developed to evaluate FSE impacts. All non-treatment direct medical costs were based on the previous assessment, inflated to 2024 USD. A hypothetical comparator was created to reflect the weighted average clinical outcomes and wholesale acquisition costs of three available SMA type 1 treatments (Spinraza, Zolgensma, Evrysdi) using efficacy data from a published matching-adjusted indirect treatment comparison and real-world utilization patterns. FSE estimates for primary informal caregivers were estimated across patient motor function milestones, per published health-related quality of life (HRQoL) data and productivity costs estimated via a published algorithm. FSE quality-adjusted life years (QALY) and productivity costs were added to patient outcomes. Drivers of results were explored through sensitivity analyses.
RESULTS: With FSE excluded, the lifetime incremental cost-effectiveness ratio (ICER) for the hypothetical treatment was $1,066,300 (incremental $4,863,476 costs and 4.56 QALYs). When HRQoL and productivity FSE were added, the ICER reduced to $572,520 (incremental $5,062,221 and 8.84 QALYs). ICER changes were primarily driven by caregiver HRQoL improvements given low caregiver utility associated with caring for not sitting (0.484) or sitting (0.628) patients. All scenarios including FSE led to reductions in the ICER and were most sensitive to caregiver utility and treatment efficacy assumptions.
CONCLUSIONS: The addition of FSE for primary informal caregivers of children with SMA Type 1 led to a projected 54% reduction in the base-case ICER. Future CEAs should explore FSE using available caregiver data and productivity algorithms to estimate treatment impacts and value for the family.
METHODS: A lifetime CEA, aligned to a published 2019 SMA assessment, was developed to evaluate FSE impacts. All non-treatment direct medical costs were based on the previous assessment, inflated to 2024 USD. A hypothetical comparator was created to reflect the weighted average clinical outcomes and wholesale acquisition costs of three available SMA type 1 treatments (Spinraza, Zolgensma, Evrysdi) using efficacy data from a published matching-adjusted indirect treatment comparison and real-world utilization patterns. FSE estimates for primary informal caregivers were estimated across patient motor function milestones, per published health-related quality of life (HRQoL) data and productivity costs estimated via a published algorithm. FSE quality-adjusted life years (QALY) and productivity costs were added to patient outcomes. Drivers of results were explored through sensitivity analyses.
RESULTS: With FSE excluded, the lifetime incremental cost-effectiveness ratio (ICER) for the hypothetical treatment was $1,066,300 (incremental $4,863,476 costs and 4.56 QALYs). When HRQoL and productivity FSE were added, the ICER reduced to $572,520 (incremental $5,062,221 and 8.84 QALYs). ICER changes were primarily driven by caregiver HRQoL improvements given low caregiver utility associated with caring for not sitting (0.484) or sitting (0.628) patients. All scenarios including FSE led to reductions in the ICER and were most sensitive to caregiver utility and treatment efficacy assumptions.
CONCLUSIONS: The addition of FSE for primary informal caregivers of children with SMA Type 1 led to a projected 54% reduction in the base-case ICER. Future CEAs should explore FSE using available caregiver data and productivity algorithms to estimate treatment impacts and value for the family.
Conference/Value in Health Info
2025-05, ISPOR 2025, Montréal, Quebec, CA
Value in Health, Volume 28, Issue S1
Code
EE201
Topic
Economic Evaluation
Topic Subcategory
Novel & Social Elements of Value
Disease
SDC: Rare & Orphan Diseases