Shi, Min

INTRODUCTION Nearly 20% of patients (pts) are ≥ 80 years (yrs) of age at the time of CLL diagnosis. Increased medical comorbidities, as well as declining functional status and organ function, often accompany advanced age. However, clinical trials often enroll a disproportionally low number of people from this age demographic due to stringent eligibility parameters, which provides limited evidence to guide decisions. Here, we report clinical characteristics and outcomes of pts ≥ 80 yrs of age at the time of CLL diagnosis. METHODS Between 1/1995 and 3/2020, we identified previously untreated CLL pts from the Mayo Clinic CLL Database who were ≥ 80 yrs of age at the time of CLL diagnosis, and seen within 3 yrs of diagnosis. Baseline characteristics, treatments administered, and time to first treatment (TFT) were analyzed for all pts. Overall survival (OS) was measured from diagnosis date in all pts and separately from treatment date for treated pts. Time to next treatment (TTNT) was measured in treated pts from first treatment date to date of second treatment or last known treatment. TFT and TTNT were analyzed accounting for competing risk of death. Standardized mortality ratio (SMR) compared observed survival to survival in a Minnesota population. Cox multivariable regression models were used to determine which factors were associated with OS (treatment as a time-dependent covariate) and TTNT (accounting for competing risk of death). RESULTS Among the 213 pts identified, the median age was 83 yrs (range 80-97); baseline characteristics are summarized in Table 1. The median number of medical comorbidities among all pts was 4 (range 0-8). At least 1 comorbidity was present in 97% of pts, most commonly hypertension (57%), genitourinary (n=48%), rheumatological (46%), and dyslipidemia (n=43%). Median follow-up was 3.8 yrs. A total of 56 pts received treatment and the median TFT was 6.7 yrs. Over this 25 year interval, the treatment approaches included monoclonal antibody alone (n=17), chemotherapy alone (n=17), or chemoimmunotherapy (n=14), novel agents (n=3), and multi-agent Richter's transformation regimens (n=5). Chlorambucil-based treatments (chlorambucil n=13, chlorambucil, prednisone n=3) were the most frequently used chemotherapy regimens. The most common chemoimmunotherapy regimens included rituximab, cyclophosphamide, prednisone (RCP) with (n=3) or without vincristine (n=6), and chlorambucil with an anti-CD20 monoclonal antibody (n=4; obinutuzumab n=2, rituximab n=2). Among 17 pts who received monoclonal antibody alone, treatments included rituximab alone (n=11), rituximab plus methylprednisolone (n=2), obinutuzumab (n=2), and rituximab with alemtuzumab (n=2). Frontline novel agent treatments included ibrutinib alone (n=1), acalabrutinib alone (n=1), and ibrutinib, obinutuzumab, venetoclax (n=1). Five pts with Richter's transformation (diagnosed concurrent with CLL n=4) received multi-agent chemotherapy. Among the 56 treated pts, 22 pts received second line therapy after a median TTNT of 2.8 yrs from start of first therapy. The most common second line treatments were chlorambucil-based (n=6) and rituximab-based (n=6) regimens. Age, sex, absolute lymphocyte count, del17p, and unmutated IGHV were not predictive of TTNT. The median OS among all 213 pts was 4.6 yrs. SMR was 1.2 (p=0.008) when excluding pts with Richter's transformation. In univariable analyses, receipt of therapy (HR 3.92, 95%CI 2.11-7.28; p<0.001), age (per 5 year increase; HR 1.84, 95%CI 1.43-2.38; p<0.001) and unmutated IGHV (HR 2.03, 95%CI 1.12-3.67; p=0.02) were predictors of shorter OS. The OS among pts who received treatment (Figure 1) was similar when compared across time periods of treatment start year grouped as 1995-2001 (n=10), 2002-2013 (n=32), and 2014-2020 (n=14). Treatment categories by time period are shown in Table 2. CONCLUSIONS In this study of 213 pts ≥ 80 yrs of age at time of CLL diagnosis, the median time to first therapy was ~7 yrs. Although survival outcomes did not differ by era across the 25-year span of this study, pts treated with novel agents were underrepresented and are a patient population which warrants additional evaluation. The finding that pts with CLL in this cohort had a 20% higher risk of death compared to an age- and sex-matched population emphasize the need for ongoing efforts to improve clinical outcomes for CLL pts in this demographic category. Disclosures Kenderian: Torque: Consultancy; Mettaforge: Patents & Royalties; Humanigen: Consultancy, Patents & Royalties, Research Funding; Novartis: Patents & Royalties, Research Funding; Kite: Research Funding; Gilead: Research Funding; Juno: Research Funding; BMS: Research Funding; Tolero: Research Funding; Sunesis: Research Funding; MorphoSys: Research Funding; Lentigen: Research Funding. Wang:Incyte: Research Funding; Innocare: Research Funding; Novartis: Research Funding. Shanafelt:Genentech, Pharmacyclics LLC, an AbbVie Company, AbbVie, GlaxoSmithKline, and Merck: Research Funding; Mayo Clinic: Patents & Royalties: and other intellectual property. Braggio:DASA: Consultancy; Bayer: Other: Stock Owner; Acerta Pharma: Research Funding. Kay:Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Bristol Meyer Squib: Membership on an entity's Board of Directors or advisory committees, Research Funding; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncotracker: Membership on an entity's Board of Directors or advisory committees; Juno Theraputics: Membership on an entity's Board of Directors or advisory committees; Rigel: Membership on an entity's Board of Directors or advisory committees; Cytomx: Membership on an entity's Board of Directors or advisory committees; Sunesis: Research Funding; MEI Pharma: Research Funding; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees; Agios Pharma: Membership on an entity's Board of Directors or advisory committees; Abbvie: Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Acerta Pharma: Research Funding; Dava Oncology: Membership on an entity's Board of Directors or advisory committees. Ding:alexion: Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Membership on an entity's Board of Directors or advisory committees; Octapharma: Membership on an entity's Board of Directors or advisory committees; Abbvie: Research Funding; Astra Zeneca: Research Funding; Beigene: Membership on an entity's Board of Directors or advisory committees; DTRM: Research Funding; Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding. Parikh:Merck: Research Funding; AstraZeneca: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; MorphoSys: Research Funding; Pharmacyclics: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding; Ascentage Pharma: Research Funding; Genentech: Honoraria; Verastem Oncology: Honoraria; GlaxoSmithKline: Honoraria; TG Therapeutics: Research Funding.

Background: Cytogenetic abnormalities detected by fluorescence in situ hybridization (FISH) are known to differentially impact prognosis in patients with chronic lymphocytic leukemia (CLL). Deletion6q23 (del6q23) has been reported in ~2-3% of CLL patients at diagnosis; however, its prognostic significance remains indeterminate. Methods: We identified previously untreated CLL patients from the Mayo Clinic CLL Database seen between 1/1995 - 2/2020 who had FISH performed. The clinical characteristics, concomitant cytogenetic abnormalities, time to first therapy (TTFT), and overall survival (OS) were compared between patients with del6q23 to those without this abnormality. TTFT was analyzed from FISH date until treatment or last known untreated date, accounting for competing risk of death. OS was analyzed using Kaplan-Meier methods from FISH date. In a matched (CLL-IPI risk score and sex) analysis, Cox regression analysis was used to determine the association between TTFT/OS and presence of del6q23. The Mayo Clinic IRB approved this study. Results: A total of 3101 CLL patients were identified; their median age at diagnosis was 64 years and 66% were male. Of these patients, 42 (1.3%) had evidence of del6q23 by FISH. Compared to patients without del6q23, patients with del6q23 carried a more adverse clinical and cytogenetic profile at the time of diagnosis including advanced Rai stage (22% Rai III/IV vs. 9% Rai III/IV; P = 0.002), unmutated IGHV genes (91% vs. 43%; P < 0.001), and high/very high risk CLL-IPI (50% vs. 27%; P < 0.001). Del6q23 was the sole abnormality in 13 patients (31%). Of the remaining patients, del6q23 was concomitantly present with del13q in 8 patients (19%), and with either del11q or del17p in 21 patients (50%). Of the 42 patients with del6q23, 29 received first line therapy: chemoimmunotherapy in 16 patients, BTK inhibitor in 7 patients, and an anti-CD20 monoclonal antibody alone in 6 patients. The median follow-up of the entire cohort was 7.3 years. The median TTFT in patients with del6q23 was 0.7 years while the 5-year OS was 76%. Patients with del6q23 demonstrated significantly shorter TTFT and reduced OS when compared to patients without del6q23 (Figures 1A and 1B). The shorter TTFT was also evident for patients with del6q23 compared to patients without del6q23 divided according to the Dohner risk category (Figure 2A), although there was no difference in OS between these groups of patients (Figure 2B). Because del6q23 patients were enriched for other unfavorable prognostic markers, we identified four control patients without del6q23, matched by CLL-IPI risk score and sex, to each treatment-naïve patient with del6q23. Patients with del6q23 showed a borderline statistically significant shorter TTFT (median 0.7 years versus 3.9 years; P = 0.07) and a nonsignificant association with OS (median 10.9 years versus 10.3 years; P = 0.28). Conclusion: Del6q23 by FISH in previously untreated CLL represents an uncommon abnormality. When compared to patients without del6q23, patients with del6q23 tend to have more adverse clinical and cytogenetic profiles at baseline, which likely confer a worse prognosis as reflected by shorter TTFT compared to patients without this abnormality. Figure Disclosures Ding: Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding; DTRM: Research Funding; Beigene: Membership on an entity's Board of Directors or advisory committees; alexion: Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Membership on an entity's Board of Directors or advisory committees; Octapharma: Membership on an entity's Board of Directors or advisory committees; Abbvie: Research Funding; Astra Zeneca: Research Funding. Wang:Novartis: Research Funding; Innocare: Research Funding; Incyte: Research Funding. Braggio:DASA: Consultancy; Bayer: Other: Stock Owner; Acerta Pharma: Research Funding. Kay:Sunesis: Research Funding; Abbvie: Research Funding; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Meyer Squib: Membership on an entity's Board of Directors or advisory committees, Research Funding; Juno Theraputics: Membership on an entity's Board of Directors or advisory committees; Dava Oncology: Membership on an entity's Board of Directors or advisory committees; Oncotracker: Membership on an entity's Board of Directors or advisory committees; Rigel: Membership on an entity's Board of Directors or advisory committees; Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Cytomx: Membership on an entity's Board of Directors or advisory committees; Agios Pharma: Membership on an entity's Board of Directors or advisory committees; Acerta Pharma: Research Funding; MEI Pharma: Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees. Kenderian:Juno: Research Funding; Gilead: Research Funding; Lentigen: Research Funding; MorphoSys: Research Funding; Sunesis: Research Funding; Kite: Research Funding; Novartis: Patents & Royalties, Research Funding; Torque: Consultancy; Humanigen: Consultancy, Patents & Royalties, Research Funding; Mettaforge: Patents & Royalties; Tolero: Research Funding; BMS: Research Funding. Parikh:Ascentage Pharma: Research Funding; Merck: Research Funding; AbbVie: Honoraria, Research Funding; AstraZeneca: Honoraria, Research Funding; TG Therapeutics: Research Funding; Pharmacyclics: Honoraria, Research Funding; GlaxoSmithKline: Honoraria; Janssen: Honoraria, Research Funding; MorphoSys: Research Funding; Genentech: Honoraria; Verastem Oncology: Honoraria.

AbstractAcute undifferentiated leukemia (AUL) is a very rare hematologic neoplasm that expresses no markers specific for either myeloid or lymphoid lineages. While commonly observed in several acute leukemias, KMT2A rearrangements in AUL have been rarely reported in the literature. We report the third case to our knowledge of AUL harboring a KMT2A rearrangement. Furthermore, the KMT2A/GIMAP8 gene fusion identified in this case represents a novel KMT2A rearrangement.

Abstract Objectives The diagnosis of T-cell large granular lymphocytic leukemia (T-LGLL) is challenging because of overlapping immunophenotypic features with reactive T cells and limitations of T-cell clonality assays. We studied whether adding an antibody against T-cell receptor β constant region 1 (TRBC1) to a comprehensive flow cytometry panel could facilitate the diagnosis of T-LGLL. Methods We added TRBC1 antibody to the standard T-cell and natural killer (NK) cell panel to assess T-cell clonality in 56 T-LGLLs and 34 reactive lymphocytoses. In addition, 20 chronic lymphoproliferative disorder of NK cells (CLPD-NKs) and 10 reactive NK-cell lymphocytoses were analyzed. Results Clonal T cells were detected in all available T-LGLLs by monotypic TRBC1 expression and clonal/equivocal T-cell receptor gene rearrangement (TCGR) studies, compared with only 27% of T-LGLLs by killer-cell immunoglobulin-like receptor (KIR) restriction. Overall, 85% of T-LGLLs had a blood tumor burden greater than 500 cells/µL. Thirty-four reactive cases showed polytypic TRBC1 expression, except for 5 that revealed small T-cell clones of uncertain significance. All CLPD-NKs showed expected clonal KIR expression and negative TRBC1 expression. Conclusions Addition of TRBC1 antibody to the routine flow cytometry assay could replace the TCGR molecular study and KIR flow cytometric analysis to assess clonality, simplifying the diagnosis of T-LGLL.

Abstract Objectives Distinguishing between T-cell and natural killer (NK)–cell neoplasms could be difficult given their overlapping immunophenotype. In this study, we investigated whether a flow cytometry assay with cytoplasmic staining for CD3 could be used for this purpose. Methods Flow cytometry immunophenotyping was performed on 19 surface CD3 (sCD3)–negative mature T-cell neoplasms, 10 sCD3-positive mature T-cell neoplasms, 13 mature NK-cell neoplasms, and 19 normal controls. In addition to routine antibody panels (CD2, sCD3, CD4, CD5, CD7, CD8, CD16, CD45, CD56, CD57, CD94, CD158a, CD158b, CD158e, NKG2A TCRγ/δ), cytoplasmic staining for a monoclonal CD3 antibody (clone SK7/Leu-4) was assessed in all cases. A molecular study for T-cell receptor (TCR) gene rearrangement and an immunohistochemical study for TCRβ were performed. Results Our data showed all T-cell neoplasms were uniformly positive for cytoplasmic CD3 (cCD3) regardless of sCD3 expression, whereas 85% of NK-cell neoplasms completely lacked cCD3 expression. The 2 cases with classic NK-cell immunophenotype but partial cCD3 expression showed no molecular genetic features of T-cell lineage by TCR gene rearrangement studies. Conclusions Uniform cCD3 positivity and homogeneous cCD3 negativity highly suggest T-cell and NK lineage, respectively. When partial cCD3 expression is encountered, additional confirmatory studies should be pursued for the most accurate lineage assignment.

Abstract Background Flow cytometric detection of T‐cell clonality is challenging. The current available methodology for T‐cell receptor (TCR) Vβ repertoire evaluation is a complex assay and has limited sensitivity especially for detecting low levels of disease. Therefore, there is an unmet need for a reliable, simple, and rapid assay to identify T‐cell clonality. The rearrangement of the TCRB gene involves the random and mutually exclusive expression of one of two constant β chain genes (TRBC1 and TRBC2), analogous to the kappa and lambda gene utilization by B cells. Methods Here, we used a single TRBC1 antibody, in conjunction with other T‐cell associated markers, to detect T‐cell clonality in tissue biopsies and body fluids. A total of 143 tissue/body fluid specimens from 46 patients with a definitive diagnosis of a T‐cell neoplasm and 97 patients with no T‐cell malignancy were analyzed with a cocktail of monoclonal antibodies including CD2/CD3/CD4/CD5/CD7/CD8/CD45/TCRγδ/TRBC1. Results We examined TRBC1 expression on neoplastic T‐cell populations identified based on their immunophenotypic aberrancies, and monotypic TRBC1 expression was identified in all 46 known T‐cell lymphoma cases. We applied a similar gating strategy to the 97 cases without T‐cell neoplasms, and arbitrarily dissected T‐cell populations into immunophenotypically distinct subsets; in this group, we found that all cases revealed an expected polytypic TRBC1 expression in all subsets. Conclusions Single TRBC1 antibody detection of T‐cell clonality by flow cytometry is a simple, rapid, and robust assay that could be routinely utilized in flow cytometric laboratories.

Background: The 2018 iwCLL guidelines recommend close observation of early stage CLL pts who do not meet indications for therapy ("watch and wait" strategy). Prior attempts at early therapeutic intervention in unselected early-stage CLL pts using alkylating agents such as chlorambucil and chemoimmunotherapy failed to show a significant benefit; and these therapies were associated with substantial toxicities. The introduction of Bruton tyrosine kinase (BTK) inhibitors has revolutionized the treatment landscape of CLL. The German CLL Study group recently presented results of the CLL12 study which demonstrated a significant improvement in event-free survival (EFS) among untreated early stage high risk CLL pts who received ibrutinib compared to placebo (median EFS not reached vs. 47.8 months, respectively; Langerbeins, EHA, 2019). Acalabrutinib is a more selective second-generation BTK inhibitor that has fewer adverse events in pts with CLL, and has shown equally impressive clinical activity for CLL pts. We are conducting an investigator initiated randomized phase 2 study to compare acalabrutinib with or without obinutuzumab (a glycoengineered anti-CD20 monoclonal antibody approved in the treatment of CLL) among high risk early stage CLL pts. Study Design: All pts with newly diagnosed (<2 years from registration) previously untreated early stage CLL who do not meet the 2018 iwCLL guidelines for initiation of therapy are eligible for enrollment in this study. Pts undergo risk stratification according to the CLL-International prognostic index (CLL-IPI) which consists of the following 5 variables: age >65 years (1 point), Rai stage I-IV (1 point), del17p and/or TP53 mutation (4 points), unmutated immunoglobulin heavy chain (IGHV) genes (2 points), and serum β2-microglobulin >3.5 g/dL (2 points). Pts with high (4-6) and very high (7-10) risk CLL-IPI are randomly (1:1) assigned to acalabrutinib 100 mg orally twice daily (Arm A) or acalabrutinib with obinutuzumab at a standard approved schedule (Arm B). Treatment with acalabrutinib is continued for a minimum of 2 years unless the patient has unacceptable side effects or withdraws consent. Pts with low (0-1) and intermediate (2-3) risk CLL-IPI score are assigned to an observation arm with follow-up once every 6 months for 2 years, and then according to routine clinical practice (Arm C). Endpoints: The primary endpoint of the intervention arms (Arms A and B) is the achievement of minimal residual disease (MRD)-negative complete remission in the bone marrow after 2 years of therapy. MRD is assessed using an 8-color flow cytometry with a detection limit of 0.01%. The primary endpoint of the observation arm (Arm C) is time to first therapy. Secondary endpoints for all arms are: progression-free survival, overall survival, and safety. Statistical design: A randomized trial comparing the experimental arm (acalabrutinib plus obinutuzumab) against the control arm (acalabrutinib alone) will be conducted as described by Rubinstein. A sample size of 36 pts per arm provides 80% power to detect an improvement in MRD-negative complete response rate from 10% to 30%, using a one-sided test at a significance level of 0.10 (EAST 6.4). We anticipate accruing an additional 8 high/very high risk pts (4 in each arm) to account for ineligibility, cancellation, or major treatment violation. The total enrollment for Arms A and B will be 80 pts. We will enroll 40 pts to Arm C; for a total enrollment of 120 pts. Key correlatives: Comprehensive profiling to assess the innate and adaptive immune system in paired peripheral blood and bone marrow will be conducted in all pts registered to Arms A and B at baseline, 12 and 24 months after enrollment. In addition, bone marrow hematopoietic function will be assessed in all pts at these time points. We will employ a CLL focused custom 61-gene panel to estimate tumor mutational burden as well as mutational profiles for each patient at baseline, 12, and 24 month time points, as well at the time of disease progression. Preliminary results: The trial is registered at clinicaltrials.gov NCT03516617. The trial opened to accrual at all three Mayo Clinic sites (Rochester, MN; Jacksonville, FL; and Scottsdale, AZ) in September 2018. Twenty-eight pts have been registered; the baseline characteristics are shown in Table 1. The trial is expected to complete enrollment in September 2020; and the primary analysis will be available in September 2022. Disclosures Parikh: Janssen: Research Funding; AstraZeneca: Honoraria, Research Funding; Pharmacyclics: Honoraria, Research Funding; MorphoSys: Research Funding; AbbVie: Honoraria, Research Funding; Acerta Pharma: Research Funding; Ascentage Pharma: Research Funding; Genentech: Honoraria. Ding:DTRM Biopharma: Research Funding; Merck: Research Funding. Ailawadhi:Pharmacyclics: Research Funding; Cellectar: Research Funding; Takeda: Consultancy; Amgen: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Celgene: Consultancy. Kenderian:Novartis: Patents & Royalties, Research Funding; Tolero: Research Funding; Humanigen: Other: Scientific advisory board , Patents & Royalties, Research Funding; Lentigen: Research Funding; Morphosys: Research Funding; Kite/Gilead: Research Funding. Chanan-Khan:Mayo Clinic: Employment; Ascentage: Research Funding; Millennium: Research Funding; Jansen: Research Funding; AbbVie: Research Funding; Xencor: Research Funding; Pharmacyclics: Research Funding; Merck: Research Funding. Kay:Infinity Pharmaceuticals: Other: DSMB; Celgene: Other: Data Safety Monitoring Board; Agios: Other: DSMB; MorphoSys: Other: Data Safety Monitoring Board. OffLabel Disclosure: Drug: Acalabrutinib Purpose: treatment of CLL