Management of patients with previously untreated chronic lymphocytic leukaemia with obinutuzumab and chlorambucil

Cost-Effectiveness and Economic Burden Analyses on All First-Line Treatments of Chronic Lymphocytic Leukemia

OBJECTIVES

Several chemoimmunotherapy and targeted treatment regimens are approved as front-line therapies in chronic lymphocytic leukemia. We estimated for the 10-year cost-effectiveness of these treatment regimens and the economic burden of following the estimated risk-stratified 21 040 patients with chronic lymphocytic leukemia diagnosed in 2020 for 10 years.

METHODS

A Markov model with 7 exclusive health states was specified over a 10-year time horizon. Treatment effectiveness inputs were obtained from a novel network meta-analysis on the progression-free survival, overall survival curves, and time to next treatment. Costs and utilities inputs were included for each health state for each treatment and discounted at 3.0%/year. Life-years (LYs) and quality-adjusted LYs (QALYs) for each treatment were determined. Using the lowest cost regimen as reference, the incremental cost-effectiveness ratio (ICER) and incremental cost-utility ratio (ICUR) were estimated. The 10-year per-patient cost was determined by risk status and by initial treatment.

RESULTS

Venetoclax-plus-obinutuzumab was the lowest cost regimen, hence the reference. Superior in effectiveness to all chemoimmunotherapies, it was cost saving. With the highest effectiveness gains at 6.26 LYs and 5.01 QALYs and despite being the most expensive regimen ($1 298 638 per patient), acalabrutinib-plus-obinutuzumab yielded the best ICER ($409 343/LY gained) and ICUR ($501 236/QALY gained). The remaining ICERs of targeted therapies ranged from $512 101/LY gained to $793 236/LY gained and the ICURs from $579 737/QALY gained to $869 300/QALY gained. The 10-year postdiagnosis low/high (venetoclax-plus-obinutuzumab/acalabrutinib-plus-obinutuzumab) economic burden ranges were $42 690 to $98 665 for low-risk, $141 339 to $326 660 for intermediate-risk, and $273 650 to $632 453 for high-risk patients.

CONCLUSIONS

Compared with venetoclax-plus-obinutuzumab, chemoimmunotherapies are associated with less health benefits at higher cost. The targeted therapies achieve greater benefits at higher cost.

Real world risk of infusion reactions and effectiveness of front-line obinutuzumab plus chlorambucil compared with other frontline treatments for chronic lymphocytic leukemia

Background

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in North America. Previous studies have shown improved progression free survival (PFS) and response rates in unfit patients treated with obinutuzumab compared to other regimens. The aim of this study was to evaluate the obinutuzumab-chlorambucil regimen in the context of historical treatments and first-dose infusion reactions at CancerCare Manitoba (CCMB).

Methods

A retrospective chart review was conducted for patients treated with obinutuzumab from January 1, 2014 to December 31, 2017 at CCMB. A minimum data set was extracted for patients treated with other front-line therapies. Descriptive statistics were used to evaluate patient demographics, toxicity, duration and dosing of obinutuzumab treatment. Kaplan–Meier curves were used to evaluate time-to-next-treatment (TTNT), overall survival (OS) and PFS for patients treated with obinutuzumab. A multivariable logistic regression model was used to investigate associations between infusion related reactions (IRRs) and age at treatment, pre-treatment lymphocyte count, cumulative illness rating scale (CIRS) and receipt of prior chemotherapy.

Results

Forty seven percent of patients receiving frontline therapy received chlorambucil and obinutuzumab. Sixty-seven patients were treated with obinutuzumab and consisted of 36 males (53.7%) and 31 females (46.3%) with 29 patients (43.3%) over age 75 years. Rates of grade 3 and 4 obinutuzumab IRRs were lower (6%) compared to the CLL11 clinical trial (20%) due to local practices including slower infusion rates and using chlorambucil before starting obinutuzumab treatment. Many patients had difficulty tolerating the full dosage of chlorambucil. Only 26 patients (38.8%) had their dose of chlorambucil escalated to the full dose of 0.5 mg/kg. In addition, only 18 patients (26.9%) received all doses of obinutuzumab and all 12 doses of chlorambucil.

Conclusions

In summary, first dose infusion reactions with obinutuzumab can be markedly reduced by using chlorambucil to decrease the lymphocyte count before obinutuzumab and by using a very slow initial obinutuzumab infusion rate. Modifications in chlorambucil dosing and obinutuzumab administration can improve tolerance without significant loss in efficacy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09256-2.

Comparative Efficacy of First-Line Treatments of Chronic Lymphocytic Leukemia: Network Meta-Analyses of Survival Curves

BACKGROUND

Multiple treatment options in first-line chronic lymphocytic leukemia (CLL) pose a challenge in identifying the best treatment. We performed novel network meta-analyses (NMA; 8 trials, 11 treatments) on the Kaplan-Meier curves to compare treatments for fludarabine-ineligible patients on progression-free survival (PFS), time-to-next-treatment (TTNT) and overall survival (OS).

METHODS

Using the Guyot method of enhanced secondary analysis of digitized survival data and applying the fixed lognormal distribution model, we extracted the survival proportions and hazard ratios (HR) over 60 months of follow-up, including PFS comparisons by unmutated/mutated IGHV and del 17p.

RESULTS

Acalabrutinib-plus-obinutuzumab was associated with higher 5-year PFS proportions than ibrutinib (HR = 0.42, 95% CrI = 0.25-0.63) but not acalabrutinib, ibrutinib-plus-obinutuzumab, ibrutinib-plus-rituximab or venetoclax-plus-obinutuzumab. In patients with un-mutated (but not with mutated) IGHV higher PFS proportions and favorable HRs were observed for acalabrutinib, acalabrutinib-plus-obinutuzumab, and ibrutinib-plus-obinutuzumab relative to ibrutinib; and targeted therapies were superior over chemoimmunotherapies in patients with del 17p. Targeted therapies containing ibrutinib or acalabrutinib regimens were associated with superior TTNT over venetoclax-plus-obinutuzumab and all chemoimmunotherapies. OS NMA generally found no difference between therapies except for some chemoimmunotherapies.

CONCLUSIONS

Overall, only acalabrutinib-plus-obinutuzumab was associated with superior 5-year PFS gains over ibrutinib, which in turn was similar or superior in PFS benefit over other targeted therapies. Acalabrutinib and ibrutinib with obinutuzumab and acalabrutinib monotherapy were associated with greater 5-year TTNT benefits. Despite marked 5-year OS for many regimens, a differential 5-year OS benefit could not be ascertained.

Clinical application of obinutuzumab for treating chronic lymphocytic leukemia

Alkylators and nucleoside analogs were the main drugs for treatingchronic lymphoblastic leukemia (CLL), which have been replaced by monoclonal antibodies, such as rituximab in the past 10 years for refractory or relapsed CLL. The first-line immunochemotherapy regimen, rituximab combined with nucleoside analogs, significantly increased CLL patients’ first-reaction rate and improved progression-free survival. Despite the long-lasting remissions by the use of chemoimmunotherapy, most CLL patients will relapse eventually. The obinutuzumab (GA101), an updated CD20 antibody, that is thought to achieve a more durable response with unique molecular and functional characteristics. Obinutuzumab is a humanized, monoclonal type II CD20 antibody modified by glycoengineering. The glycoengineered Fc portion enhances the binding affinity to the FcγRIII receptor on immune effector cells, resulting in increased antibody-dependent cellular cytotoxicity and phagocytosis. In addition, the type II antibody binding characteristics of obinutuzumab to CD20 lead to an efficient induction of direct non-apoptotic cell death. This review summarizes the results of clinical studies using obinutuzumab and looks forward to its further application in treating CLL clinically.

Obinutuzumab for the treatment of chronic lymphocytic leukemia and other B-cell lymphoproliferative disorders

INTRODUCTION

Chemoimmunotherapeutic regimens using the anti-CD20 antibody rituximab improved significantly the survival rates in various B-cell lymphoproliferative disorders (LPDs), including chronic lymphocytic leukemia (CLL). The next-generation CD20 antibody obinutuzumab represents an addition to the drug armamentarium used for the therapeutic management of patients with LPDs. Areas covered: Herein, the authors discuss the biochemical and conformational engineering of obinutuzumab to increase antibody-dependent cell-mediated cytotoxicity and direct cell death. They also describe the available preclinical data on obinutuzumab's role in B-cell LPDs. Furthermore, the authors summarize the Phase I and II clinical trials of obinutuzumab, focusing on the main pharmacokinetic/pharmacodynamic characteristics, the most common clinically significant adverse events, dose optimization, and clinical outcomes of patients with CLL and other B-cell LPDs treated with obinutuzumab as monotherapy or in combination with other agents. To put these data in perspective, the use of obinutuzumab is compared with that of rituximab in CLL and other B-cell LPDs. Expert opinion: Clinical trials have demonstrated that obinutuzumab is well tolerated. The novel mechanism of action of obinutuzumab is associated with significant efficacy in CLL and other B-cell LPDs. Ongoing clinical trials are expected to determine the optimal use of obinutuzumab in these diseases.