Williams, Rhys

Abstract Introduction Bruton tyrosine kinase inhibitors (BTKis) have changed the treatment algorithm for patients with high-risk relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL). Efficacy was demonstrated for zanubrutinib and ibrutinib in high-risk R/R CLL patients in the ALPINE (NCT03734016) trial, for ibrutinib and acalabrutinib in the ELEVATE-RR (NCT02477696) trial, and for acalabrutinib in the ASCEND (NCT00135226) trial. While there is limited head-to-head comparative trial data of all covalent BTKis in the treatment of high-risk R/R CLL, a previously published network meta-analysis (NMA) used data from the ALPINE, ELEVATE-RR, and ASCEND trials, and reported that zanubrutinib demonstrated significantly improved relative efficacy compared to ibrutinib and acalabrutinib in high-risk R/R CLL (Shadman 2025). Within this NMA, high-risk R/R CLL populations were defined based on the prespecified definitions within each trial, including patients with del(17p) and/or TP53 mutations in the ALPINE and ASCEND trials, and del(17p)/del(11q) in the ELEVATE-RR trial. This study aimed to compare zanubrutinib versus ibrutinib and acalabrutinib in high-risk R/R CLL by calculating the number needed to treat (NNT) to avoid one progression or death. Methods A model was developed to evaluate the NNT among high-risk R/R CLL patients to avoid a progression or death. Progression free survival (PFS) data for zanubrutinib in high-risk patients were extracted from the ALPINE trial. PFS values for ibrutinib and acalabrutinib were derived from the previously published NMA study. PFS for ibrutinib and acalabrutinib were calculated by applying PFS hazard ratio from the NMA results to the zanubrutinib PFS value for the high-risk population in the ALPINE trial. 24-month PFS (72.6% for zanubrutinib, 52.0% for ibrutinib, and 55.9% for acalabrutinib) were used for the base case analysis of the model. Sensitivity analyses were conducted to examine the impact of alternative PFS inputs for ibrutinib, derived directly from the high-risk populations in ALPINE trial (unadjusted). Results The base case results from the NNT model indicate that for the treatment of patients with high-risk R/R CLL over 24-months, every five patients treated with zanubrutinib instead of ibrutinib results in the avoidance of one disease progression or death and every six patients treated with zanubrutinib instead of acalabrutinib results in the avoidance of one disease progression or death. Applying the model result to a hypothetical scenario of 100 patients with high-risk R/R CLL treated with zanubrutinib versus ibrutinib for two years finds approximately 20 patients will avoid disease progression events or deaths. Treating the same population with zanubrutinib versus acalabrutinib for two years will result in the avoidance of 17 disease progression events or death. Sensitivity analysis showed consistent NNT results.Conclusions The NNT analysis suggests that among high-risk R/R CLL patients, zanubrutinib is associated with more favorable clinical outcomes compared to ibrutinib and acalabrutinib. Over 24 months, zanubrutinib demonstrated a NNT of five to prevent one disease progression or death compared to ibrutinib, and an NNT of six compared to acalabrutinib, in high-risk R/R CLL patients. Study findings should be interpreted based on modeling assumptions and potential patient population differences across trials.

e19049 Background: Acala and zanu are 2nd generation Bruton tyrosine kinase inhibitors (BTKis) that have demonstrated improved safety profiles vs 1st generation BTKi ibrutinib in clinical trials. While head-to-head comparison of zanu vs acala is lacking, a recent meta-analysis of clinical trials provided a comprehensive, indirect comparison of the AE profiles in B-cell malignancies (Hwang, Hemasphere. 2023;7(S3):1134). This study aims to evaluate costs and impacts on quality of life (QoL) for zanu vs acala using their AE profiles. Methods: A health economic model was developed to determine cost and QoL associated with AE management for zanu and acala. The incidence rates ( IRs) of all grade and grade ≥3 AEs of interest (n=21, including bleeding events, hypertension, atrial fibrillation, cytopenias, infections, headache, arthralgia, diarrhea) were taken from the meta-analysis. Additional model inputs, such as disutility, average duration of AE, and unit cost of each AE were sourced from published literature and publicly available cost databases in consultation with clinical experts. The model was developed from the US perspective, considering Medicare costs, inflated to 2023 USD. Model outcomes were AE management cost (= IR * unit cost) and quality-adjusted life years (QALYs) lost due to AE (= IR * Disutility * Duration/365.25). Results: In the base-case scenario (considering all AEs), treating a hypothetical cohort of 1000 patients (pts) with zanu instead of acala yielded cost savings of $124K and 3.7 QALY gains (i.e., 3.7 years extra in full health). Subgroup analysis for severe (grade ≥3) and non-severe AEs (grade 1-2) demonstrated similar trends. A sensitivity analysis limited to AEs significantly different between zanu and acala (n=13) yielded consistent results. Additionally, a probabilistic sensitivity analysis, conducted with 1000 iterations to account for uncertainty in model parameters, confirmed robustness of the model, indicating stable conclusions across a wide range of parameter uncertainties. Conclusions: This analysis suggested that zanu is cost-saving and associated with added health benefits compared to acala in terms of AE management in pts with B-cell malignancies. Should these results derived from meta-analysis of clinical trial data be applicable to real-world pt populations across different indications, the potential cost savings could be considerable. These results could be further improved if the differences in efficacy of zanu vs acala are also incorporated. [Table: see text]