Chronic Lymphocytic Leukemia Population Research Articles

Risk factors and mortality associated with venous thromboembolism in the elderly US population with chronic lymphocytic leukemia

BackgroundVenous thromboembolism (VTE) causes morbidity and mortality in cancer patients. The association of VTE with known risk factors in chronic lymphocytic leukemia (CLL) is not known. ObjectiveTo examine risk factors and mortality associated with VTE in White, Black, and Asian CLL patients. MethodsThe United States SEER-Medicare database (2000–2015) was used for CLL patients ≥ 65 years. Logistic regression was used to examine VTE risk factors and Cox proportional regression was used to evaluate the effect of VTE on mortality in White, Black, and Asian CLL patients. ResultsAmong 34,075 CLL patients, VTE was diagnosed in 11.6 % of 31,395 White, 14.6 % of 2062 Black and 6.3 % of 618 Asian patients. Risk of having VTE was, ORa = 1.2 (95 % CI, 1.0–1.4) for Black patients and ORa = 0.5 (95 % CI, 0.4–0.7) for Asian patients compared to White patients. Anemia and heart failure were associated with VTE in all three racial cohorts and were the only risk factors in Asian patients. Other risk factors in White patients were the same as in the overall population, including hypertension, obesity, COPD, kidney disease, diabetes, hyperlipidemia, myocardial infarction, and chemotherapy. In Black patients, other risk factors were hypertension, and chemotherapy. Mortality was slightly higher with VTE in the overall population and in White patients. ConclusionThere was difference in VTE risk factors in White, Black, and Asian patients. VTE was marginally associated with mortality in CLL patients. Our findings may help to identify patients at higher risk of VTE in racially diverse CLL populations.

Acalabrutinib-based regimens in frontline or relapsed/refractory higher-risk CLL: pooled analysis of 5 clinical trials

AbstractBefore targeted therapies, patients with higher-risk chronic lymphocytic leukemia (CLL), defined as del(17p) and/or TP53 mutation (TP53m), unmutated immunoglobulin heavy chain variable region genes (uIGHV), or complex karyotype (CK), had poorer prognosis with chemoimmunotherapy. Bruton tyrosine kinase inhibitors (BTKis) have demonstrated benefit in higher-risk patient populations with CLL in individual trials. To better understand the impact of the second-generation BTKi acalabrutinib, we pooled data from 5 prospective clinical studies of acalabrutinib as monotherapy or in combination with obinutuzumab (ACE-CL-001, ACE-CL-003, ELEVATE-TN, ELEVATE-RR, and ASCEND) in patients with higher-risk CLL in treatment-naive (TN) or relapsed/refractory (R/R) cohorts. A total of 808 patients were included (TN cohort, n = 320; R/R cohort, n = 488). Median follow-up was 59.1 months (TN cohort) and 44.3 months (R/R cohort); 51.3% and 26.8% of patients in the TN and R/R cohorts, respectively, remained on treatment at last follow-up. In the del(17p)/TP53m, uIGHV, and CK subgroups in the TN cohort, median progression-free survival (PFS) and median overall survival (OS) were not reached (NR). In the del(17p)/TP53m, uIGHV, and CK subgroups in the R/R cohort, median PFS was 38.6 months, 46.9 months, and 38.6 months, respectively, and median OS was 60.6 months, NR, and NR, respectively. The safety profile of acalabrutinib-based therapy in this population was consistent with the known safety profile of acalabrutinib in a broad CLL population. Our analysis demonstrates long-term benefit of acalabrutinib-based regimens in patients with higher-risk CLL, regardless of line of therapy.

COVID-19 severity in patients with chronic lymphocytic leukemia treated with venetoclax: a single-center observational cohort study

Patients with chronic lymphocytic leukemia (CLL) are at high risk of developing severe COVID-19. The present study was undertaken to elucidate COVID-19 related morbidity and mortality in CLL patients treated with venetoclax. We present a single-center study of 108 patients with small lymphocytic lymphoma or CLL treated with venetoclax. Primary outcome was 30-day COVID-19 mortality. Secondary outcomes included COVID-19 severity and hospitalization rate. Forty-eight (44%) patients had PCR-verified SARS-COV-2 between March 2020 and January 2023. Thirty-six patients (75%) presented with asymptomatic/mild COVID-19 and 12 (25%) with severe/critical disease. The hospitalization rate was 46% with a 30-day mortality rate of only 4% and severe comorbidities as the primary cause of death. COVID-19 severity and mortality were similar before and during the Omicron era. High CIRS-scores (P < 0.02) and thrombocytopenia (P < 0.01) were more frequent in patients with severe/critical disease. In real-world data, most venetoclax treated patients presented with mild COVID-19. Hospitalization and mortality rates were low compared to data of general CLL populations. Our data indicate that venetoclax was a safe treatment option for CLL patients during the pandemic.

Abstract P13: Genetic and epigenetic characterization of B-cell chronic lymphocytic leukemia with IG::BCL3-translocation provides evidence for a distinct biological entity

Abstract IG translocations occur in various B-cell neoplasms and result in the deregulation of (onco)genes due to their juxtaposition with regulatory elements in the immunoglobulin loci, predominantly the immunoglobulin heavy chain (IGH) locus (14q32). Some of these IGH translocations are pathognomonic for distinct disease entities, like those involving MYC, BCL2 or CCND1 in Burkitt, Follicular or Mantle Cell Lymphomas, respectively. In Chronic Lymphocytic Leukemia (CLL), the BCL3 gene (19q13), a transcriptional coactivator of the nuclear factor-kappaB (NF-κB) family, is a known partner gene in these translocations. Two subsets of IG::BCL3 translocation-positive B-cell neoplasms have been described that exhibit differences in chromosomal aberrations, IGHV mutation status, and histopathology [Martín-Subero et al. 2007]. In CLL, IG::BCL3 translocation is linked to a younger age at diagnosis, a more aggressive clinical course, and an atypical tumor cell phenotype [Michaux et al. 1997; Au et al. 2002]. A total of 89 B-cell neoplasms, primarily diagnosed as CLL, displaying IG::BCL3 translocation detected by fluorescence in situ hybridization (FISH), were examined. Analysis of DNA methylation and copy number aberrations (CNA) was conducted for 86 IGH::BCL3-translocated B-cell neoplasms using 850K EPIC BeadChip array data. Evaluation of chromosomal aberrations typical for CLL was moreover performed by FISH and the IGHV mutation status was determined. IGH::BCL3 breakpoint junctions were sequenced in 23 samples using targeted capture and whole-genome sequencing approaches. RNA expression of BCL3 was assessed using the HTG mRNA pan B-cell panel. In UMAP analysis of DNA methylation, CLLs with IG::BCL3 translocation exhibited segregation from other CLLs, irrespective of IGH translocations. Supervised analysis revealed global hypomethylation of B-cell neoplasms with IG::BCL3 translocation compared to other CLL. A total of 66/69 CLLs with IG::BCL3 translocation showed an unmutated IGHV status (96%). Copy number determination using BeadChip data (n=86) and FISH analysis (n=85) showed a significantly higher incidence of trisomy 12 in IG::BCL3-translocated cases compared to the general CLL population (p=0.011). Breakpoint sequencing indicated IG::BCL3 junctions to be recurrently associated with aberrant class-switch recombination at the IGH locus, involving IGHA (n=11/23), IGHG (n=5/23) and IGHM segments (n=5/23). Breakpoints at the BCL3 locus displayed two groups. 80 cases (all CLL) were located upstream of BCL3 and two other B-cell neoplasms (NHL, DLBCL) were located downstream of BCL3. BCL3 expression analysis in 15 IG::BCL3-translocated CLLs confirmed its transcriptional upregulation compared to the general CLL population. Our genetic and epigenetic analyses support the view that CLL with IG::BCL3 translocation may constitute a genetically and epigenetically distinct subtype of B-cell neoplasms, diverging from the typical CLL. Citation Format: Cosima Drewes, Cristina López, Nnamdi Okeke, Sina Hillebrecht, Petra Schütz, Anja Fischer, Anja Mottok, Susanne Bens, Christof Schneider, Stephan Stilgenbauer, Eugen Tausch, Reiner Siebert. Genetic and epigenetic characterization of B-cell chronic lymphocytic leukemia with IG::BCL3-translocation provides evidence for a distinct biological entity [abstract]. In: Proceedings of the Blood Cancer Discovery Symposium; 2024 Mar 4-6; Boston, MA. Philadelphia (PA): AACR; Blood Cancer Discov 2024;5(2_Suppl):Abstract nr P13.

Pirtobrutinib: A New and Distinctive Treatment Option for B-Cell Malignancies.

The objective was to evaluate the efficacy/safety of pirtobrutinib in the treatment of B-cell malignancies and distinguish it from other available Bruton's tyrosine kinase (BTK) inhibitors. A literature search of PubMed (January 2021 through November 2023) and Clinicaltrials.gov was conducted using terms pirtobrutinib, Jaypirca, and LOXO 305. Licensing trials of available BTK inhibitors were also reviewed. Relevant English-language clinical trials were evaluated. Pirtobrutinib was approved by the US Food and Drug Administration for the treatment of relapsed/refractory mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL) based largely on a phase 1/2 study in B-cell malignancies. Pirtobrutinib demonstrated a 73% overall response rate (ORR) in the CLL population and 58% in MCL. Pirtobrutinib has activity in patients resistant to earlier-generation, covalent BTK inhibitors. In fact, the ORRs were similar in BTK-pretreated and naïve patients. Adverse effects include fatigue, diarrhea, bleeding, and infection. Atrial fibrillation, a class effect of BTK inhibitors, may be less common with pirtobrutinib. Compared with earlier-generation BTK inhibitors, pirtobrutinib is more selective for BTK and binds noncovalently to the receptor. Ongoing studies are evaluating pirtobrutinib's use in multiple B-cell malignancies and comparing it with other BTK inhibitors. The characteristics of pirtobrutinib render it useful in the treatment of B-cell malignancies no longer responding to a previous BTK inhibitor, and results from ongoing clinical trials may support future expanded use.

Similar Efficacy of Ibrutinib Arms across ALPINE and ELEVATE-RR Trials in Relapsed/Refractory Chronic Lymphocytic Leukemia: A Matching-Adjusted Indirect Comparison

Background: Bruton tyrosine kinase inhibitors (BTKi) are currently widely used for the treatment of patients with chronic lymphocytic leukemia (CLL). Ibrutinib, the first BTKi approved for the treatment of CLL, was followed by the second-generation BTKi, acalabrutinib, and recently the next-generation BTKi, zanubrutinib. Both zanubrutinib and acalabrutinib were compared to ibrutinib in phase 3 randomized controlled trials in relapsed/refractory (R/R) CLL. In the ALPINE trial (NCT03734016), zanubrutinib demonstrated a superior progression-free survival (PFS) when compared with ibrutinib in the all-comer R/R CLL population with hazard ratio (HR)=0.65, whereas the ELEVATE-RR trial (NCT02477696) showed noninferior PFS of acalabrutinib vs ibrutinib in R/R CLL patients with the presence of del(17p) or del(11q) with HR=1. Recent attempts to compare the efficacy results of the ibrutinib arm across trials omitted some patient characteristics that are critical for appropriate cross-trial comparisons. This study aimed to compare the efficacy of the ibrutinib control arm across ALPINE and ELEVATE-RR trials using a comprehensive matching-adjusted indirect comparison (MAIC). Methods: Individual patient data from the ibrutinib arm of ALPINE were adjusted to match the published population-level profile from the ibrutinib arm of ELEVATE-RR. To obtain comparable populations for MAIC, a subgroup of patients from ALPINE was included in the analysis. An unanchored MAIC was conducted to adjust for all relevant treatment effect modifiers (EM). The following were considered for population adjustment: IGHV status, del17p, del11q, TP53 status, serum β2-microglobulin, number of prior therapies, and Binet stage. Additional prognostic factors (PF) were also adjusted in sensitivity analyses. ALPINE data cutoff of August 2022 was used given the availability of both independent review committee (IRC) and investigator (INV) assessed data, and the possibility of a comparison vs other recently published MAICs (median follow-up: 29.6 months). Efficacy of ibrutinib in ALPINE was compared with efficacy of ibrutinib in ELEVATE-RR (median follow-up: 40.9 months). After population adjustment, HR obtained by weighted Cox proportional hazard model was applied to assess PFS and overall survival (OS) outcomes. PFS was analyzed as per IRC and INV. As the ALPINE trial was conducted during the COVID-19 pandemic and ELEVATE-RR was not, sensitivity analysis was conducted by adjusting the ALPINE PFS and OS for COVID-19 impact by censoring the patients who died due to COVID-19 at the most recent disease assessment prior to death or at the death due to COVID-19. Results: The high-risk population in ALPINE included 123 patients in the ibrutinib arm, which were matched against 265 patients in the ibrutinib arm of the ELEVATE-RR trial. After population adjustment, no statistically significant differences were observed in ALPINE-ibrutinib vs ELEVATE-ibrutinib with regards to PFS-IRC (HR=0.80 [0.49-1.28], P=0.3485) (Figure 1), PFS-INV (HR=1.18 [0.75-1.86], P=0.4827) (Figure 2), and OS (HR=0.91 [0.50-1.65], P=0.7539). Sensitivity analysis with COVID-19 adjustment yielded similar results as the main analysis. Scenarios matching for both EM and PF also generated results consistent with the main analysis. Conclusion: Using a comprehensive list of matching variables, this MAIC compares the performance of ibrutinib across ALPINE and ELEVATE-RR trials and demonstrates no evidence of a difference. Comparing the common comparator arms of 2 trials (ibrutinib vs ibrutinib) instead of the different investigational arms (zanubrutinib vs acalabrutinib) allows for eliminating some of the residual confounding that is inherent in MAICs. Despite decreased estimated sample size due to considering a comprehensive list of variables in the adjustment, results were consistent across multiple scenarios tested. While MAIC provides a basis for testing hypotheses with regards to treatment efficacy across trials, the ultimate evidence of relative efficacy must be sought within randomized controlled trials.

Real-World Effectiveness and Safety of Ibrutinib in Patients with Chronic Lymphocytic Leukemia (CLL) in Belgium after 4 Years

Background: The Belgian ibrutinib Real-world Data (BiRD) study is a multicenter, non-interventional, observational cohort study of adults with confirmed CLL, mantle cell lymphoma, or Waldenström's macroglobulinemia. Aim: To assess the effectiveness and safety of ibrutinib treatment of CLL in routine clinical practice in Belgium. Methods: Eligible patients initiated reimbursed ibrutinib treatment upon or after commercial availability in Belgium (August 1, 2015) or participated in the Medical Need Program and switched to reimbursed ibrutinib with commercial availability. The primary outcome measures were progression-free survival (PFS) and overall response rate (ORR); secondary outcome measures included overall survival (OS) and safety. Data were collected both prospectively (pro) and retrospectively (ret). Pro-collected adverse events (AEs) included all treatment-emergent AEs (TEAEs), whereas ret-collected AEs included only those considered related to ibrutinib; therefore, TEAEs for the pro group and AEs for the ret group are reported separately. To account for patients who could not be included in the ret group as they died before study entry and were therefore unable to provide consent, total population effectiveness results were adjusted with left truncation. We report results from the fourth interim analysis (cutoff: August 20, 2022) for patients with CLL, with a median follow-up of 49.1 months. Results: The effectiveness population included 221 patients (pro, n = 71; ret, n = 150). Median age at ibrutinib initiation was 72 years (range, 38-90); 64.3% were male; median time from diagnosis to ibrutinib initiation was 5.8 years (range, 0-31.4). Del17p/ TP53 mutation was present in 78/132 (59.1%) patients; 22/80 (27.5%) were IGHV-mutated. Nearly one-third of patients (27.4%) were treated first line, 24.2% received 1 prior line of therapy (LOT), 27.9% received 2 prior LOTs, and 20.5% received ≥ 3 LOTs. A history of significant cardiovascular disease was reported by 17.8% patients. Ibrutinib was initiated at 420 mg/day in 88.1% of patients, and 91 (40.3%) patients had ≥ 1 dose modification. Among these patients, who may have had more than 1 modification (increase or decrease), the most common reasons for dose modification were physician preference (59.3%) and toxicity (45.1%). Of the total 226 patients, 58 (25.7%) had ≥ 1 dose increase and 89 (39.4%) had ≥ 1 dose decrease. With ibrutinib treatment, median PFS was 46.0 months in the overall CLL population (Figure), and 49.1/53.6 months in the pro/ret groups. ORR was 90.9% (CR 21.7%, PR 53.4%, PR with lymphocytosis 15.8%). Median OS was 62.3 months (not estimable/91.0 months in pro/ret). Main effectiveness outcomes stratified according to age, prior LOT, and mutation status are listed in the Table. The safety population included 226 patients (pro, n = 73; ret, n = 153). TEAEs/AEs and serious TEAEs/AEs were reported in 100.0/85.6% and 69.9/50.3% in the pro/ret groups, respectively. TEAEs/AEs led to dose reduction, interruption, or withdrawal in 24.7/13.7%, 45.2/28.8%, or 30.1/21.6% of patients in the pro/ret groups, respectively. TEAEs/AEs of interest in the pro/ret groups were major bleeding (5.5/2.6%), infection (76.7/65.4%), hypertension (17.8/11.8%), atrial fibrillation (13.7/9.2%), arthralgia/myalgia (27.4/11.1%), diarrhea (24.7/13.7%), and rash (16.4/9.8%). Ibrutinib was permanently discontinued in 164 (72.6%) patients, most commonly due to disease progression (n = 40). The median duration of treatment was 35.8 months; 32 of the 226 patients discontinued ibrutinib due to toxicity (14.2%), and 27.4% of patients remain on treatment. Conclusions: In this Belgian real-world study, ibrutinib was found to be an effective treatment for patients with CLL, including those with higher risk mutations, several prior LOTs, and older age, with first-line patients who joined the study later responding particularly well. These findings are consistent with those from clinical trials, which support more effective outcomes for ibrutinib when utilized in the frontline (eg, RESONATE-2: Barr PM, et al. Blood Adv. 2022;6:440-3450; RESONATE: Munir T, et al. Am J Hematol. 2019;94:1353-1363). TEAEs/AEs are consistent with the known safety profile of ibrutinib.

Counting Chromosome Abnormalities in Chronic Lymphocytic Leukemia: Comparison of Iscn 2020 and MDS International Working Group Guidelines for Establishing Karyotype Complexity

Karyotype complexity is established by enumerating the number of chromosome abnormalities present in a karyotype. In chronic lymphocytic leukemia (CLL), karyotype complexity, defined as ≥3 chromosome abnormalities, is an important prognostic indicator associated with poor outcomes. Additionally, stratifying patients (pts) by highly complex karyotypes (≥5 chromosome abnormalities) has shown significantly poorer outcomes compared to pts with 3-4 abnormalities (Baliakas, Blood, 2019). In principle, counting chromosome abnormalities is straightforward; however, in practice it can be nuanced, and the number of abnormalities counted for the same karyotype can differ across laboratories. A lack of standardized rules has resulted in variability in establishing complexity across CLL studies. We and others have proposed adapting the international working group on myelodysplastic syndrome (MDS) framework for use in CLL (Chun, Leuk Res, 2010; Jondreville, Am J Hematol, 2020). Additionally, a separate set of guidelines were published in the 2020 International System for Human Cytogenomic Nomenclature (ISCN). To investigate how different guidelines may impact patient categorization in correlative studies, we evaluated karyotype complexity using both guidelines in a previously reported, well-characterized, dataset with long term follow-up of patients with CLL treated with ibrutinib (Kittai, Blood, 2021). 456 patient karyotypes underwent expert review by two cytogeneticists. Discordant scores were discussed to reach consensus. Pts were categorized as not complex (0-2 abnormalities), complex (3-4), or highly complex (≥5) for each set of guidelines. The weighted kappa was used to evaluate agreement between the two guidelines. Progression free survival (PFS) from ibrutinib start and overall survival (OS) were evaluated by the Kaplan-Meier method. Univariable Cox regression model discrimination power for PFS and OS were evaluated by Uno's concordance statistic. MDS guidelines categorized 50.2% as not complex, 19.7% complex and 30.1% as highly complex; similarly, ISCN categorized 50.2% as not complex, 20.2% complex and 29.6% as highly complex. Complexity categories assigned by the two guidelines had a weighted kappa agreement of 0.88 (95% CI 0.84-0.91), with 11% of pts placed in discordant complexity categories. Albeit numbers of pts were small, evaluation of these discordant cases compared to the consensus concordant cases showed outcomes varied. Discordant cases categorized by the MDS guidelines as complex and by ISCN as highly complex showed longer OS compared to the concordant complex and highly complex cases, suggesting ISCN overrated complexity (Fig 1). Conversely, discordant cases categorized by MDS guidelines as highly complex while ISCN categorized as complex showed decreased OS compared to the concordant complex and highly complex cases, suggesting ISCN underrated complexity in these cases (Fig 2). PFS trended similarly for these groups. Both the MDS and the ISCN guidelines showed increased karyotype complexity was significantly associated with shorter PFS (both with p&amp;lt;0.0001) and OS (both with p&amp;lt;0.0001). Comparing the classifiers not complex, complex and highly complex for the entire cohort found no significant difference between the prediction power of the MDS and ISCN guidelines for PFS. For OS, the MDS guidelines had a statistically stronger prediction power compared to ISCN (p=0.0235). Further, when the poorest prognostic group (highly complex) was compared to all others, the MDS guidelines showed significantly stronger prediction power for both PFS (p=0.0359) and OS (p=0.0039) compared to ISCN. Although both sets of guidelines were prognostically significant, in this predominately relapsed/refractory CLL patient population receiving ibrutinib, the MDS guidelines performed more robustly when used as a categorical variable. Clinical trials incorporating karyotype complexity for prognostication, or for treatment stratification, should specify a set of guidelines to apply consistently across the trial. Given the importance of karyotype complexity, particularly with targeted therapies, further studies are needed to evaluate these two sets of guidelines across varying CLL populations to establish recommendations for assigning karyotype complexity uniformly in CLL.

Comparison of Dietary Intake and Dietary Inflammatory Index in Patients with Chronic Lymphocytic Leukemia By Treatment Status to Cohabitating Controls

Chronic lymphocytic leukemia (CLL) is an incurable disease with a varied presentation ranging from indolent and asymptomatic to morbid and life-limiting. As tumor biology insufficiently explains this variability, we hypothesized that behavioral and environmental factors including diet and the gut microbiome, where diet is a key influence, may influence CLL pathogenesis and response to therapy. We performed a cross-sectional sample and survey collection study of the gut microbiome, blood, and diet in patients with CLL treated at the University of Nebraska Medical Center between 2021-2023. Eligible subjects included 1) untreated CLL with Rai stage 2-4 disease (untreated CLL), 2) CLL treated with a Bruton's tyrosine kinase inhibitor (BTKi), and 3) individuals without cancer cohabitating with enrolled CLL subjects (control). All subjects provided stool samples for microbial analysis, and subjects with CLL provided blood for serum cytokine analysis. All subjects completed the Diet History Questionnaire version 3.0 (DHQ-3). The DHQ-3 is a self-administered food frequency questionnaire, where participants complete 135 questions on food/beverages and 26 on dietary supplements consumed in the past month. A total and component healthy eating index (HEI) score was derived from the DHQ-3 and represents how well diet intake corresponds to the dietary guidelines recommended by the United States Department of Agriculture and Health and Human Services. The HEI is based on 13 individual components (Figure 1) and scored from 0-100, where higher scores indicate healthier diets. Inflammatory capacity of the diet was assessed by the Dietary Inflammatory Index (DII) (Shivappa et al, Public Health Nutrition, 2013), a measure of dietary components associated with serum markers of inflammation. The DII has a range of scores up to 7.98 suggestive of greater systemic inflammation (median DII score 0.23), and a minimum of -8.87, suggestive of consumption of anti-inflammatory foods. The DII was calculated and compared between each cohort. Statistical analysis was performed using ANOVA. A total of 58 subjects enrolled on the study, 42 with CLL and 16 cohabitating controls. A total of 27 subjects were included in the analysis after data cleaning. Fifteen subjects (56%) were treated with a BTKi, 5 (19%) had untreated Rai stage 2 disease, and 7 (26%) were cohabitating controls. Median ages (72 vs 67 vs 71 for BTKi, untreated, control, respectively) were similar. Median absolute lymphocyte count was 3.2 cells x10^3/µL (1.3 - 131 range) in the BTKi and 55 cells x10^3/µL (13-134 range) in the untreated cohort. There were 5/15 (33%) with 17p deletion and/or p53 mutation in the BTKi cohort and 2/5 (40%) in the untreated cohort. Median time from diagnosis to study entry was 30 months (range 3-151 months) in the untreated cohort, and median time on BTKi therapy was 30 months (range 2-92 months). Within the BTKi cohort, 33% received ibrutinib, 20% received zanubrutinib, and 47% received acalabrutinib. Overall dietary habits were largely similar between the 3 cohorts (Table 1). The mean total HEI score was higher in the untreated (66) and control (66) populations compared to the BTKi cohort (59) ( p = 0.23), although not significantly different. These scores are similar to the 2020 median score of 61 for Americans 60 years and above. Added sugar intake was highest in the untreated cohort (HEI component score of 9.6, 6.3, 8.6 untreated, BTKi, control p = 0.005, respectively) (Figure 1). After calculating the DII for each cohort, no statistically significant differences were observed (Table 1). The range of DII scores across subjects was -5.2 - 4.0, within the expected range for DII calculations. DII scores were 0.44, 0.2, 0.82 p = 0.89 for BTKI, untreated CLL, and control cohorts respectively. To our knowledge, this study is the first to analyze dietary patterns in well-defined homogenous CLL populations (BTKi vs Rai stage 2+ CLL cohort) and compare them to cohabitating individuals. Although overall dietary patterns and DII were similar across cohorts, slight differences in added sugar intake was observed between the cohorts, suggestive that subtle yet important dietary differences may be observed. These data provide a baseline to study personalize dietary approaches to patients with CLL, who increasingly ask clinicians for nutritional interventions as part of their comprehensive cancer care.

MRD-Guided Zanubrutinib, Venetoclax and Obinutuzumab after an Optional Debulking with Bendamustine in Patients with Relapsed/Refractory Chronic Lymphocytic Leukemia: Primary Endpoint Analysis of the Phase 2 CLL2-Bzag Study

Background In chronic lymphocytic leukemia (CLL) triple combinations of BTK inhibitors (BTKi), venetoclax (ven) and CD20 antibodies have been tested mostly as first-line treatments and so far sparse data is available on their efficacy in the relapsed/refractory (r/r) setting. In this phase 2 trial, we evaluate the combination of zanubrutinib (zanu), ven and obinutuzumab (obi) in r/r CLL. In order to tailor therapy to the different needs of differently pretreated patients (pts), treatment duration was based on detection of measurable residual disease (MRD). Furthermore, a ctDNA-based MRD monitoring and a ctDNA-based real-time screen of resistance and driver mutations were performed throughout the study. Methods The CLL2-BZAG study evaluated a combination of obi, zanu and ven after an optional debulking with bendamustine in r/r CLL. In the induction, obi was administered 3 times in cycle 1 (days 1/2, 8 &amp; 15) and monthly in cycles 2-6. Zanu was added in cycle 2 and ven in cycle 3 with a dose ramp-up over 5 weeks. Maintenance with continuous zanu and ven and 3-monthly obi was administered either until achievement of a deep remission with undetectable MRD &amp;lt;10 -4 (uMRD) in peripheral blood (PB) or for up to 24 months. The primary endpoint was the uMRD rate by flow cytometry (FCM) in PB at the final restaging (RE, after 6 months of triple therapy). MRD was measured by FCM from PB and by digital droplet PCR (ddPCR) of patient-specific VDJ rearrangements from blood plasma. uMRD was defined as &amp;lt;1 CLL cell/10,000 leukocytes (&amp;lt;10 -4) and no detectable patient-specific VDJ ctDNA. Results Between 11/2020 and 10/2022, 42 pts were enrolled, 2 pts with ≤2 induction cycles were excluded from the analysis population as predefined by the protocol. Median age was 64 years (range 40-82), 32.5% of pts were female. All 40 pts had r/r CLL with a median of 1 prior therapy (range 1-5), 18 pts (45%) had already received a BTKi, 7 pts ven (17.5%), of these 5 pts (12.5%) had received both. Fifteen pts (37.5%) had a del(17p)/ TP53 mutation, 31 (77.5%) had unmutated IGHV and 19 of 38 pts with available information (50%) a complex karyotype. Nineteen pts (47.5%) received bendamustine debulking, 37 pts (92.5%) completed 6 induction cycles and 19 pts (47.5%) have already stopped MRD-guided maintenance treatment with 2 pts who discontinued maintenance early due to adverse events (AEs). With a median observation time of 21.5 months (range 8.0-35.3), 445 AEs were reported, including 90 AEs of CTC grades 3-4. Two pts had fatal AEs (COVID-19, fungal pneumonia secondary to COVID-19). The most common AEs were COVID-19 (n=26 pts), diarrhea (n=15), infusion-related reactions (n=15), thrombocytopenia (n=14), nausea (n=12), fatigue (n=12) and neutropenia (n=12). The most frequent grade ≥3 AEs were neutropenia (n=10 pts), COVID-19 (n=9), thrombocytopenia (n=7) and pneumonia (n=5, Table 1). Two pts had grade ≥3 cardiac AEs (1 pt with grade 3 non-ST-elevation myocardial infarction, 1 pt with 2 AEs of grade 3 atrial fibrillation and a history of atrial fibrillation). At RE all pts responded and 21 (52.5%) showed uMRD in PB ( Figure 1A). In many pts remissions deepened over time, with 34 (85%) achieving uMRD in PB in the course of the study. The proportion of pts with uMRD was similar in pts with TP53 aberrations (80%) and in pts previously exposed to venetoclax and/or BTKi (80%). The estimated PFS and OS rates at 18 months were 96% and 96.8% ( Figure 1B). PFS rates at 18 months were similar for pts with TP53 aberrations (100%) and pts pretreated with BTKi/ven (90%). Two pts had a disease progression per iwCLL criteria, however no pt has yet required a subsequent treatment. Of 22 pts who achieved uMRD and are now off-treatment, only 1 had MRD recurrence (≥10 -4) during follow-up. Serial MRD (FCM) and ctDNA (ddPCR) assessments were done on 281 paired blood/plasma samples throughout the study. At RE, 8 pts who achieved uMRD by FCM still had detectable VDJ ctDNA in blood plasma. Four pts without ctDNA were still MRD positive by FCM at RE. Apart from one PLCG2_S707F mutation that occurred 11 months after the end of treatment, no acquisition of known resistance mutations - in particular in BTK, BCL2 - was observed using ddPCR. Conclusions The time-limited MRD-guided triple combination of zanu, ven and obi induced deep remissions in a r/r CLL population enriched for pts previously treated with BTKi and/or ven. Apart from COVID-19, low rates of infectious AEs were observed and cardiac toxicities were rare.

17th International Conference on Malignant Lymphoma, Palazzo dei Congressi, Lugano, Switzerland, 13 - 17 June, 2023.

Introduction: Biological mechanisms undergoing Richter Syndrome diffuse large B-cell lymphoma type (DLBCL-RS) from a previous chronic lymphocytic leukemia (CLL) arouse a great scientific interest, but the pattern of markers expressed in DLBCL-RS cases has been scarcely studied. Our aim was to immunophenotypically characterize DLBCL-RS and compare it with the prior CLL population. Methods: Retrospective unicenter study of patients histologically diagnosed with DLBCL-RS (DLBCL not otherwise specified subtype) from a prior or concomitant CLL (N = 12). Multiparametric flow cytometry (FCM) and immunohistochemistry (IHC) were used to cluster cases according to their expression level for each marker: bright or moderate (positive), low (dim), or absent (negative). Comparisons were made between CLL and DLBCL-RS in available tissues (lymph node, blood, bone marrow, and others). Results: Median age at DLBCL-RS diagnosis was 74 years (IQR 65-79) and 42% were males. Three cases were concomitantly diagnosed with CLL and DLBCL-RS; the median time of transformation in the remaining 9/12 was 76 months (IQR 51-112), and all of them had received at least 1 therapeutic line for the CLL (median 2). Clonal relationship was demonstrated in 9/10 cases with available information. Figure 1 shows the most relevant phenotypic comparisons between CLL and DLBCL-RS populations. Although phenotypic variability was seen for all antigens, some of them showed tendency to increase or decrease their pattern of expression. CD19, CD20, CD5, CD79b, and CD200 tended to lose expression in the DLBCL-RS phase (3/5 DLBCL-RS CD20 negative cases had received anti-CD20 therapy during the 12-month period prior to transformation). On contrary, CD38 and Ki67 were constant in the increasing of expression. Other markers such as CD23, CD43, CD22, and CD11c presented higher variability. One case showed CD10 dim expression of the DLBCL-RS, while it remained negative in the other 11/12. The light-chain restriction was the same in 10/12 (κ:λ ratio of 1.5:1); 1/12 presented a switch from κ to λ, and 1/12 DLBCL-RS showed negativity for κ/λ, when κ was restricted in the CLL phase. p53 expression was available in 7 cases, being negative in CLL tissue in all of them: 3/7 retained p53 negativity in the DLBCL-RS, while 4/7 showed p53 overexpression after transformation. Treatment for the DLBCL-RS was initiated in 8/12 cases, being 92% death at data cut-off date (median follow-up 6.5 months from DLBCL-RS diagnosis, IQR 2.4–9.7). Keywords: diagnostic and prognostic biomarkers, pathology and classification of lymphomas, tumor biology and heterogeneity No conflicts of interests pertinent to the abstract.

Response to COVID-19 Infection and Vaccination in the CLL Population: A Large Single-Center Experience

BACKGROUND: Patients with chronic lymphocytic leukemia (CLL) are at increased risk of morbidity and mortality after infection with severe adult respiratory syndrome coronavirus 2 (SARS-CoV-2) and illness with coronavirus disease 2019 (COVID-19). Vaccination is of crucial importance in this patient population yet CLL patients demonstrate impaired vaccination responses with decreased ability to produce neutralizing anti-SARS-CoV-2 antibodies. COVID-19 boosters increase response rates in most patients with CLL, but their impact on "real-word” disease-related outcomes warrants further study. Therefore, we evaluated the outcomes of COVID-19 infection and response to COVID-19 vaccination and boosters in patients with CLL. METHODS: This was a retrospective cohort study conducted in a single-center, North American academic teaching hospital in a large, urban area. Data was collected from January 2020 to December 2021. This time period coincided with SARS-CoV-2 Alpha and Delta variant predominant waves of infection in New York City, with Omicron (BA.1) dominating the last two weeks of December 2021. Patients with a diagnosis of CLL were evaluated for inclusion based on retrospective chart review. In total, 338 patients with CLL were included. RESULTS: Of 338 patients with CLL, 252 patients (74.6%) underwent testing for COVID-19, of whom 57 (16.9%) had evidence of active or resolved infection. 10 patients tested positive by ECLIA, 38 by RT-PCR, and 9 by both detection methods. Characteristics of patients with documented infection are depicted in Figure 1A. 51 patients (89.5%) were symptomatic, and 6 (10.5%) were asymptomatic. 24 patients (42.1%) required hospitalization and 9 deaths were recorded (15.6% case fatality rate). 7 of 32 patients (21.8%) who had received CLL therapy died, versus 2 of 25 (8.0%) who never received therapy. Mortality was 19.6% in patients > 60 years compared to 0% in those ≤ 60 years. 269 patients were vaccinated against COVID-19, and 127 patients received a booster vaccination (third vaccine dose). The response rate in 114 evaluable patients who were tested for antibody response after 2 doses of vaccine was 66.6% (76/114, median assessment at 160 days [range, 1-253 days] after dose #2). 77 patients had antibody response evaluated only after receiving booster vaccination. In these patients, 70.1% had an antibody response at a median of 42 days (range, 5-145 days). In patients with both pre- and post-booster data (n=28), the response rate increased from 46.2% (13/28) to 85.7% (24/28) after receiving a third vaccination. Across the entire cohort, 74.3% (142/191) of evaluable patients responded to vaccination either on initial evaluation or on serial testing (Figure 1B-C). 11 COVID-19 infections occurred following at least one vaccination, and one patient died 2 days after receiving a second vaccination. Receipt of prior or current CLL-directed therapy differed between the antibody-positive and negative groups (53.5% vs 77.6%), although both groups had received a median of 2 lines of therapy. BTK inhibitors and combination venetoclax/anti-CD20 antibody were the most commonly used treatments in both groups. Median IgG (740 vs 504 mg/dL) and the proportion of patients with an IgG level < 700 mg/dL (43.0% vs 75.5%) differed between the antibody-positive and negative groups, respectively. The case-fatality rate was 9.1% (1/11) in the vaccinated group compared to 17.8% (8/45) in the unvaccinated group. There were 6 documented COVID infections in patients who had a documented vaccination response and none in patients without documented response. No deaths occurred in the former group. CONCLUSIONS: Serologic response to COVID-19 vaccination occurred in three-quarters of patients with CLL. This antibody response to vaccination compares very favorably to earlier, large studies that reported a response rate of 40-50%. A significant improvement in serologic response in patients between second and third vaccinations offers real-world evidence to support the efficacy of booster vaccination in this population. An additional expanded analysis including subsequent data from the Omicron variant predominant BA.1, BA.2, and BA.4/5 waves is in progress and will be presented. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

CD49d Expression Identifies a Biologically Distinct Subtype of Chronic Lymphocytic Leukemia with Inferior Progression Free Survival on BTK Inhibitor Therapy

Background: Acalabrutinib, a highly selective Bruton tyrosine kinase inhibitor (BTKi), is effective and well tolerated for patients with chronic lymphocytic leukemia (CLL). During treatment with BTKis, transient lymphocytosis is observed due to the efflux of CLL cells from lymphoid organs. CD49d, the alpha chain of the CD49d/CD29 integrin very late antigen-4 (VLA-4), is a key mediator in CLL microenvironmental interactions. High CD49d expression has been associated with inferior response to ibrutinib (Tissino, 2018). Here, we investigated the role of CD49d in response to acalabrutinib in 48 patients with CLL enrolled in a single-center, phase 2 study (NCT02337829). Methods: Patients were divided into CD49d positive (CD49d+, n = 27, 56%) and CD49d negative (CD49dneg, n = 21, 44%) groups based on the established 30% cutoff, as assessed by flow cytometry. CD49d activation was measured as VLA-4 receptor occupancy (RO), as described (Tissino, 2018). Time to progression was estimated using the Kaplan-Meier method. RNA sequencing (RNA-seq) of CD19+ selected CLL cells from CD49d+ (n = 10) and CD49dneg (n = 10) subsets was performed at baseline and 6 months on acalabrutinib. Results: After the first month on acalabrutinib, the median increase in absolute lymphocyte count (ALC) for CD49d+ CLL was 6.4% vs. 50.4% for CD49dneg (P = .02). However, the increase in ALC on day 3 of 42% and 48%, respectively, was comparable (P = .8). A subset of patients showed bimodal CD49d (bimCD49d) expression, with concomitant presence of CD49d positive and negative subpopulations. In these cases, the fraction of CD49d+ CLL cells increased significantly on day 3 (P = .002), but decreased at 6 months (P = .004), suggesting that CD49d+ cells may be better able to remain tissue bound on chronic therapy or reenter lymphoid tissues at higher rates than CD49dneg cells. While constitutive VLA-4 activation was reduced in patients on acalabrutinib, BCR and CXCR4 stimulation still increased VLA-4 RO on CLL cells even after 6 months of treatment. PI3K, in addition to BTK signaling, is implicated in inside-out activation of VLA-4. In vitro, addition of the PI3K inhibitor duvelisib to acalabrutinib-treated CLL cells completely blocked BCR- but not CXCR4- induced VLA-4 activation. The overall response rate of the study was 95.8% (Sun, 2020). Sixteen patients progressed at a median of 42.5 months, 3 with transformation. Time to progression for patients with CD49d+ and CD49dneg CLL (applying 30% cutoff) did not differ (P = .4). However, at 72 months 50% of the combined CD49d+ and bimCD49d patients (n = 37) were estimated progression-free vs 90% of patients with a homogeneous CD49dneg CLL population (n = 11, P = .02). Of 13 patients progressing with CLL, 12 (92%) were CD49d+ or bimodal CD49d and 11 (85%) had BTK and/or PLCG2 mutations. To dissect the impact of CD49d expression on CLL pathobiology and the response to acalabrutinib, we compared transcriptomes of CD49d+ and CD49dneg subsets by RNA-seq. A distinct gene expression profile separated the groups by principal component analysis. Using gene set enrichment analysis, CD49d+ CLL showed constitutively more immunoreceptor, NF-kappa B, and cytokine/JAK-STAT signaling, as well as enhanced cell survival, adhesion and migration capacity compared to CD49dneg CLL (FDR <.25). After 6 months on acalabrutinib, all 20 patients achieved a clinical response and all samples showed downregulation of B-cell receptor and NF-kappa B target genes, as expected for BTKi therapy. Interestingly, on acalabrutinib, CD49d+ samples not only maintained a higher level of activation compared to CD49dneg CLL, but differences in the degree of cytokine (IL-6, IL-10) and STAT3 signaling became more prominent. Conclusion. CD49d+ and CD49dneg CLL cells are rapidly mobilized out of lymph nodes at the start of acalabrutinib therapy, but CD49d+ cells appear able to reenter or persist in lymphoid tissues better than CD49dneg cells. Bimodal CD49dneg and CD49d+ cases share an increased risk of disease progression, with most patients having detectable BTK or PLCG2 mutations at the time of progression. The transcriptional program of CD49d+ CLL reflects upregulation of survival and activation pathways that may increase tolerance to BTKi therapy and set the stage for clonal evolution. Thus, CD49d/VLA-4 emerges as a microenvironmental factor that contributes to BTKi resistance and a possible therapeutic target to improve on BTKi therapy.

Combined Treatment with Ibrutinib and Anti-CD38 Monoclonal Antibody Daratumumab in Relapsed/Refractory Chronic Lymphocytic Leukemia with TP53 Aberrations: Results of the Filo Phase II Study IDA53

Background: Despite significant improvement with BTK inhibitors, long-term disease control of relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL) with TP53 abnormalities remains challenging. CD38 expression is an independent adverse prognostic factor in CLL. This has been related to the involvement of CD38 in CLL cells migration, proliferation, tissue invasion and BCR signaling (Vaisiti 2015; Matas-Cespedes 2016). Daratumumab is the first in class anti-CD38 monoclonal antibody approved in multiple myeloma in both relapse and frontline settings. Preclinical studies have shown daratumumab to induce significant effect on viability and migration of patient-derived CLL cells (Matas-Céspedes et al, 2016). Moreover, the combination of daratumumab and ibrutinib demonstrated synergistic effect on both in vitro CLL cells killing and in vivo tumor burden reduction and survival prolongation in a CLL xenograft model (Manna et al, 2019). We therefore hypothesized that daratumumab would improve ibrutinib efficacy in R/R CLL patients with TP53 aberrations. Methods: This phase 2 trial enrolled patients with R/R CLL and TP53 abnormalities regardless of cell surface CD38 expression. Treatment consisted of ibrutinib (420 mg/d) alone for one month then combined to intravenous daratumumab (16 mg/kg/d) administered weekly for 8 weeks, every other week for the subsequent 4 months then monthly until intolerance or disease progression. The primary endpoint was the complete response (CR) rate according to iwCLL criteria after 12 months (M12) of combined therapy. We estimated a 20% CR rate at M12 to be the target threshold for treatment efficacy and 7% the minimum acceptable. We planned to recruit 44 patients. Results: Between December 2018 and May 2022, 29 patients have been enrolled. The study prematurely closed due to drop in patient accrual and failure to achieve the primary endpoint. Median age was 69 years [45-86] and sex ratio M/F was 18/11. Median number of previous lines was 1 [1-4]. Four patients (14%) had bulky adenopathy. Median lymphocytosis was 55 G/L (4.5-385). Median hemoglobin level and platelet count were 13.2 g/dL (8.1-17.3) and 127 G/L (37-188) respectively. All patients had TP53 disruption with 17p deletion in 16 cases (55%), TP53 mutations in 26 (93%), both in 14 (48%). Five had 11q deletion (18.5%). IGHV was unmutated in 16 patients (62%) and 2 additional patients had subset#2 stereotyped BCR. Eighteen patients had complex karyotype (72%) of whom 9 (36%) had very complex karyotype. Elevated b2microglobulin was present in 19 patients (73%). CD38 expression ranged from 0 to 87%. At data cutoff (18 JUL 2022), 21 patients have reached M12 and 15 are still on treatment. Fourteen patients went off study of whom 6 before M12. Reasons of discontinuation were progressive disease (PD) in 4 patients (at month 4, 13, 19 and 25) of whom 2 Richter transformation (RT), related adverse event (AE) in 3 (grade 3 infusion related reaction (IRR), recurrent cutaneous carcinoma, atrial fibrillation), COVID-19 in 3, pandemic context in 1, death of unknown cause in 1, and consent withdrawal in 2 patients. Five patients died (1 RT, 3 COVID-19, 1 unknown cause). AEs and serious AEs (SAE) were reported in 29 and 19 patients, respectively. Grade ≥3 AEs were hematological (n=9), infections (n=7), metabolism disorder (n=5), IRR, renal deficiency, myalgia, urologic disorder, death of unknown cause (all n=1). Grade 1-2 AEs reported in ≥ 10% of patients included gastrointestinal disorder (n=16), metabolism disorder (n=10), cardiovascular disorder (n=7), cutaneous neoplasms (n=6), ENT infections (n=5), COVID 19 (n=5), bleedings (n=4) and skin disorders (n=3). No tumor lysis syndrome occurred. At M12, one patient achieved CR, 20 patients achieved PR. Overall response and CR rate were 78% and 3.7% in intend-to-treat calculation, and 95% and 4.5% in per protocol calculation, respectively. With a median FU of 20.2 months, median progression free and overall survival were 27.1 [95%CI 23.4-NR] and 33.5 [95%CI 27.1-NR] months, respectively. Although not significant, there was a trend toward shorter PFS in CD38+ patients that daratumumab did not reverse. Conclusions: Daratumumab was safely combined with ibrutinib without unexpected toxicity in CLL. However, this combination did not provide any clear improvement of complete response rate in this very high-risk CLL population, as compared with ibrutinib alone. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

P603: GUT MICROBIOME IN CHRONIC LYMPHOCYTIC LEUKEMIA SHOWS DEPLETION OF SHORT-CHAIN FATTY ACIDS PRODUCING BACTERIA

Background: Recent studies have shown extensive crosstalk between our immune system and gut microbiome (GM). The host immune system plays a vital role in the maintenance of GM homeostasis by 1) establishing a balance between eliminating invading pathogens and promoting the growth of beneficial microbes, 2) producing short-chain fatty acids (SCFA), the main source of nutrition for the colon cells, and 3) modulating the immune system by cytokine production. Mounting evidence shows that the GM of patients with high rates of infection are characterized by an imbalance of bacteria, inducing proinflammatory states and reduced capacity for SCFA synthesis. As chronic lymphocytic leukemia (CLL) is, among others, also characterized by high rate of infectious complications and an altered immune system, it is warranted to explore composition of the CLL microbiome. Aims: We aim to investigate the hypothesis that deviation of the GM from homeostasis, i.e. loss of ‘health promoting’ gut microbes and/or overgrowth of pathogenic bacteria, distinguishes patients with CLL from the background population. Methods: Feces samples of patients with CLL were collected, immediately fixated and frozen within 72 h; total genomic DNA was sequenced. Feces samples of healthy controls were chosen to match the CLL population with respect to age, demographic data, sample collection method, and sequencing platform. Taxonomical profiling was done using an in-house bioinformatics pipeline. Results: A total of 61 CLL patients and 30 healthy individuals were included in the study. We observed reduced GM alpha diversity, and depletion of bacterial members of Lachnospiraceae and Ruminococcaceae families among the CLL patients when compared to healthy individuals. Our data show that members of the Lachnospiraceae family (Anaerostipes hadrus, Coprococcus comes, Blautia spp., Dorea spp.), and 3 members of Ruminococcaeae family (Ruminococcus torques, Ruminococcus bromii, Faecalibacterium prausnitzii) were among the most differentially abundant bacterial species between the microbiomes of healthy individuals and CLL. Their mean proportions were shown to be significantly higher in healthy microbiome samples. As further differentially abundant species we observed Bacteroides sp. and Alistipes finegoldii, which both demonstrated significantly higher mean proportions in CLL microbiomes (Fig 1). Image:Summary/Conclusion: To sum up, the CLL microbiomes in comparison to healthy controls demonstrated lower enrichment of Lachnospiraceae and Ruminococcaceae families, the major SCFAs-producing bacterial taxa reported to have a protective effect against inflammation. This supports the notion that proinflammatory risk factors identified in other cohorts with GM dysbiosis are also present within CLL patients. As CLL represents an antigen driven malignancy with immune dysfunction, we hypothesize that GM dysbiosis could both be implicated in the pathogenesis of CLL, through antigenic drive, and contribute to the distortion of the immune system in CLL. Notably, both immune dysfunction and treatment (e.g. antimicrobials) may influence the CLL microbiome itself and therefore confound cross-sectional clinical studies. We therefore plan to investigate the interaction between microbiome and CLL development in the TCL1 mouse model of CLL. Also, identification of potential mechanistic links between the GM and the microenvironment in CLL should be investigated, e.g. extravesicular vesicles or cytokines released from or impacted by the GM. In addition, modulation of the microbiome in animal models may help to establish causal connections between the GM and CLL development.

Abstract 1257: Early blood uMRD correlates with improved PFS in patients with CLL

Abstract The approval of targeted therapies has greatly improved outcomes for patients (pts) with chronic lymphocytic leukemia (CLL) in both 1L and relapsed/refractory (R/R) settings. The use of long-term outcomes such as progression free survival (PFS) and overall survival (OS) to inform early drug development can extend timelines and delay approval of potentially beneficial novel treatments. Establishing correlations between short-term treatment effects and long-term outcomes could shorten development timelines. Minimal residual disease (MRD) is a sensitive indicator of disease burden, with achievement of undetectable MRD (uMRD: &amp;lt; 1 CLL in 10,000 leukocytes [10-4]) either during or at the end of therapy being prognostic of prolonged PFS and OS. Our current work explores correlations between PFS and earlier dynamic changes in lymphocyte counts and peripheral blood (PB) MRD as potential tools for guiding drug development decisions in CLL. Data from five trials (NCT numbers 01328626, 01889186, 02141282, 02756611 (receiving Venetoclax monotherapy and primarily R/R CLL pts) and 01682616 (R/R CLL pts receiving venetoclax + rituximab therapy) were analyzed. PB MRD was quantified by either flow cytometry or next generation sequencing at various timepoints. Many of these pts had high risk features such as 17pDEL or prior BCRi therapy. The relationships between absolute lymphocyte count (ALC) and percent change in lymphocytes at 1, 3, 6, and 9 months (M) of treatment and PB MRD status were explored. Additionally, the relationship between PB MRD levels at 6±2 M and achievement of uMRD was assessed. Lastly, we evaluated the relationship between PB MRD status at different time points (6±2, 9 and 12 M) and PFS using Kaplan Meier plots. Across the trials, 708 CLL pts were treated, with 496 pts having PB MRD assessments at any time on therapy. PB uMRD rate of the evaluable population was 47.6% (236/496). Analysis of pts with PB MRD assessments at ~6 M (6±2 M, n=310) demonstrated that achievement of uMRD correlated with improved PFS (with median PFS of 56 M compared to 26 M in pts who had detectable MRD, p=0.037). Moreover, pts with residual disease in the PB (&amp;gt; 10-4) at ~6 M and achieved uMRD later while on therapy had a significantly lower residual disease at this timepoint than pts who did not achieve uMRD (p&amp;lt;0.001). Pts with residual disease &amp;lt; 10-3 (&amp;lt;1 CLL cell/1,000 leukocytes) at ~6 M were more likely to demonstrate PB uMRD at 12 M (72% vs 6%, p&amp;lt;0.001) compared to pts with residual disease ≥10-3 at this assessment. Neither ALC or percent change in lymphocytes at 1, 3, 6, and 9 M of treatment correlated with PB uMRD. In this R/R CLL population who received continuous dosing of venetoclax, uMRD at ~6 M correlated with PFS outcomes. Additionally, MRD levels at ~6 M of therapy correlated with uMRD at 12 M. These suggest that including PB MRD assessments at early timepoints may be a useful tool in assessing efficacy and informing RP2D decisions during the development of novel agents in this indication. Citation Format: Ibrahim Y. Abdelgawad, Ahmed A. Suleiman, Brenda Chyla, Majd Ghanim, Ahmed H. Salem, Mohamed Badawi. Early blood uMRD correlates with improved PFS in patients with CLL [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 1257.

Abstract 4007: Evolutionary history of transformation from chronic lymphocytic leukemia to Richter’s syndrome

Abstract Richter’s syndrome (RS) arising from chronic lymphocytic leukemia (CLL) is a striking example of an aggressive malignant histology that emerges from indolent cancer. RS is a major barrier to disease control in CLL and is associated with poor clinical outcomes and limited survival. The genetic basis of RS is poorly understood, and its relationship to the antecedent CLL remains incompletely characterized. To study RS, we performed whole-exome sequencing (WES) on samples collected from 52 patients with RS of diffuse large B cell lymphoma (DLBCL) histology. For this genomic characterization, samples from 42 patients were analyzed as ‘trios’ (matched germline, CLL and RS tissue DNA) and those from 10 as ‘duos’ (matched CLL and RS DNA). Beyond addressing contamination of CLL DNA in the germline sample, we developed methods for discriminating between the RS and CLL clones which often coexist in the same samples. The discovery cohort revealed that RS and CLL were clonally-related in 45/52 (87%) cases based on WES analysis, with a distinct RS clone emerging from a CLL subclone. The remaining 13% were determined to be clonally unrelated. RS clones presented ~3x higher rates of additional mutations than the ancestral CLL clones from which they developed. We identified novel RS somatic driver mutations (in IRF2BP2, SRSF1, B2M, DNMT3A and others), a high rate of copy number variations with recurrent deletions (e.g., del(17p) [TP53], del(13q14.3), del(7q36), and del(15q13.11) [MGA], del(9p21.3) [CDKN2A/B], del(16q12.2)), focal amplifications (amp(7q21.2) [CDK6], amp(8q24.2) [RECQL4, MYC], amp(13q31.2) [ERCC5], and frequent whole genome duplication. To further investigate RS and CLL clonal evolution, we performed single-cell RNA-sequencing on biopsies at the time of RS diagnosis in 5 individuals with clonally related transformation. Using our novel tool, CNVSingle, we inferred allele specific single-cell copy number alterations, yielding cluster-specific copy number profiles that matched the WES results of individual subclones of the RS and CLL populations. This enabled mapping genetic clones to specific expression patterns. Finally, we devised and tested a methodology that uses cfDNA for early detection of emerging Richter’s disease and have successfully identified Richter‘s tumor DNA in the blood several months prior to the clinical diagnosis. Our study thus defines drivers, distinct molecular subtypes and evolutionary path to RS and suggests strategies for its improved detection. Citation Format: Erin M. Parry, Ignaty Leshchiner, Romain Guièze, Connor Johnson, Eugen Tausch, Sameer Parikh, Camilla Lemvigh, Conor Messer, Daniel Rosebrock, Filippo Utro, Chaya Levovitz, Kahn Rhrissorrakrai, Matthew Davids, Raquel A. Jacobs, Kara Slowik, Julien Broseus, Shanye Yin, Shuqiang Li, Geoff Fell, Ziao Lin, Binyamin A. Knisbacher, Neil Ruthen, Dimitri Livitz, Christof Schneider, Jialin Ma, Julian Hess, Laura Z. Rassenti, Thomas J. Kipps, Nitin Jain, William Wierda, Florence Cymbalista, Neil E. Kay, Kenneth J. Livak, Brian P. Danysh, Chip Stewart, Donna Neuberg, Jennifer R. Brown, Laxmi Parida, Stephan Stilgenbauer, Gad Getz, Catherine J. Wu. Evolutionary history of transformation from chronic lymphocytic leukemia to Richter’s syndrome [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 4007.

Influence of racial and ethnic identity on overall survival in patients with chronic lymphocytic lymphoma.

7508 Background: Chronic lymphocytic leukemia (CLL) is the most prevalent adult leukemia and results in highly variable clinical outcomes. Epidemiologically, CLL occurs in White ethnicity more frequently and thus, CLL outcomes among underrepresented minorities are not well studied. We sought to examine differences in treatment patterns and survival outcomes based on racial identity of CLL patients and how these have changed over time. Methods: The National Cancer Database was used to identify CLL patients diagnosed from 2004-2018. Demographic and treatment characteristics were compared between White, Black, Asian, Hispanic and other minority groups. Kaplan Meier and adjusted Cox regression survival analysis were used to compare overall survival (OS) between races. Survival analysis was repeated by year of diagnosis in Black and White populations. Results: Of 97,804 CLL pts identified, 90.7% of patients were White, 7.6% Black (N = 7,391), 2.6% Hispanic (N = 2,487), 0.6% Asian (N = 613), and 1.1% were other. Compared to White pts, Black pts were younger at diagnosis (median age 66 years [interquartile range 61-79] vs. 70 years [range 58-75], more likely to have ≥1 comorbidity (27.9% vs. 21.3%), and be uninsured (6.6% vs. 2.1%) (all p &lt; 0.001). Black pts were more likely than White pts to have CLL directed treatment immediately after diagnosis (35.9% vs 23.6%; p &lt; 0.001). With a median follow-up of 4.3 years, median OS for all CLL patients was 9.0 years (CI 8.9-9.1 years). Black pts had a shorter median OS of 7.0 years (CI 6.7-7.3 years) compared to White pts (9.14 years [CI 9.0-9.3]), p &lt; 0.001), as well as inferior OS at 5-years (61% vs. 69%) and 10-years (36% vs. 46%), p &lt; 0.001. On multivariate analysis adjusted for age and Charlson-Deyo score, Black race was independently associated with shorter OS (HR 1.51 [CI 1.46-1.57], p &lt; 0.001). While OS lengthened with successive year of diagnosis for all races, the relative survival of Black compared to White pts did not improve over the observed time period. Referenced to the White population, Black pts diagnosed between 2004-2006 had a HR of 1.64 (CI 1.52-1.76) for mortality, and those diagnosed between 2016-2018 had a HR of 1.64 (CI 1.44-1.85). Conclusions: We present the largest study to date describing racial disparities in CLL. Black pts have significantly shorter OS compared to White pts, which is sustained when adjusted for the higher prevalence of comorbidities in the Black CLL population. Unfortunately, the survival gap between White and Black patients has not improved since 2004, highlighting the need for targeted research directed at improving survival in Black pts with CLL. [Table: see text]

Awareness, Knowledge, and Preferences of United States (US) Patients with Chronic Lymphocytic Leukemia (CLL) and Their Caregivers Related to Finite Duration (FD) Therapy and Minimal (Measurable) Residual Disease (MRD)

Awareness, Knowledge, and Preferences of United States (US) Patients with Chronic Lymphocytic Leukemia (CLL) and Their Caregivers Related to Finite Duration (FD) Therapy and Minimal (Measurable) Residual Disease (MRD)

Atrial Fibrillation (AF) and Ibrutinib, a Monocentric Experience: Should Cardiological Evaluation be a Guide in Clinical Practice?

IntroductionReported prevalence of AF in patients with chronic lymphocytic leukemia (CLL) on ibrutinib is approximately 5-10%. Management of AF in ibrutinib treated patients represents a multidisciplinary and challenging clinical need. Despite therapeutic advances, substantial morbidity and mortality still remain, and preventive or therapeutic strategies need to be implemented. Older age, male gender, arterial hypertension (AH) and valvular heart disease have recently been recognized as strong predictors of AF on ibrutinib. A clear relationship exists between an enlarged left atrium (LA), assessed by transthoracic echocardiography (TTE), and incidence of AF. LA dysfunction at ibrutinib start has been suggested as a predictor of AF: it helps identifying a selected cohort of patients who may benefit from strict follow-up and preventive strategies to reduce incidence of AF and associated complications. To date no prospective clinical trials have been conducted.AimTo analyse cardiovascular predictors and incidence of AF in a monocentric population of CLL patients on ibrutinib and in regular cardio-oncologic follow-up.MethodsFrom June 2014 to June 2017 we prospectively evaluated CLL patients requiring ibrutinib treatment at our Institution. Before starting therapy a full cardiovascular evaluation including accurate history, clinical examination and assessment of concomitant cardiovascular risk factors and cardioactive therapy were performed by an expert cardio-oncologist. All patients underwent non-invasive instrumental investigations performed by the same clinician: baseline electrocardiography (ECG) was used for rhythm documentation and TTE was focused on studying LA size and function. In a selected group of patients a 24 hours ECG monitoring was performed.ResultsFourty-three patients on ibrutinib were evaluated for a median of 12 months (range 1-37). Male/female ratio was 2.07 (M/F 29/14) and median age was 71 years (range 54-86). AF occurred in 7 patients (16.3%) after a median period of 6 months from the beginning of ibrutinib. Before starting therapy 30 patients (69.8%) had at least one cardiovascular risk factor, with 23 (53.5%) suffering from AH and 27 (62.8%) having more than one cardiovascular comorbidity. Twenty-three patients (53.5%) were regularly taking at least one cardioactive drug. We observed male gender and AH (p=0.009) to be significantly related to incidence of AF (p=0.04). One or more pre-existent cardiovascular comorbidity was found to be a strong predictive factor for AF (p=0.03). Concomitant cardioactive therapy and incidence of AF failed to show a significant correlation. Analysing TTE data, a strong predictive value of increased LA linear dimensions (p 0.02) and area (p 0.03) clearly emerged. Sixteen patients (37.2%) were evaluated through prolonged ECG-monitoring. We observed a trend to significance (p=0.07) of a higher maximal heart rate (HR) (109,5±0,7) reached in AF patients compared to those in stable sinus rhythm (73,35±30,6): higher HR, uncovering an increased sympathetic tone, is known to be a risk factor for AF. No significant correlation emerged between occurrence of AF and atrial conduction abnormalities recorded by baseline ECG.ConclusionsDue to the widespread use of ibrutinib in CLL population prompt recognition of AF high risk patients represents an emerging issue.As reported in literature, male sex and AH significantly correlate with AF development. LA enlargement represents a strong predictive factor for AF and TTE can reliably be used as a non-invasive exam to detect early signs of atrial dysfunction. In our cohort AF has occurred in a slightly higher percentage of patients treated with Ibrutinib than in literature. This finding, especially if validated in a larger CLL cohort, can suggest that silent, undetected AF is a common and a often underdiagnosed event in older patients with multiple risk factors. These initial results support a systematic cardiologic monitoring and AF screening program. Proper cardiological evaluation aims to identify patients at higher risk of AF. Educating patients to early recognize adverse events and behave accordingly to clinician's instructions allow to avoid unnecessary drug suspension. Comorbidity control and implementation of cardioactive therapy by an expert cardio-oncologist, preventing LA dilation and dysfunction, could be pursued as a means of reducing AF on ibrutinib. DisclosuresNo relevant conflicts of interest to declare.