The cost-effectiveness of combination therapy: Challenges of the present, solutions for the future? A myeloma analysis

Abstract

Background: The number of treatments for cancer has increased over recent years. Monotherapy for some malignancies delivers only marginal benefit, whilst combination therapy (CT) improves results by using synergistic mechanisms of action. CT increases treatment cost however, and in an era of health care constrained by cost-containment, national reimbursement of CT conditional on cost-effectiveness is challenging. This research assesses drivers of CT cost-effectiveness, using myeloma as an example, to inform approaches to evidence based approaches to reimbursement. Methods: A 3-state cost-effectiveness model (pre-progression; post-progression; dead) for front-line treatment of myeloma was developed. Continuous lenalidomide + dexamethasone (Ld) data were extracted from published results and, using parametric modelling, extrapolated to 20 years, with costs based on UK prices. Add-on drug X was assumed to deliver survival benefit (PFS HR = 0.7; OS HR = 0.7), be dosed Q4W until disease progression, and cost £2,000/dose. Post-progression costs were £4,000/month. Scenario analyses considering differing evidence and treatment approaches included: improved PFS and OS; reduced dosing schedules; limited treatment duration; use as a doublet (i.e. Xd); reduced Drug X cost. Results: Combination therapy XLd compared with Xd resulted in a base-case incremental cost-effectiveness ratio (ICER) of £111K/quality-adjusted life year (QALY). Scenario analysis representing 28.5% improvement in both PFS (ICER = £131K/QALY) and OS (ICER = £96K/QALY) did not substantially improve CE. In contrast, scenarios which induced substantial cost savings improved CE (X dosed Q8W, ICER = £69K/ QALY; X cost = £1000/dose, ICER = £64k/QALY; halved Ld dosing, ICER = £8K/ QALY; 24-month treatment cap, ICER = -£89K/QALY; doublet, ICER = -£96k/QALY). Conclusions: Clinical trials assess clinical outcomes, however these results suggest clinical outcomes alone may be insufficient to establish CT cost-effectiveness in myeloma. Pursuit of economic benefit beyond clinical outcomes, including resource-sparing approaches to treatment, may mitigate this risk and facilitate national reimbursement, and should therefore be considered in clinical trial design.