The rapid development of novel agents and combinations in chronic lymphocytic leukemia/small lymphocytic lymphoma has led to multiple options for frontline therapy and relapse, including continuous therapy and fixed duration regimens. The choice of therapy may be affected by the patient performance status, molecular abnormalities, potential side effects, logistics, patient expectations, and sequencing options in patients who will likely need more than one therapy in their lifetime. Current therapy options consist of several Bruton tyrosine kinase inhibitors (BTKis; covalent and noncovalent), one BCL-2 inhibitor (with others in development), and antibodies, with the possibility of single-agent therapy, doublets, or, less frequently, triplet therapy. In addition, treatment for double-refractory patients (refractory to both a BTKi and a BCL-2i) is available, but options are limited, so additional therapies for treatment in these high-risk patients are needed and in development.

Abstract Acalabrutinib is a selective, covalent Bruton tyrosine kinase inhibitor approved for marketing in chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). We report final, long-term phase 1/2 study results in 99 patients with treatment-naive (TN) and 134 with relapsed/refractory (R/R) CLL/SLL. At final data cutoff, 71% and 31% of patients in the TN and R/R cohorts, respectively, remained on acalabrutinib treatment (median follow-up of 73.7 and 52.6 months). Among the events of clinical interest (any grade) in the TN and R/R cohorts, atrial fibrillation was reported in 6.1% and 9.0%, hypertension in 29.3% and 23.1%, other malignancies (excluding nonmelanoma skin cancer) in 14.1% and 17.2%, and major bleeding in 8.1% and 8.2% of patients, respectively. The incidence of the most common adverse events decreased over time. Overall response rates were 97.0% and 94.8% in the TN and R/R cohorts, respectively, with similar response findings among patients with standard and high-risk genomic features. In the TN cohort, median progression-free survival (PFS) was not reached and the 72-month PFS rate was 86.7% (95% confidence interval [CI], 77.0-92.5). For the R/R cohort, median PFS was 66.1 months (range, 0.4-87.8) and the 72-month PFS rate was 45.1% (95% CI, 35.6-54.1). This final analysis extends the duration of benefit observed with acalabrutinib, demonstrates that no new safety signals are apparent with longer follow-up, and confirms the safety and tolerability of acalabrutinib monotherapy for patients with CLL/SLL. This trial was registered at www.clinicaltrials.gov as #NCT02029443.

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is a clinically indolent lymphoproliferative disorder characterized by accumulation of mature B-cell lymphocytes. Given the common CD5 co-expression, mantle cell lymphoma (MCL) is one of the most important entities in the differential diagnosis. MCL and CLL/SLL might exhibit overlapping morphologic and immunohistochemical features, making diagnosis particularly difficult in cases of composite lymphomas. Here, we present a unique case of composite lymphoma in an 86-year-old male, along with a literature review on the immunophenotypic variability of both MCL and CLL, which should always be confirmed with additional ancillary cytogenetic and molecular studies.

BACKGROUND:Bruton's tyrosine kinase inhibitors (BTKi) have prolonged survival in chronic lymphocytic leukemia (CLL), however continuous administration increases toxicity. Little is known about clinical outcomes of patients who discontinue BTKi for reasons other than CLL progression. We aimed to report these outcomes. PATIENTS/METHODS:With the CLL Society, we solicited volunteers with CLL who self-reported BTKi discontinuation for reasons other than CLL progression to participate in a web-based survey. RESULTS:In 170 patients, BTKi was discontinued for toxicity, because CLL was in remission, or personal choice in 62%, 14% and 8%, respectively. When asked how they felt about stopping the BTKi, most were relieved that they may eliminate toxicity (45%), could focus less on CLL (11%), and would not have to pay for the medicine (7%), while 29% experienced anxiety. A statistically significant increase in perceived quality of life (QOL) was observed from prior- versus post-BTKi discontinuation. Of patients who reported that they experienced clinical CLL progression (n = 80), 46% reported that these events did not happen for ≥ 1 year after BTKi discontinuation. Those that were on a BTKi for ≥ 2 years before discontinuation had more time without CLL relapse. CONCLUSIONS:These data provide a unique report of patient experiences. The data suggest that BTKi may be feasible and result in a period of treatment-free remission. The data also indicate that patients are generally relieved when they anticipate BTKi discontinuation and observe significant QOL improvements after BTKi discontinuation. As such, these data should prompt prospective study of time-limited BTKi therapy for CLL.

Supplemental Table 3. Frequency of BTK and PLCG2 mutations in previously untreated patients or those with relapsed/refractory disease who experienced Richter's transformation

ABSTRACT:In patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL), high-risk cytogenetic features such as del(17p), del(11q), and unmutated immunoglobulin variable heavy chain (IGHV) may be associated with unfavorable outcomes. In this large retrospective cohort study, data from a nationwide electronic health record-derived deidentified database were analyzed to assess real-world overall survival (rwOS) among patients treated with first-line (1L) ibrutinib with and without high-risk cytogenetic features (ie, del(17p), del(11q), unmutated IGHV). Inverse probability of treatment weighting was used to account for differences in patient characteristics between cohorts. Of 1242 patients included, 969 and 273 had high- and non-high-risk CLL/SLL, with a mean age of 70.0 and 70.8 years, and a median follow-up of 32 and 31 months, respectively. Within the high-risk cohort, 32.9%, 36.7%, and 58.7% had the presence of del(17p), del(11q), and unmutated IGHV, respectively. The median rwOS was not reached for either cohort; the hazard ratio (HR) comparing rwOS between the 2 cohorts was 1.09 (95% confidence interval [CI], 0.79-1.51). In a sensitivity analysis in which del(11q) was not part of the high-risk definition, similar results were found, with a HR of 1.19 (95% CI, 0.86-1.64) and median rwOS not reached for either cohort. Similarly, among the subgroup of patients with Medicare coverage, the HR was 0.98 (95% CI, 0.63-1.53), and median rwOS was not reached. In this real-world study using a large community health care data set, there was no difference in rwOS between patients treated with 1L ibrutinib with and without high-risk cytogenetic features.

Some CLL patients who develop progressive disease (PD) during treatment with covalent Bruton tyrosine kinase inhibitors (cBTKi) acquire pathway resistance mutations in BTK or PLCG2. Here, we report gene mutation data from paired baseline and PD peripheral blood samples from 52 patients (zanubrutinib, n=24; ibrutinib, n=28) who, at an early median follow-up time of 25.7 months, progressed on zanubrutinib or ibrutinib treatment in the ALPINE trial (NCT03734016). No BTK mutations were observed at baseline; at PD, eight patients (zanubrutinib, n=5, ibrutinib, n=3) acquired a total of 17 BTK mutations. Among BTK mutations, 82.4% (zanubrutinib, n=11/14; ibrutinib, n=3/3) were at C481. Non-C481 mutations were detected in 12.5% (3/24) of zanubrutinib-treated patients (L528W: n=2, cancer cell fraction [CCF]=9.58% and 17.6%; A428D, n=1, CCF=37.03%); these were not detected in ibrutinib-treated patients. At baseline, 48/52 patients had ≥1 driver gene mutation/s, most frequently in: NOTCH1 (n=21), TP53 (n=19), BRAF (n=10), SF3B1 (n=8), and ATM (n=8). At PD, acquired driver gene mutations were observed in one zanubrutinib-treated patient (TP53, XPO1) and five ibrutinib-treated patients (TP53, n=1 patient; SETD2, n=1; SF3B1, n=1; ASXL1, n=2). Baseline driver gene mutations were not associated with later development of BTK mutations, but patients with ≥2 baseline driver gene mutations were more likely to acquire BTK mutations at PD. In conclusion, patients in this data set had a short treatment duration and a low incidence of BTK mutations, suggesting that mechanisms other than BTK/PLCG2 mutations are driving most instances of early PD. NCT03734016

7025 Background: CB-010 is an allogeneic anti-CD19 CAR-T cell therapy derived from healthy donor T cells using CRISPR hybrid RNA-DNA (chRDNA) technology. This technology is used to introduce 3 genome edits: (1) knockout of TRACto eliminate TCR expression and reduce risk of GvHD, (2) insertion of a CD19-specific CAR (scFv FMC63) into the TRAC locus, and (3) knockout of PD-1 to prevent premature CAR-T cell exhaustion and potentially enhance antitumor activity. Methods: ANTLER is a Phase 1 clinical trial (NCT04637763) with a 3+3 dose escalation phase and a dose expansion phase designed to evaluate safety, tolerability, and antitumor activity of CB-010 in patients (pts) with r/r B-NHL and determine RP2D. In dose escalation, pts must have received ≥2 prior lines of chemoimmunotherapy or had primary refractory disease to 1L therapy. Pts received lymphodepletion with sequential cyclophosphamide (60 mg/kg/day x 2 days) and fludarabine (25 mg/m2/day x 5 days) followed by a single CB-010 infusion. Results: 16 pts with r/r B-NHL (10 LBCL, 3 MCL, 2 FL with POD24, 1 MZL) received CB-010 at 40 x 106 CAR-T cells (dose level 1; N=8), 80 x 106 CAR-T cells (dose level 2; N=5), or 120 x 106 CAR-T cells (dose level 3; N=3) during dose escalation. Median age was 66 years (range 55-82). Median time since first diagnosis was 2.4 years (range 0.2-16.4). Median prior lines of therapy was 2 (range 1-8). CB-010 was generally well tolerated. No GvHD was seen. CRS occurred in 7/16 (44%) pts (no CRS grade ≥3). Median time to CRS onset was 3.5 days and median duration was 3 days. ICANS occurred in 4/16 (25%) pts (13% grade ≥3). Median time to ICANS onset was 7.5 days and median duration was 2 days. The 3 most common TEAEs grade ≥3 were thrombocytopenia (11/16; 69%), neutropenia (9/16; 56%), and anemia (8/16; 50%). One grade 3 infection (antecubital cellulitis) occurred unrelated to CB-010. After a single CB-010 infusion, 15/16 (94%) pts achieved an overall response, 11/16 (69%) achieved a CR, and 7/16 (44%) achieved a CR at ≥6 months. Median time to CR was 28 days. Among LBCL pts (n=10), 9 (90%) achieved an overall response, 7 (70%) achieved a CR, and 5 (50%) achieved a CR at ≥6 months. To date,2 pts have completed the 24-month study period with ongoing CR. Peak expansion of CB-010 occurred at days 7-10 post-infusion. T and NK cells recovered rapidly in peripheral blood (<3 weeks) after lymphodepletion, and B cells remained below the limit of quantification beyond 3 months, supporting specific targeting of B cells by CB-010. Conclusions: CB-010 showed a manageable safety profile and promising efficacy for treatment of pts with r/r B-NHL, including aggressive subtypes. The dose escalation phase is complete. Enrollment of 2L LBCL pts in dose expansion is ongoing. Initial dose expansion data at the CB-010 RP2D and translational data will be presented for the first time at the meeting. Clinical trial information: NCT04637763 .

Abstract SWOG 1318 evaluated the feasibility of combining the tyrosine kinase inhibitor (TKI) dasatinib with prednisone and blinatumomab in older patients (pts) with Philadelphia chromosome positive (Ph+) B-acute lymphoblastic leukemia (ALL). Here, we present longer follow up (median follow up 5.6 years) with outcomes, predictors of response, and translational medicine studies. Methods: This trial was activated through the NCTN in January 2014 and closed to accrual in April 2021. Pt eligibility included: age > 65 years, Ph+ ALL, no evidence of central nervous system (CNS) disease, and adequate organ function. Treatment has been previously described (Blood Adv 2023; 7(7): 1279-85). Statistics: Categorical and quantitative endpoints comparisons used Fisher's exact and Wilcoxon tests. Survival endpoints used the Kaplan-Meier method and Cox regression models and were landmarked for post-baseline events as needed (i.e., number of cycles). Translational medicine studies: Single cell ATAC seq (10x genomics) was performed on 9 archived cryopreserved diagnostic samples from patients with > 500,000 cells. All samples successfully completed library preparation, sequencing, and demonstrated adequate blast clusters for analysis. Briefly, cryopreserved cells were thawed, and transposases were introduced into nuclei in single cell suspension and used to generate GEM beads. ATAC seq libraries were prepared per manufacture instructions. Libraries were then sequenced on a 25B flow cell on Novaseq X plus (Illumina). The data were analyzed with cloupe (version 9.0.0). Results: Twenty-four eligible patients were enrolled. The median age was 73 years (range 65-87). All pts had newly diagnosed Ph+ ALL. Seventy-nine percent of pts had additional cytogenetic abnormalities. Twenty-two pts (92%) achieved a complete remission (CR) during dasatinib and prednisone induction therapy. Most sites also monitored patient's blood or bone marrow with real-time quantitative PCR to quantify the BCR-ABL1 transcript for molecular response. Of 19 patients analyzed 17 (89%) were in a major or complete molecular remission at some point after treatment, with at least 12 of these patients achieving complete molecular remission. Three patients remain on maintenance. The median follow up for patients who are alive is 5.6 years (range 4.4-8.3). Five- year OS and DFS estimates are 63% (95% CI: 40-78%) and 64% (95% CI: 40-80%). Two patients relapsed in the CNS. One pt proceeded to allogeneic hematopoietic stem cell transplant (HSCT) and 1 to autologous HSCT. Increased age was associated with a decreased chance of achieving CR as best response (median age in responder group 73.2 years [range 65-82.9]; median age in non-responder group 85.5 [range 83.8-87.3]; p=0.02). Patients with extramedullary disease had shorter DFS (HR 0.22, 95% CI 0.04-1.15, p=0.07). Increased number of cycles of blinatumomab received was associated with a trend towards improved OS (HR 0.66, 95% CI 0.41-1.08, p=0.10). Translational medicine studies for chromatin accessibility in the blast clusters demonstrated improved OS in patients with homogeneous blast clusters (HR 0.42, 95% CI 0.06-3.04, p=0.39), high DUX4 differential accessibility (HR 0.26, 95% CI 0.03-2.55, p=0.25), and ATAC seq data corresponding to decreased chromatin accessibility in HOXA2 (HR 0.09, 95% CI 0.01-1.05. p=0.06). Conclusions: Despite an elderly population, this trial demonstrated impressive outcomes with longer follow-up for patients with Ph+ ALL. The number of cycles of blinatumomab and the presence of extramedullary disease may be important factors in outcome. Translational studies suggest additional markers may be predictors of overall survival, and these will need to be studied on larger scale studies. Decreased chromatin accessibility to HOXA2 was associated with a trend towards improved OS. Additional translational medicine will also be presented at the meeting.

Supplemental Table 2. Detailed information on samples with detected BTK mutations

Background:There are no head-to-head studies comparing the efficacy of the Bruton tyrosine kinase inhibitors, zanubrutinib and acalabrutinib, in relapsed or refractory chronic lymphocytic leukemia (R/R CLL). Objective:To compare the relative efficacy of zanubrutinib and acalabrutinib in R/R CLL using indirect treatment comparison. Design:An unanchored matching-adjusted indirect comparison (MAIC) was performed. Methods:Individual patient-level data from ALPINE (zanubrutinib) were reweighted using prognostic/effect-modifying variables to match aggregate data from ASCEND (acalabrutinib). MAIC outcomes included investigator-assessed progression-free survival (PFS-INV), overall survival (OS), and complete response (CR). Results:Post-matching, PFS-INV was improved significantly for zanubrutinib versus acalabrutinib (hazard ratio (HR) = 0.68 (95% confidence interval (CI): 0.46-0.99); p = 0.0448) and OS showed a trend toward improvement for zanubrutinib (HR = 0.60; 95% CI: 0.35-1.02, p = 0.0575). CR was significantly higher for zanubrutinib versus acalabrutinib (odds ratio = 2.90 (95% CI: 1.13-7.43); p = 0.0270). Conclusion:Zanubrutinib was associated with a significant PFS-INV and CR advantage over acalabrutinib, with a trend toward improvement in OS.

ABSTRACT:Patients with relapsed/refractory diffuse large B-cell lymphoma progressing after chimeric antigen receptor T-cell (CAR-T) therapy have dismal outcomes. The prespecified post-CAR-T expansion cohort of the ELM-1 study investigated the efficacy and safety of odronextamab, a CD20×CD3 bispecific antibody, in patients with disease progression after CAR-Ts. Sixty patients received IV odronextamab weekly for 4 cycles followed by maintenance until progression. The primary end point was objective response rate (ORR) by independent central review. The median number of prior lines of therapy was 3 (range, 2-9), 71.7% were refractory to CAR-Ts, and 48.3% relapsed within 90 days of CAR-T therapy. After a median follow-up of 16.2 months, ORR and complete response (CR) rate were 48.3% and 31.7%, respectively. Responses were similar across prior CAR-T products and time to relapse on CAR-T therapy. Median duration of response was 14.8 months and median duration of CR was not reached. Median progression-free survival and overall survival were 4.8 and 10.2 months, respectively. The most common treatment-emergent adverse event was cytokine release syndrome (48.3%; no grade ≥3 events). No cases of immune effector cell-associated neurotoxicity syndrome were reported. Grade ≥3 infections occurred in 12 patients (20.0%), 2 of which were COVID-19. Odronextamab monotherapy demonstrated encouraging efficacy and generally manageable safety, supporting its potential as an off-the-shelf option for patients after CAR-T therapy. This trial was registered at www.clinicaltrials.gov as #NCT02290951.

Supplemental Table 1 Listing of all detected BTK mutations (by NGS) in samples from previously untreated patients or those with relapsed/refractory disease

Abstract Introduction: Patients diagnosed with chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL/SLL) exhibit an elevated risk of developing other cancers (OC) relative to the general population. Historically, chemoimmunotherapy (CIT) represented the cornerstone of CLL/SLL management. A systematic review of clinical trials of CIT for CLL that included 28 studies reported 352/3297 (12.6%) patients developed OC (Csanadi 2022). The introduction of targeted agents beginning in the mid-2010's, including Bruton tyrosine kinase inhibitors (BTKi) and BCL2 inhibitors, has shifted the standard of care toward these novel therapies. In this study, we determined the risk of OC in newly diagnosed CLL/SLL patients cared for at the US Department of Veteran Affairs (VA), The University of Texas MD Anderson Cancer Center, and Mayo Clinic in Rochester, MN. Methods: We identified patients with newly diagnosed CLL/SLL after 1/1/2016 using the VA Central Cancer Registry, MD Anderson, and the Mayo Clinic CLL Databases. The baseline clinical characteristics, CLL treatments, and the occurrence of OC were abstracted by electronic health record (EHR) review. Receipt of CLL directed therapy was categorized into a) CIT only; b) targeted therapy only; c) CIT and targeted therapy; and d) other (including monotherapy with monoclonal antibody therapy). The occurrence of OC was modeled using CLL treatment as a time-dependent variable. Prior and concurrent OC diagnosed within 3 months of CLL/SLL were excluded from analyses, to reduce ascertainment bias. Results: We identified 6844 patients with CLL/SLL who met inclusion criteria. Median follow up was 3.6 years (interquartile range [IQR] 1.9-5.8). The median age at diagnosis of CLL/SLL was 71 years (range, 23 - 102); most patients were white (81%) and male (90%). Although many patients had missing values, among those with available information, IGHV genes were unmutated in 884 (51%), CLL FISH panel showed del17 in 213 (7%), del11q in 389 (13%), trisomy 12 in 674 (23%), and del13q in 1508 patients (50%). A total of 2344 patients received CLL directed therapy during follow-up: 278 (12%) received CIT only, 1809 (77%) received targeted therapy (+/- monoclonal antibody), only 99 (4%) received CIT and targeted therapy and 150 (6%) monoclonal antibody therapy only. Among patients treated with targeted therapies, 950 (50%) received ibrutinib, 381 (20%) received acalabrutinib, 164 (9%) received zanubrutinib, 4 (<1%) received orelabrutinib, 280 (15%) received venetoclax, and 3 (<1%) received sonrotoclax. Other treatments included combinations of a covalent BTKi (cBTKi) and BCL2i in 52 (3%) patients, among others. A total of 583 patients were diagnosed with OC during the study period. Types of OC observed included neoplasms of the prostate (n=129, 22%), lung (n=118, 20%), hematologic malignancies (n=91, 16%), gastrointestinal tract (n=68, 12%), melanoma (n=66, 11%), kidney and bladder (n=44, 8%), head and neck (n=19, 3%), and other/unknown (n=48, 8%). Estimated risk of occurrence of OC was 4.2% (95%CI 3.8-4.8%) at 24 months and 9.7% (95%CI 8.9-10.6%) at 60 months after a diagnosis of CLL/SLL. Multivariable analyses demonstrated that older age (HR: 1.013, 95%CI: 1.00-1.021), male sex (HR: 1.6, 95%CI: 1.1-2.3), and receipt of CLL directed therapy (HR: 1.4, 95%CI: 1.2-1.7) were associated with an increased risk of OC. When considering different types of CLL directed treatments, those who received CIT with or without targeted therapies had the highest risk of development of OC (HR: 1.6, 95%CI: 1.2-2.1). Risk of OC were also increased for those who received CIT only (HR: 1.41, 95%CI: 0.97-2.05) and those who received targeted treatments alone (HR: 1.27, 95%CI: 1.02-1.58). Conclusion: In this large dataset of newly diagnosed patients with CLL/SLL in the past ten years, approximately 10% patients developed OC at 5 years. Receipt of CLL directed therapy was associated with a 40% increased risk of development of OC compared to those patients who did not receive therapy. The risk was highest among patients who received CIT with or without targeted therapy and was still elevated in those who received CIT only or targeted therapy only.

Supplemental methods discussing mutation testing.

Objective: There are significant disparities in outcomes among Hispanic patients with acute lymphoblastic leukemia (ALL). Recent studies have demonstrated favorable outcomes of pegaspargase-containing ALL regimens (PEG-CAR) in young adults however, outcomes in Hispanic ethnicity continue to be underreported.Methods: We evaluated outcomes of newly diagnosed, adult B-cell ALL Hispanic and non-Hispanic patients consecutively treated with a PEG-CAR or HyperCVAD between January 2011 and November 2022. The primary endpoint was event-free survival (EFS) while secondary endpoints included cumulative incidence of relapse and overall survival (OS).Results: Among 105 included patients, 48 (45.7%) were treated with a PEG-CAR and 57 (54.3%) with HyperCVAD. Median age was 38 years (range, 18-75 years), 61% were Hispanic, and 35.2% had poor-genetic risk. Hispanic patients demonstrated significantly worse 5-year EFS with a PEG-CAR compared to that seen with HyperCVAD (HR, 2.58; 95% CI, 1.32-5.04; p = .006) whereas non-Hispanic patients had better outcomes with PIR (52.4% vs. 42.0%). Hispanic ethnicity (p = .015) and male sex (p = .019) were independent predictors for poor OS.Conclusions: Hispanic patients with B-cell ALL had worse EFS with a PEG-CAR as compared with HyperCVAD. Future studies will aim to confirm these findings and establish a tailored treatment approach for this high-risk population.

Early phase clinical trials with various MCL-1 inhibitors

We report on the long-term efficacy and safety of a phase 2 trial of sequential cladribine and rituximab in hairy cell leukemia (HCL). One-hundred and thirty-nine patients were enrolled: 111 in the frontline setting, 18 in first relapse, and 10 with variant HCL (HCLv). A complete response (CR) was achieved in 133 of 137 evaluable participants (97%) with measurable residual disease (MRD) negativity in 102 (77%). MRD status was not associated with significant differences in event-free survival (EFS) or overall survival (OS). With a median follow-up of 7.8 years (range: 0.40-18.8), eight patients have experienced disease relapse (5.8%), 4/111 with newly diagnosed HCL (3·6%) and 4/10 with HCLv (40%) (p = 0.002). The 10-year EFS and OS rates were 86.7% and 91.1%, respectively. Grade 3 adverse events were observed in 28 participants (20·1%), mostly due to infections. Treatment of HCL with sequential cladribine followed by rituximab is associated with excellent efficacy and safety results both in the frontline and relapsed settings.