Model-based evaluation of cost-effectiveness of nerve growth factor inhibitors in knee osteoarthritis: impact of drug cost, toxicity, and means of administration

Objective: Studies suggest nerve growth factor inhibitors (NGFi) relieve pain but may accelerate disease progression in some patients with osteoarthritis (OA). We sought cost and toxicity thresholds that would make NGFi a cost-effective treatment for moderate-to-severe knee OA. Design: We used the Osteoarthritis Policy (OAPol) model to estimate the cost-effectiveness of NGFi compared to standard of care (SOC) in OA, using Tanezumab as an example. Efficacy and rates of accelerated OA progression were based on published studies. We varied the price/dose from $200 to $1000. We considered self-administered subcutaneous (SC) injections (no administration cost) vs provider-administered intravenous (IV) infusion ($69-$433/dose). Strategies were defined as cost-effective if their incremental cost-effectiveness ratio (ICER) was less than $100,000/quality-adjusted life year (QALY). In sensitivity analyses we varied efficacy, toxicity, and costs. Results: SOC in patients with high levels of pain led to an average discounted quality-adjusted life expectancy of 11.15 QALYs, a lifetime risk of total knee replacement surgery (TKR) of 74%, and cumulative discounted direct medical costs of $148,700. Adding Tanezumab increased QALYs to 11.42, reduced primary TKR utilization to 63%, and increased costs to between $155,400 and $199,500. In the base-case analysis, Tanezumab at $600/dose was cost-effective when delivered outside of a hospital. At $1000/dose, Tanezumab was not cost-effective in all but the most optimistic scenario. Only at rates of accelerated OA progression of 10% or more (10-fold higher than reported values) did Tanezumab decrease QALYs and fail to represent a viable option. Conclusions: At $100,000/QALY, Tanezumab would be cost effective if priced <=$400/dose in all settings except IV hospital delivery. (c) 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.