Cardiovascular events reported in patients with B-cell malignancies treated with zanubrutinib

ABSTRACT

First-generation Bruton tyrosine kinase (BTK) inhibitor, ibrutinib, has been associated with an increased risk of cardiovascular toxicities. Zanubrutinib is a more selective, next-generation BTK inhibitor. In this analysis, incidence rates of atrial fibrillation, symptomatic (grade ≥2) ventricular arrhythmia, and hypertension were evaluated in a pooled analysis of 10 clinical studies with zanubrutinib monotherapy in patients (N = 1550) with B-cell malignancies and a pooled analysis of head-to-head studies comparing zanubrutinib with ibrutinib (ASPEN cohort 1; ALPINE). Among the 10 studies, most patients (median age, 67 years) were male (66.3%) and had CLL/SLL (60.5%). Overall incidence and exposure-adjusted incidence rates (EAIR) for atrial fibrillation, symptomatic ventricular arrhythmia, and hypertension were lower with zanubrutinib than ibrutinib. Despite a similar prevalence of preexisting cardiovascular events in ASPEN and ALPINE, atrial fibrillation/flutter incidence rates (6.1% vs 15.6%) and EAIR (0.2 vs 0.64 persons per 100 person-months; P < .0001) were lower with zanubrutinib than with ibrutinib. Symptomatic ventricular arrhythmia incidence was low for both zanubrutinib (0.7%) and ibrutinib (1.7%) with numerically lower EAIR (0.02 vs 0.06 persons per 100 person-months, respectively) for zanubrutinib. The hypertension EAIR was lower with zanubrutinib than ibrutinib in ASPEN but similar between treatment arms in ALPINE. The higher hypertension EAIR in ALPINE was inconsistent with other zanubrutinib studies. However, fewer discontinuations (1 vs 14) and deaths (0 vs 6) due to cardiac disorders occurred with zanubrutinib versus ibrutinib in ALPINE. These data support zanubrutinib as a treatment option with improved cardiovascular tolerability compared with ibrutinib for patients with B-cell malignancies in need of BTK inhibitors. These trials were registered at www.ClinicalTrials.gov as # NCT03053440, NCT03336333, NCT03734016, NCT04170283, NCT03206918, NCT03206970, NCT03332173, NCT03846427, NCT02343120, and NCT03189524.

Biomarker analysis of the ASPEN study comparing zanubrutinib with ibrutinib for patients with Waldenström macroglobulinemia

ABSTRACT

The phase 3 ASPEN trial (NCT03053440) compared Bruton tyrosine kinase inhibitors (BTKis), zanubrutinib and ibrutinib, in patients with Waldenström macroglobulinemia (WM). Post-hoc biomarker analysis was performed using next-generation sequencing on pretreatment bone marrow samples from 98 patients treated with zanubrutinib and 92 patients treated with ibrutinib with mutated (MUT) MYD88 and 20 patients with wild-type (WT) MYD88 treated with zanubrutinib. Of 329 mutations in 52 genes, mutations in CXCR4 (25.7%), TP53 (24.8%), ARID1A (15.7%), and TERT (9.0%) were most common. TP53MUT, ARID1AMUT, and TERTMUT were associated with higher rates of CXCR4MUT (P < .05). Patients with CXCR4MUT (frameshift or nonsense [NS] mutations) had lower very good partial response (VGPR) and complete response rates (CR; 17.0% vs 37.2%, P = .020) and longer time to response (11.1 vs 8.4 months) than patients with CXCR4WT treated with BTKis. CXCR4NS was associated with inferior progression-free survival (PFS; hazard ratio [HR], 3.39; P = .017) in patients treated with ibrutinib but not in those treated with zanubrutinib (HR, 0.67; P = .598), but VGPR + CR rates were similar between treatment groups (14.3% vs 15.4%). Compared with ibrutinib, patients with CXCR4NS treated with zanubrutinib had a favorable major response rate (MRR; 85.7% vs 53.8%; P = .09) and PFS (HR, 0.30; P = .093). In patients with TP53MUT, significantly lower MRRs were observed for patients treated with ibrutinib (63.6% vs 85.7%; P = .04) but not for those treated with zanubrutinib (80.8% vs 81.9%; P = .978). In TP53MUT, compared with ibrutinib, patients treated with zanubrutinib had higher VGPR and CR (34.6% vs 13.6%; P < .05), numerically improved MRR (80.8% vs 63.6%; P = .11), and longer PFS (not reached vs 44.2 months; HR, 0.66; P = .37). Collectively, patients with WM with CXCR4MUT or TP53MUT had worse prognosis compared with patients with WT alleles, and zanubrutinib led to better clinical outcomes.

Plain language summary of zanubrutinib or ibrutinib in chronic lymphocytic leukemia that is resistant to treatment or has come back after treatment

WHAT IS THIS SUMMARY ABOUT?

This is a plain language summary of a research study called ALPINE. The study involved people who had been diagnosed with, and previously treated at least once for, relapsed or refractory chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL). Lymphocytes help to find and fight off viruses and infections in the body, but when someone has CLL or SLL, the body creates abnormal lymphocytes, leaving the patient with a weakened immune system and susceptible to illness. In CLL, these lymphocytes are in the bone marrow and bloodstream, whereas for SLL, they are mostly found in the lymph nodes, such as those in the neck.

HOW WAS THE RESEARCH DONE?

The ALPINE study was designed to directly compare the cancer-fighting effects and side effects of zanubrutinib and ibrutinib as treatment for patients with relapsed or refractory CLL/SLL.

WHAT WERE THE RESULTS?

After 30 months, zanubrutinib was more effective than ibrutinib at reducing and keeping the cancer from coming back. Clinical Trial Registration: NCT03734016 (ClinicalTrials.gov).

An unappreciated cell survival-independent role for BAFF initiating chronic lymphocytic leukemia

Background

Chronic Lymphocytic Leukemia (CLL) is characterized by the expansion of CD19+ CD5+ B cells but its origin remains debated. Mutated CLL may originate from post-germinal center B cells and unmutated CLL from CD5+ mature B cell precursors. Irrespective of precursor types, events initiating CLL remain unknown. The cytokines BAFF and APRIL each play a significant role in CLL cell survival and accumulation, but their involvement in disease initiation remains unclear.

Methods

We generated novel CLL models lacking BAFF or APRIL. In vivo experiments were conducted to explore the impact of BAFF or APRIL loss on leukemia initiation, progression, and dissemination. Additionally, RNA-seq and quantitative real-time PCR were performed to unveil the transcriptomic signature influenced by BAFF in CLL. The direct role of BAFF in controlling the expression of tumor-promoting genes was further assessed in patient-derived primary CLL cells ex-vivo.

Results

Our findings demonstrate a crucial role for BAFF, but not APRIL, in the initiation and dissemination of CLL cells. In the absence of BAFF or its receptor BAFF-R, the TCL1 transgene only increases CLL cell numbers in the peritoneal cavity, without dissemination into the periphery. While BAFF binding to BAFF-R is dispensable for peritoneal CLL cell survival, it is necessary to activate a tumor-promoting gene program, potentially linked to CLL initiation and progression. This direct role of BAFF in controlling the expression of tumor-promoting genes was confirmed in patient-derived primary CLL cells ex-vivo.

Conclusions

Our study, involving both mouse and human CLL cells, suggests that BAFF might initiate CLL through mechanisms independent of cell survival. Combining current CLL therapies with BAFF inhibition could offer a dual benefit by reducing peripheral tumor burden and suppressing transformed CLL cell output.

Australia and New Zealand consensus position statement: use of COVID-19 therapeutics in patients with haematological malignancies

Despite widespread vaccination rates, we are living with high transmission rates of SARS-CoV-2. Although overall hospitalisation rates are falling, the risk of serious infection remains high for patients who are immunocompromised because of haematological malignancies. In light of the ongoing pandemic and the development of multiple agents for treatment, representatives from the Haematology Society of Australia and New Zealand and infectious diseases specialists have collaborated on this consensus position statement regarding COVID-19 management in patients with haematological disorders. It is our recommendation that both patients with haematological malignancies and treating specialists be educated regarding the preventive and treatment options available and that patients continue to receive adequate vaccinations, keeping in mind the suboptimal vaccine responses that occur in haematology patients, in particular, those with B-cell malignancies and on B-cell-targeting or depleting therapy. Patients with haematological malignancies should receive treatment for COVID-19 in accordance with the severity of their symptoms, but even mild infections should prompt early treatment with antiviral agents. The issue of de-isolation following COVID-19 infection and optimal time to treatment for haematological malignancies is discussed but remains an area with evolving data. This position statement is to be used in conjunction with advice from infectious disease, respiratory and intensive care specialists, and current guidelines from the National COVID-19 Clinical Evidence Taskforce and the New Zealand Ministry of Health and Cancer Agency Te Aho o Te Kahu COVID-19 Guidelines.

Sustained remissions in CLL after frontline FCR treatment with very-long-term follow-up

Chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab (FCR) achieves durable remissions, with flattening of the progression-free survival (PFS) curve in patients with mutated immunoglobulin heavy chain variable gene (IGHV-M). We updated long-term follow-up results from the original 300-patient FCR study initiated at MD Anderson in 1999. The current median follow-up is 19.0 years. With this extended follow-up, the median PFS for patients with IGHV-M was 14.6 years vs 4.2 years for patients with unmutated IGHV (IGHV-UM). Disease progression beyond 10 years was uncommon. In total, 16 of 94 (17%) patients in remission at 10 years subsequently progressed with the additional follow-up compared with the patients in our prior report in 2015. Only 4 of 45 patients (9%) with IGHV-M progressed beyond 10 years. Excluding Richter transformation, 96 of 300 patients (32%) developed 106 other malignancies, with 19 of 300 (6.3%) developing therapy-related myeloid neoplasms (tMNs), which were fatal in 16 of 19 (84%). No pretreatment patient characteristics predicted the risk of tMNs. In summary, FCR remains an option for patients with IGHV-M chronic lymphocytic leukemia (CLL), with a significant fraction achieving functional cure of CLL. A risk-benefit assessment is warranted when counseling patients, balancing potential functional cure with the risk of late relapses and serious secondary malignancies.

Zanubrutinib Versus Ibrutinib in Symptomatic Waldenström Macroglobulinemia: Final Analysis From the Randomized Phase III ASPEN Study

The phase III ASPEN study demonstrated the comparable efficacy and improved safety of zanubrutinib versus ibrutinib in patients with Waldenström macroglobulinemia (WM). Here, we report long-term follow-up outcomes from ASPEN. The primary end point was the sum of very good partial response (VGPR) + complete response (CR) rates; secondary and exploratory end points were also reported. Cohort 1 comprised 201 patients (myeloid differentiation primary response 88-mutant WM: 102 receiving zanubrutinib; 99 receiving ibrutinib); cohort 2 comprised 28 patients (myeloid differentiation primary response 88 wild-type WM: 28 zanubrutinib; 26 efficacy evaluable). At 44.4-month median follow-up, VGPR + CR rates were 36.3% with zanubrutinib versus 25.3% with ibrutinib in cohort 1 and 30.8% with one CR in cohort 2. In patients with CXC motif chemokine receptor 4 mutation, VGPR + CR rates were 21.2% with zanubrutinib versus 10.0% with ibrutinib (cohort 1). Median progression-free survival and overall survival were not reached. Any-grade adverse events (AEs) of diarrhea (34.7% v 22.8%), muscle spasms (28.6% v 11.9%), hypertension (25.5% v 14.9%), atrial fibrillation/flutter (23.5% v 7.9%), and pneumonia (18.4% v 5.0%) were more common with ibrutinib versus zanubrutinib; neutropenia (20.4% v 34.7%) was less common with ibrutinib versus zanubrutinib (cohort 1). Zanubrutinib was associated with lower risk of AE-related treatment discontinuation. Overall, these findings confirm the long-term response quality and tolerability associated with zanubrutinib.

Allogeneic stem cell transplantation achieves long-term remissions in mantle cell lymphoma, including in TP53-mutated disease

Cytarabine-containing chemoimmunotherapy followed by autologous transplantation and rituximab maintenance achieves durable remissions for most patients with mantle cell lymphoma (MCL). However, patients with TP53-mutated disease have poor outcomes with standard approaches. We previously reported that allogeneic stem cell transplantation (alloSCT) achieved durable remissions in MCL, however follow-up among patients with TP53-mutated disease was limited. Here we report extended follow-up of the overall cohort (n = 36) and TP53-mutated subset (n = 13) (median follow-up 10.8 and 4.2 years, respectively). Estimated overall survival was 56% at 10 years for the overall cohort and 59% at 4 years for the TP53-mutated subset. Among patients with TP53-mutated disease, no relapses occurred beyond 6 months post-transplant. Survival after post-alloSCT disease relapse was poor (median 2.1 years). These data confirm that alloSCT can be curative in MCL, including patients with TP53-mutated disease, and should be considered for earlier utilization in this subgroup for whom conventional chemoimmunotherapy is ineffective.

Cognition following chimeric antigen receptor T-cell therapy: A systematic review

BACKGROUND

This systematic review aimed to characterise the cognitive outcomes of patients who received chimeric antigen receptor T-cell therapy.

METHODS

A systematic search of the literature was performed using PubMed, PsycINFO, SCOPUS, EMBASE, Medline, and CINAHL (February 2023). Risk of bias was assessed using the JBI Checklist for Case Reports and the Risk of Bias Assessment Tool for Non-randomised Studies.

RESULTS

Twenty-two studies met inclusion criteria with a total of 1104 participants. There was considerable methodological heterogeneity with differing study designs (e.g., cohort studies, clinical trials, case studies, a qualitative interview, and a focus group), measures of cognition (e.g., self-report, neuropsychological measures, clinician assessed/neurological examinations), and longest follow-up time points (i.e., five days to five years).

DISCUSSION

Results of the studies were heterogenous with studies demonstrating stable, improved, or reduced cognition across differing time points. Overall, cognitive symptoms are common particularly in the acute stage (<2 weeks) post-infusion. Most deficits that arise in the acute stage resolve within one to two weeks, however, there is a subset of patients who continue to experience and self-report persistent deficits in the subacute and chronic stages. Future studies are needed to comprehensively analyse cognition using a combination of self-report and psychometric measures following chimeric antigen receptor T-cell therapy in the acute, subacute, and chronic settings.

Health-related quality of life outcomes associated with zanubrutinib versus ibrutinib monotherapy in patients with relapsed/refractory chronic lymphocytic leukemia and small lymphocytic lymphoma: results from the ALPINE Trial

OBJECTIVE

The purpose of this analysis was to assess health-related quality of life (HRQoL) in patients treated with zanubrutinib and ibrutinib in the ALPINE trial (NCT03734016).

METHODS

HRQoL was measured by the EORTC QLQ-C30 and EQ-5D-5L at baseline, cycle 1, and every third cycle until the end of treatment. Key patient-reported outcome (PRO) endpoints included global health status (GHS), physical and role functioning, as well as symptoms of fatigue, pain, diarrhea, and nausea/vomiting. A mixed model repeated-measure analysis using key PRO endpoints at key clinical cycles (cycles 7 and 13) was performed.

RESULTS

652 patients were randomized to receive zanubrutinib (n = 327) or ibrutinib (n = 325). By cycle 7, GHS scores improved with zanubrutinib versus ibrutinib, and in cycle 13, GHS scores remained higher in the zanubrutinib arm. The zanubrutinib arm experienced clinically meaningful improvements in physical and role functioning, as well as pain and fatigue symptoms at both cycles. Patients in the zanubrutinib arm reported lower diarrhea scores. Nausea/vomiting scores maintained in both arms. EQ-VAS scores showed greater improvement from baseline at both cycle 7 (7.92 versus 3.44) and cycle 13 (7.75 versus 3.92) of treatment with zanubrutinib compared to ibrutinib, respectively.

CONCLUSIONS

Patients with R/R CLL/SLL treated with zanubrutinib demonstrated improvement versus ibrutinib in the GHS scale at cycle 7. Other endpoints continued to improve, suggesting treatment with zanubrutinib positively affected HRQoL over time. Given the generally good HRQoL at baseline in both arms, the differences between the arms were not significant.

Health-related quality-of-life in treatment-naive CLL/SLL patients treated with zanubrutinib versus bendamustine plus rituximab

OBJECTIVE

Zanubrutinib is a highly selective, next-generation Bruton's tyrosine kinase inhibitor. In the phase 3 SEQUOIA trial (NCT03336333), treatment with zanubrutinib resulted in significantly improved progression-free survival compared to bendamustine plus rituximab (BR) in adult patients with treatment-naïve chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) without del(17p). The current analysis compared the effects of zanubrutinib versus BR on patients' health-related quality-of-life (HRQoL).

METHODS

In the SEQUOIA trial, patient-reported outcomes (PROs) were assessed at baseline and every 12 weeks (3 cycles) using the EORTC QLQ-C30 and EQ-5D-5L. Descriptive analyses were performed on all the questionnaires' scales and a mixed model for repeated measures was performed using the key QLQ-C30 endpoints of global health status/QoL (GHS/QoL), physical and role functioning, and symptoms of fatigue, pain, diarrhea, and nausea/vomiting at weeks 12 and 24.

RESULTS

Compared with BR-treated patients, those in the zanubrutinib arm experienced greater improvements in HRQoL outcomes at both weeks 12 and 24. By week 24, mean change differences (95% confidence interval) between the arms were significant for GHS/QoL (4.9 [0.9, 9.0]), physical functioning (3.8 [0.8, 6.7]), diarrhea (-6.2 [-10.0, -2.5]), fatigue (-4.5 [-8.9, -0.1]), and nausea/vomiting (-4.5 [-8.9, -0.1]); role functioning (4.8 [-0.2, 9.7]) was marginally better in the zanubrutinib arm and there were no differences in pain symptoms (-0.4 [-4.3, 5.1]) between the arms.

CONCLUSIONS

During the first 24 weeks of treatment, zanubrutinib was associated with better HRQoL outcomes in patients with treatment-naive CLL/SLL without del(17p) compared to BR.

TRIAL REGISTRATION

The SEQUOIA trial is registered on clinicaltrials.gov as SEQUOIA trial (NCT03336333).

Immune restoration with ibrutinib plus venetoclax in first-line chronic lymphocytic leukemia: the phase 2 CAPTIVATE study

We evaluated immune cell subsets in patients with chronic lymphocytic leukemia (CLL) who received first-line therapy with 3 cycles of ibrutinib then 13 cycles of ibrutinib plus venetoclax in the minimal residual disease (MRD) cohort of the CAPTIVATE study (NCT02910583). Patients with Confirmed undetectable MRD (uMRD) were randomly assigned to placebo or ibrutinib groups; patients without Confirmed uMRD were randomly assigned to ibrutinib or ibrutinib plus venetoclax groups. We compared immune cell subsets in samples collected at 7 time points with age-matched healthy donors. CLL cells decreased within 3 cycles after venetoclax initiation; from cycle 16 onward, levels were similar to healthy donor levels (HDL; ≤0.8 cells per μL) in patients with Confirmed uMRD and slightly above HDL in patients without Confirmed uMRD. By 4 months after cycle 16, normal B cells had recovered to HDL in patients randomly assigned to placebo. Regardless of randomized treatment, abnormal counts of T cells, classical monocytes, and conventional dendritic cells recovered to HDL within 6 months (median change from baseline -49%, +101%, and +91%, respectively); plasmacytoid dendritic cells recovered by cycle 20 (+598%). Infections generally decreased over time regardless of randomized treatment and were numerically lowest in patients randomly assigned to placebo within 12 months after cycle 16. Sustained elimination of CLL cells and recovery of normal B cells were confirmed in samples from patients treated with fixed-duration ibrutinib plus venetoclax in the GLOW study (NCT03462719). These results demonstrate promising evidence of restoration of normal blood immune composition with ibrutinib plus venetoclax.

Zanubrutinib: past, present, and future

In recent years, Bruton tyrosine kinase (BTK) inhibitors have provided significant advances in the treatment of patients with B-cell malignancies. Ibrutinib was the first BTK inhibitor to be approved, and it changed the standard-of-care treatment for diseases such as chronic lymphocytic leukemia, mantle cell lymphoma, marginal zone lymphoma, and Waldenström macroglobulinemia, improving efficacy outcomes and safety compared to chemotherapy. In this article, we review the development of zanubrutinib, a next-generation BTK inhibitor, from molecular design to patient-related outcomes. We start this journey by providing insights into the discovery of BTK and the physiologic, genetic, and molecular characterization of patients lacking this kinase, together with the brief treatment landscape in the era of chemo-immunotherapies. Zanubrutinib was originally developed by applying a structure-activity strategy to enhance the specificity as well as enzymatic and pharmacokinetic properties. Preclinical studies confirmed greater specificity and better bioavailability of zanubrutinib compared with that of ibrutinib, which supported the initiation of clinical trials in humans. Preliminary clinical results indicated activity in B-cell malignancies together with an improved safety profile, in line with less off-target effects described in the preclinical studies. The clinical program of zanubrutinib has since expanded significantly, with ongoing studies in a wide range of hemato-oncological diseases and in combination with many other therapies. Zanubrutinib currently is approved for various B-cell malignancies in multiple countries. This story highlights the importance of multidisciplinary collaborative research, from bench to bedside, and provides an example of how the commitment to finding improved treatment options should always run parallel to patient care.

Chronic lymphocytic leukaemia Australasian consensus practice statement

Chronic lymphocytic leukaemia (CLL) is the most common haematological malignancy in Australia and New Zealand (ANZ). Considerable changes to diagnostic and management algorithms have occurred within the last decade. The availability of next-generation sequencing and measurable residual disease assessment by flow cytometry allow for advanced prognostication and response assessments. Novel therapies, including inhibitors of Bruton's tyrosine kinase (BTKi) and B-cell lymphoma 2 (BCL2) inhibitors, have transformed the treatment landscape for both treatment-naïve and relapsed/refractory disease, particularly for patients with high-risk genetic aberrations. Recommendations regarding appropriate supportive management continue to evolve, and special considerations are required for patients with CLL with respect to the global SARS-CoV-2 pandemic. The unique funding and treatment environments in Australasia highlight the need for specific local guidance with respect to the investigation and management of CLL. This consensus practice statement was developed by a broadly representative group of ANZ experts in CLL with endorsement by peak haematology bodies, with a view to providing this standardised guidance.

Long-term outcomes of second-line versus later-line zanubrutinib treatment in patients with relapsed/refractory mantle cell lymphoma: An updated pooled analysis

BACKGROUND

We previously reported results of a pooled analysis of two zanubrutinib studies in relapsed or refractory (R/R) MCL showing better survival outcomes when zanubrutinib is used in second-line versus later-line. Here, we present an updated pooled analysis with a longer follow-up of 35.2 months.

METHODS

Data were pooled from two studies-BGB-3111-AU-003 (NCT02343120) and BGB-3111-206 (NCT03206970) of zanubrutinib in R/R MCL. The patients were divided into two groups based on the treatment line of zanubrutinib: the second-line and the later-line group. The inverse propensity score weighting method was used to balance the baseline covariates between the groups. The primary outcome was overall survival (OS). Secondary outcomes included progression-free survival (PFS), PFS, and OS rates, objective response rate (ORR), duration of response (DOR), and safety.

RESULTS

Among 112 pooled patients, 41 (36.6%) patients received zanubrutinib as second-line and 71 (63.4%) patients as later-line therapy. After weighting, OS was significantly improved in the second-line versus later-line group (HR, 0.459 [95% CI: 0.215, 0.98]; p = 0.044) with median OS not estimable in both groups. The PFS was similar between the two groups (HR, 0.78 [95% CI: 0.443, 1.373]; p = 0.389) but with numerically longer median PFS in the second-line versus later-line group (27.8 vs. 22.1 months). ORR was numerically higher in the second-line versus later-line (88.6% vs. 85.7%), and DOR was similar between the two groups (25.2 vs. 25.1 months). Zanubrutinib showed a similar safety profile in both groups.

CONCLUSION

Zanubrutinib in second-line treatment was associated with significantly improved OS compared with later-line treatment of R/R MCL.

Pirtobrutinib in Covalent Bruton Tyrosine Kinase Inhibitor Pretreated Mantle-Cell Lymphoma

PURPOSE

Pirtobrutinib is a highly selective, noncovalent (reversible) Bruton tyrosine kinase inhibitor (BTKi). We report the safety and efficacy of pirtobrutinib in patients with covalent Bruton tyrosine kinase inhibitor (cBTKi) pretreated mantle-cell lymphoma (MCL), a population with poor prognosis.

METHODS

Patients with cBTKi pretreated relapsed/refractory (R/R) MCL received pirtobrutinib monotherapy in a multicenter phase I/II trial (BRUIN; ClinicalTrials.gov identifier: NCT03740529). Efficacy was assessed in the first 90 consecutively enrolled patients who met criteria for inclusion in the primary efficacy cohort. The primary end point was overall response rate (ORR). Secondary end points included duration of response (DOR) and safety.

RESULTS

The median patient age was 70 years (range, 46-87), the median prior lines of therapy was 3 (range, 1-8), 82.2% had discontinued a prior cBTKi because of disease progression, and 77.8% had intermediate- or high-risk simplified MCL International Prognostic Index score. The ORR was 57.8% (95% CI, 46.9 to 68.1), including 20.0% complete responses (n = 18). At a median follow-up of 12 months, the median DOR was 21.6 months (95% CI, 7.5 to not reached). The 6- and 12-month estimated DOR rates were 73.6% and 57.1%, respectively. In the MCL safety cohort (n = 164), the most common treatment-emergent adverse events (TEAEs) were fatigue (29.9%), diarrhea (21.3%), and dyspnea (16.5%). Grade ≥3 TEAEs of hemorrhage (3.7%) and atrial fibrillation/flutter (1.2%) were less common. Only 3% of patients discontinued pirtobrutinib because of a treatment-related adverse event.

CONCLUSION

Pirtobrutinib is a first-in-class novel noncovalent (reversible) BTKi and the first BTKi of any kind to demonstrate durable efficacy after prior cBTKi therapy in heavily pretreated R/R MCL. Pirtobrutinib was well tolerated with low rates of treatment discontinuation because of toxicity.

Outcomes in Patients with High-Risk Features after Fixed-Duration Ibrutinib plus Venetoclax: Phase II CAPTIVATE Study in First-Line Chronic Lymphocytic Leukemia

PURPOSE

The CAPTIVATE study investigated first-line ibrutinib plus venetoclax for chronic lymphocytic leukemia in 2 cohorts: minimal residual disease (MRD)-guided randomized discontinuation (MRD cohort) and Fixed Duration (FD cohort). We report outcomes of fixed-duration ibrutinib plus venetoclax in patients with high-risk genomic features [del(17p), TP53 mutation, and/or unmutated immunoglobulin heavy chain (IGHV)] in CAPTIVATE.

PATIENTS AND METHODS

Patients received three cycles of ibrutinib 420 mg/day then 12 cycles of ibrutinib plus venetoclax (5-week ramp-up to 400 mg/day). FD cohort patients (n = 159) received no further treatment. Forty-three MRD cohort patients with confirmed undetectable MRD (uMRD) after 12 cycles of ibrutinib plus venetoclax received randomized placebo treatment.

RESULTS

Of 195 patients with known status of genomic risk features at baseline, 129 (66%) had ≥1 high-risk feature. Overall response rates were >95% regardless of high-risk features. In patients with and without high-risk features, respectively, complete response (CR) rates were 61% and 53%; best uMRD rates: 88% and 70% (peripheral blood) and 72% and 61% (bone marrow); 36-month progression-free survival (PFS) rates: 88% and 92%. In subsets with del(17p)/TP53 mutation (n = 29) and unmutated IGHV without del(17p)/TP53 mutation (n = 100), respectively, CR rates were 52% and 64%; uMRD rates: 83% and 90% (peripheral blood) and 45% and 80% (bone marrow); 36-month PFS rates: 81% and 90%. Thirty-six-month overall survival (OS) rates were >95% regardless of high-risk features.

CONCLUSIONS

Deep, durable responses and sustained PFS seen with fixed-duration ibrutinib plus venetoclax are maintained in patients with high-risk genomic features, with similar PFS and OS to those without high-risk features. See related commentary by Rogers, p. 2561.

Pirtobrutinib after a Covalent BTK Inhibitor in Chronic Lymphocytic Leukemia

BACKGROUND

Patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) have poor outcomes after the failure of covalent Bruton's tyrosine kinase (BTK) inhibitor treatment, and new therapeutic options are needed. Pirtobrutinib, a highly selective, noncovalent (reversible) BTK inhibitor, was designed to reestablish BTK inhibition.

METHODS

We conducted a phase 1-2 trial in which patients with relapsed or refractory B-cell cancers received pirtobrutinib. Here, we report efficacy results among patients with CLL or SLL who had previously received a BTK inhibitor as well as safety results among all the patients with CLL or SLL. The primary end point was an overall response (partial response or better) as assessed by independent review. Secondary end points included progression-free survival and safety.

RESULTS

A total of 317 patients with CLL or SLL received pirtobrutinib, including 247 who had previously received a BTK inhibitor. Among these 247 patients, the median number of previous lines of therapy was 3 (range, 1 to 11), and 100 patients (40.5%) had also received a B-cell lymphoma 2 (BCL2) inhibitor such as venetoclax. The percentage of patients with an overall response to pirtobrutinib was 73.3% (95% confidence interval [CI], 67.3 to 78.7), and the percentage was 82.2% (95% CI, 76.8 to 86.7) when partial response with lymphocytosis was included. The median progression-free survival was 19.6 months (95% CI, 16.9 to 22.1). Among all 317 patients with CLL or SLL who received pirtobrutinib, the most common adverse events were infections (in 71.0%), bleeding (in 42.6%), and neutropenia (in 32.5%). At a median duration of treatment of 16.5 months (range, 0.2 to 39.9), some adverse events that are typically associated with BTK inhibitors occurred relatively infrequently, including hypertension (in 14.2% of patients), atrial fibrillation or flutter (in 3.8%), and major hemorrhage (in 2.2%). Only 9 of 317 patients (2.8%) discontinued pirtobrutinib owing to a treatment-related adverse event.

CONCLUSIONS

In this trial, pirtobrutinib showed efficacy in patients with heavily pretreated CLL or SLL who had received a covalent BTK inhibitor. The most common adverse events were infections, bleeding, and neutropenia. (Funded by Loxo Oncology; BRUIN ClinicalTrials.gov number, NCT03740529.).

Pirtobrutinib: a new hope for patients with BTK inhibitor-refractory lymphoproliferative disorders

Patients with lymphoproliferative disorders such as chronic lymphocytic leukemia and mantle cell lymphoma (MCL) who are resistant to covalent Bruton tyrosine kinase inhibitors (cBTKis), especially if also venetoclax refractory, have an unmet therapeutic need. Pirtobrutinib, a noncovalent BTKi, achieves high response rates in patients who are refractory to cBTKi, regardless of mechanism of cBTKi resistance. This led to recent accelerated US Food and Drug Administration approval in MCL. The toxicity profile in early studies suggests suitability for use in combination approaches. We summarize existing preclinical and clinical data for pirtobrutinib.

BTK and PLCG2 remain unmutated in one-third of patients with CLL relapsing on ibrutinib

Patients with chronic lymphocytic leukemia (CLL) progressing on ibrutinib constitute an unmet need. Though Bruton tyrosine kinase (BTK) and PLCG2 mutations are associated with ibrutinib resistance, their frequency and relevance to progression are not fully understood. In this multicenter retrospective observational study, we analyzed 98 patients with CLL on ibrutinib (49 relapsing after an initial response and 49 still responding after ≥1 year of continuous treatment) using a next-generation sequencing (NGS) panel (1% sensitivity) comprising 13 CLL-relevant genes including BTK and PLCG2. BTK hotspot mutations were validated by droplet digital polymerase chain reaction (ddPCR) (0.1% sensitivity). By integrating NGS and ddPCR results, 32 of 49 relapsing cases (65%) carried at least 1 hotspot BTK and/or PLCG2 mutation(s); in 6 of 32, BTK mutations were only detected by ddPCR (variant allele frequency [VAF] 0.1% to 1.2%). BTK/PLCG2 mutations were also identified in 6 of 49 responding patients (12%; 5/6 VAF <10%), of whom 2 progressed later. Among the relapsing patients, the BTK-mutated (BTKmut) group was enriched for EGR2 mutations, whereas BTK-wildtype (BTKwt) cases more frequently displayed BIRC3 and NFKBIE mutations. Using an extended capture-based panel, only BRAF and IKZF3 mutations showed a predominance in relapsing cases, who were enriched for del(8p) (n = 11; 3 BTKwt). Finally, no difference in TP53 mutation burden was observed between BTKmut and BTKwt relapsing cases, and ibrutinib treatment did not favor selection of TP53-aberrant clones. In conclusion, we show that BTK/PLCG2 mutations were absent in a substantial fraction (35%) of a real-world cohort failing ibrutinib, and propose additional mechanisms contributing to resistance.

Utility of Measurable Residual Disease (MRD) Assessment in Mantle Cell Lymphoma

OPINION STATEMENT

Mantle cell lymphoma (MCL) treatment advances have significantly improved disease-free remission, with greater focus in clinical trials being placed on measurable residual disease (MRD) as a marker of subclinical disease assessment. While this concept is used extensively in other haematological neoplasms, there is yet to be a consensus on the threshold for MRD in MCL that demonstrates prognostic and therapeutic significance, and in this context has yet to reach routine clinical practice. The historical long-term method for MCL MRD assessment has been real-time quantitative polymerase chain reaction (PCR), targeting the clonal immunoglobulin heavy locus (IGH) rearrangement or the IGH::CCND1 translocation rearrangement. A significant problem at present relates to identifying alternative assays for patients who do not have a suitable molecular target by this method. This article reviews existing techniques used in MRD assessment for MCL and describes novel methods which may overcome existing limitations, including next-generation sequencing modalities. The use of circulating tumour DNA is explored, with techniques such as CAPP-Seq and PhasED-Seq demonstrating promise in B-lymphoproliferative disorders, though application in MCL requires further study. The other aspect of practice using MRD is identifying therapeutic options which can address a subclinical molecular relapse. Developing suitable interventions that can alter the disease trajectory based on longitudinal MRD kinetics are needed to justify its incorporation into standard care.

Report of consensus panel 1 from the 11th International Workshop on Waldenstrom's Macroglobulinemia on management of symptomatic, treatment-naïve patients

Consensus Panel 1 (CP1) of the 11th International Workshop on Waldenstrom's Macroglobulinemia (IWWM-11) was tasked with updating guidelines for the management of symptomatic, treatment-naïve patients with WM. The panel reiterated that watchful waiting remains the gold standard for asymptomatic patients without critically elevated IgM or compromised hematopoietic function. For first-line treatment, chemoimmunotherapy (CIT) regimens such as dexamethasone, cyclophosphamide, rituximab (DRC), or bendamustine, rituximab (Benda-R) continue to play a central role in managing WM, as they are effective, of fixed duration, generally well-tolerated, and affordable. Covalent BTK inhibitors (cBTKi) offer a continuous, generally well-tolerated alternative for the primary treatment of WM patients, particularly those unsuitable for CIT. In a Phase III randomized trial updated at IWWM-11, the second-generation cBTKi, zanubrutinib, was less toxic than ibrutinib and induced deeper remissions, thus categorizing zanubrutinib as a suitable treatment option in WM. While the overall findings of a prospective, randomized trial updated at IWWM-11 did not show superiority of fixed duration rituximab maintenance over observation following attainment of a major response to Benda-R induction, a subset analysis showed benefit in patients >65 years and those with a high IPPSWM score. Whenever possible, the mutational status of MYD88 and CXCR4 should be determined before treatment initiation, as alterations in these 2 genes predict sensitivity towards cBTKi activity. Treatment approaches for WM-associated cryoglobulins, cold agglutinins, AL amyloidosis, Bing-Neel syndrome (BNS), peripheral neuropathy, and hyperviscosity syndrome follow the common principle of reducing tumor and abnormal protein burden rapidly and deeply to improve symptoms. In BNS, ibrutinib can be highly active and produce durable responses. In contrast, cBTKi are not recommended for treating AL amyloidosis. The panel emphasized that continuous improvement of treatment options for symptomatic, treatment-naïve WM patients critically depends on the participation of patients in clinical trials, whenever possible.

Report of consensus panel 7 from the 11th international workshop on Waldenström macroglobulinemia on priorities for novel clinical trials

Recent advances in the understanding of Waldenström macroglobulinemia (WM) biology have impacted the development of effective novel agents and improved our knowledge of how the genomic background of WM may influence selection of therapy. Consensus Panel 7 (CP7) of the 11th International Workshop on WM was convened to examine the current generation of completed and ongoing clinical trials involving novel agents, consider updated data on WM genomics, and make recommendations on the design and prioritization of future clinical trials. CP7 considers limited duration and novel-novel agent combinations to be the priority for the next generation of clinical trials. Evaluation of MYD88, CXCR4 and TP53 at baseline in the context of clinical trials is crucial. The common chemoimmunotherapy backbones, bendamustine-rituximab (BR) and dexamethasone, rituximab and cyclophosphamide (DRC), may be considered standard-of-care for the frontline comparative studies. Key unanswered questions include the definition of frailty in WM; the importance of attaining a very good partial response or better (≥VGPR), within stipulated time frame, in determining survival outcomes; and the optimal treatment of WM populations with special needs.

Report of consensus Panel 4 from the 11th International Workshop on Waldenstrom's macroglobulinemia on diagnostic and response criteria

Consensus Panel 4 (CP4) of the 11th International Workshop on Waldenstrom's Macroglobulinemia (IWWM-11) was tasked with reviewing the current criteria for diagnosis and response assessment. Since the initial consensus reports of the 2nd International Workshop, there have been updates in the understanding of the mutational landscape of IgM related diseases, including the discovery and prevalence of MYD88 and CXCR4 mutations; an improved recognition of disease related morbidities attributed to monoclonal IgM and tumor infiltration; and a better understanding of response assessment based on multiple, prospective trials that have evaluated diverse agents in Waldenstrom's macroglobulinemia. The key recommendations from IWWM-11 CP4 included: (1) reaffirmation of IWWM-2 consensus panel recommendations that arbitrary values for laboratory parameters such as minimal IgM level or bone marrow infiltration should not be used to distinguish Waldenstrom's macroglobulinemia from IgM MGUS; (2) delineation of IgM MGUS into 2 subclasses including a subtype characterized by clonal plasma cells and MYD88 wild-type, and the other by presence of monotypic or monoclonal B cells which may carry the MYD88 mutation; and (3) recognition of "simplified" response assessments that use serum IgM only for determining partial and very good partial responses (simplified IWWM-6/new IWWM-11 response criteria). Guidance on response determination for suspected IgM flare and IgM rebound related to treatment, as well as extramedullary disease assessment was also updated and included in this report.

Report of consensus panel 2 from the 11th international workshop on Waldenström's macroglobulinemia on the management of relapsed or refractory WM patients

The consensus panel 2 (CP2) of the 11th International Workshop on Waldenström's macroglobulinemia (IWWM-11) has reviewed and incorporated current data to update the recommendations for treatment approaches in patients with relapsed or refractory WM (RRWM). The key recommendations from IWWM-11 CP2 include: (1) Chemoimmunotherapy (CIT) and/or a covalent Bruton tyrosine kinase (cBTKi) strategies are important options; their use should reflect the prior upfront strategy and are subject to their availability. (2) In selecting treatment, biological age, co-morbidities and fitness are important; nature of relapse, disease phenotype and WM-related complications, patient preferences and hematopoietic reserve are also critical factors while the composition of the BM disease and mutational status (MYD88, CXCR4, TP53) should also be noted. (3) The trigger for initiating treatment in RRWM should utilize knowledge of patients' prior disease characteristics to avoid unnecessary delays. (4) Risk factors for cBTKi related toxicities (cardiovascular dysfunction, bleeding risk and concurrent medication) should be addressed when choosing cBTKi. Mutational status (MYD88, CXCR4) may influence the cBTKi efficacy, and the role of TP53 disruptions requires further study) in the event of cBTKi failure dose intensity could be up titrated subject to toxicities. Options after BTKi failure include CIT with a non-cross-reactive regimen to one previously used CIT, addition of anti-CD20 antibody to BTKi, switching to a newer cBTKi or non-covalent BTKi, proteasome inhibitors, BCL-2 inhibitors, and new anti-CD20 combinations are additional options. Clinical trial participation should be encouraged for all patients with RRWM.

Plain Language Summary of the iNNOVATE study: ibrutinib plus rituximab is well-tolerated and effective in people with Waldenström's macroglobulinemia

WHAT IS THIS SUMMARY ABOUT?

This article provides a short summary of 5-year results from the iNNOVATE trial. The original paper was published in the Journal of Clinical Oncology in October 2021. People with Waldenström's macroglobulinemia (WM) were randomly divided into two groups of 75 people each. One group received a combination treatment composed of two drugs, ibrutinib plus rituximab, and the other group took placebo ("sugar pill") plus rituximab. Ibrutinib (also known by the brand name Imbruvica^®) is a drug that reduces cancer cells' ability to multiply and survive. Ibrutinib is an FDA-approved drug for the treatment of WM. Rituximab is a drug that helps the immune system find and kill cancer cells. Participants in the trial were treated and their health monitored for up to 5 years (63 months).

WHAT WERE THE RESULTS?

During the 5 years of monitoring, more people who took ibrutinib plus rituximab experienced an improvement in their disease and lived longer without their disease getting worse compared to those who took placebo plus rituximab. Side effects from ibrutinib and rituximab were manageable and generally decreased over time. Participants in both study groups reported improvements in quality of life, but those who took ibrutinib plus rituximab reported significantly greater improvement in their quality of life (as measured by FACT-An score) compared to those who took placebo plus rituximab.

WHAT DO THE RESULTS MEAN?

These results show that ibrutinib plus rituximab is better than rituximab alone in people with WM and that ibrutinib plus rituximab is safe and effective in the long term. This information confirms the role of ibrutinib plus rituximab as a standard of care for WM. Clinical Trial Registration: NCT02165397 (ClinicalTrials.gov).

Zanubrutinib Versus Ibrutinib in Relapsed/Refractory Chronic Lymphocytic Leukemia and Small Lymphocytic Lymphoma: Interim Analysis of a Randomized Phase III Trial

PURPOSE

Zanubrutinib is a potent, irreversible next-generation Bruton tyrosine kinase (BTK) inhibitor designed to maximize BTK occupancy and minimize off-target kinase inhibition. We hypothesized that complete/sustained BTK occupancy may improve efficacy outcomes and increased BTK specificity may minimize off-target inhibition-related toxicities.

PATIENTS AND METHODS

ALPINE (ClinicalTrials.gov identifier: NCT03734016) is a global, randomized, open-label phase III study of zanubrutinib versus ibrutinib in patients with relapsed/refractory chronic lymphocytic leukemia. The primary end point was investigator-assessed overall response rate (ORR). The preplanned interim analysis was scheduled approximately 12 months after the first 415 patients were enrolled.

RESULTS

Between November 1, 2018, and December 14, 2020, 652 patients were enrolled. We present the interim analysis of the first 415 enrolled patients randomly assigned to receive zanubrutinib (n = 207) or ibrutinib (n = 208). At 15 months of median follow-up, ORR (partial or complete response) was significantly higher with zanubrutinib (78.3%; 95% CI, 72.0 to 83.7) versus ibrutinib (62.5%; 95% CI, 55.5 to 69.1; two-sided P < .001). ORR was higher with zanubrutinib versus ibrutinib in subgroups with del(17p)/TP53 mutations (80.5% v 50.0%) and del(11q) (83.6% v 69.1%); 12-month progression-free survival in all patients was higher with zanubrutinib (94.9%) versus ibrutinib (84.0%; hazard ratio, 0.40; 95% CI, 0.23 to 0.69). Atrial fibrillation rate was significantly lower with zanubrutinib versus ibrutinib (2.5% v 10.1%; two-sided P = .001). Rates of cardiac events, major hemorrhages, and adverse events leading to treatment discontinuation/death were lower with zanubrutinib.

CONCLUSION

Zanubrutinib had a significantly higher ORR, lower atrial fibrillation rate, and improved progression-free survival and overall cardiac safety profile versus ibrutinib. These data support improved efficacy/safety outcomes with selective BTK inhibition.

Treatment approaches for patients with TP53-mutated mantle cell lymphoma

Mantle cell lymphoma is an uncommon subtype of lymphoma characterised by clinical and biological heterogeneity. Although most patients with mantle cell lymphoma have durable responses after chemoimmunotherapy, there is a need to prospectively identify high-risk subsets of patients for whom disease control with standard chemotherapy will be short lived. Among the available prognostic factors, TP53 mutations are uniquely informative owing to their strong association with early disease progression and death among patients receiving conventional chemoimmunotherapy, with the highest negative prognostic value compared with other established risk indicators, including the mantle cell lymphoma international prognostic index, histological features, elevated Ki-67, and other genetic lesions. The poor outcomes for patients with TP53-mutated mantle cell lymphoma receiving chemoimmunotherapy and second-line Bruton tyrosine kinase inhibitors represent an urgent need for alternative approaches. In this Review, we synthesise the available data to inform the management of this high-risk subset of patients and present a treatment strategy prioritising clinical trials and early use of cellular therapies.

Real-world experience of Australian and New Zealand patients with chronic lymphocytic leukemia and mantle cell lymphoma accessing ibrutinib through a Named Patient Program

Ibrutinib is a small molecule inhibitor of Bruton's tyrosine kinase indicated for the treatment of relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma (SLL), and mantle cell lymphoma (MCL). The Named Patient Program in Australia and New Zealand (ANZ NPP) provided access to ibrutinib treatment to 1126 R/R CLL/SLL and 330 R/R MCL patients, prior to Pharmaceutical Benefits Scheme listing. This study aimed to assess the duration of treatment for the ANZ NPP patients, as an indicator of efficacy and tolerability of ibrutinib in the real world. Based on the NPP data, ibrutinib provided a median of 47 months clinical benefit for participants with CLL/SLL and 14 months clinical benefit for those with MCL; outcomes that are consistent with the clinical trial results and further support the well-established efficacy and safety profile of ibrutinib in the real world.

Zanubrutinib or Ibrutinib in Relapsed or Refractory Chronic Lymphocytic Leukemia

BACKGROUND

In a multinational, phase 3, head-to-head trial, ibrutinib, a Bruton's tyrosine kinase (BTK) inhibitor, was compared with zanubrutinib, a BTK inhibitor with greater specificity, as treatment for relapsed or refractory chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL). In prespecified interim analyses, zanubrutinib was superior to ibrutinib with respect to overall response (the primary end point). Data from the final analysis of progression-free survival are now available.

METHODS

We randomly assigned, in a 1:1 ratio, patients with relapsed or refractory CLL or SLL who had received at least one previous course of therapy to receive zanubrutinib or ibrutinib until the occurrence of disease progression or unacceptable toxic effects. In this final analysis, progression-free survival (a key secondary end point) was assessed with the use of a hierarchical testing strategy to determine whether zanubrutinib was noninferior to ibrutinib. If noninferiority was established, the superiority of zanubrutinib was assessed and claimed if the two-sided P value was less than 0.05.

RESULTS

At a median follow-up of 29.6 months, zanubrutinib was found to be superior to ibrutinib with respect to progression-free survival among 652 patients (hazard ratio for disease progression or death, 0.65; 95% confidence interval, [CI], 0.49 to 0.86; P = 0.002), as assessed by the investigators; the results were similar to those as assessed by an independent-review committee. At 24 months, the investigator-assessed rates of progression-free survival were 78.4% in the zanubrutinib group and 65.9% in the ibrutinib group. Among patients with a 17p deletion, a TP53 mutation, or both, those who received zanubrutinib had longer progression-free survival than those who received ibrutinib (hazard ratio for disease progression or death, 0.53; 95% CI, 0.31 to 0.88); progression-free survival across other major subgroups consistently favored zanubrutinib. The percentage of patients with an overall response was higher in the zanubrutinib group than in the ibrutinib group. The safety profile of zanubrutinib was better than that of ibrutinib, with fewer adverse events leading to treatment discontinuation and fewer cardiac events, including fewer cardiac events leading to treatment discontinuation or death.

CONCLUSIONS

In patients with relapsed or refractory CLL or SLL, progression-free survival was significantly longer among patients who received zanubrutinib than among those who received ibrutinib, and zanubrutinib was associated with fewer cardiac adverse events. (Funded by BeiGene; ALPINE ClinicalTrials.gov number, NCT03734016.).

Prospective comprehensive profiling of immune responses to COVID-19 vaccination in patients on zanubrutinib therapy

Zanubrutinib-treated and treatment-naïve patients with chronic lymphocytic leukaemia (CLL) or Waldenstrom's macroglobulinaemia were recruited in this prospective study to comprehensively profile humoral and cellular immune responses to COVID-19 vaccination. Overall, 45 patients (median 72 years old) were recruited; the majority were male (71%), had CLL (76%) and were on zanubrutinib (78%). Seroconversion rates were 65% and 77% following two and three doses, respectively. CD4⁺ and CD8⁺ T-cell response rates increased with third dose. In zanubrutinib-treated patients, 86% developed either a humoral or cellular response. Patients on zanubrutinib developed substantial immune responses following two COVID-19 vaccine doses, which further improved following a third dose.

Consensus opinion from an international group of experts on measurable residual disease in hairy cell leukemia

A significant body of literature has been generated related to the detection of measurable residual disease (MRD) at the time of achieving complete remission (CR) in patients with hairy cell leukemia (HCL). However, due to the indolent nature of the disease as well as reports suggesting long-term survival in patients treated with a single course of a nucleoside analog albeit without evidence of cure, the merits of detection of MRD and attempts to eradicate it have been debated. Studies utilizing novel strategies in the relapse setting have demonstrated the utility of achieving CR with undetectable MRD (uMRD) in prolonging the duration of remission. Several assays including immunohistochemical analysis of bone marrow specimens, multi-parameter flow cytometry and molecular assays to detect the mutant BRAF V600E gene or the consensus primer for the immunoglobulin heavy chain gene (IGH) rearrangement have been utilized with few comparative studies. Here we provide a consensus report on the available data, the potential merits of MRD assessment in the front-line and relapse settings and recommendations on future role of MRD assessment in HCL.

Development of a distributed international patient data registry for hairy cell leukemia

Hairy cell leukemia (HCL) is a rare lymphoproliferative disorder, comprising only 2% of all leukemias. The Hairy Cell Leukemia Foundation (HCLF) has developed a patient data registry to enable investigators to better study the clinical features, treatment outcomes, and complications of patients with HCL. This system utilizes a centralized registry architecture. Patients are enrolled at HCL Centers of Excellence (COE) or via a web-based portal. All data are de-identified, which reduces regulatory burden and increases opportunities for data access and re-use. To date, 579 patients have been enrolled in the registry. Efforts are underway to engage additional COE's to expand access to patients across the globe. This international PDR will enable researchers to study outcomes in HCL in ways not previously possible due to the rarity of the disease and will serve as a platform for future prospective research.

Treatment of Patients with Waldenström Macroglobulinaemia: Clinical practice update from the Myeloma Foundation of Australia Medical and Scientific Advisory Group

Waldenström macroglobulinaemia (WM) is an indolent B-cell malignancy characterised by the presence of IgM paraprotein, bone marrow infiltration by clonal small B lymphocytes with plasmacytic differentiation and the MYD88 L265P mutation in >90% of cases. Traditionally, WM has been treated with chemoimmunotherapy. Recent trials have demonstrated the efficacy and safety of Bruton tyrosine kinase inhibitors in WM, both as monotherapy and in combination with other drugs. There is emerging evidence on use of other agents including BCL2 inhibitors and on treatment of rare presentations of WM. In this update, the Medical and Scientific Advisory Group of Myeloma Australia review the available evidence on the treatment of WM since the last publication in 2017 and provide specific recommendations to assist Australian clinicians in the management of this disease.

Genomic profiling for clinical decision making in lymphoid neoplasms

With the introduction of large-scale molecular profiling methods and high-throughput sequencing technologies, the genomic features of most lymphoid neoplasms have been characterized at an unprecedented scale. Although the principles for the classification and diagnosis of these disorders, founded on a multidimensional definition of disease entities, have been consolidated over the past 25 years, novel genomic data have markedly enhanced our understanding of lymphomagenesis and enriched the description of disease entities at the molecular level. Yet, the current diagnosis of lymphoid tumors is largely based on morphological assessment and immunophenotyping, with only few entities being defined by genomic criteria. This paper, which accompanies the International Consensus Classification of mature lymphoid neoplasms, will address how established assays and newly developed technologies for molecular testing already complement clinical diagnoses and provide a novel lens on disease classification. More specifically, their contributions to diagnosis refinement, risk stratification, and therapy prediction will be considered for the main categories of lymphoid neoplasms. The potential of whole-genome sequencing, circulating tumor DNA analyses, single-cell analyses, and epigenetic profiling will be discussed because these will likely become important future tools for implementing precision medicine approaches in clinical decision making for patients with lymphoid malignancies.

Single-cell multiomics reveal the scale of multilayered adaptations enabling CLL relapse during venetoclax therapy

Venetoclax (VEN) inhibits the prosurvival protein BCL2 to induce apoptosis and is a standard therapy for chronic lymphocytic leukemia (CLL), delivering high complete remission rates and prolonged progression-free survival in relapsed CLL but with eventual loss of efficacy. A spectrum of subclonal genetic changes associated with VEN resistance has now been described. To fully understand clinical resistance to VEN, we combined single-cell short- and long-read RNA-sequencing to reveal the previously unappreciated scale of genetic and epigenetic changes underpinning acquired VEN resistance. These appear to be multilayered. One layer comprises changes in the BCL2 family of apoptosis regulators, especially the prosurvival family members. This includes previously described mutations in BCL2 and amplification of the MCL1 gene but is heterogeneous across and within individual patient leukemias. Changes in the proapoptotic genes are notably uncommon, except for single cases with subclonal losses of BAX or NOXA. Much more prominent was universal MCL1 gene upregulation. This was driven by an overlying layer of emergent NF-κB (nuclear factor kappa B) activation, which persisted in circulating cells during VEN therapy. We discovered that MCL1 could be a direct transcriptional target of NF-κB. Both the switch to alternative prosurvival factors and NF-κB activation largely dissipate following VEN discontinuation. Our studies reveal the extent of plasticity of CLL cells in their ability to evade VEN-induced apoptosis. Importantly, these findings pinpoint new approaches to circumvent VEN resistance and provide a specific biological justification for the strategy of VEN discontinuation once a maximal response is achieved rather than maintaining long-term selective pressure with the drug.

Effective Tumor Debulking with Ibrutinib Before Initiation of Venetoclax: Results from the CAPTIVATE Minimal Residual Disease and Fixed-Duration Cohorts

PURPOSE

The phase II CAPTIVATE study investigated first-line treatment with ibrutinib plus venetoclax for chronic lymphocytic leukemia in two cohorts: minimal residual disease (MRD)-guided randomized treatment discontinuation (MRD cohort) and fixed duration (FD cohort). We report tumor debulking and tumor lysis syndrome (TLS) risk category reduction with three cycles of single-agent ibrutinib lead-in before initiation of venetoclax using pooled data from the MRD and FD cohorts.

PATIENTS AND METHODS

In both cohorts, patients initially received three cycles of ibrutinib 420 mg/day then 12 cycles of ibrutinib plus venetoclax (5-week ramp-up to 400 mg/day).

RESULTS

In the total population (N = 323), the following decreases from baseline to after ibrutinib lead-in were observed: percentage of patients with a lymph node diameter ≥5 cm decreased from 31% to 4%, with absolute lymphocyte count ≥25 × 109/L from 76% to 65%, with high tumor burden category for TLS risk from 23% to 2%, and with an indication for hospitalization (high TLS risk, or medium TLS risk and creatinine clearance <80 mL/minute) from 43% to 18%. Laboratory TLS per Howard criteria occurred in one patient; no clinical TLS was observed.

CONCLUSIONS

Three cycles of ibrutinib lead-in before venetoclax initiation provides effective tumor debulking, decreases the TLS risk category and reduces the need for hospitalization for intensive monitoring for TLS.

Zanubrutinib versus bendamustine and rituximab in untreated chronic lymphocytic leukaemia and small lymphocytic lymphoma (SEQUOIA): a randomised, controlled, phase 3 trial

BACKGROUND

Zanubrutinib is a next-generation, selective Bruton tyrosine kinase inhibitor with efficacy in relapsed chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL). We compared zanubrutinib with bendamustine-rituximab to determine its effectiveness as frontline therapy in patients with CLL or SLL.

METHODS

We conducted an open-label, multicentre, phase 3 study at 153 academic or community hospitals in 14 countries and regions. Eligible patients had untreated CLL or SLL requiring treatment as per International Workshop on CLL criteria; were aged 65 years or older, or 18 years or older and had comorbidities; and had an Eastern Cooperative Oncology Group performance status score of 0-2. A central interactive web response system randomly assigned patients without del(17)(p13·1) to zanubrutinib (group A) or bendamustine-rituximab (group B) by sequential block method (permutated blocks with a random block size of four). Patients with del(17)(p13·1) were enrolled in group C and received zanubrutinib. Zanubrutinib was administered orally at 160 mg twice per day (28-day cycles); bendamustine at 90 mg/m² of body surface area on days 1 and 2 for six cycles plus rituximab at 375 mg/m² of body surface area the day before or on day 1 of cycle 1, and 500 mg/m² of body surface area on day 1 of cycles 2-6, were administered intravenously. The primary endpoint was progression-free survival per independent review committee in the intention-to-treat population in groups A and B, with minimum two-sided α of 0·05 for superiority. Safety was analysed in all patients who received at least one dose of study treatment. The study is registered with ClinicalTrials.gov, NCT03336333, and is closed to recruitment.

FINDINGS

Between Oct 31, 2017, and July 22, 2019, 590 patients were enrolled; patients without del(17)(p13·1) were randomly assigned to zanubrutinib (group A; n=241) or bendamustine-rituximab (group B; n=238). At median follow-up of 26·2 months (IQR 23·7-29·6), median progression-free survival per independent review committee was not reached in either group (group A 95% CI not estimable [NE] to NE; group B 28·1 months to NE). Progression-free survival was significantly improved in group A versus group B (HR 0·42 [95% CI 0·28 to 0·63]; two-sided p<0·0001). The most common grade 3 or worse adverse event was neutropenia (27 [11%] of 240 patients in group A, 116 [51%] of 227 in group B, and 17 [15%] of 111 patients in group C). Serious adverse events occurred in 88 (37%) of 240 patients in group A, 113 (50%) of 227 patients in group B, and 45 (41%) of 111 patients in group C. Adverse events leading to death occurred in 11 (5%) of 240 patients in group A, 12 (5%) of 227 patients in group B, and three (3%) of 111 patients in group C, most commonly due to COVID-19 (four [2%] of 240 patients in group A), diarrhoea, and aspiration pneumonia (two each [1%] of 227 patients in group B).

INTERPRETATION

Zanubrutinib significantly improved progression-free survival versus bendamustine-rituximab, with an acceptable safety profile consistent with previous studies. These data support zanubrutinib as a potential new treatment option for untreated CLL and SLL.

FUNDING

BeiGene.

Abstract CT028: Fixed-duration (FD) ibrutinib (Ibr) + venetoclax (Ven) for first-line treatment of chronic lymphocytic leukemia (CLL) in patients (pts) with high-risk features: phase 2 CAPTIVATE study

Background: CAPTIVATE (PCYC-1142; NCT02910583) is an international, multicenter phase 2 study of first-line Ibr + Ven in CLL with 2 cohorts: the Minimal Residual Disease (MRD) and FD cohorts. FD Ibr + Ven provides deep, durable responses (Ghia, ASCO 2021; Wierda, J Clin Oncol 2021). Here, we report efficacy and safety of FD Ibr + Ven in pts with high-risk features.

Methods: Pts aged ≤70 y with previously untreated CLL received 3 cycles of Ibr then 12 cycles of Ibr + Ven (Ibr 420 mg/d orally; Ven ramp-up to 400 mg/d orally). Pts in the FD cohort received no further treatment. Pts in the MRD cohort were randomized to subsequent treatment according to MRD status, including a placebo arm for pts who achieved confirmed undetectable MRD (uMRD) with 12 cycles of Ibr + Ven. Data from the FD cohort and MRD cohort placebo arm were pooled for pts with high-risk features (del(17p), TP53 mutated, or unmutated IGHV) treated with FD Ibr + Ven.

Results: Of 202 pts treated with FD Ibr + Ven in the FD cohort (n=159) or MRD cohort placebo arm (n=43), 129 pts had high-risk features (Table). Median time on study for these pts was 28.7 mo (range 0.8-45.1). 94% of pts completed planned treatment with Ibr and Ven. Median treatment duration was 13.8 mo (range 0.7-24.9) for Ibr and 11.1 mo (range 9.9-22.1) for Ven. Best response rates of CR and uMRD in peripheral blood and bone marrow were high (Table). The 18-mo landmark estimate for duration of CR was 95%. 24-mo PFS rate was 94%, which was similar to pts without high-risk features (97%). Only 3% of pts discontinued Ibr or Ven due to AEs. The AE profile of Ibr + Ven in pts with high-risk features showed no new safety findings for this FD regimen (Table).

Conclusion: First-line Ibr + Ven for a fixed duration provides durable treatment-free remissions and sustained PFS in pts with CLL. These clinical outcomes are maintained in pts with high-risk features, with PFS rates that were similar to pts without high-risk features.

Table. Baseline characteristics, efficacy outcomes, and safety Pts with high-risk features (n=129) BASELINE CHARACTERISTICS Median age, y (range) 60 (33-70) Rai stage III/IV, n (%) 36 (28) Bulky disease ≥5 cm, n (%) 47 (36) Genomic risk features, n (%) del(17p) and/or TP53 mutated 29 (22) Unmutated IGHV 119 (92) Complex karyotypea 27 (21) EFFICACY OUTCOMES Overall response rate, n (%) 126 (98) CR, n (%) 76 (59) 18-mo DOCR, % (95% CI) 95 (85-98) uMRD &lt;10-4 by flow, n (%) Peripheral blood 114 (88) Bone marrow 93 (72) 24-mo PFS rate, % (95% CI) 94 (88-97) 24-mo OS rate, % (95% CI) 98 (93-99) SAFETY OUTCOMES Grade 3/4 AEs in ≥5% of pts, n (%) Neutropenia 38 (29) Hypertension 12 (9) Neutrophil count decreased 9 (7) aDefined as ≥3 abnormalities by CpG-stimulated cytogenetics.

Citation Format: John N. Allan, Ian W. Flinn, Tanya Siddiqi, Paolo Ghia, Constantine S. Tam, Thomas J. Kipps, Paul M. Barr, Anna Elinder Camburn, Alessandra Tedeschi, Xavier C. Badoux, Ryan Jacobs, Bryone J. Kuss, Livio Trentin, Cathy Zhou, Anita Szoke, Maoko Naganuma, William G. Wierda. Fixed-duration (FD) ibrutinib (Ibr) + venetoclax (Ven) for first-line treatment of chronic lymphocytic leukemia (CLL) in patients (pts) with high-risk features: phase 2 CAPTIVATE study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT028.