The efficacy and safety of venetoclax therapy in elderly patients with relapsed, refractory chronic lymphocytic leukaemia

Individualized medication of venetoclax based on therapeutic drug monitoring in Chinese acute myeloid leukemia patients using an HPLC method

OBJECTIVE

The aim of this study was to establish a simple and sensitive high-performance liquid chromatography method for therapeutic drug monitoring of venetoclax (VEN) and optimize regimens.

METHODS

The analysis required the extraction of a 50 μl plasma sample and the precipitation of proteins using acetonitrile extraction. The chromatographic method employed a mobile phase of acetonitrile: 0.5% KH 2 PO 4 (pH 3.5) (60/40, v/v) on a Diamond C 18 (4.6 mm × 250 mm, 5 μm) column at a flow rate of 1.0 ml/min. The quantitative method was validated based on standards described in 'Bioanalytical Method Validation: Guidance for Industry' published by the US Food and Drug Administration (FDA).

RESULTS

The calibration curve was linear ( R2  = 0.9998) over the range of 75-4800 ng/ml, with limits of quantification of 25 ng/ml. The coefficients of intraday and interday validation, specificity, recovery, and stability all met the criteria of FDA guidance. The method was successfully applied to analyze VEN concentrations in 30 cases of acute myeloid leukemia patients. The peak concentration ( Cmax ) was 1881.19 ± 756.61 ng/ml, while the trough concentration ( Cmin ) was 1212.69 ± 767.92 ng/ml in acute myeloid leukemia patients.

CONCLUSION

Our study establishes a simple, precise, and sensitive high-performance liquid chromatography method for monitoring VEN and confirms its applicability for therapeutic drug monitoring of VEN in hematological cancers.

Disparity in treatment patterns among Medicare beneficiaries diagnosed with chronic lymphocytic leukemia: an analysis of patient and contextual factors

This study characterizes the patterns and timing of CLL treatment and, to our knowledge, is the first to identify social vulnerability factors associated with CLL treatment receipt in the Medicare population. A total of 3508 Medicare beneficiaries diagnosed with CLL from 2017 to 2019 were identified. We reported the proportion of individuals who received CLL treatment and the time until the first CLL treatment receipt after the first observed claim with a CLL diagnosis. Logistic regression and time-to-event models provided adjusted odds ratios and hazard ratios associated with baseline individual-level and county-level factors. Sixteen percent of individuals received CLL treatment, and the median follow-up time was 540 d. The median time to receipt of CLL treatment was 61 d. Older age and residence in a county ranked high in social vulnerability (as defined by minority status and language) were negatively associated with treatment receipt and time to treatment receipt.

Idelalisib (PI3Kδ inhibitor) therapy for patients with relapsed/refractory chronic lymphocytic leukemia: A Swedish nation-wide real-world report on consecutively identified patients

OBJECTIVES

We examined the efficacy and toxicity of the PI3Kδ inhibitor idelalisib in combination with rituximab salvage therapy in consecutively identified Swedish patients with chronic lymphocytic leukemia (CLL).

METHODS AND RESULTS

Thirty-seven patients with relapsed/refractory disease were included. The median number of prior lines of therapy was 3 (range 1-11); the median age was 69 years (range 50-89); 22% had Cumulative Illness Rating Scale (CIRS) >6 and 51% had del(17p)/TP53 mutation. The overall response rate was 65% (all but one was partial response [PR]). The median duration of therapy was 9.8 months (range 0.9-44.8). The median progression-free survival was 16.4 months (95% CI: 10.4-26.3) and median overall survival had not been reached (75% remained alive at 24 months of follow-up). The most common reason for cessation of therapy was colitis (n = 8, of which seven patients experienced grade ≥3 colitis). The most common serious adverse event was grade ≥3 infection, which occurred in 24 patients (65%).

CONCLUSIONS

Our real-world results suggest that idelalisib is an effective and relatively safe treatment for patients with advanced-stage CLL when no other therapies exist. Alternative dosing regimens and new PI3K inhibitors should be explored, particularly in patients who are double-refractory to inhibitors of BTK and Bcl-2.

Real-world evidence on venetoclax in chronic lymphocytic leukemia: The Italian experience

Chronic lymphocytic leukemia (CLL) is the most common form of adult leukemia in the western world. In Italy, venetoclax was approved for use in patients with CLL as monotherapy in 2017 and in combinations in 2019. As a result of this delayed approval, there are relatively few real-world studies from Italian clinical practice and much of the data are in heavily pretreated patients. We have collected the available studies in Italian routine practice. Three studies confirm the effectiveness and tolerability of this agent in patients with relapsed/refractory CLL and high-risk disease characteristics, many of whom had received prior B-cell receptor signaling treatment. Addition of rituximab to venetoclax produced more complete responses in patients with relapsed/refractory CLL, while higher disease burden and progression while receiving a prior Bruton's tyrosine kinase inhibitor were both associated with poorer outcomes in patients treated with venetoclax. Venetoclax was well-tolerated with low discontinuation rates. No studies of venetoclax plus obinutuzumab for the first-line treatment of patients with CLL were available due to the short time since approval in Italy. Several cohorts addressed the impact of COVID-19 on patient management and outcomes, suggesting that treated patients and those in clinical observation had similar rates of COVID-19-related hospital admission, intensive care unit admission, and mortality. Overall, the responses and tolerance to venetoclax observed in the Italian real-world setting confirm the tolerability and effectiveness of venetoclax regimens in high-risk patients.

LC-MS/MS method for the quantitation of decitabine and venetoclax in rat plasma after SPE: Application to pharmacokinetic study

This study developed a novel, sensitive and selective LC-MS/MS method for the concurrent determination of DCB and VTX in rat plasma using encorafenib as internal standard (IS). To identify DCB, VTX, and IS, the positive multiple reaction monitoring (MRM) mode was used. Chromatographic separation was carried out using a reversed-phase Agilent Eclipse plus C18 column (100 mm × 2.1 mm, 3.5 µm) and an isocratic mobile phase made up of water with 0.1% formic acid and acetonitrile (50:50, v/v, pH 3.2) at a flow rate of 0.30 mL/min for 3.0 min. Prior to analysis, the DCB and VTX with the IS were extracted from plasma using the solid-phase extraction (SPE) method. High recovery rates for DCB, VTX and IS were achieved using the C18 cartridge without interference from plasma endogenous. The developed method was validated as per the FDA guidelines over a linear concentration range in rat plasma from 5-3000 and 5-1000 ng/mL for DCB and VTX, respectively with r2 ≥ 0.998. For both drugs, the lower limits of detection (LLOD) were 2.0 ng/mL. After the HLOQ sample was injected, less than 20% of the LLOQ of DCB, VTX, and less than 5% of the IS carry-over in the blank sample was attained. The overall recoveries of DCB and VTX from rat plasma were in the range of 90.68-97.56%, and the mean RSD of accuracy and precision results was ≤6.84%. For the first time, the newly developed approach was effectively used in a pharmacokinetic study on the simultaneous oral administration of DCB and VTX in rats that received 15.0 mg/kg of DCB and 100.0 mg/kg of VTX.

Treatment Discontinuation Patterns for Patients With Chronic Lymphocytic Leukemia in Real-World Settings: Results From a Multi-Center International Study

INTRODUCTION

This study assessed treatment discontinuation patterns and reasons among chronic lymphocytic leukemia (CLL) patients initiating first-line (1L) and second-line (2L) treatments in real-world settings.

MATERIALS AND METHODS

Using deidentified electronic medical records from the CLL Collaborative Study of Real-World Evidence, premature treatment discontinuation was assessed among FCR, BR, BTKi-based, and BCL-2-based regimen cohorts.

RESULTS

Of 1364 1L patients (initiated in 1997-2021), 190/13.9% received FCR (23.7% discontinued prematurely); 255/18.7% received BR (34.5% discontinued prematurely); 473/34.7% received BTKi-based regimens, of whom 28.1% discontinued prematurely; and 43/3.2% received venetoclax-based regimens, of whom 16.3% discontinued prematurely (venetoclax monotherapy: 7/0.5%, of whom 42.9% discontinued; VG/VR: 36/2.6%, of whom 11.1% discontinued). The most common reasons for treatment discontinuation were adverse events (FCR: 25/13.2%; BR: 36/14.1%; BTKi-based regimens: 75/15.9%) and disease progression (venetoclax-based: 3/7.0%). Of 626 2L patients, 20/3.2% received FCR (50.0% discontinued); 62/9.9% received BR (35.5% discontinued); 303/48.4% received BTKi-based regimens, of whom 38.0% discontinued; and 73/11.7% received venetoclax-based regimens, of whom 30.1% discontinued (venetoclax monotherapy: 27/4.3%, of whom 29.6% discontinued; VG/VR: 43/6.9%, of whom 27.9% discontinued). The most common reasons for treatment discontinuation were adverse events (FCR: 6/30.0%; BR: 11/17.7%; BTKi-based regimens: 60/19.8%; venetoclax-based: 6/8.2%).

CONCLUSION

The findings of this study highlight the continued need for tolerable therapies in CLL, with finite therapy offering a better tolerated option for patients who are newly diagnosed or relapsed/refractory to prior treatments.

Pooled analysis of first-line treatment with targeted agents in patients with chronic lymphocytic leukemia aged 80 years and older

Patients aged 80 years and older make up a fifth of patients with CLL but are underrepresented in clinical trials. We analyzed the outcomes of these patients treated with targeted agents in the front-line setting in six trials of the German CLL Study Group. Targeted agents included venetoclax, ibrutinib, and idelalisib, mainly used in combination with anti-CD20 antibodies. Among 716 patients, 33 matched the selection criteria (5%). Of those, the majority had relevant comorbidity, organ dysfunctions, and/or high-/very high-risk disease. The overall response rate was 73%. The median progression-free survival was 49.2 months compared with those not reached in younger patients. There were 11 documented deaths of which two were deemed related to therapy. Additional results including 40 patients treated with BTK-inhibitors from the GCLLSG registry suggest that treatment with targeted agents is feasible and effective. Dedicated studies are warranted for this particular subgroup of patients.

Real-world incidence of venetoclax toxicities in British Columbia

Introduction

Venetoclax is used to treat relapsed/refractory chronic lymphocytic leukemia (r/r CLL). Tumour lysis syndrome (TLS) is a serious toxicity associated with venetoclax, and real-world studies suggest that the incidence may be higher than in clinical trials. The purpose of this study is to describe the incidence of venetoclax toxicities in British Columbia (BC).

Methods

Retrospective review of electronic medical charts for patient characteristics and clinical outcomes of patients treated with venetoclax for r/r CLL in BC. Patients were classified according to their risk for developing TLS. The incidence of TLS was categorized based on laboratory metrics or clinical diagnosis. Other non-TLS toxicities were also collected.

Results

Of 33 patients identified, 40%, 33%, and 27% were at low, intermediate, and high risk for TLS, respectively. Laboratory TLS occurred in 1/33 patients (3%), and no clinical TLS was reported. Grade 3 or 4 toxicities occurred in 19/33 patients (58%). Of these, neutropenia was the most common, occurring in 16 patients (84%) followed by thrombocytopenia, which occurred in 8 patients (42%).

Conclusions

The incidence of TLS in patients treated with venetoclax for r/r CLL in BC was lower than in other real-world studies. Findings may warrant further investigation to determine if the higher incidence of TLS in real-world reports may be mitigated through modifying TLS risk categorization and associated prophylactic measures. Neutropenia was the most common grade 3 or 4 venetoclax toxicity reported, and the incidence in BC is comparable to other centres.

Quantification of Venetoclax for Therapeutic Drug Monitoring in Chinese Acute Myeloid Leukemia Patients by a Validated UPLC-MS/MS Method

Venetoclax has emerged as a breakthrough for treatment of leukemia with a wide interindividual variability in pharmacokinetics. Herein, a rapid, sensitive, and reliable UPLC-MS/MS method for quantification of venetoclax in plasma was developed and validated. The method was operated in the multiple-reaction monitoring (MRM) mode to detect venetoclax at m/z transition 868.5 > 321.0 and IS at 875.5 > 321.0, respectively. Protein precipitation prior to injection into the LC-MS/MS and the analyte was separated on an ACQUITY UPLC BEH C18 column by gradient elution with acetonitrile and 0.1% formic acid in water. Linear calibration curves were obtained in the range of 25−8000 ng/mL. The specificity, recovery, matrix effect, and stability also met the acceptance criteria of FDA guidance. The method was successfully applied to analyze plasma in acute myeloid leukemia (AML) patients. The peak plasma concentration (Cmax) of venetoclax in Chinese AML patient was 2966.0 ± 1595.0 ng/mL while the trough concentration (Cmin) was 1018.0 ± 729.4 ng/mL. Additionally, Cmax and Cmin showed a positive correlation with AST levels. Furthermore, Cmax was significantly higher in the older patients. The present method can be applied for TDM of venetoclax in treatment of hematological cancers.

Treatment Options for Elderly/Unfit Patients with Chronic Lymphocytic Leukemia in the Era of Targeted Drugs: A Comprehensive Review

Chronic lymphocytic leukemia (CLL) incidence increases with age reaching 37.9/100,000 in patients over 85 years. Although there is no standardized geriatric tool specifically validated for CLL, a correct framing of the fitness status is of critical importance to individualize treatment strategies. Based on the evidence available to date, frontline chemoimmunotherapy has an increasingly narrowing application, being eligible for candidacy only in elderly fit patients without or with minimal geriatric syndromes. On the other hand, treatment with BCR inhibitors, monotherapy, or in combination with anti-CD20 antibodies (e.g., obinutuzumab), must be preferred both for frontline and relapsed CLL not only in unfit patients, but also in fit patients with unmutated IGHV or harboring del(17p) and/or TP53 mutations/deletions. Second-generation inhibitors (e.g., acalabrutinib, zanubrutinib, pirtobrutinib) are novel compounds that, due to their better safety profile and different specificity, will help physicians overcome some of the safety issues and treatment resistances. In the era of targeted therapies, treatment decisions in elderly and/or unfit patients with CLL must be a balance between efficacy and safety, carefully evaluating comorbidities and geriatric syndromes to ensure the best approach to improve both quality of life and life expectancy.

Treatment strategies for a rapidly evolving landscape in chronic lymphocytic leukemia management

With the advent of targeted therapies for chronic lymphocytic leukemia (CLL), treatment choice has expanded and patients are living longer. Careful consideration is needed regarding treatment duration and sequence, how best to meet patients' needs, balancing toxicities while improving long-term survival and maximizing depth of response. This review addresses these considerations and discusses current targeted treatment dilemmas. Targeted therapies have dramatically transformed the CLL treatment landscape. Two treatment paradigms have emerged using B-cell lymphoma 2 inhibitors (BCL2i) and Bruton's tyrosine kinase (BTK): (i) fixed duration and (ii) continuous treatment. The BCL2i venetoclax can attain deep remissions with a fixed-duration approach, resulting in high rates of undetectable minimal residual disease (uMRD) in treatment-naïve and relapsed/refractory (R/R) patients with CLL. BTKis such as ibrutinib and acalabrutinib achieve high objective response rates and long-term disease control, although they rarely attain complete response or uMRD status as monotherapy. Numerous studies are evaluating the clinical utility of BTKi and BCL2i as combination therapies, where deep remissions have been found to occur. MRD status may also be a useful marker for deciding when to stop continuous therapy, and randomized trials on MRD-guided treatment strategies are currently ongoing. The current treatment choice between continuous or fixed-duration therapy should be based on comorbidities, risks, preferences, and treatment goals, whilst areas of emerging clinical interest include the potential utility of BTKi-BCL2i combination therapies, as well as an MRD-guided treatment strategies in the future.

A comprehensive approach to therapy of haematological malignancies in older patients

Haematological malignancies are a heterogeneous group of diseases with diverse incidence. In Europe, the median age at diagnosis across all disease entities is 69 years. Incidence generally increases with age, reaching a maximum at 75-99 years, with the notable exceptions of Hodgkin lymphoma and acute lymphocytic leukaemia. Overall survival for patients aged 75 years and older with haematological malignancies is generally poor, particularly for acute leukaemias. Understanding the heterogeneity in outcomes for haematological malignancies, treatment challenges, and management of frailty and comorbidities among older patients could help physicians to better address the haematological cancer burden and mortality in ageing populations. The aim of this Series paper is to provide an updated overview of the knowledge accumulated over the past decade regarding treatment options and broader management considerations in older adults with haematological malignancies, focusing on the most common entities encountered across lymphoma, acute leukaemia, chronic leukaemia, and multiple myeloma disease categories. Future strategies, such as increasing enrolment rates of older adults in clinical trials and incorporating patient-reported outcome measurements in daily clinical practice, will assist in providing more individualised health care.

Efficacy of Venetoclax Combined with Decitabine-Based Treatment for Heavily Pre-Treated Relapsed or Refractory AML Patients in a Real-World Setting

Purpose

We report the efficacy and safety of venetoclax plus decitabine-based treatment in heavily pre-treated relapsed or refractory acute myeloid leukaemia (RR-AML) in a real-world setting.

Patients and Methods

There were 22 patients in this study and the median age was 47.5 (12–84) years old, including 11 males and 11 females. Among them, 8 patients were relapsed AML including 2 patients relapsed after HSCT and 14 patients with primary refractory AML including 4 secondary AML. The median number of cycles of previous chemotherapy was 4 (range, 2–10).

Results

After a course of venetoclax plus decitabine-based treatment, 9 patients achieved complete remission (CR) and 1 patient achieved complete remission with incomplete haematological recovery (CRi). The overall response rate (ORR) was 45.5% and the CR rate was 40.9%, and the median time to reach CR/CRi was 21 (13–46) days. Four of the 10 CR/CRi patients relapsed again, and the median time of relapse was 5 (1.0–24) months. The one-year overall survival rate was 31.8%, and the median survival time was 6 months (95% CI, 1–9 months). The one-year overall survival rate of 10 CR/CRi patients was 59.1%, and the 12 NR patients was 10.4% (p=0.001). Nausea and vomiting occurred in 11 patients (50.0%). All patients had grade IV neutropenia and IV thrombocytopenia (100%). Pneumonia occurred in 14 patients (63.6%) and septicaemia occurred in 2 patients (9.0%). The cause of death in all patients was primary disease progression, and no patients died due to the side effects.

Conclusion

The efficacy of venetoclax plus decitabine-based treatment in the real-world treatment of heavily pre-treated RR-AML is similar to that in clinical trials, and the side effects are controllable.

Autoimmune Cytopenia in CLL: Prognosis and Management in the Era of Targeted Therapies

ABSTRACT

Chronic lymphocytic leukemia (CLL) is frequently associated with autoimmune hemolytic anemia and immune thrombocytopenia and, less frequently, with pure red cell aplasia and immune neutropenia. The emergence of these complications is related to an intertwined and complex relationship between patient, disease, and treatment characteristics. The prognostic repercussion of autoimmune cytopenia (AIC) in patients with CLL mainly depends on its response to therapy. For patients with AIC and nonactive CLL, treatment is as in primary, uncomplicated AIC, keeping in mind that no response is an indication for CLL therapy. The success of treating active CLL-related AIC widely relies on a flexible strategy that should include initial therapy with corticosteroids and a rapid shift to effective CLL therapy in nonresponding patients. Targeted therapies (e.g., ibrutinib) that have already demonstrated to be effective in CLL-related AIC will likely offer a unique possibility of treating both AIC and CLL as a single target.

A retrospective observational study to evaluate the clinical outcomes and routine management of patients with chronic lymphocytic leukaemia treated with idelalisib and rituximab in the UK and Ireland (RETRO-idel)

Idelalisib (IDL) is an oral first‐in‐class phosphatidylinositol 3‐kinase delta (PI3Kδ) inhibitor approved for chronic lymphocytic leukaemia (CLL) alongside rituximab (R) since 2014. However, little data exist on routine practice. The RETRO‐idel was a protocol‐led, retrospective study of 110 patients [n = 27 front‐line (1L)] who received IDL‐R. The primary end‐point was clinical overall response rate (ORR). The median (range) follow‐up of the whole cohort was 30·2 (0·1–51·9) months. The median (range) age was 72 (48–89) years. Tumour protein p53‐disruption was common [100% 1L, 32·5% relapsed/refractory (R/R)]. The best ORR (intention‐to‐treat) was 88·2% (1L 96·3%, R/R 85·5%). Overall, the median event‐free survival (mEFS) was 20·3 months and time‐to‐next treatment was 29·2 months. The mEFS for 1L patients was 18·7 months and R/R patients was 21·7 months. The 3‐year overall survival was 56·1% (95% confidence interval 45·7–65·3). IDL was discontinued in 87·3% (n = 96). More patients discontinued due to adverse events in the front‐line setting (1L 63·0% vs. R/R 44·6%) and due to progressive disease in R/R patients (20·5% vs. 3·7% in 1L). Lower respiratory tract infection/pneumonia were reported in 34·5% (Grade ≥3, 19·1%), diarrhoea in 30·9% (Grade ≥3, 6·4%), and colitis in 9·1% (Grade ≥3, 5·5%). Overall, these data describe clear efficacy for IDL‐R in routine practice. No new safety signals were identified, although careful management of known toxicities is required.

Treatment of Chronic Lymphocytic Leukemia After Discontinuation of Bruton's Tyrosine Kinase Inhibitors

The Bruton's tyrosine kinase inhibitors (BTKis) ibrutinib and acalabrutinib have led to durable responses for patients with both treatment-naïve and relapsed/refractory chronic lymphocytic leukemia (CLL). Many patients, however, ultimately discontinue BTKis due to toxicity or progressive CLL. This article reviews the two most common reasons for ibrutinib and acalabrutinib discontinuation, including adverse events as well as CLL progression. The data for specific CLL-directed therapies following BTKi discontinuation, including venetoclax, phosphatidylinositol 3-kinase inhibitors, cellular therapies, and ongoing clinical trials, are reviewed. An evidence-based sequencing algorithm for treatment of CLL following BTKi discontinuation is proposed.

Allogeneic hematopoietic cell transplantation after prior targeted therapy for high-risk chronic lymphocytic leukemia

Allogeneic hematopoietic cell transplantation (alloHCT) can cure previously treated high-risk chronic lymphocytic leukemia (CLL) patients if they are suitable for transplant through the graft-versus-leukemia effect. However, since the emergence of targeted therapies, the role of alloHCT for high-risk CLL is less clear. To address this question, we evaluated 108 high-risk CLL patients who underwent alloHCT from 2010 to 2018. Thirty patients from the period of 2013 to 2018 received targeted therapy prior to alloHCT. The median age for the targeted therapy cohort was 60 years (range, 30-71 years), and 20% and 73% had complete and partial remission, respectively: 76% had del(17p), 46.2% had 5 or more cytogenetic abnormalities, and 78.9% were IGHV unmutated. The median number of prior therapies was 4 (range, 1-9). With a median follow-up time of 36 months (range, 10-72 months), the 3-year overall (OS) and progression-free survival (PFS) were 87% and 69%, respectively. The 3-year cumulative incidence of nonrelapse mortality and relapse was 7% and 24%, respectively. For the control cohort of 78 patients who underwent alloHCT from 2010 to 2014 and received only chemoimmunotherapy prior to transplant, the 3-year OS and PFS were 69% and 58%, respectively. Patients treated with targeted therapy prior to alloHCT had a significantly higher number of circulating T and B cells and a lower ratio of CD4 regulatory T cells to CD4 conventional T cells early after transplant. In summary, despite multiple high-risk features, the clinical outcome of CLL patients who receive targeted therapy prior to transplant is excellent and alloHCT should be offered while the disease is under control.

Treatment patterns and outcomes of unfit and elderly patients with Mantle cell lymphoma unfit for standard immunochemotherapy: A UK and Ireland analysis

Mantle cell lymphoma (MCL) presenting in elderly, unfit patients represents a clinical challenge. Front-line 'attenuated' or low-intensity immunochemotherapy is often employed, although outcomes are relatively unexplored. We report outcomes of attenuated immunochemotherapy in 95 patients with MCL across 19 centres in the UK and Ireland considered unfit for full-dose rituximab-bendamustine or rituximab-cyclophosphamide, doxorubicin, vincristine, prednisolone (R-CHOP). Regimens examined were rituximab-cyclophosphamide, vincristine, prednisolone (R-CVP) (n = 19), dose-attenuated R-CHOP (n = 22), dose attenuated rituximab-bendamustine (n = 24) and rituximab-chlorambucil (n = 30). The primary outcome was progression-free survival (PFS). The secondary outcomes included overall response, overall survival (OS) and toxicity. The median (range) age was 79 (58-89) years and 50% were aged ≥80 years. The median (range) Cumulative Illness Rating Scale-Geriatric score was 6 (0-24). The median PFS for all patients was 15 months [95% confidence interval (CI) 8·7-21·2) and median OS was 31·4 months (95% CI 19·7-43·2). By multivariable analysis (MVA), the only clinical factor associated with an inferior PFS was blastoid morphology [hazard ratio (HR) 2·90, P = 0·01). Notably, higher treatment intensity (R-CHOP/R-bendamustine composite) provided an independently superior PFS compared with R-CVP/R-chlorambucil (MVA HR 0·49, P = 0·02). Factors associated with inferior OS by MVA were Eastern Cooperative Oncology Group Performance Status (HR 2·14, P = 0·04), blastoid morphology (HR 4·08, P = 0·001) and progression of disease at <24 months status (HR 5·68, P < 0·001). Overall, survival after front-line dose-attenuated immunochemotherapy is unsatisfactory. Clinical trials investigating novel agents such as Bruton tyrosine kinase and B-cell lymphoma 2 inhibitors in this specific clinical setting are warranted.

Assessment of the Efficacy of Therapies Following Venetoclax Discontinuation in CLL Reveals BTK Inhibition as an Effective Strategy

PURPOSE

Venetoclax-based therapy is a standard-of-care option in first-line and relapsed/refractory chronic lymphocytic leukemia (CLL). Patient management following venetoclax discontinuation remains nonstandard and poorly understood.

EXPERIMENTAL DESIGN

To address this, we conducted a large international study to identify a cohort of 326 patients who discontinued venetoclax and have been subsequently treated. Coprimary endpoints were overall response rate (ORR) and progression-free survival for the post-venetoclax treatments stratified by treatment type [Bruton's tyrosine kinase inhibitor (BTKi), PI3K inhibitor (PI3Ki), and cellular therapies].

RESULTS

We identified patients with CLL who discontinued venetoclax in the first-line (4%) and relapsed/refractory settings (96%). Patients received a median of three therapies prior to venetoclax; 40% were BTKi naïve (n = 130), and 81% were idelalisib naïve (n = 263). ORR to BTKi was 84% (n = 44) in BTKi-naïve patients versus 54% (n = 30) in BTKi-exposed patients. We demonstrate therapy selection following venetoclax requires prior novel agent exposure consideration and discontinuation reasons.

CONCLUSIONS

For BTKi-naïve patients, selection of covalently binding BTKis results in high ORR and durable remissions. For BTKi-exposed patients, covalent BTK inhibition is not effective in the setting of BTKi resistance. PI3Kis following venetoclax do not appear to result in durable remissions. We conclude that BTKi in naïve or previously responsive patients and cellular therapies following venetoclax may be the most effective strategies.See related commentary by Rogers, p. 3501.