Malone DC, Dean R, Miller B, Arjunji R, Feltner DE, Sproule D, Jensen IS, Maru B, Dabbous O. 2019. Abstract ND2: Cost-utility analysis of single dose gene-replacement therapy for spinal muscular atrophy type 1 compared to chronic nusinersen treatment. Value in Health 22(Sup 2):S42-S43; doi: 10.1016/j.jval.2019.04.060.
Abstract
Objectives: To assess the incremental cost-effectiveness ratio (ICER) of investigational single-dose gene-replacement therapy AVXS-101 (onasemnogene abeparvovec) vs. the current standard of care (nusinersen) in patients with Spinal Muscular Atrophy Type 1 (SMA 1) in the United States. Methods: We developed a multi-state survival Markov model over a lifetime. Health state transitions were based on milestone attainment (sitting, walking) from published clinical trials. Survival benefit was estimated using long-term survival data from sitting and walking SMA patients and natural history data. Costs related to drug acquisition and administration, expected hospital markups, adverse events and SMA care were sourced from published claims analysis data, literature, and expert opinion. Utilities were from a published study of type 2 SMA patients using nusinersen. Results: Undiscounted total quality-adjusted life-years (QALYs) per patient were 30.3 for AVXS-101 and 7.2 for nusinersen (if discounted at 3%: 15.9 and 5.3 respectively). Estimated discounted lifetime costs were $6.33M for nusinersen. Lifetime discounted costs for AVXS-101 at hypothetical price points from $2M to $3M per dose ranged from $3.7M to $4.7M per patient, resulting in cost savings and QALY gains compared to nusinersen; i.e., AVXS-101 was dominant over nusinersen. In a scenario where sitting gene therapy patients experienced survival trajectory of walking patients, AVXS-101 undiscounted QALYs were 57.5 (if discounted at 3%: 21.9) and AVXS-101 again dominated nusinersen at a price of $3M. Conclusions: AVXS-101 is cost-effective compared to nusinersen and may deliver up to 57.5 QALYs (undiscounted). Discounting QALYs at the US standard rate of 3% results in a substantial underestimate of health benefits. Decision makers such as NICE consider undiscounted QALY gain in certain cases. We recommend that US-based decision makers also consider undiscounted QALY gain when assessing the value of innovative therapies.
