Bruton's Tyrosine Kinase Inhibitor Research Articles

Bruton's tyrosine kinase inhibitor-related cardiotoxicity: The quest for predictive biomarkers and improved risk stratification.

Ibrutinib was the first Bruton's tyrosine kinase (BTK) inhibitor approved for the treatment of patients with chronic lymphocytic leukemia (CLL). While producing durable responses and prolonging survival, roughly 20-25% of patients experience dose limiting side effects, mostly consisting of cardiovascular toxicities like severe hypertension and atrial fibrillation. While clinical predictors of BTK inhibitor-related cardiotoxicity have been proposed and may aid in risk stratification, there is no routine risk model used in clinical practice today to identify patients at highest risk. A recent study investigating genetic predictors of ibrutinib-related cardiotoxicity found that single nucleotide polymorphisms in KCNQ1 and GATA4 were significantly associated with cardiotoxic events. If replicated in larger studies, these biomarkers may improve risk stratification in combination with clinical factors. A clinicogenomic risk model may aid in identifying patients at highest risk of developing BTK inhibitor-related cardiotoxicity in which further risk mitigation strategies may be explored.

BGB-11417-203: An ongoing, phase 2 study of sonrotoclax (BGB-11417), a next-generation BCL2 inhibitor, in patients with Waldenström macroglobulinemia.

TPS7090 Background: Bruton tyrosine kinase (BTK) inhibitors and anti-CD20 antibody-based systemic therapy are included within the preferred treatment algorithms for Waldenström macroglobulinemia (WM). However, to date, no treatments have been approved for patients with WM that is refractory to both BTK inhibitors and anti-CD20 therapy. Venetoclax, the first-generation BCL2 inhibitor, has demonstrated clinical activity in patients with relapsed/refractory (R/R) WM (Castillo et al. J Clin Oncol. 2022), but it has no regulatory approvals in WM. Sonrotoclax, a next generation BCL2 inhibitor, is more selective and a more pharmacologically potent inhibitor of BCL2 than venetoclax. In a phase 1 trial, sonrotoclax monotherapy was well tolerated at all dose levels tested up to 640 mg and showed promising evidence of antitumor activity in patients with R/R WM (Soumerai et al. Blood. 2022). Based on the data from these earlier studies, a phase 2 study of sonrotoclax monotherapy in patients with WM has been initiated and is currently recruiting. Methods: BGB-11417-203 (NCT05952037) is an open-label, international, phase 2 study. Eligible patients have histologically confirmed WM that is R/R to both BTK inhibitor therapy and anti-CD20–based systemic therapy combined with chemotherapy or a proteasome inhibitor (PI; Cohort 1); R/R to anti-CD20–based systemic therapy combined with chemotherapy or a PI and who are intolerant to BTK inhibitor therapy (Cohort 2); or R/R to a BTK inhibitor and who are unsuitable for chemoimmunotherapy (Cohort 3). Patients who have received previous treatment with a BCL2 inhibitor are ineligible. Approximately 85 patients will be enrolled across cohorts and will receive sonrotoclax until disease progression, death, unacceptable toxicity, patient withdrawal, loss to follow-up, or study termination. The primary endpoint is major response rate (MRR; defined as partial response or better) in Cohort 1 per IWWM-11 criteria, as assessed by independent review committee (IRC). Key secondary endpoints include MRR assessed by investigator (INV) in Cohort 1 and by IRC and INV in both Cohorts 2 and 3; overall response rate, duration of response, and progression-free survival by IRC and INV; overall survival; and safety and tolerability. Patient recruitment is ongoing in Australia, the US, China, and Europe. Clinical trial information: NCT05952037 .

Risk of new-onset hypertension in patients (pts) with newly diagnosed chronic lymphocytic leukemia (CLL) treated with Bruton tyrosine kinase inhibitors (BTKi): A real-world data study using the Symphony Health Solution database.

e19014 Background: BTKis provide an important therapeutic option for pts diagnosed with CLL. Concerns have arisen about a potential association with the risk of cardiovascular events with BTKi. Using the Symphony Health Solutions database, this study describes the risk of new-onset hypertension in CLL pts treated with and without BTKis. Methods: Newly diagnosed CLL pts who started ibrutinib or acalabrutinib and those not treated with an approved BTKi between 2019 and 2022 were included in the analysis. The prevalence of hypertension prior to and risk of new-onset hypertension after treatment initiation were defined by use of antihypertensive medication. Pt demographics and comorbidities were described. Multivariate regression and inverse probability treatment weight based on propensity score were used to account for bias due to differences in pt characteristics between groups. Results: In CLL pts treated with (n=7,114) and without BTKis (n=34,571), demographics and clinical characteristics included age at the index date (mean: 70.2 yrs, BTKi; 69.0 yrs, without BTKi), sex (male: 59.8%, BTKi; 55.7%, without BTKi), and Charlson comorbidity scores (mean: 3.3, BTKi; 3.1, without BTKi). At baseline, the prevalence of hypertension defined by the use of antihypertensive medication was 67.8% with BTKi and 67.6% without BTKi. Among pts without any antihypertensive medication use at baseline, the rates of new-onset hypertension within 1 yr after treatment initiation were greater in pts with BTKis than without BTKis (Table). Conclusions: In this real-world analysis, CLL pts treated with BTKis had a higher burden of comorbidities, and use of antihypertensive medication was common. The risk of new-onset hypertension was higher in pts initiated on BTKis than those on non-BTKi treatments. These data suggest that development of hypertension is an important consideration in the long-term management of CLL pts undergoing BTKi treatment. [Table: see text]

Real-world risk of bleeding events in patients with chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL/SLL) treated with BTKi.

7052 Background: Bruton tyrosine kinase inhibitors (BTKis) are effective treatments for various B-cell malignancies including CLL/SLL but are known to be associated with increased bleeding risk. Current evidence indicating this association has largely been demonstrated in clinical trial research. However, bleeding risk in real-world CLL/SLL patients, who are often sicker with more comorbidities requiring anticoagulant (AC) or antiplatelet (AP) use is not well described. This study aimed to assess the prevalence of AC/AP use and explore risk factors for bleeding among real-world CLL/SLL patients receiving BTKi therapies. Methods: We conducted a retrospective cohort study using the claims-linked Premier PINC AI Healthcare Database of patients aged ≥18 years with a diagnosis of CLL/SLL from July 1, 2016 to March 31, 2022. Patients were followed from first BTKi prescription fill (index date) to earliest of BTKi discontinuation, death, or end of the study period. Patient comorbidities, treatments, and bleeding events were assessed using diagnosis and procedure codes and prescription claims. Multivariable-adjusted risk for bleeding events was assessed with Cox proportional-hazards regression. Results: Among 2091 patients with CLL/SLL receiving BTKi therapies, mean age was 65.7 years, 61.8% were men, and 77.7% were White. BTKi treatments included ibrutinib (86.3%), acalabrutinib (13.1%), and zanubrutinib (<1%). Overall, 4.3% of patients switched BTKis during follow-up; 615 (29.4%) had AC/AP use at any time during the study period, of whom 411 (66.8%) started after BTKi initiation. Bleeding events occurred in 526 (25.2%) patients during a mean BTKi exposure of 14.2 months, with an incidence of 26.6 per 100 person-years (PYs) overall, and 37.2 and 22.0 per 100 PYs in patients with and without any prescription AC/AP use, respectively. The proportion of patients with fatal bleeding was <0.3%. In adjusted models, risk of first bleeding event was higher for AC use (HR [95% CI] 2.33 [1.83–2.98]), age ≥65 years (1.32 [1.14–1.53]), women (1.28 [1.10–1.48]), and history (during 90 days prior to BTKi start) of bleeding (2.27 [1.87–2.76]), ulcers (2.21 [1.06–4.63]) or myocardial infarction (MI) (1.74 [1.31–2.33]) (all P≤0.05). Prescription AP use, race/ethnicity, and history of chronic kidney disease or thrombocytopenia were not statistically significant. Conclusions: In this large real-world study of bleeding risk in patients receiving BTKis, bleeding events occurred in 26.6 per 100 patients per year, with higher risk in AC users, women, and patients with history of bleeding, ulcers, or MI. However, the risk of fatal bleeding was low.

RN486, a Bruton's Tyrosine Kinase inhibitor, antagonizes multidrug resistance in ABCG2-overexpressing cancer cells.

Overcoming ATP-binding cassette subfamily G member 2 (ABCG2)-mediated multidrug resistance (MDR) has attracted the attention of scientists because one of the critical factors resulting in MDR in cancer is the overexpression of ABCG2. RN486, a Bruton's Tyrosine Kinase (BTK) inhibitor, was discovered to potentially reverse ABCB1-mediated MDR. However, there is still uncertainty about whether RN486 has a reversal off-target impact on ABCG2-mediated MDR. MTT assay was used to detect the reversal effect of RN486 on ABCG2-overexpressing cancer cells. The ABCG2 expression level and subcellular localization were examined by Western blotting and immunofluorescence. Drug accumulation and eflux assay and ATPase assay were performed to analyze the ABCG2 transporter function and ATPase activity. Molecular modeling predicted the binding between RN486 and ABCG2 protein. Non-toxic concentrations of RN486 remarkably increased the sensitivity of ABCG2-overexpressing cancer cells to conventional anticancer drugs mitoxantrone and topotecan. The reversal mechanistic studies showed that RN486 elevated the drug accumulation because of reducing the eflux of ABCG2 substrate drug in ABCG2-overexpressing cancer cells. In addition, the inhibitory efect of RN486 on ABCG2-associated ATPase activity was also verified. Molecular docking study implied a strong binding afinity between RN486 and ABCG2 transporter. Meanwhile, the ABCG2 subcellular localization was not altered by the treatment of RN486, but the expression level of ABCG2 was down-regulated. Our studies propose that RN486 can antagonize ABCG2-mediated MDR in cancer cells via down-regulating the expression level of ABCG2 protein, reducing ATPase activity of ABCG2 transporter, and inhibiting the transporting function. RN486 could be potentially used in conjunction with chemotherapy to alleviate MDR mediated by ABCG2 in cancer.

Efficacy outcomes of treatments for double exposed chronic lymphocytic leukemia/small lymphocytic lymphoma: A systematic literature review.

e19019 Background: Bruton's tyrosine kinase inhibitors (BTKis) and the B-cell lymphoma 2 inhibitor (BCL2i) venetoclax have improved outcomes and achieved durable remission in patients with chronic lymphocytic leukemia (CLL)/small lymphocytic leukemia (SLL) in both first-line and relapsed/refractory settings. Despite advances in treatment with these targeted agents, some CLL/SLL patients remain incurable. Notably, patients who fail to respond to both BTKis and venetoclax, termed 'double-exposed,' often exhibit poor outcomes. Data on treatment efficacy for this subgroup is limited. This study systematically reviews treatments and their efficacy outcomes in double-exposed CLL/SLL patients. Methods: A comprehensive search was conducted across MEDLINE/PubMed, Embase, and Web of Science databases from inception to November 2023, using relevant keywords and MeSH terms. The search focused on identifying studies reporting treatments and efficacy outcomes in double-exposed CLL/SLL patients, irrespective of discontinuation reasons. Key efficacy outcomes included progression-free survival (PFS), overall survival (OS), and overall response rate (ORR). Results: From 3942 retrieved articles, 12 publications covering 8 unique studies (4 clinical trials and 4 observational studies) were included. The median patient age ranged from 60-69 years in clinical trials to 56-76 years in observational studies. Two clinical trials reported PFS, with pirtobrutinib-treated patients showing a median PFS of 16.8 months (95% CI, 13.2-18.7) and lisocabtagene maraleucel-treated patients demonstrating a median PFS of 13 months (95% CI,2.8-not reached). BELLWAVE-001 was the sole study reporting a median OS of 10.1 months (95%CI, 7.4-15.9) in nemtabrutinib-treated patients. ORR varied, with 58% in nemtabrutinib-treated patients and 80% in those receiving lisocabtagene maraleucel. In the four observational studies, PFS ranged from 3 months (chemoimmunotherapy) to 12 months (BTKis), and ORR ranged from 31.8% (chemoimmunotherapy) to 85.7% (CAR T-cell therapy). Conclusions: This study underscores the scarcity of clinical data addressing efficacy outcomes in double-exposed CLL/SLL patients. Treatments like pirtobrutinib and CAR-T cell therapy show promise for this group. However, the limited treatment options and efficacy data following failure on BTKis and venetoclax highlight a significant unmet medical need. Further research is necessary to comprehensively understand efficacy outcomes in the double-exposed CLL/SLL population.

Real-world adherence and healthcare resource utilization of Bruton tyrosine kinase inhibitors (BTKi) in mantle cell lymphoma.

e19048 Background: This study aimed to examine treatment adherence and healthcare resource utilization (HCRU) of BTKi treatment in mantle cell lymphoma (MCL). Methods: The Symphony Integrated Dataverse (IDV) was used to conduct a retrospective observational study. Adult patients with MCL initiating their first BTKi or second BTKi (after ibrutinib) between 01/2020 and 10/2023 were included in the study. The index was defined as the date of BTKi initiation. Patients without 30 days of continuous enrollment pre- and post-index date were excluded. Patients were followed until the end of the study period or lost to follow-up. Adherence was evaluated by compliance and persistence. Compliance was calculated as the proportion of days covered >0.80 using 30-day intervals from initiation to 1 year. Persistence was measured as the proportion of patients who remained in treatment among patients with sufficient follow-up periods. HCRU was measured by all-cause outpatient visits, inpatient services, and other medical/hospital services per-patient-per-month (PPPM) during BTKi treatment. Results: Among 2,122 patients who were first-time BTKi users, there were significant differences for mean age at index (acalabrutinib=70; ibrutinib=68; zanubrutinib=70, P<.0001), commercial insurance (acalabrutinib=34%; ibrutinib=42%; zanubrutinib=47%, P<.0001), and baseline atrial fibrillation (acalabrutinib=1.94%; ibrutinib=1.24%; zanubrutinib=3.47%, P=0.0232). A total of 228 patients switched from ibrutinib to acalabrutinib or zanubrutinib. Adherence results suggested zanubrutinib had numerically better 1-year compliance ( P=0.2176) and treatment persistence at 1 and 2 years ( P=0.2687; P=0.6270) for patients who switched from ibrutinib to zanubrutinib or acalabrutinib (Table). HCRU showed that the mean (SD) outpatient visits (1.12 [1.67] vs 1.62 [3.17]; P=0.1755) and inpatient services (0.22 [0.68] vs 0.68 [3.12]; P=0.1693) were lower in patients switched from ibrutinib to zanubrutinib than acalabrutinib. Conclusions: In this study, zanubrutinib was associated with a trend towards improved compliance, persistence, and HCRU when used as the first BTKi and after prior ibrutinib. [Table: see text]

Cardiotoxicity from bruton tyrosine kinase inhibitors (BTKi)—an analysis of an administrative health claims database

BackgroundFirst generation Bruton tyrosine kinase inhibitors (BTKi) such as ibrutinib have been associated with cardiovascular toxicities. Newer generation BTKi (e.g.,acalabrutinib and zanabrutinib) have been associated with lower incidence of cardiotoxicity in clinical trials.ObjectiveGiven paucity in real-world data on the overall cardiac risk factor profile, especially with the newer BTKi, our study evaluated the incidence of cardiotoxicity with various BTKi among a large, commercially insured population of patients.MethodsWe performed a retrospective cohort analysis of all adults with a diagnosis of B-cell malignancy undergoing treatment with BTKi acalabrutinib and ibrutinib between January 2018 and June 2020 using Optum’s de-identified Clinformatics® Data Mart Database. We then identified patients who had pre-existing cardiac disease one year prior to starting BTKi. New incidence of atrial fibrillation/flutter, hypertension, bleeding, ventricular tachycardia/fibrillation and sudden cardiac death from the time of index presciption were compared with standard Chi Square or Student t-test where appropriate. Multivariate logistic regression models were also estimated to evaluate for confounding.ResultsA total of 1691 patients were included in the final analysis. 1595 (94%, median age 75 (19–90) years, 61% male gender) patients received ibrutinib, and 96 (6%, median age 73.5 (32–90) years, 62.5% male gender) patients received acalabrutinib. The median duration of drug exposure of ibrutinib was 238 (2-1084) days vs. 150 (30–870) days for acalabrutinib. There was lower new incidence of atrial fibrillation/flutter (4.6%-vs-17%, p = 0.013), hypertension (6.3%-vs-25%, p = NS), sudden cardiac arrest/death (0% vs. 1.5%, p = NS) in the acalabrutinib group compared to ibrutinib, of which only the lower incidence of atrial fibrillation/flutter was statistically significant. This was despite the finding of a higher prevalence of atrial fibrillation/flutter at baseline in patients receiving acalabrutinib.ConclusionsThere was lower incidence of new atrial fibrillation/flutter with acalabrutinib when compared to ibrutinib in a real-world cohort of patients.

Risk of hypertension in patients with CLL/SLL who participated in ALPINE: A post hoc analysis.

e19016 Background: Bruton tyrosine kinase (BTK) inhibitors are an important therapeutic option for patients with CLL/SLL. The first-generation BTK inhibitor, ibrutinib (ibru), is associated with an increased risk of hypertension. Zanubrutinib (zanu) is a next-generation BTK inhibitor designed to maximize BTK occupancy and minimize toxicity with fewer off-target effects. This analysis evaluated the risk of developing hypertension based on initiation of antihypertensives (anti-HTN) in ALPINE (NCT03734016). Methods: Anti-HTN use in the zanu (n=324) and ibru (n=324) treatment arms was assessed. The definition of anti-HTN was based on Standardized Drug Grouping; concomitant anti-HTN were adjudicated by an independent hypertension specialist blinded to BTK inhibitor assignment. Time to initiating new anti-HTN and time to adding a new class of anti-HTN were assessed using the Kaplan-Meier method. Comparisons of time-to-onset endpoints were analyzed based on the log-rank test. Results: At baseline, patient characteristics were generally balanced between zanu and ibru arms (median age, 66.7 vs 67.1 y; male, 65.1% vs 71.4%; history of hypertension, 50.9% vs 50.0%; type 2 diabetes mellitus, 10.1% vs 8.9%). Among patients not on anti-HTN at baseline, 20.7% (n=35/169) of zanu- and 28.7% (n=51/178) of ibru-treated patients initiated anti-HTN during the study. Among all patients, fewer patients in the zanu arm initiated new anti-HTN (28.4% [n=92/324] vs 32.4% [n=105/324]) and the anti-HTN were initiated later (hazard ratio [HR], 0.77; P-value=.071). Additionally, statistically fewer patients in the zanu arm compared with the ibru arm started anti-HTN in a new class (24.1% [n=78/324] vs 29.3% [n=95/324]) and the anti-HTN were started later (HR, 0.72; P-value=.034). The event rates for initiation of new anti-HTN or a new class of anti-HTN were consistently lower in the zanu vs ibru arm at each timepoint (Table). Conclusions: In ALPINE, initiation of new anti-HTN or a new class of anti-HTN occurred less frequently in the zanu arm vs the ibru arm in patients with CLL/SLL. Adoption of anti-HTN occurred sooner with ibru than zanu. These findings should be considered when initiating BTK inhibitor therapy in patients with CLL/SLL who have an elevated cardiovascular risk. Clinical trial information: NCT03734016 . [Table: see text]

A phase IIA clinical trial to evaluate a reversible Bruton’s tyrosine kinase inhibitor (BTKi) HBW-3220 capsules in patients with relapsed/refractory (R/R) B-cell non-Hodgkin lymphoma (B-NHL).

e19042 Background: This clinical study is to evaluate HBW-3220, a novel BTKi with an improved in vitro profile than the existing non-covalent drugs pirtobrutinib (approved) and nemtabrutinib (Phase III). HBW-3220 shows superior inhibition against BTK wild-type and several common mutants, such as C481S, C481R, T474I, T316A, and L528W (enriched in pirtobrutinib resistance), and hematopoietic cell kinase (HCK, a key contributor to BTKi resistance due to kinase-defective BTK). Methods: This phase IIA clinical study is conducted in R/R B-NHL patients who had received two or more prior lines of treatment. The dose escalation study adopts accelerated titration and a "3+3" design, with a daily single dose of 15, 30, 60, 90, 120, or 150 mg. During the dose escalation phase, the sponsor and investigators determine whether to expand the cohort of the previous dose based on the existing data. Adverse events (AEs) are assigned according to NCI Common Terminology Criteria for Adverse Events (CTCAE) v5.0. Response assessment is based on iwCLL 2018 guidelines for chronic lymphocytic leukemia (CLL), IWWM-7 consensus for Waldenstrom macroglobulinemia (WM), and Lugano 2014 guidelines for all other lymphomas, including small lymphocytic lymphoma (SLL), diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma (MCL), marginal zone lymphoma (MZL), and follicular lymphoma (FL). Results: 29 patients have been enrolled, and the dose escalation study has been completed. No dose-limiting toxicity (DLT) occurred in any patient, implicating good tolerability. Adverse events (AEs), similar to other BTKis, were mostly Grade 1 or 2, including fever (36%), diarrhea (32%), headache (18%), anemia (39%), infectious pneumonia (18%), decreased neutrophils count (39%), decreased platelet count (29%), increased alanine aminotransferase (21%), etc. Drug-related Grade 3 AEs included decreased neutrophil count (n=3, 11%), increased lymphocyte count (n=2, 7%), and infectious pneumonia (n=2, 7%). 23 patients underwent at least 1 response assessment. The overall response rate (ORR) in CLL/SLL (all with prior irreversible BTKi treatment, and 4 of them with additional BCL2 inhibitor treatment), MZL, MCL, and DLBCL patients were 83% (5/6), 50% (2/4), 40% (2/5) and 33% (1/3), respectively. Among the ORR, 90% (9/10) were in the 90 mg and above dose group, regardless of previous BTKi treatment history or mutation status of p53 and BTK. After oral administration, the drug exposures showed dose-dependent increases. The time to maximum plasma concentration (Tmax) was 2 hours, and the elimination half-life (T1/2) was 19 hours. Conclusions: The current data show that HBW-3220 is well tolerated with no DLT occurred at daily doses up to 150 mg, displaying most promising efficacy in patients with CLL/SLL, MZL, and MCL. Clinical trial information: ChiCTR2200062537.

Real-world treatment switching and sequencing to next line of therapy of zanubrutinib, acalabrutinib, and ibrutinib in CLL/SLL.

e19022 Background: Evaluating use of Bruton tyrosine kinase inhibitors (BTKis) for the treatment of CLL/SLL is crucial to understand real-world outcomes of these therapies in diverse populations. The objective of this study was to evaluate real-world switching and sequencing to next line of therapy in patients (pts) initiating BTKis as first-line (1L) or second-line (2L) CLL/SLL treatment. Methods: A retrospective study was conducted using IntegraConnect PrecisionQ to identify adult pts with ≥1 diagnosis for CLL/SLL initiating zanubrutinib (zanu), acalabrutinib (acala), or ibrutinib (ibru) in 1L or 2L between 1/1/2020-2/28/2023 (index period). Index date was defined as date of BTKi initiation. Pts were required to be continuously enrolled for ≥30 days pre- and post-index date. Treatment switching was measured as pts initiating another treatment within same line or advancing to next line of therapy within 90 days. Sequencing to next line of therapy was calculated from time to next treatment Kaplan-Meier curve, censoring patients at end of follow-up, and reported as proportion of pts receiving next line of therapy at 180 days. Results: 2,816 pts initiated a 1L BTKi (zanu=157; acala=1,238; ibru=1,421) and 1,253 initiated a 2L BTKi (zanu=107; acala=672; ibru=474). No major differences were observed in baseline demographic and clinical characteristics among 1L and 2L BTKi cohorts. Median follow-up in 1L was 123 days for zanu, 406 days for acala, and 637 days for ibru. Regardless of line of therapy, switching rate at ≤60 days and 61-89 days was statistically significantly lower for pts receiving zanu vs acala and ibru (P<0.0001, both 1L and 2L) (Table). Proportion of pts receiving next line of therapy at 180 days was lower for zanu vs acala and ibru (1L P=0.2958; 2L P<0.0001) (Table). Conclusions: Zanu pts had significantly lower switching rate within 90 days and lower proportion of pts receiving next line of therapy at 180 days when compared with acala and ibru in 1L and 2L. Longer follow-up and larger zanu sample size are required for a comprehensive assessment of treatment outcomes associated with use of BTKis in CLL/SLL. [Table: see text]

Real-world understanding of the unmet need for treatment of non-covalent BTKi in chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL).

e19028 Background: Non-covalent (nc) Bruton Tyrosine Kinase inhibitors (BTKi) for the treatment of Chronic Lymphocytic Leukemia and Small Lymphocytic Lymphoma (CLL/SLL) provide patients with a new treatment option after resistance to on-target BTK mutations or PLCγ2 mutations that bypass BTK inhibition. Given the December 1, 2023 accelerated FDA approval for pirtobrutinib, a nc-BTKi, in the treatment of CLL/SLL for treatment of patients who have received at least two prior lines of therapy with a covalent (c) BTKi and a B-Cell Lymphoma 2 Protein Inhibitor (BCL2i), we sought to understand the addressable population for treatment with nc-BTKI therapy in a real-world database of CLL/SLL patients. Methods: We used the Integra Connect PrecisionQ real-world de-identified database of over 3 million cancer pts across 500 sites of care to identify CLL/SLL pts for the analysis. The CLL patients included for the analysis were on a treatment in 2023 and must have had either >5 CLL/SLL diagnosed visits or more CLL/SLL visits than non-CLL/SLL visits if <5 CLL/SLL diagnosed visits. Descriptive analyses were used for this study. Results: Of the 6,992 patients treated for CLL/SLL in 2023, the median age at treatment start was 71, 62% were male, 65% identified as White, 6% as African American, and 29% as Other. Of the pts, 12% received a c-BTKi and BCL2i, 64% received a c-BTKi only, and 12% received a BCL2i only. Of the 12% of pts who received a c-BTKi and BCL2i, 191 pts started a subsequent line of therapy. Among pts who received a c-BTKi and BCL2i, 79% received a BTKi therapy first, 10% received a BCL2i therapy first, and 12% had a line of therapy with both a BTKi and BCL2i. We found 59 pts who received nc-BTKi; among those pts, 51% received a c-BTKi and BCL2i prior to initiation of nc-BTKi. The median age at first treatment for CLL/SLL was 71.7 for those who received a c-BTKi, 71.1 for those who received a BCL2i, and 70.8 for those who received nc-BTKi. The median age at first diagnosis for CLL/SLL was 68 for those who received a c-BTKi, 66 for those who received a BCL2i, and 63 for those who received nc-BTKi. The median time to first treatment was 470 days for pts treated with a c-BTKi, 507 days for pts treated with BCL2i, and 587 days for pts treated with nc-BTKi. Conclusions: We found that among nearly 7,000 treated patients in the database, 12% were treated with both a c-BTKi and BCL2i; of those, just 23% started a subsequent treatment. Among patients who were treated with a nc-BTKi we found their median age at treatment start and diagnosis was lower than those who received a c-BTKi or BCL2i respectively.

Real-world treatment patterns and outcomes of zanubrutinib in chronic lymphocytic leukemia and small lymphocytic leukemia (CLL/SLL).

11158 Background: Zanubrutinib (zanu) is a next-generation selective Bruton’s tyrosine kinase inhibitor (BTKi) with superior efficacy over first generation ibrutinib (ibru) in CLL/SLL patients (pts). Herein we present real-world treatment patterns based on a formulary change from ibrutinib to zanubrutinib in pts with CLL/SLL in an integrated community oncology practice. Methods: We retrospectively analyzed CLL/SLL pts 18 years and older who received at least 3 months of zanubrutinib from October 1, 2018 to September 15, 2023 at Kaiser Permanente Northern California. Treatment patterns, treatment-emergent adverse events (TEAEs: AEs reported during BTKi use), treatment-limiting adverse events (TLAEs: AEs leading to BTKi discontinuation), and mortality were reported. Results: A total of 281 pts received zanu (median age: 71 years; 64% male); 190 pts switched from ibru (ibru-zanu), and 91 pts received zanu only. Most pts were White (75%) followed by Black (10%). Compared with ibru-zanu pts, zanu-only pts were older (median age 74 vs 69 years) and had more comorbidities but were comparable in sex, race, and insurance type. The primary reasons for switching to zanu were formulary change (73%) and progression (15%). Median follow-up time after initiation of first BTKi was longer in the ibru-zanu group (Table). Similar TEAE rates were seen with use of both BTKi therapies, with lower TLAE rates with zanu (Table). Most common TLAE were atrial fibrillation and fatigue for ibru, and cytopenias and rash/bruising for zanu. Cardiac TLAE and non-TLAE rates overall were higher with ibru than zanu, and the rates decreased while on zanu after switching from ibru (Table). Dose modification occurred in 34 pts on ibru and 50 pts on zanu (18 ibru-zanu pts, 32 zanu-only pts), with reductions primarily for grade 1-2 AEs. Of the 281 pts who received zanu, 79% remain on treatment at the end of data collection; 13 pts died (8 from infection, including 5 from COVID), with no reports of treatment-related deaths. Conclusions: In the real-world setting post-formulary change, zanu is effective and safe in pts with or without prior ibru use. Zanu use had lower cardiotoxicity and TLAE rates than ibru though data was limited by a difference in follow-up time. Similar results were seen in zanu-only pts despite being older and having more comorbidities, with discontinuation most often due to grade <3 AEs. [Table: see text]

A first-in-human study of the potent and highly selective BTK degrader ABBV-101 in patients with relapsed/refractory B-cell malignancies.

TPS7091 Background: Bruton tyrosine kinase (BTK) is a clinically validated target with an integral role in the proliferation and survival of neoplastic cells in several B-cell malignancies. Inhibitors of BTK, such as ibrutinib, have revolutionized the treatment landscape for B-cell malignancies. However, long-term use can lead to disease progression and clinical resistance associated with mutations in BTK. ABBV-101 is a reversible BTK degrader. By preclinical kinome profiling, ABBV-101 has demonstrated high selectivity with the potential for best-in-class AE profile. ABBV-101 has also shown potent activity against BTK wildtype and multiple therapy-resistant mutant forms. Degradation eliminates BTK scaffolding and enzymatic functions, which has led to deeper, more durable responses vs covalent and reversible BTKi in animal models (Pan C, et al. ASH 2023). Herein, we describe the first-in-human study of ABBV-101 monotherapy in patients with relapsed/refractory B-cell NHL. Methods: This international phase 1, open-label, multicenter study (NCT05753501) is evaluating the safety, tolerability, pharmacokinetics (PK), and preliminary efficacy of ABBV-101. Eligible patients(≥18 years) have measurable disease, received ≥2 prior systemic therapies, and have no available therapies known to provide clinical benefit.Primary objectives are to characterize safety and tolerability of ABBV-101; secondary objectives are to evaluate PK and preliminary efficacy. The study is conducted in 2 parts: dose escalation (part 1) and dose expansion (part 2). Part 1 aims to establish the maximum administered dose and maximum tolerated dose of ABBV-101 guided by a Bayesian optimal interval design; additional patients may be enrolled to a previous dose level to further explore safety, PK, and efficacy. Patients with WHO-defined chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL), diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma, follicular lymphoma, marginal zone lymphoma, lymphoplasmacytic lymphoma (including Waldenström macroglobulinemia), and transformed indolent NHL (including Richter’s transformation) are eligible. Part 2 will further characterize the safety and preliminary efficacy of ABBV-101; patients diagnosed with CLL/SLL (up to 3 dose cohorts) and non-germinal center DLBCL (1 cohort) are being enrolled. ABBV-101 is administered orally until disease progression, intolerable toxicity, or other study discontinuation criteria are met. Safety assessments include, but are not limited to, AEs, clinical laboratory parameters, vital signs, and ECG. Response evaluations are performed per disease-specific response criteria at screening and every 8 weeks (1st year), 3 months (2nd year), or 4 months (3rd year onward) until progressive disease. Enrollment is ongoing with active sites in the US and Japan. Clinical trial information: NCT05753501 .

Evolving patterns of transplant strategies for mantle cell lymphoma in the era of BTK inhibitors and CAR-T therapy.

e19012 Background: Mantle cell lymphoma is an aggressive lymphoma with poor survival after chemotherapy alone. Both autologous (auto) and allogeneic (allo) transplants have improved outcomes over the years, but transplant strategies most beneficial for MCL are not clearly defined. Recently, BTK inhibitors and chimeric antigen therapies (CAR T) therapy approach has changed the landscape of Mantle cell Lymphoma. Methods: Patient Population:A total of 71 patients underwent transplant for diagnosis of MCL at Penn State Cancer Institute, between March 1993 and March 2023. Median follow up was 3.1 years (32 days-9883 days) after transplant. Patient Characteristics: A total of 71 patients (62 M: 9 F) underwent transplants, including autologous (n=30), allogeneic (n=32), and CAR T (n=9). Since 2020, 19 transplants were performed: CAR T (n=9) auto transplants (n=9) and allogeneic transplants (n=1). Relapsed and refractory MCL (n=4) patients received CAR T whereas patients achieving CR 1 (n=8) and PR1 (n=1) received auto transplants. Most patients were Caucasian (n= 68), with few Hispanic (1), African American (1), or Asian (1). Results: Median age at the time of transplant was 61 (37-70) years for autologous, 56 (33-67) years for allogenic and 63 (55 -75) years for CAR T respectively. Disease status at transplant was CR 52.1% (n=37), primary induction failure or relapsed/refractory 36.6% (n=26), PR 11.3% (n=8). High LDH was seen at the time of transplant in 16.9% (n=12) patients and normal in 83.1%(n=59) patients. Blastoid morphology was seen in only 13.8% (n=4) autologous, 37.9% (n=11) allogenic and 33.3% (n=3) CAR T patients. Outcomes: Overall survival (OS) at 1 year and 3 years was 93.3% and 85.9% for autologous (auto) transplants, 62.5% and 52.9% for Allogeneic (allo) transplants, 88.9% and 76.2% for CAR-T therapy respectively (P = 0.007). Progression free survival at 1 year and 3 years was 86.3% and 75.0% for auto transplants; 50.0% and 43.3% for allo Transplants; 66.7% and 66.7% for CART Therapy (P = 0.03). Primary cause of death was Treatment Related Mortality (TRM) (n= 9) (GVHD=4; Pulmonary=3; MOF=2) and disease progression (n=10); unknown (n=4); other (n=1). Primary cause of death for CAR T therapy was grade IV ICANS and disease progression. Conclusions: Recently CAR T therapies have changed the landscape of MCL treatment algorithm in both Blastoid and non-Blastoid histology MCL patients. But in the era of CAR T therapy and BTK inhibitors for MCL, achieving CR at the time of transplant predicts improved long-term outcomes. Randomized studies or larger retrospective CIBMTR data analysis may be important to answer best transplant strategy for MCL patients. [Table: see text]

EE91 Clinical Consequences and Associated Costs of Treating Patients With Chronic Lymphocytic Leukemia (CLL) With Bruton Tyrosine Kinase Inhibitors (BTKis) in the First-Line (1L) and Relapsed/Refractory (R/R) Settings

EE91 Clinical Consequences and Associated Costs of Treating Patients With Chronic Lymphocytic Leukemia (CLL) With Bruton Tyrosine Kinase Inhibitors (BTKis) in the First-Line (1L) and Relapsed/Refractory (R/R) Settings

Real-world comparison of time to next treatment for patients with high-risk CLL/SLL in first line of treatment.

e19027 Background: The International Workshop on CLL recommends testing patients (pts) with CLL/SLL for deletion 17p (del17p) and tumor protein (TP) 53 mutations for prognosis and treatment decisions. Both Bruton Tyrosine Kinase inhibitors (BTKi) and B-cell lymphoma 2 protein inhibitor (BCL2i) are approved as effective frontline therapies for CLL/SLL pts, particularly those with high-risk features such as del17p and TP53. However, there is no clinical study directly comparing the efficacy of BTKi and BCL2i. We sought to understand the real-world use of BTKi and BCL2i as well as the differences in time to next treatment, a surrogate for progression-free survival, among CLL/SLL pts who were identified as having either del17p or TP53 mutations and treated with a BTKi or BCL2i in the 1L setting. Methods: We used the Integra Connect PrecisionQ real-world de-identified database of over 3 million cancer pts across 500 sites of care to identify CLL/SLL pts for the analysis. We observed pts who started 1L treatment between 3/4/2016 and 12/4/2023. Risk status was captured via medical chart curation to determine the presence del17p or TP53 mutations. Time to next treatment was measured from the treatment start to the first of the initiation of a subsequent line of therapy or death. Descriptive analyses were used and time to next treatment was analyzed using a Kaplan Meier analysis. Results: We identified 295 CLL/SLL pts with high-risk features. The median (IQR) age of these pts at treatment start was 74 (66,81) years old, 62% were male, 77% identified as White, 8% as African American, and 15% as Other. Of these high-risk pts, 72% had only a deletion 17p, 13% had only TP53 mutation, and 15% had both. The percent of high-risk pts who received a BTKi in 1L was 69% with a median (IQR) age of 75 (65, 81) at treatment start, while 13% received a BCL2i in 1L with a median (IQR) age of 70 (64,77) at treatment start. The percent of pts who received neither a BTKi or BCL2i in 1L was 18% with median (IQR) age of 74 (68,80) at treatment start. The median time to next treatment for those who received a BTKi was 68.4 months (95% Confidence Interval [CI]: 48.4, NA) compared to 45.5 months (CI: NA, NA) for pts who received a BCL2i. The median (IQR) duration for patients treated with a BCL2i +/- obinutuzumab was 396 (285,603) days. The probability of pts who did not initiate a next treatment at 30 months was found to be 71% (95% CI, 64% to 78%) for those who received a BTKi (p <0.05) compared to 92% (95% CI, 83% to 100%) for those who received a BCL2i. Conclusions: The real-world data comparison of 1L treatment in high-risk pts with CLL/SLL shows that, after 30 months, the probability of not initiating the next treatment is 92% for those treated with a BCL2i compared to 76% for those treated with a BTKi. Additional follow-up and a larger sample may be needed to further validate these findings.

BELLWAVE-010: A phase 3 study of nemtabrutinib plus venetoclax versus venetoclax plus rituximab (VR) in previously treated patients (pts) with relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL).

TPS7089 Background: VR is a standard of care option for pts with CLL/SLL who have relapsed after ≥1 line of prior therapy. However, there is an unmet need for more effective treatments. Bruton tyrosine kinase (BTK) plays an important role in the pathogenesis of CLL. Nemtabrutinib is a BTK inhibitor that targets both wild type and C481-mutant forms of BTK. In the ongoing BELLWAVE-001 study, nemtabrutinib demonstrated manageable safety and durable antitumor activity in pts with R/R CLL/SLL with and without C481 mutations. The randomized, open-label, phase 3 BELLWAVE-010 study (NCT05947851) is designed to evaluate the efficacy and safety of nemtabrutinib + venetoclax versus VR as second-line or later treatment for pts with R/R CLL/SLL. Methods: Eligible pts are aged ≥18 years with active R/R CLL/SLL after ≥1 prior therapy per iwCLL 2018 criteria and an ECOG PS of 0-2. Approximately 720 pts will be enrolled in 2 parts. Part 1 is an open-label, nonrandomized dose escalation and confirmation phase to evaluate safety and determine the optimal dose of nemtabrutinib + venetoclax. Part 1 will enroll 30 pts to establish the dose of nemtabrutinib using a modified toxicity probability interval design. Pts will receive nemtabrutinib at 2 dose levels (45 mg PO QD starting dose, escalating to 65 mg PO QD) for 28 days, followed by nemtabrutinib + venetoclax (20-400 mg PO QD ramp up over 4 weeks). Part 2 is an open-label, parallel-group, randomized phase comparing the efficacy and safety of nemtabrutinib + venetoclax with VR. In part 2, approximately 690 pts will be randomly assigned 1:1 to receive either nemtabrutinib at the recommended dose for 28 days followed by the nemtabrutinib + venetoclax or venetoclax + rituximab (or rituximab biosimilar; 375 mg/m2 at week 6, followed by 500 mg/m2 every 4 weeks starting at week 10 until week 26 [total 6 doses]). Study treatment will continue for approximately 2 years or until unacceptable toxicity, disease progression, or other discontinuation criteria are met. Randomization will be stratified by BTK-C481 mutation status (detected vs not detected), geographic region (US/Canada vs Europe vs rest of world) and risk (high risk [del(17p) and/or TP53-mutated and/or IGHV-unmutated] vs low risk [absence of high-risk factors]). The primary end point for part 2 is progression-free survival by blinded independent central review (BICR) per iwCLL 2018 criteria. Secondary end points for part 2 are undetectable minimal residual disease in bone marrow at month 14 by central laboratory assessment, objective response rate (ORR), and duration of response by BICR per iwCLL 2018 criteria, overall survival, and safety. Exploratory end points are ORR including partial response with lymphocytosis, pharmacokinetics, and health-related quality of life. Recruitment is ongoing. Clinical trial information: NCT05947851 .

A retrospective observational study of rapid titration of venetoclax (VEN) in patients with mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL).

e19018 Background: CLL and MCL can present with rapid disease progression that requires quick control. VEN is an oral, small-molecule inhibitor of BCL-2 that requires careful dose titration to avoid TLS. However, standard outpatient titration of VEN takes 29 days to reach max dose, with the low doses achieving little disease control. A common practice at our site is to rapidly titrate VEN to 100mg within 1 week with hospitalization for careful TLS monitoring and management. We present the safety and outcomes of 39 identified patients treated as such. Methods: The rapid VEN titration plan was: VEN 20mg x 2 days, 50mg x 2 days, then 100mg daily with q6-q8 hour monitoring of TLS labs plus ongoing IV hydration and allopurinol with or without rasburicase per clinical judgment. Most patients were treated in such manner if TLS did not occur. Clinically stable patients were typically discharged after 2 days of VEN 100mg, then continued weekly outpatient dose escalation to the 200mg and then the 400mg dose levels. If a patient was progressing on a Bruton's Tyrosine Kinase inhibitor, the inhibitor was often given concurrently with the early doses of VEN. Results: Patient characteristics are listed in the table. 23% (5 of 22) of patients with CLL and 35% (6 of 17) of patients with MCL had laboratory TLS (Howard SC, NEJM2011). In the patients with CLL, 2/5 were low risk for TLS, and in the patients with MCL, 3/6 were low risk for TLS. Only 4.5% (1 of 22) of CLL patients and no MCL patients had clinical TLS (Grade 2 creatinine elevation). In that specific patient, considered low risk for TLS, the elevated creatinine did not recover but was subsequently deemed secondary to Richter’s transformation involving the kidneys. No unexpected toxicity was observed outside of those typically associated with VEN and anti-CD20 antibody, when used. The mean number of days to reach 100mg was 6.5 days (quartile [Q] 1:5d; Q3: 10d), and the mean number of days to reach the planned VEN target dose was 18.8 with range (Q1:14d; Q3: 25d). Sixty-four percent of patients achieved the 400mg dose level. Conclusions: This single-institution retrospective analysis highlights the low rate of clinical TLS when using VEN with rapid titration in a controlled environment for high-risk patients needing rapid disease control. However, lab TLS occurred in low-risk patients treated in this manner, necessitating hospitalization despite low risk. No unexpected or additional toxicity was observed. [Table: see text]

Glofitamab monotherapy in patients with heavily pretreated relapsed/refractory (R/R) mantle cell lymphoma (MCL): Updated analysis from a phase I/II study.

7008 Background: Glofitamab, a bispecific antibody with a novel 2:1 (CD20:CD3) format, engages and redirects T cells to eliminate malignant B cells. In a Phase I/II study (NCT03075696), fixed-duration glofitamab monotherapy showed high, durable complete responses (CR) and manageable safety in patients (pts) with heavily pretreated R/R MCL (Phillips et al. ASH 2022). We report updated efficacy and safety data for pts with R/R MCL. Methods: Pts received obinutuzumab pretreatment (Gpt; 1000mg or 2000mg) 7 days before their first glofitamab dose. Glofitamab step-up dosing was given on Cycle (C) 1 Day (D) 8 (2.5mg) and D15 (10mg), and target dose (16mg or 30mg) from C2D1 to C12 as a fixed-duration therapy. Efficacy endpoints were CR, overall response rate (ORR), duration of CR (DOCR), duration of response (DOR) and progression-free survival (PFS). Post-hoc PFS and overall survival (OS) landmark analyses were performed in pts with a CR at end of treatment (EOT). Results: As of Sept 4, 2023, 61 pts were enrolled; 60 received study treatment (1000mg Gpt, n=16; 2000mg Gpt, n=44). Median number of prior lines of therapy was 2 (range: 1–5); 73.3% were refractory to the last line of prior therapy. Median duration of glofitamab therapy was 7.4 months; median number of cycles was 12. Of the 31 pts (51.7%) who received prior Bruton’s tyrosine kinase inhibitor (BTKi) therapy, 29 (93.5%) were BTKi refractory; median number of prior lines of therapy was 3 (range: 1–5); 90.0% were refractory to the last line of prior therapy. At a median PFS follow-up of 17.2 months, ORR and CR rate were 85.0% and 78.3%, respectively. Median DOCR was 15.4 months; the majority of CRs (28/47; 59.6%) were ongoing at data cut-off. Of 19 pts with a CR, 9 had disease progression and 10 died (fatal adverse event [AE], n=8; COVID, n=7; septic shock, n=1). Estimated 12-month DOCR and DOR rates were 71.0% and 66.6%, respectively. Median PFS was 16.8 months. Landmark analyses indicated that most pts with a CR at EOT were alive and progression free 15 months post-EOT (OS rate, 72.7%; PFS rate, 59.2%). Observed efficacy data were consistent across both Gpt cohorts. In post-BTKi pts after a median PFS follow-up of 26.1 months, ORR and CR rate were 74.2% and 71.0%, respectively. Median DOCR was 12.6 months; median PFS was 8.6 months. No new safety signals were observed. Cytokine release syndrome (CRS) remained the most common AE (42/60, 70.0%; Grade 1/2, 58.3%) and was lower in the 2000mg (63.6%) vs the 1000mg (87.5%) Gpt cohort. Glofitamab monotherapy (2000mg Gpt) is currently under investigation in the Phase III GLOBRYTE study (NCT06084936). Conclusions: Fixed-duration glofitamab continues to demonstrate compelling response rates that are maintained beyond EOT, with long-term durability observed in heavily pretreated pts with R/R MCL, including pts with prior BTKi therapy. The safety profile was manageable and CRS mainly low grade. Clinical trial information: NCT03075696 .