Lalla, Deepa

6023 Background: The addition of trastuzumab (H) to a standard adjuvant therapy regimen (doxorubicin, cyclophosphamide, and paclitaxel; AC→T) is associated with a 52% reduction in risk (p < 0.0001) of disease recurrence in patients with HER2 positive operable breast cancer (Romond et al, NEJM 2005). A cost-effectiveness analysis was performed to assess the lifetime clinical and economic implications of this important clinical finding. Methods: A Markov model with three health states (disease-free survival [DFS], recurrence, and death) was used to estimate the likely cost-effectiveness (CE) for a 50 yr old woman. Efficacy results from both trials (NCCTG N9831/NSABP B-31) were used through 4 years, and projections of time to recurrence and death were based on the literature (EBCTCG, Lancet 2005). After 4 years, annual transition probabilities to recurrence and death are assumed to be the same in both arms. Cardiotoxicity was higher with H (Perez EA, ASCO 2005). Actual total dose of H was used which was lower than scheduled dose. Incremental costs associated with addition of H to adjuvant therapy were estimated using average wholesale prices, Medicare reimbursement rates and other published data. These costs included testing for HER2 status, drug and administration costs for H, cardiac monitoring, treatment of cardiotoxicity, treatment following recurrence, and end-of-life costs for dying patients. Utility estimates were derived from the literature. Results: Over a lifetime, the cost per quality-adjusted life year gained (QALY; discount rate 3%) is $27,800, with a range of $17,900 to $39,100 under multi-way sensitivity analysis. Projected life expectancy from the Markov model is 3 years longer for H patients (19.4 v 16.4 yrs). Over a 20-year horizon, addition of H to AC→T is estimated to cost an additional $46,300 on average, with an expected gain of 1.28 QALYs-a cost/QALY of $36,100. The key drivers of CE are the cost of treatment and the improvement in DFS. Conclusion: The model projects a cost-utility ratio that is below that of many treatments used for oncology patients. The use of trastuzumab in the adjuvant setting for HER2+ breast cancer is projected to be cost-effective. [Table: see text]

BACKGROUNDFluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) tests are commonly used to assess human epidermal growth factor 2 (HER2) status of tumors in patients with breast cancer. This analysis evaluates the likely cost‐effectiveness of expanded retesting to assess HER2 tumor status in women with early stage breast cancer.METHODSWe developed a decision‐analytic model to estimate the incremental cost‐effectiveness ratio (ICER) of expanded reflex testing from a US payer perspective. Expanded reflex testing is defined as retesting tumor specimens from patients whose tumors are IHC0, IHC1+, or FISH‐negative on their first test. In the base case, we assumed that 80% of patient tumors are initially IHC‐tested and 20% are FISH‐tested. Testing outcomes for IHC and FISH with and without retesting were based on published meta‐analyses. The cost of tests and treatment and the long‐term health outcomes were obtained from the literature.RESULTSIn the base case, we estimated that 2.27% of women who received expanded reflex testing would be HER2‐positive and receive trastuzumab treatment: the projected ICER was $36,721 per life year or $39,745 per quality‐adjusted life year (QALY). This varied between $47,100 per QALY and $35,500 per QALY if we assumed that 1%‐8% of patients retested were then HER2+, respectively. The results of deterministic and probabilistic sensitivity analysis were robust. This strategy would result in 4700 (2000‐17,000) patients being eligible to receive trastuzumab treatment annually.CONCLUSIONSRetesting patients who are IHC0, IHC1+, or FISH‐negative is projected to be a cost‐effective clinical strategy. Cancer 2013;119:3113–3122. © 2013 American Cancer Society.