Cost effectiveness of amifostine for prevention of radiation-induced xerostomia

Abstract

5526 Background: Chronic xerostomia resulting from head and neck irradiation (HNXRT) greatly affects quality of life. Concurrent amifostine administration can reduce absolute incidence of chronic xerostomia by 23%, but with unclear cost effectiveness. Methods: Patients >1 year post-HNXRT were evaluated through an interactive decision analysis computer program by Mahmud Kattan to determine utility through a Time Trade Off model. Costs of medical procedures were calculated using institutional cost to charge ratios. Average wholesale costs for drugs were used. We assumed a BSA of 2.0, and anti-emetic use according to NCCN guidelines (moderate emetogenicity). Event frequencies were based on Brizel Phase III data. Using FCCC data, we assumed chronic oral pilocarpine use was required by 32% of patients with grade ≥2 and 0% with grade ≤1 xerostomia. Costs and benefits were discounted 3% annually. Cost effectiveness of amifostine vs. no amifostine was evaluated through a Markov model using Monte Carlo simulation. Quality Adjusted Life Years (QALY)=utility*life years. Cost effective ratio (C/E)=(TC-CWA)/incremental QALY. Results: Thirty-three patients were evaluated. Characteristics of 12 patients 12 with grade ≤1 xerostomia were: median age 68, median days from HNXRT 719, male 5, female 2. Characteristics of 21 patients with grade ≥2 xerostomia were: median age 58, median days from HNXRT 1346, male 14, female 7. Amifostine vs. no amifostine resulted in 0.12 incremental QALY. Incremental C/E for amifostine was $142,000 per QALY. Sensitivity analysis showed that amifostine would be cost effective at a lower cost or at a lower utility for grade ≥2 xerostomia (see table), but not by BSA or utility for grade ≤1 xerostomia. Conclusions: Based on this single-institution study of a small number of patients, amifostine administration for prevention of chronic xerostomia from HNXRT may not be cost-effective. A larger study in a more diverse population is warranted. Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration MedImmune MedImmune