Cost-Effectiveness of Rituximab Post CVP Induction for the Treatment of Low-Grade NHL.

Background: Extended Rituximab (R) therapy after CVP (cyclophosphamide, vincristine, prednisone) induction in the first-line treatment of low-grade, CD20-positive, B-cell NHL significantly prolongs progression-free survival (PFS). A societal cost-effectiveness analysis is performed to estimate projected lifetime clinical and economic implications of this treatment.

Methods: A Markov model with 3 health states (progression-free, post-progression, and death) was developed to estimate the direct medical costs and quality-adjusted life-years (QALYs) for a representative patient cohort with low-grade, CD20-positive, B-cell NHL. Kaplan-Meier estimates of PFS and overall survival (OS) up to 4 years are obtained from the ECOG/CALGB intergroup E1496 trial. After 4 years, transition rates are assumed to be the same in both arms. Costs include drug and administration costs, adverse events, treatment of relapses, and end-of-life costs. Incremental costs associated with R are based on Medicare reimbursement rates and published drug prices. Utilities are derived from the literature and a 3% discount rate is employed.

Results: Projected mean OS is 1.2-yrs longer for patients assigned to extended R therapy versus observation alone (15.2 v 14.0 yrs). Extended R therapy is estimated to cost $42,822 on average, with an expected gain of 0.85 years of quality-adjusted survival. Over a lifetime, the cost per QALY gained is $57,515. Sensitivity analyses performed on all variables contributing to the model results showed that utility for follicular NHL patients (range: 0.68–1) and number of R infusions (range: 8–17) most influence the incremental cost-effectiveness ratio (ICER).

Conclusion: The ICER of extended R dosing following CVP induction remains well below the threshold considered acceptable for oncology in the United States. Additional analysis of long term follow-up data will be useful for further evaluation of clinical and economic implications of this treatment for low-grade, CD20-positive, B-cell NHL patients.