Economic evaluation of six and 12 month (m) treatment with isatuximab and carfilzomib and dexamethasone (IKd) versus daratumumab and carfilzomib and dexamethasone (DKd) in patients with relapsed or refractory multiple myeloma (RRMM).

Abstract

e20010 Background: Isatuximab and daratumumab target the CD38 transmembrane glycoprotein on MM cells. IKd and DKd regimens have shown reductions of HR=0.53 (95%CI 0.32-0.89) and HR=0.63 (95%CI 0.46-0.85) resp. in progression or death risk compared to Kd in RRMM. In the absence of a direct IKd vs DKd trial, we performed an indirect treatment comparison on progression free survival (PFS) to enable cost-effectiveness analyses. Methods: A 3-state (pre-progression, progression, death) partitioned survival model was specified. NMA-adjusted transition probabilities were estimated from fitted exponential functions (time horizon of 6 and 12 m; cycle length 28 days). Inputs included the Wholesale Acquisition Cost of IKd, DKd, and premedications; cost of medication administration; and cost of adverse event management. Utility inputs for pre-progression (0.65) and progression (0.61) were per literature. Costs and utilities were discounted at 3.5%/y. A payer perspective was adopted. Life years (LY), quality adjusted LY (QALY), and incremental cost-effectiveness (ICER) and cost-utility ratios (ICUR) were estimated in base case (BCA) and probabilistic sensitivity analyses (PSA). Cost-effectiveness acceptability curves (CEAC) were generated. Results: As detailed in the Table, 6m of IKd treatment was associated with incremental gains of 0.01 (PSA 0.01) LYs but no gains in QALYs at cost savings of $24,188 ($23,762), yielding a dominant ICER of $ -2,418,800 ($-2,376,200) per LYg (ICUR not estimable). Further, 12m of IKd treatment was associated with incremental gains of 0.04 (PSA 0.04) LYs (or 0.48m) and 0.02 (0.03) QALYs at incremental cost of $1,585 ($2,239), yielding ICER of $39,625 ($55,975) per LYg and ICUR of $79,250 ($74,633) per QALYg. Per CEAC, IKd is the dominated strategy in the 6m model and had probability of 50% of being cost-effective at WTP of $100,000 in the 12m model. Conclusions: Clinically, compared to DKd, IKd is associated with slight incremental gains in LYs of 0.12m over 6m and 0.48m over 1y. The 6m clinical gain comes with cost savings of approximately $24,000 or about 15% of IKd therapy, while the 12m gain requires a minimal cost commitment of around $2,000 or 0.6% of DKd treatment. These findings imply a clinico-economic benefit of isatuximab compared to daratumumab containing regimens in RRMM. [Table: see text]