Prediction of outcomes for high-count monoclonal B lymphocytosis using an epigenetic and immunogenetic signature

ABSTRACT

Monoclonal B-cell lymphocytosis (MBL) progresses to chronic lymphocytic leukemia (CLL) requiring therapy at 1% to 5% per year. Improved prediction of progression would greatly benefit individuals with MBL. Patients with CLL separate into 3 distinct epigenetic subtypes (epitypes) with high prognostic significance, and recently the intermediate epitype has been shown to be enriched for high-risk immunoglobulin lambda variable (IGLV) 3-21 rearrangements, impacting outcomes for these patients. Here, we employed this combined strategy to generate the epigenetic and light chain immunoglobulin (ELCLV3-21) signature to classify 219 individuals with MBL. The ELCLV3-21 high-risk signature distinguished MBL individuals with a high probability of progression (39.9% and 71.1% at 5 and 10 years, respectively). ELCLV3-21 improved the accuracy of predicting time to therapy for individuals with MBL compared with other established prognostic indicators, including the CLL international prognostic index (c-statistic, 0.767 vs 0.668, respectively). Comparing ELCLV3-21 risk groups in MBL vs a cohort of 226 patients with CLL revealed ELCLV3-21 high-risk individuals with MBL had significantly shorter time to therapy (P = .003) and reduced overall survival (P = .03) compared with ELCLV3-21 low-risk individuals with CLL. These results highlight the power of the ELCLV3-21 approach to identify individuals with a higher likelihood of adverse clinical outcome and may provide a more accurate approach to classify individuals with small B-cell clones.

Tumor mutational load is prognostic for progression to therapy among high-count monoclonal B-cell lymphocytosis (HCMBL)

HCMBL is a precursor condition to chronic lymphocytic leukemia (CLL). We have shown that among individuals with HCMBL the CLL-International Prognostic Index (CLL-IPI) is prognostic for time-to-first therapy (TTFT). Little is known about the prognostic impact of somatically mutated genes among individuals with HCMBL. We sequenced DNA from 371 HCMBL individuals using a targeted sequencing panel of 59 recurrently mutated genes in CLL to identify high-impact mutations. We compared the sequencing results to that of our treatment-naïve CLL cohort(N=855) and employed Cox regression to estimate hazard ratios and 95% confidence intervals (CI) for associations with TTFT. Compared to CLL, the frequencies of any mutated genes were lower in HCMBL (70% versus 52%). At 10-years, 37% of HCMBL individuals with any mutated gene had progressed requiring treatment compared to 10% among HCMBL individuals with no mutations; this led to 5.4-fold shorter TTFT (95%CI:2.6-11.0) among HCMBL with any mutated gene versus none, independent of CLL-IPI. When considering individuals with low-risk of progression according to CLL-IPI, HCMBL individuals with any mutations had 4.3-fold shorter TTFT (95%CI:1.6-11.8) versus those with none. Finally, when considering both CLL-IPI and any mutated gene status, we observed HCMBL individuals who were high-risk for both prognostic factors with worse prognosis compared to low-risk CLL patients (i.e., 5-year progression rate of 32% versus 21%, respectively). Among HCMBL, the frequency of somatically mutated genes at diagnosis is lower than that of CLL. Accounting for both the number of mutated genes and CLL-IPI can identify HCMBL individuals with more aggressive clinical course.

One thousand patients with essential thrombocythemia: the Mayo Clinic experience

We describe 1000 patients with essential thrombocythemia seen at the Mayo Clinic between 1967 and 2023: median age 58 years (18-90), females 63%, JAK2/CALR/MPL-mutated 62%/27%/3%, triple-negative (TN) 8%, extreme thrombocytosis (ExT; platelets ≥1000 × 109/L) 26%, leukocytosis (leukocyte count >11 × 109/L) 20%, and abnormal karyotype 6%. JAK2-mutated patients were older (median 71 years), and CALR mutated (52 years), and TN (50 years) younger (p < 0.01). Female gender clustered with TN (73%) and JAK2 (69%) vs. CALR/MPL (49%/47%) mutations (p < 0.01). ExT clustered with CALR (type-2 more than type-1) and TN and leukocytosis with JAK2 mutation (p < 0.01). In multivariable analysis, risk factors for overall survival were older age (p < 0.01), male gender (HR 1.8), absolute neutrophil count (ANC) ≥ 8 × 109/L (HR 1.6), absolute lymphocyte count (ALC) < 1.7 × 109/L (HR 1.5), hypertension (HR 1.7), and arterial thrombosis history (HR 1.7); for leukemia-free survival, ExT (HR 2.3) and abnormal karyotype (HR 3.1); for myelofibrosis-free survival, ANC ≥ 8 × 109/L (HR 2.3) and MPL mutation (HR 3.9); for arterial thrombosis-free survival, age ≥60 years (HR 1.9), male gender (HR 1.6), arterial thrombosis history (HR 1.7), hypertension (HR 1.7), and JAK2 mutation (HR 1.8); for venous thrombosis-free survival, male gender (HR 1.8) and venous thrombosis history (HR 3.0). Associations between ExT and leukemic transformation and between ANC and fibrotic progression were limited to JAK2-mutated cases. Aspirin therapy appeared to mitigate both arterial (HR 0.4) and venous (HR 0.4) thrombosis risk. HR-based risk models delineated patients with median survivals ranging from 10 years to not reached and 20-year leukemia/myelofibrosis incidences from 3%/21% to 12.8%/49%. The current study provides both novel and confirmatory observations of essential thrombocythemia.

A globally applicable "triple A" risk model for essential thrombocythemia based on Age, Absolute neutrophil count, and Absolute lymphocyte count

We examined the individual prognostic contribution of absolute neutrophil (ANC), lymphocyte (ALC), and monocyte (AMC) counts, on overall (OS), leukemia-free (LFS), and myelofibrosis-free (MFFS) survival in essential thrombocythemia (ET). Informative cases (N = 598; median age 59 years; females 62%) were retrospectively accrued from a Mayo Clinic database: JAK2 59%, CALR 27%, triple-negative 11%, and MPL 3%; international prognostic scoring system for ET (IPSET) risk high 21%, intermediate 42%, and low 37%; 7% (37/515) had abnormal karyotype and 10% (21/205) adverse mutations (SF3B1/SRSF2/U2AF1/TP53). At median 8.4 years, 163 (27%) deaths, 71 (12%) fibrotic, and 20 (3%) leukemic transformations were recorded. Multivariable analysis resulted in HR (95% CI) of 16.5 (9.9-27.4) for age > 70 years, 3.7 (2.3-6.0) for age 50-70 years, 2.4 (1.7-3.3) for ANC ≥8 × 109 /L, and 1.9 (1.4-2.6) for ALC <1.7 × 109 /L. The corresponding HR-based scores were 4, 2, 1, and 1, resulting in an new 4-tiered AgeAncAlc (AAA; triple A) risk model: high (5-6 points; median survival 8 years; HR 30.1, 95% CI 17.6-54), intermediate-2 (4 points; median 13.5 years; HR 12.7, 95% CI 7.1-23.0), intermediate-1 (2-3 points; median 20.7 years; HR 3.8, 95% CI 2.3-6.4) and low (0-1 points; median 47 years). The AAA model (Akaike Information Criterion [AIC] 621) performed better than IPSET (AIC 647) and was subsequently validated by an external University of Florence ET cohort (N = 485). None of the AAA variables predicted LFS while ALC <1.7 × 109 /L was associated with inferior MFFS (p = .01). Adverse mutations (p < .01) and karyotype (p < .01) displayed additional prognostic value without disqualifying the prognostic integrity of the AAA model. This study proposes a simple and globally applicable survival model for ET, which can be used as a platform for further molecular refinement. This study also suggests a potential role for immune-related biomarkers, as a prognostic tool in myeloproliferative neoplasms.

Predictors of response to venetoclax plus hypomethylating agent therapy and survival in blast-phase myeloproliferative neoplasm

Not available.

Progression and survival of MBL: a screening study of 10 139 individuals

Monoclonal B-cell lymphocytosis (MBL) is a common hematological premalignant condition that is understudied in screening cohorts. MBL can be classified into low-count (LC) and high-count (HC) types based on the size of the B-cell clone. Using the Mayo Clinic Biobank, we screened for MBL and evaluated its association with future hematologic malignancy and overall survival (OS). We had a two-stage study design including discovery and validation cohorts. We screened for MBL using an eight-color flow-cytometry assay. Medical records were abstracted for hematological cancers and death. We used Cox regression to evaluate associations and estimate hazard ratios and 95% confidence intervals (CIs), adjusting for age and sex. We identified 1712 (17%) individuals with MBL (95% LC-MBL), and the median follow-up time for OS was 34.4 months with 621 individuals who died. We did not observe an association with OS among individuals with LC-MBL (P = .78) but did among HC-MBL (hazard ratio, 1.8; 95% CI, 1.1-3.1; P = .03). Among the discovery cohort with a median of 10.0 years follow-up, 31 individuals developed hematological cancers with two-thirds being lymphoid malignancies. MBL was associated with 3.6-fold risk of hematological cancer compared to controls (95% CI, 1.7-7.7; P < .001) and 7.7-fold increased risk for lymphoid malignancies (95% CI:3.1-19.2; P < .001). LC-MBL was associated with 4.3-fold risk of lymphoid malignancies (95% CI, 1.4-12.7; P = .009); HC-MBL had a 74-fold increased risk (95% CI, 22-246; P < .001). In this large screening cohort, we observed similar survival among individuals with and without LC-MBL, yet individuals with LC-MBL have a fourfold increased risk of lymphoid malignancies. Accumulating evidence indicates that there are clinical consequences to LC-MBL, a condition that affects 8 to 10 million adults in the United States.

Clinical outcomes in patients with chronic lymphocytic leukemia with disease progression on ibrutinib

Patients with chronic lymphocytic leukemia (CLL) with disease progression on ibrutinib have worse outcomes compared to patients stopping ibrutinib due to toxicity. A better understanding of expected outcomes in these patients is necessary to establish a benchmark for evaluating novel agents currently available and in development. We evaluated outcomes of 144 patients with CLL treated at Mayo Clinic with 2018 iwCLL disease progression on ibrutinib. The median overall survival (OS) for the entire cohort was 25.5 months; it was 29.8 months and 8.3 months among patients with CLL progression (n = 104) and Richter transformation (n = 38), respectively. Longer OS was observed among patients with CLL progression who had received ibrutinib in the frontline compared to relapsed/refractory setting (not reached versus 28.5 months; p = 0.04), but was similar amongst patients treated with 1, 2, or ≥3 prior lines (18.5, 30.9, and 26.0 months, respectively, p = 0.24). Among patients with CLL disease progression on ibrutinib, OS was significantly longer when next-line treatment was chimeric antigen receptor T-cell therapy (median not reached) or venetoclax-based treatment (median 29.8 months) compared to other approved treatments, such as chemoimmunotherapy, phosphoinositide 3'-kinase inhibitors, and anti-CD20 monoclonal antibodies (9.1 months; p = 0.03). These findings suggest an unmet need for this growing patient population.

Long-term outcomes for ibrutinib-rituximab and chemoimmunotherapy in CLL: updated results of the E1912 trial

Herein, we present the long-term follow-up of the randomized E1912 trial comparing the long-term efficacy of ibrutinib-rituximab (IR) therapy to fludarabine, cyclophosphamide, and rituximab (FCR) and describe the tolerability of continuous ibrutinib. The E1912 trial enrolled 529 treatment-naïve patients aged ≤70 years with chronic lymphocytic leukemia (CLL). Patients were randomly assigned (2:1 ratio) to receive IR or 6 cycles of FCR. With a median follow-up of 5.8 years, median progression-free survival (PFS) is superior for IR (hazard ratio [HR], 0.37; P < .001). IR improved PFS relative to FCR in patients with both immunoglobulin heavy chain variable region (IGHV) gene mutated CLL (HR: 0.27; P < .001) and IGHV unmutated CLL (HR: 0.27; P < .001). Among the 354 patients randomized to IR, 214 (60.5%) currently remain on ibrutinib. Among the 138 IR-treated patients who discontinued treatment, 37 (10.5% of patients who started IR) discontinued therapy due to disease progression or death, 77 (21.9% of patients who started IR) discontinued therapy for adverse events (AEs)/complications, and 24 (6.8% of patients who started IR) withdrew for other reasons. Progression was uncommon among patients able to remain on ibrutinib. The median time from ibrutinib discontinuation to disease progression or death among those who discontinued treatment for a reason other than progression was 25 months. Sustained improvement in overall survival (OS) was observed for patients in the IR arm (HR, 0.47; P = .018). In conclusion, IR therapy offers superior PFS relative to FCR in patients with IGHV mutated or unmutated CLL, as well as superior OS. Continuous ibrutinib therapy is tolerated beyond 5 years in the majority of CLL patients. This trial was registered at www.clinicaltrials.gov as #NCT02048813.

Abstract 5256: Incidence of squamous cell carcinoma (SCC) in a large screening cohort of monoclonal B-cell lymphocytosis (MBL)

MBL is a common pre-malignant condition characterized by circulating clonal B-cells with an absolute B-cell count &lt;5x109/L and no lymphadenopathy, organomegaly, or cytopenias. MBL is the precursor to CLL. The incidence of cutaneous SCC in CLL is significantly higher compared to controls. The incidence of SCC in MBLs has not yet been determined. Study participants from the Mayo Clinic Biobank who had no prior history of hematologic malignancy, were 40 years or older, and were Olmsted County residents completed a health questionnaire and provided blood samples between 7/2009 and 12/2020. Stored peripheral blood mononuclear cells were screened for MBL using flow cytometry. We defined three MBL immunophenotypes: CLL-like MBL (CD5+, CD20dim), atypical MBL (CD5+, CD20+), and non-CLL-like MBL (CD5-, CD20+). MBL individuals were also classified by cell count into low-count MBL (LC-MBL) and high-count MBL (HC-MBL), with HC-MBL having a percent clonal B-cell count ≥85%. Data on newly diagnosed SCC was abstracted from the medical records, and prior history of skin cancer before sample collection was ascertained from patient questionnaires. Individuals were followed from sample date to the earliest of SCC, death, loss to follow-up, progression, or 12/31/2020. Cumulative SCC incidence was adjusted for competing risk of death. Cox regression was used to calculate hazard ratios (HR) and 95% confidence intervals (CIs) adjusted for age and sex. A total of 5,470 participants were screened for MBL and included 949 (17%) with LC-MBL, 63 (1%) with HC-MBL, and 4,458 (81%) controls (negative for MBL). Individuals with HC-MBL (median age 75 years) or LC-MBL (median age 73 years) were significantly older (P&lt;0.001) than controls (median age 66 years). There were 41 (65%) males among HC-MBL, 447 (47%) among LC-MBL, and 1,551 (35%) among controls. Prior skin cancer history was highest among HC-MBLs (N=17, 27%) or LC-MBLs (N=236, 25%) compared to controls (N=767, 17%). After a median follow-up of 18 months (range 0-138), 154 of the 5,470 individuals were identified to have incident SCC following MBL screening. At least one SCC was observed in 3 individuals with HC-MBL, 33 individuals with LC-MBL, and 118 controls. The 5- and 10-year cumulative incidence of SCC in individuals with MBLs was 7% and 16%, respectively; control estimates were 4% and 8%, respectively. However, after adjusting for age and sex, we observed no evidence of an association between MBL and risk of incident SCC (HR=0.95, CI=0.65-1.40, P=0.80), nor when we stratified individuals by age or by sex (all P&gt;0.05). In the largest MBL screening cohort to date, individuals with MBL do not have an increased risk of incident SCC compared to controls. In contrast to individuals with CLL, these individuals with screening MBL do not need increased dermatologic examination for skin cancer, which is important given the high prevalence of MBL (18% of the population above age 40).

Citation Format: Ahmed Nadeem Ansari, Sara J. Achenbach, Sameer A. Parikh, Geffen Kleinstern, Aaron D. Norman, Kari G. Rabe, Connie E. Lesnick, Timothy G. Call, Janet E. Olson, James R. Cerhan, Neil E. Kay, Celine M. Vachon, Esteban Braggio, Curtis A. Hanson, Tait D. Shanafelt, Christian L. Baum, Susan L. Slager. Incidence of squamous cell carcinoma (SCC) in a large screening cohort of monoclonal B-cell lymphocytosis (MBL) [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 5256.

Cytogenetic abnormalities in essential thrombocythemia: Clinical and molecular correlates and prognostic relevance in 809 informative cases

Cytogenetic studies among 809 consecutive patients with essential thrombocythemia (ET; median age 59 years; 65% females) revealed normal karyotype in 754 (93%), loss of chromosome Y only (-Y) in 16 (2%), and abnormalities other than -Y in 39 (4.8%), the most frequent being sole 20q- (n = 8). At presentation, abnormal karyotype, excluding -Y, was associated with older age (p = 0.04), higher leukocyte count (p = 0.03) and arterial thrombosis history (p = 0.02); no associations were apparent for JAK2/CALR/MPL mutations whereas ASXL1 mutations clustered with normal karyotype/-Y and TP53 with abnormal karyotype. Survival was significantly shorter in patients with abnormal karyotype or -Y, compared to those with normal karyotype (median 12, 10, and 21 years, respectively; p < 0.0001). During multivariable analysis that included IPSET (international prognostic score for ET) variables, abnormal karyotype (p < 0.01, HR 2.0), age >60 years (p < 0.01, HR 4.5), leukocytosis >11 × 10⁹/L (p < 0.01, HR 1.5), and male gender (p < 0.01, HR 1.4) were independently associated with inferior survival; abnormal karyotype and age >60 years remained significant, along with SF3B1/SRSF2/U2AF1/TP53 mutations (p = 0.04; HR 2.9), when the latter was included in the multivariable model. The current study suggests prognostic relevance for karyotype in ET.

Chronic lymphocytic leukemia (CLL) with Reed-Sternberg-like cells vs Classic Hodgkin lymphoma transformation of CLL: does this distinction matter?

The distinction between chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) with isolated Hodgkin/Reed-Sternberg cells (CLL-HRS; background milieu with a paucity of inflammatory cells) and overt transformation to classic Hodgkin lymphoma (CLL-HL; mixed inflammatory background) is incompletely understood. This retrospective study examined the clinicopathologic features of CLL-HRS (n = 15) and CLL-HL (n = 31) patients seen over the past three decades from a single institution. The phenotypic features of Reed-Sternberg cells in both groups were similar, including expression of CD30, CD15, and PAX5, as well as EBV status. However, a spectrum of background CLL/SLL infiltration amongst the HRS cells was noted on pathologic review, and four patients had both diagnoses, either concurrently or in succession. The median overall survival (OS) of patients with CLL-HRS was 17.5 months compared to 33.5 months for patients with CLL-HL (P = 0.24). Among patients with CLL-HRS, those who received Hodgkin-directed therapy had a significantly longer median OS (57 months) compared to those who received CLL-directed therapy (8.4 months, P = 0.02). Our clinical and pathologic findings suggest a biologic continuum between CLL-HRS and CLL-HL and indicate that CLL-HRS patients may benefit from Hodgkin-directed therapy.

European LeukemiaNet-defined primary refractory acute myeloid leukemia: the value of allogeneic hematopoietic stem cell transplant and overall response

We sought to appraise the value of overall response and salvage chemotherapy, inclusive of allogeneic hematopoietic stem cell transplant (AHSCT), in primary refractory acute myeloid leukemia (prAML). For establishing consistency in clinical practice, the 2017 European LeukemiaNet (ELN) defines prAML as failure to attain CR after at least 2 courses of intensive induction chemotherapy. Among 60 consecutive patients (median age 63 years) correspondent with ELN-criteria for prAML, salvage was documented in 48 cases, 30/48 (63%) being administered intensive chemotherapy regimens and 2/48 consolidated with AHSCT as first line salvage. 13/48 (27%) attained response: CR, 7/13 (54%), CRi, 2/13 (15%), MLFS, 4/13 (31%). The CR/CRi rate was 9/48 (19%), with CR rate of 7/48 (15%). On univariate analysis, intermediate-risk karyotype was the only predictor of response (44% vs 17% in unfavorable karyotype; P = 0.04). Administration of any higher-dose (>1 g/m²) cytarabine intensive induction (P = 0.50), intensive salvage chemotherapy (P = 0.72), targeted salvage (FLT3 or IDH inhibitors) (P = 0.42), greater than 1 salvage regimen (P = 0.89), age < 60 years (P = 0.30), and de novo AML (P = 0.10) did not enhance response achievement, nor a survival advantage. AHSCT was performed in 12 patients with (n = 8) or without (n = 4) CR/CRi/MLFS. 1/2/5-year overall survival (OS) rates were 63%/38%/33% in patients who received AHSCT (n = 12) vs 27%/0%/0% in those who achieved CR/CRi/MLFS but were not transplanted (n = 5), vs 14%/0%/0% who were neither transplanted nor achieved CR/CRi/MLFS (n = 43; P < 0.001); the median OS was 18.6, 12.6 and 5.6 months, respectively. Although CR/CRi/MLFS bridged to AHSCT (n = 8), appeared to manifest a longer median OS (20 months), vs (13.4 months) for those with no response consolidated with AHSCT (n = 4), the difference was not significant P = 0.47. We conclude AHSCT as indispensable for securing long-term survival in prAML (p = 0.03 on multivariate analysis), irrespective of response achievement.

Measurable residual disease does not preclude prolonged progression-free survival in CLL treated with ibrutinib

E1912 was a randomized phase 3 trial comparing indefinite ibrutinib plus 6 cycles of rituximab (IR) to 6 cycles of fludarabine, cyclophosphamide, and rituximab (FCR) in untreated younger patients with CLL. We describe measurable residual disease (MRD) levels in E1912 over time and correlate them with clinical outcome. Undetectable MRD rates (<1 CLL cell per 104 leukocytes) were 29.1%, 30.3%, 23.4%, and 8.6% at 3, 12, 24, and 36 months for FCR, and significantly lower at 7.9%, 4.2%, and 3.7% at 12, 24, and 36 months for IR, respectively. Undetectable MRD at 3, 12, 24, and 36 months was associated with longer progression-free survival (PFS) in the FCR arm, with hazard ratios (MRD detectable/MRD undetectable) of 4.29 (95% confidence interval [CI], 1.89-9.71), 3.91 (95% CI, 1.39-11.03), 14.12 (95% CI, 1.78-111.73), and not estimable (no events among those with undetectable MRD), respectively. In the IR arm, patients with detectable MRD did not have significantly worse PFS compared with those in whom MRD was undetectable; however, PFS was longer in those with MRD levels <10-1 than in those with MRD levels above this threshold. Our observations provide additional support for the use of MRD as a surrogate end point for PFS in patients receiving FCR. In patients on indefinite ibrutinib-based therapy, PFS did not differ significantly by undetectable MRD status, whereas those with MRD <10-1 tended to have longer PFS, although continuation of ibrutinib would very likely be necessary to maintain treatment efficacy.

De novo isolated myeloid sarcoma: comparative analysis of survival in 19 consecutive cases

Institutional database search (1999-2020) for acute myeloid leukaemia (AML) identified 109 cases of myeloid sarcoma (MS), of which 19 were isolated and presented de novo. The latter displayed longer survival (median 78 months), compared to MS with synchronous intramedullary AML (n = 32; median 16 months) and de novo AML without MS (n = 729; median 22 months; P = 0·13). However, the difference in survival was no longer apparent after accounting for bone marrow cytogenetic risk status (P = 0·67). Treatment-induced MS tumour resolution was not affected by the presence of intramedullary disease (P = 0·61). The current study clarifies the prognosis of de novo isolated MS, in the context of AML.

MCIR1: A patient-derived mantle cell lymphoma line for discovering new treatments for ibrutinib resistance

BACKGROUND

Despite the unprecedented success of ibrutinib in lymphoma therapy, the development of ibrutinib resistance due to acquired BTK or PLCγ2 mutations has become a new clinical problem. However, not all resistance is mediated by these mutations and these mechanisms are poorly understood due to a lack of study tools that truly recapitulate this clinical scenario.

METHODS

We established a novel patient-derived ibrutinib-resistant mantle cell lymphoma (MCL) line named MCIR1. Using immunological, molecular, and cytogenetic approaches, we comprehensively characterized MCIR1 and further demonstrated its utility in the study of resistance mechanisms and treatments to overcome this resistance.

RESULTS

We show that MCIR1 is a bona fide ibrutinib-resistant MCL cell line with normal BTK-/PLCγ2 but ibrutinib-resistant ERK1/2 and AKT1 signaling. RNA-Seq analysis revealed a robust non-canonical NF-kB signaling that drives the ibrutinib resistance. We also demonstrate the potential utility of a MCIR1-based cell and mouse model for the discovery of new treatments to overcome BTK inhibitor resistance.

CONCLUSIONS

We have established the first patient-derived ibrutinib-resistant MCL cell line MCIR1 that lacks BTK or PLCγ2 mutations but exhibits a hyperactive non-canonical NF-kB pathway. We further demonstrate its utility in the discovery and validation of new drugs to overcome this resistance.

Venetoclax with azacitidine or decitabine in blast-phase myeloproliferative neoplasm: A multicenter series of 32 consecutive cases

Venetoclax (Ven) combined with a hypomethylating agent (HMA) has now emerged as an effective treatment regimen for acute myeloid leukemia, in both de novo and relapsed/refractory setting. The current multicenter study retrospectively examined Ven + HMA treatment outcome among 32 patients (median age 69 years; 59% males) with blast‐phase myeloproliferative neoplasm (MPN‐BP). Pre‐leukemic phenotype included essential thrombocythemia (ET)/post‐ET myelofibrosis (34%), polycythemia vera (PV)/post‐PV myelofibrosis (38%) and primary myelofibrosis (28%). Twenty‐nine study patients were fully annotated cytogenetically and molecularly (NGS): 69% harbored complex karyotype and/or mutations, including TP53 (41%), IDH1/2 (21%), ASXL1 (21%), N/KRAS (14%), SRSF2 (10%), EZH2 (10%) and U2AF1 (7%). All patients received Ven combined with either azacitidine (n = 12) or decitabine (n = 20); either up front (n = 23) or after failing another induction therapy (n = 9). Complete remission with (CR) or without (CRi) count recovery was achieved in 14 (44%) patients and was more likely to occur in the absence of pre‐leukemic PV/post‐PV myelofibrosis phenotype (p < .01), complex karyotype (p < .01) or K/NRAS (p = .03) mutations; seven of eight patients (88%) without vs four of 21 (19%) with complex karyotype or K/NRAS mutation achieved CR/CRi (p < .01); all 11 informative patients with pre‐leukemic PV/post‐PV myelofibrosis phenotype displayed complex karyotype (p < .01). In contrast, neither TP53 (p = .45) nor IDH1/2 (p = .63) mutations affected response. Compared to historical controls treated with HMA alone (n = 26), the CR/CRi rate (44% vs 4%) and median survival (8 vs 5.5 months) were more favorable with Ven + HMA, but without significant difference in overall survival. Importantly, six patients with CR/CRi subsequently received allogeneic hematopoietic stem cell transplant (AHSCT). Note, Ven + HMA produces robust CR/CRi rates in MPN‐BP, especially in the absence of RAS mutations and complex karyotype, thus enabling AHSCT, in some patients.

Natural history of monoclonal B-cell lymphocytosis among relatives in CLL families

Chronic lymphocytic lymphoma (CLL) has one of the highest familial risks among cancers. Monoclonal B-cell lymphocytosis (MBL), the precursor to CLL, has a higher prevalence (13%-18%) in families with 2 or more members with CLL compared with the general population (5%-12%). Although, the rate of progression to CLL for high-count MBLs (clonal B-cell count ≥500/µL) is ∼1% to 5%/y, no low-count MBLs have been reported to progress to date. We report the incidence and natural history of MBL in relatives from CLL families. In 310 CLL families, we screened 1045 relatives for MBL using highly sensitive flow cytometry and prospectively followed 449 of them. MBL incidence was directly age- and sex-adjusted to the 2010 US population. CLL cumulative incidence was estimated using Kaplan-Meier survival curves. At baseline, the prevalence of MBL was 22% (235/1045 relatives). After a median follow-up of 8.1 years among 449 relatives, 12 individuals progressed to CLL with a 5-year cumulative incidence of 1.8%. When considering just the 139 relatives with low-count MBL, the 5-year cumulative incidence increased to 5.7%. Finally, 264 had no MBL at baseline, of whom 60 individuals subsequently developed MBL (2 high-count and 58 low-count MBLs) with an age- and sex-adjusted incidence of 3.5% after a median of 6 years of follow-up. In a screening cohort of relatives from CLL families, we reported progression from normal-count to low-count MBL to high-count MBL to CLL, demonstrating that low-count MBL precedes progression to CLL. We estimated a 1.1% annual rate of progression from low-count MBL, which is in excess of that in the general population.

Abstract 650: MCIR1: A patient-derived ibrutinib-resistant mantle cell lymphoma line for the study of ibrutinib resistance and drug discovery

Constitutive activation of B-cell receptor (BCR) signaling is a major driving mechanism for the proliferation and survival of various B-cell lineage non-Hodgkin lymphomas (NHL). Blocking BCR signaling using the first-in-class Bruton's tyrosine kinase (BTK) inhibitor, ibrutinib, has proved effective and is currently FDA approved for the treatment of several B-cell lymphomas. Unfortunately, significant subsets of patients possess either primary or acquired resistance to ibrutinib, often resulting in worse prognosis and poorer responses to subsequent therapies. Therefore, overcoming ibrutinib resistance is an urgent clinical need requiring new tools to both delineate the molecular mechanisms of resistance and develop viable therapeutics.

To that end, we developed a mantle cell lymphoma (MCL) cell line, MCIR1, from a patient with clinically acquired ibrutinib resistance. MCIR1 is a bona fide MCL cell line featuring CD19+/CD5+/CD10-/CD23-/t(11;14)+/TP53+/-; and lacking the previously described mutations in BTK (C481S) and phospholipase C-gamma-2 (R665W, L845F). Importantly, MCIR1 cells possess hallmarks of ibrutinib resistance, including the insensitivity of ERK1/2 phosphorylation to ibrutinib in vitro, and the irresponsiveness of MCIR1 xenograft tumors to ibrutinib treatment in mice as compared with ibrutinib-sensitive Jeko-1 tumors. To delineate the molecular mechanism(s) of ibrutinib resistance, we identified by RNA-Seq analysis that MCIR1 cells possess robust activity of the non-canonical NFkB pathway and elevated expression of NFkB target genes, suggesting that this pathway likely drives their resistance to ibrutinib. Finally, we demonstrated the utility of MCIR1 as a tool for testing new drugs to combat ibrutinib resistance in vitro by showing its sensitivity to the anti-apoptotic B-cell lymphoma-2 (Bcl-2) protein inhibitor, venetoclax.

To our knowledge, MCIR1 is the first patient-derived ibrutinib-resistant cell line to be established. Hence, MCIR1 is especially useful because uniquely possesses the relevant clinical and biological features of patients with ibrutinib-resistant MCL. We propose MCIR1 as a tool to further the understanding of molecular mechanisms conferring ibrutinib resistance by providing a clinically relevant system with the capacity for molecular and genetic manipulations. Further, these features make MCIR1 an ideal model to screen drugs for combating ibrutinib resistance through both in vivo and in vitro approaches.

Citation Format: Kevin E. Nowakowski, Jithma P. Abeykoon, Mary J. Stenson, Michael M. Timm, Curtis A. Hanson, Daniel L. Van Dyke, Anne J. Novak, Xiaosheng Wu, Thomas E. Witzig. MCIR1: A patient-derived ibrutinib-resistant mantle cell lymphoma line for the study of ibrutinib resistance and drug discovery [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 650.

Mutation-enhanced international prognostic systems for essential thrombocythaemia and polycythaemia vera

Survival prediction in essential thrombocythaemia (ET) and polycythaemia vera (PV) is currently based on clinically-derived variables; we examined the possibility of integrating genetic information for predicting survival. To this end, 906 molecularly-annotated patients (416 Mayo Clinic; 490 University of Florence, Italy), including 502 ET and 404 PV, were recruited. Multivariable analysis identified spliceosome mutations to adversely affect overall (SF3B1, SRSF2 in ET and SRSF2 in PV) and myelofibrosis-free (U2AF1, SF3B1 in ET) survival; TP53 mutations predicted leukaemic transformation in ET; "adverse" mutations occurred in 51 (10%) ET and 8 (2%) PV patients. We confirmed the independent survival effect of adverse mutations [hazard ratio (HR) 2·4, 95% CI 1·6-3·5], age >60 years (6·6, 4·6-9·7), male sex (1·8, 1·3-2·4) and leukocytosis ≥11 × 10⁹ /l (1·6, 1·1-2·2), in ET, and adverse mutations (7·8, 3·1-17·0), age >67 years (5·4, 3·6-8·1), leukocytosis ≥15 × 10⁹ /l (2·8, 1·8-4·2) and thrombosis history (2·0, 1·4-2·9), in PV. HR-based risk point allocation allowed development of three-tiered mutation-enhanced international prognostic systems (MIPSS) which were validated in both cohorts and performance was shown to be superior to conventional scoring systems. Spliceosome mutations enhance survival prediction in ET and PV and identify patients at risk for fibrotic progression. TP53 mutations predict leukaemic transformation in ET.

Ibrutinib-Rituximab or Chemoimmunotherapy for Chronic Lymphocytic Leukemia

BACKGROUND

Data regarding the efficacy of treatment with ibrutinib-rituximab, as compared with standard chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab, in patients with previously untreated chronic lymphocytic leukemia (CLL) have been limited.

METHODS

In a phase 3 trial, we randomly assigned (in a 2:1 ratio) patients 70 years of age or younger with previously untreated CLL to receive either ibrutinib and rituximab for six cycles (after a single cycle of ibrutinib alone), followed by ibrutinib until disease progression, or six cycles of chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab. The primary end point was progression-free survival, and overall survival was a secondary end point. We report the results of a planned interim analysis.

RESULTS

A total of 529 patients underwent randomization (354 patients to the ibrutinib-rituximab group, and 175 to the chemoimmunotherapy group). At a median follow-up of 33.6 months, the results of the analysis of progression-free survival favored ibrutinib-rituximab over chemoimmunotherapy (89.4% vs. 72.9% at 3 years; hazard ratio for progression or death, 0.35; 95% confidence interval [CI], 0.22 to 0.56; P<0.001), and the results met the protocol-defined efficacy threshold for the interim analysis. The results of the analysis of overall survival also favored ibrutinib-rituximab over chemoimmunotherapy (98.8% vs. 91.5% at 3 years; hazard ratio for death, 0.17; 95% CI, 0.05 to 0.54; P<0.001). In a subgroup analysis involving patients without immunoglobulin heavy-chain variable region (IGHV) mutation, ibrutinib-rituximab resulted in better progression-free survival than chemoimmunotherapy (90.7% vs. 62.5% at 3 years; hazard ratio for progression or death, 0.26; 95% CI, 0.14 to 0.50). The 3-year progression-free survival among patients with IGHV mutation was 87.7% in the ibrutinib-rituximab group and 88.0% in the chemoimmunotherapy group (hazard ratio for progression or death, 0.44; 95% CI, 0.14 to 1.36). The incidence of adverse events of grade 3 or higher (regardless of attribution) was similar in the two groups (in 282 of 352 patients [80.1%] who received ibrutinib-rituximab and in 126 of 158 [79.7%] who received chemoimmunotherapy), whereas infectious complications of grade 3 or higher were less common with ibrutinib-rituximab than with chemoimmunotherapy (in 37 patients [10.5%] vs. 32 [20.3%], P<0.001).

CONCLUSIONS

The ibrutinib-rituximab regimen resulted in progression-free survival and overall survival that were superior to those with a standard chemoimmunotherapy regimen among patients 70 years of age or younger with previously untreated CLL. (Funded by the National Cancer Institute and Pharmacyclics; E1912 ClinicalTrials.gov number, NCT02048813.).

3023 Mayo Clinic Patients With Myeloproliferative Neoplasms: Risk-Stratified Comparison of Survival and Outcomes Data Among Disease Subgroups

OBJECTIVE

To document the Mayo Clinic decades-long experience with myeloproliferative neoplasms (MPNs) and provide mature risk-stratified survival data and disease complication estimates.

PATIENTS AND METHODS

All Mayo Clinic patients with World Health Organization-defined MPNs constituted the core study group and included those with polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF).

RESULTS

A total of 3023 consecutive patients (median age, 62 years; range, 18-96 years) were considered: 665 PV, 1076 ET, and 1282 PMF. From October 27, 1967, through December 29, 2017, 1631 deaths (54%), 183 leukemic transformations (6%), 244 fibrotic progressions (14%), and 516 thrombotic events (17%) were recorded. Median overall survival (OS) was 18 years for ET, 15 years for PV, and 4.4 years for PMF (P<.05 for all intergroup comparisons). Inferior survival was documented in patients with ET diagnosed more recently (post-1990) (P<.001), whereas survival data were time independent in PV and PMF. After conventional risk stratification, OS in low-risk ET and low-risk PV were superimposed (P=.89) but each differed significantly from that of age- and sex-matched controls (P<.001). Leukemia-free survival was similar for ET and PV (P=.22) and significantly worse with PMF (P<.001). Compared with ET, PV was associated with higher risk of fibrotic progression (P<.001). Thrombosis risk after diagnosis was highest in PV and lowest in PMF (P=.002 for PV vs ET; P=.56 for ET vs PMF; and P=.001 for PV vs PMF).

CONCLUSION

This study provides the most mature survival and outcomes data in MPNs and highlights MPN subgroup risk categorization as key in appraising disease natural history. The OS was only marginally better in ET compared with PV, and PV displayed a higher risk of thrombosis and fibrotic progression.

IGH translocations in chronic lymphocytic leukemia: Clinicopathologic features and clinical outcomes

The prevalence, clinicopathologic correlates, and outcomes of previously untreated chronic lymphocytic leukemia (CLL) patients with IGH-BCL2 and IGH-BCL3 translocations are not well known. Using the Mayo Clinic CLL database, we identified patients seen between March 1, 2002 and September 30, 2016 who had FISH testing performed within 3 years of CLL diagnosis. The prognostic profile, time to first therapy (TTT), and overall survival (OS) of patients with IGH-BCL2 and IGH-BCL3 translocation were compared to patients without these abnormalities (non-IGH group). Of 1684 patients who met the inclusion criteria, 38 (2.2%) had IGH-BCL2, and 16 (0.9%) had IGH-BCL3 translocation at diagnosis. Patients with IGH-BCL3 translocation were more likely to have high and very-high CLL-International Prognostic Index, compared to patients with IGH-BCL2 translocation and the non-IGH group. The 5-year probability of requiring therapy was significantly higher for IGH-BCL3 compared to IGH-BCL2 and non-IGH groups (84% vs 33% vs 29%, respectively, P < 0.0001). The 5-year OS was significantly shorter for IGH-BCL3 compared to IGH-BCL2 and non-IGH groups (45% vs 89% vs 86%, respectively, P < 0.0001). On multivariable analyses, IGH-BCL3 translocation was associated with a shorter TTT (hazard ratio [HR] = 2.7; P = 0.005) and shorter OS (HR = 5.5; P < 0.0001); IGH-BCL2 translocation did not impact TTT and OS. In conclusion, approximately 3% of all newly diagnosed CLL patients have either an IGH-BCL2 or IGH-BCL3 translocation. Patients with IGH-BCL3 translocations have a distinct prognostic profile and outcome. These results support the inclusion of an IGH probe during the routine evaluation of FISH abnormalities in newly diagnosed CLL.

20+ Years and alive with primary myelofibrosis: Phenotypic signature of very long-lived patients

In the last decade, several prognostic models for primary myelofibrosis (PMF) have been introduced and shown to be effective in predicting overall survival. The main objective for this study was to identify clinical and genetic markers of very long (20+ years) survival in PMF. A total of 1282 patients with PMF were considered (median age 65 years, range 19-92; 63% males); 26 (2%) patients (median age 51 years, range 28-71; 38% males) survived their disease for at least 20 years (long-lived patients) and 626 (49%) patients (median age 68 years, range 27-92; 66% males) died within 5 years of their diagnosis (short-lived patients). Multivariable logistic regression analysis identified 7 variables that were associated with survival beyond 20 years: age ≤ 70 years (P = .002); female sex (P = .03); hemoglobin level ≥ 10 g/dL for women and ≥ 11 g/dL for men (P = .03), leukocyte count ≤25 × 10⁹ /L (P = .009), platelet count ≥100 × 10⁹ /L (P = .002), circulating blasts <2% (P = .03) and absence of constitutional symptoms (P = .04). Five-year mortality was independently predicted by high-molecular risk mutations (P < .001); unfavorable or very high risk karyotype (P < .001); absence of type 1/like CALR mutation (P < .001); age > 70 years (P < .001); constitutional symptoms (P < .001); hemoglobin level < 10 g/dL for women and < 11 g/dL for men (P < .001); leukocyte count >25 × 10⁹ /L (P = .004); and circulating blasts ≥2% (P = .001). This study suggests that genetic risk factors in PMF are associated with early mortality while survival beyond 20 years could be predicted by easily accessible clinical variables, including age, sex, blood counts, and symptoms.

The germline JAK2 GGCC (46/1) haplotype and survival among 414 molecularly-annotated patients with primary myelofibrosis

JAK2 mutations in myeloproliferative neoplasms (MPNs) are associated with the germline GGCC (46/1) haplotype. In 2010, we reported an association between shortened survival in primary myelofibrosis (PMF) and nullizygosity for the JAK2 46/1 haplotype. In the current study, we have increased the number of informative cases from 130 to 414 (median age 63 years; 63% males), in order to revisit with the phenotypic and prognostic relevance of the JAK2 46/1 haplotype in PMF. JAK2 46/1 haplotype was documented in 69% of the study patients, including 25% in homozygous and 44% in heterozygous state. Driver mutation frequency in patients homozygous/heterozygous/nullizygous for the 46/1 haplotype was 78%/60%/56% JAK2, 10%/20%/18% type 1-like CALR, 3%/2%/5% type 2-like CALR, 4%/8%/7% MPL, and 6%/10%/14% triple-negative (P = .02). In univariate analysis, nullizygosity for the JAK2 46/1 haplotype was associated with inferior overall survival (HR 1.5, 95% CI 1.1-1.9), most pronounced in JAK2 (P <.001), as opposed to CALR/MPL mutated (P = .48) or triple-negative cases (P = .27). Multivariable analysis that included karyotype, driver mutational status and high-molecular risk mutations confirmed the independent prognostic contribution of nullizygosity for the 46/1 haplotype (P = .02; HR 1.4, 95% CI 1.1-1.8). Nullizygosity for 46/1 also remained significant in the context of the genetically-inspired GIPSS risk model (P = .04), but not in the context of the integrated genetics-clinical MIPSS70+ version 2.0 model (P = .4). Leukemia-free survival was not affected by the 46/1 haplotype (P = .6). The current study confirms the association of nullizygosity for the JAK2 GGCC (46/1) haplotype with inferior survival in JAK2-mutated PMF.

Impact of an electronic decision support rule on ESR/CRP co-ordering rates in a community health system and projected impact in the tertiary care setting and a commercially insured population

INTRODUCTION

Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are common laboratory assays used as markers of inflammation. ESR suffers from higher false positive and false negative rates than CRP. To that end, the American Board of Internal Medicine's (ABIM's) Choosing Wisely campaign has recommended against ESR testing for those with undiagnosed conditions in favor of CRP testing. This study describes the impact of a computerized provider order entry (CPOE) decision support rule against ESR/CRP co-ordering within a community health system that predates the ABIM's Choosing Wisely national guidance. To demonstrate the potential impact of such a CPOE rule within other healthcare settings, ESR/CRP ordering data from a multi-site tertiary care practice and from the commercially insured population in the OptumLabs® Data Warehouse (OLDW) were analyzed and the relative reduction in ESR/CRP co-ordering achieved within the community health system was projected onto these populations.

MATERIALS AND METHODS

ESR and/or CRP orders from a community health system were assessed from 2012 to 2016. Co-ordering and test concordance rates between ESR and CRP were compared before and after CPOE decision support rule launch. Similarly, ESR/CRP co-ordering across three tertiary care sites from 2015 to 2016 and the OLDW from 2009 to 2013 were assessed and the co-ordering rate reduction achieved in the community health system was mathematically projected onto these populations. Estimated payer savings from the rule's effect were calculated within each population using Medicare reimbursement rates.

RESULTS

The CPOE decision support rule realized an unadjusted 42% relative rate reduction in ESR/CRP co-ordering within the community health system yielding an annual payer savings of $15,000 with a modest increase in ESR/CRP concordance rates. Projecting a 40% relative reduction in ESR/CRP co-ordering rates from a similarly effective CPOE rule, annual payer cost reductions exceeding $100,000 within a multi-site tertiary care setting and $1,000,000 within the OLDW would be expected.

CONCLUSION

ESR/CRP co-ordering represents an opportunity to eliminate testing waste and reduce payer costs. A CPOE decision support rule stably reduces ESR/CRP co-ordering rates. Similar results may occur as one component of new commercially available decision support platforms.

Decreased survival and increased rate of fibrotic progression in essential thrombocythemia chronicled after the FDA approval date of anagrelide

First-line cytoreductive drug of choice in high risk essential thrombocythemia (ET) is currently hydroxyurea, a practice based on the results of a randomized study; second-line drugs of choice include pegylated interferon-α, busulfan and anagrelide. Anagrelide clinical trials were pioneered by the late Murray N. Silverstein (1928-1998) of the Mayo Clinic whose studies led to FDA approval in March 1997. The current study represents a retrospective examination of the potential impact of anagrelide therapy on survival and disease complications in ET. 1076 patients with ET were considered (median age 58 years; females 63%); risk distribution, according to the international prognostic score for ET (IPSET), was 28% high, 42% intermediate, and 30% low. Overall (OS), myelofibrosis-free (MFFS) and thrombosis-free survival data were compared for ET patients diagnosed before and after the 1997 FDA approval date for anagrelide; a significant difference was apparent in OS (P = .006; HR 1.4, 95% CI 1.1-1.7) and MFFS (P < .001; HR 4.2, 95% CI 2.7-6.5), in favor of patients diagnosed prior to 1997; the difference was sustained during multivariable analysis that included IPSET. Similarly stratified survival data in polycythemia vera (n = 665) and primary myelofibrosis (n = 1282) showed no similar impact on survival (P = .3 and .17, respectively). The current study represents a retrospective analysis and suggests significantly decreased OS and MFFS in ET patients diagnosed after the FDA approval date of anagrelide. Whether or not anagrelide therapy was to blame for the worsening of OS and MFFS over time cannot be assumed and requires validation in a prospective study.

Cytogenetic abnormalities in systemic mastocytosis: WHO subcategory-specific incidence and prognostic impact among 348 informative cases

The World Health Organization (WHO) system lists five morphological categories of systemic mastocytosis (SM): indolent (ISM), smoldering, SM with an associated hematological neoplasm (SM-AHN), aggressive (ASM) and mast cell leukemia (MCL). Recent studies have highlighted the prognostic importance of mutations in SM, including ASXL1, RUNX1, and SRSF2. In contrast, information on incidence of cytogenetic abnormalities in SM and their prognostic relevance, especially in the context of mutations, is limited. In the current study, we retrospectively reviewed the cytogenetic findings in 348 consecutive cases of SM (median age 59 years; 53% males); 41% constituted ISM, 45% SM-AHN, 14% ASM and two cases of MCL. Karyotype was abnormal in 53 (15%) cases with incidences of 6% for ISM, 26% for SM-AHN and 8% for ASM (P < .001); among SM-AHN cases, abnormal karyotype incidences were 0% for SM-AHN-lymphoid and 28% for SM-AHN-myeloid (P < .001). Clinical correlative studies disclosed significant associations between abnormal karyotype and male sex (P = .002), age > 60 years (P = .04), thrombocytopenia (P < .001) and anemia (P < .001), but not with the presence of adverse mutations (P = .19). In univariate analysis, abnormal karyotype was associated with inferior survival (HR 3.0, 95% CI 2.0-4.3), specifically confirmed for ASM (HR 4.9, 95% CI 1.1-16.1) and SM-AHN (HR 1.8, 95% CI 1.2-2.7). Sample size adequacy allowed additional multivariable analysis in SM-AHN-myeloid, which disclosed independent prognostic contribution from adverse mutations (P = .003), anemia (P = .003) and thrombocytopenia (P = .001), but not from abnormal karyotype (P = .31). Our observations suggest that mutations are prognostically more relevant than karyotype in SM.

Myeloproliferative neoplasms in the young: Mayo Clinic experience with 361 patients age 40 years or younger

Between 1967 and 2017, 361 patients with myeloproliferative neoplasms (MPN), age ≤ 40 years, were seen at our institution, constituting 12% of all MPN patients (n = 3023) seen during the same time period; disease-specific incidences were 12% in polycythemia vera (PV; n = 79), 20% in essential thrombocythemia (ET; n = 219) and 5% in primary myelofibrosis (PMF; n = 63). Compared to their older counterparts, younger patients were more likely to present with low risk disease (P < .001) and display female preponderance in ET (P = .04), lower incidence of arterial events overall (P < .001), and higher incidence of venous thrombosis in PV (P = .01). Younger patients were also more likely to express CALR mutations, in ET and PMF, normal karyotype, in PV and PMF, and lower incidence of high molecular risk mutations in PMF (P significant in all instances). Over median follow-up of 11.3, 13, and 7.1 years for PV, ET, and PMF, leukemic transformations were respectively documented in 4%, 2%, and 10% (P values 0.1-0.9) while incidences of fibrotic progression in PV (22%) and ET (16%) were expectedly higher in young patients, because of their longer survival (P < .001). Median survival in young patients was 37 years for PV, 35 for ET and 20 for PMF; the corresponding values were 22, 22, and 8 years for ages 41-60 years and 10, 11, and 3 years for ages >60 years (P < .001). Young MPN patients comprise a unique disease subset defined by an attenuated-risk cytogenetic and mutational backdrop and conspicuously longer survival compared to their older counterparts, which requires assertion during patient counseling.

Mayo Alliance Prognostic Model for Myelodysplastic Syndromes: Integration of Genetic and Clinical Information

OBJECTIVE

To develop a new risk model for primary myelodysplastic syndromes (MDS) that integrates information on mutations, karyotype, and clinical variables.

PATIENTS AND METHODS

Patients with World Health Organization-defined primary MDS seen at Mayo Clinic (MC) from December 28, 1994, through December 19, 2017, constituted the core study group. The National Taiwan University Hospital (NTUH) provided the validation cohort. Model performance, compared with the revised International Prognostic Scoring System, was assessed by Akaike information criterion and area under the curve estimates.

RESULTS

The study group consisted of 685 molecularly annotated patients from MC (357) and NTUH (328). Multivariate analysis of the MC cohort identified monosomal karyotype (hazard ratio [HR], 5.2; 95% CI, 3.1-8.6), "non-MK abnormalities other than single/double del(5q)" (HR, 1.8; 95% CI, 1.3-2.6), RUNX1 (HR, 2.0; 95% CI, 1.2-3.1) and ASXL1 (HR, 1.7; 95% CI, 1.2-2.3) mutations, absence of SF3B1 mutations (HR, 1.6; 95% CI, 1.1-2.4), age greater than 70 years (HR, 2.2; 95% CI, 1.6-3.1), hemoglobin level less than 8 g/dL in women or less than 9 g/dL in men (HR, 2.3; 95% CI, 1.7-3.1), platelet count less than 75 × 10⁹/L (HR, 1.5; 95% CI, 1.1-2.1), and 10% or more bone marrow blasts (HR, 1.7; 95% CI, 1.1-2.8) as predictors of inferior overall survival. Based on HR-weighted risk scores, a 4-tiered Mayo alliance prognostic model for MDS was devised: low (89 patients), intermediate-1 (104), intermediate-2 (95), and high (69); respective median survivals (5-year overall survival rates) were 85 (73%), 42 (34%), 22 (7%), and 9 months (0%). The Mayo alliance model was subsequently validated by using the external NTUH cohort and, compared with the revised International Prognostic Scoring System, displayed favorable Akaike information criterion (1865 vs 1943) and area under the curve (0.87 vs 0.76) values.

CONCLUSION

We propose a simple and contemporary risk model for MDS that is based on a limited set of genetic and clinical variables.

A Test Utilization Approach to the Diagnostic Workup of Isolated Eosinophilia in Otherwise Morphologically Unremarkable Bone Marrow: A Single Institutional Experience

OBJECTIVES

Determine ancillary test utilization for the workup of isolated eosinophilia in otherwise morphologically unremarkable bone marrow (BM).

METHODS

We evaluated BM ancillary testing performed in cases with isolated eosinophilia and otherwise morphologically unremarkable BM. Cases with abnormal morphology (eg, dysplasia, basophilia) and/or findings suggestive of a disorder (eg, unexplained thromboses, lymphoma) are specifically excluded.

RESULTS

A total of 132 cases met inclusion criteria. Ten cases had an ancillary testing abnormality that warranted a more specific hematologic diagnosis: four cases of lymphocytic variant of hypereosinophilic syndrome, three cases of myeloid neoplasm with PDGFRA rearrangement, and one case each of myeloid neoplasm with PDGFRB rearrangement, chronic eosinophilic leukemia, and morphologically occult systemic mastocytosis. No cases revealed a cryptic PDGFRB or BCR/ABL1 rearrangement or JAK2 V617F mutation.

CONCLUSIONS

Findings from our institutional experience support initial testing in isolated eosinophilia with otherwise unremarkable BM to include PDGFRA rearrangement, tryptase/CD25 immunohistochemistry, cytogenetics, and T-cell flow cytometry/receptor gene rearrangement. This approach achieves diagnostic quality and test utilization efficiency in our clinical practice.

Autoimmune cytopenias in patients with chronic lymphocytic leukaemia treated with ibrutinib in routine clinical practice at an academic medical centre

The effects of ibrutinib on the natural history of autoimmune cytopenias (AIC) among chronic lymphocytic leukaemia (CLL) patients treated in routine clinical practice require further investigation. Using the Mayo Clinical CLL Database, 193 CLL patients treated with ibrutinib between November 2013 and January 2017 outside the context of a clinical trial were identified; complete review of their medical records was performed for details of past history of AIC and treatment-emergent AIC. We identified 29/193 (15%) patients with history of AIC prior to ibrutinib start. Of 12 patients requiring AIC therapy at ibrutinib start, 8 (67%) were able to discontinue or de-escalate AIC treatment, and no patient had worsening of their AIC after initiating ibrutinib. Eleven (6%) patients developed treatment-emergent AIC after a median of 59 (range, 6-319) days following the initiation of ibrutinib, 7 of whom (64%) were able to continue ibrutinib. Overall and event-free survival from time of ibrutinib start were not significantly different between patients with history of AIC and those with no history of AIC. Treatment-emergent AIC were seen exclusively in patients with unmutated IGHV and were associated with a shorter EFS. These results suggest a low rate of treatment-emergent AIC and improvement in patients with existing AIC.