Cost-effectiveness of a 12-month fixed-duration venetoclax treatment in combination with obinutuzumab in first-line, unfit chronic lymphocytic leukemia in the United States

Introduction

Historically chemoimmunotherapy has been the standard of care in the treatment of first-line (1L) chronic lymphocytic leukemia (CLL). More recently several effective oral targeted agents, such as ibrutinib-based regimens, have provided effective chemotherapy-free treatment options in CLL. However, these therapies require continuous treatment until disease progression. Recently FDA approved (May 2019), venetoclax plus obinutuzumab (VenG) is a highly effective chemotherapy-free therapy that is used over a 12-month fixed treatment duration (Fischer et al, N Eng J Med 2019). The objective of this study is to estimate the cost-effectiveness of VenG in the treatment of 1L CLL from a US-payer perspective.

Methods

A three-state partitioned-survival model was used to extrapolate progression-free survival and overall survival over a lifetime horizon (20 years). Cost-effectiveness was estimated by comparing a 12-month fixed duration of VenG versus (vs.) chlorambucil-obinutuzumab (ClbG) based on the CLL14 clinical trial (NCT02242942). Other comparators included treat-to-progression therapies, such as ibrutinib (IBR), IBR + rituximab (IR), and IBR + G (IG), and a 6-month course of bendamustine + rituximab (BR). Using a network meta-analysis, the relative efficacy of VenG and ClbG vs. other selected comparators was estimated. Health state utilities and adverse event (AE) disutilities were derived from a systematic literature review and published health-technology assessment reports. To generate total quality-adjusted life years (QALYs), these health state utilities and AE disutilities were applied to the relative efficacy data. US-specific costs included those for CLL treatment, routine care and monitoring, AEs, disease progression (including subsequent treatment), and end-of-life care. Cost-effectiveness results are presented in terms of incremental cost per QALY. A new treatment that is both lower in total cost and more efficacious (in QALYs) vs. identified comparator treatments is described as being "dominant". Uncertainty in the model was tested through deterministic, probabilistic, and scenario analyses.

Results

The benefits in the cost-effectiveness model (CEM) were measured in terms of total discounted QALYs which were 6.47 for VenG, 6.12 for ClbG, 6.11 for IBR, 6.08 for IR, 6.41 for IG, and 5.98 for BR. The total discounted costs incurred by VenG and ClbG were $322,613 and $847,571, respectively. IBR-based treat-to-progression regimens incurred total discounted costs of $1,485,368 for IBR, $1,447,010 for IR, and $1,988,706 for IG. BR incurred total discounted costs of $808,756. Compared to these regimens, VenG is less costly (incremental cost ranges between: -$1,666,093 to -$486,143). The incremental discounted QALYs of VenG was: 0.36 vs. GC, 0.49 vs. BR, 0.37 vs. IBR, 0.06 vs. IG, and 0.39 vs. IR. Thus, VenG with a 12-month fixed duration, has lower total costs and is more efficacious ("dominant") over all comparators in the CEM. The probabilistic sensitivity analysis results were in line with the deterministic results. Sensitivity analysis indicated the post-progression survival utility was the most influential parameter on the model outcomes. As the CLL14 trial data matures, these cost-effectiveness estimates may change and additional scenarios for post-progression survival for VenG will be explored. Updated results will be presented.

Conclusions 

VenG is projected to be cost-effective vs. ClbG within accepted US cost-effectiveness thresholds. Compared with BR and IBR-based treat-to-progression regimens (IBR, IR, and IG), a 12-month fixed-duration treatment option with VenG seems cost saving and more efficacious based on the CEM. Taken together, VenG appears to be a cost-effective standard therapy for 1L CLL patients.