Brentuximab Vedotin PLUS CHP in Frontline Systemic Anaplastic Large Cell Lymphoma (SALCL): Adjusted Estimates of Efficacy and Cost-Effectiveness Removing the Effects of Retreatment with Brentuximab Vedotin
Author(s)
Cranmer H1, Trueman D2, Woodcock F2, Evers E3, Podkonjak T4
1Takeda International, London, LON, UK, 2Source Health Economics, London, LON, UK, 3Source Health Economics, Oxford, UK, 4Takeda UK Ltd, London, LON, UK
OBJECTIVES In ECHELON-2, brentuximab vedotin (BV) plus cyclophosphamide, doxorubicin, and prednisone (CHP) demonstrated improved efficacy in frontline systemic anaplastic large cell lymphoma (sALCL) against cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP). BV is already licensed and reimbursed in relapsed/refractory sALCL in England. However, retreatment with BV is not funded. During ECHELON-2, 17 (10%) and 36 (23%) of sALCL patients received BV-containing subsequent therapy in the BV+CHP and CHOP arms, respectively. Our objective was to provide adjusted estimates of efficacy and cost-effectiveness reflecting local funding which does not include BV retreatment. METHODS To remove the effects of BV retreatment, the inverse probability of censoring weights (IPCW) and two-stage estimators (TSE) approaches, with and without re-censoring, were applied to overall survival (OS) in the BV+CHP arm of the ECHELON-2 sALCL cohort. Clinical experts provided prognostic factors for use as covariates. Cost-effectiveness was determined in a three-state partitioned survival model from a UK NHS perspective. RESULTS The unadjusted hazard ratio (HR) for OS in patients with sALCL with BV+CHP vs CHOP was 0.54 (95% CI 0.34, 0.87; p=0.011). The statistical model predicting retreatment in the IPCW approach had poor predictive power; estimates were consequently counterintuitive (HR 0.46 [95% CI 0.27, 0.77]). The TSE with and without re-censoring provided estimates of 0.41 (95% CI 0.15, 0.87; p=0.022) and 0.55 (95% CI 0.33, 86; p=0.014), respectively. The TSE analysis without re-censoring was used as the model base-case. Incremental cost-effectiveness ratios (ICERs) including and excluding retreatment were £27,096/QALY and £23,345/QALY, respectively. CONCLUSIONS The TSE without re-censoring provided the most clinically plausible estimate of efficacy whilst retaining sufficient information to permit extrapolation of OS. After adjustment for the lack of funding of BV retreatment, BV+CHP remains an efficacious and cost-effective treatment in frontline sALCL compared with CHOP.
Conference/Value in Health Info
2020-11, ISPOR Europe 2020, Milan, Italy
Value in Health, Volume 23, Issue S2 (December 2020)
Code
PCN56
Topic
Clinical Outcomes, Economic Evaluation, Methodological & Statistical Research
Topic Subcategory
Comparative Effectiveness or Efficacy, Cost-comparison, Effectiveness, Utility, Benefit Analysis
Disease
Oncology