Gangat, Naseema

Background Blast or accelerated phase myeloproliferative neoplasm (MPN-BP/AP) carries a dismal prognosis, with 3-year survival estimates of <5% (BCJ 2023;108). Patients with MPN-BP/AP were excluded from venetoclax (Ven) plus hypomethylating agent (HMA) clinical trials for acute myeloid leukemia (NEJM 2020;383:617). In the current retrospective study, we examined response patterns and long-term survival of newly-diagnosed MPN-BP/AP patients who received treatment with Ven+HMA, outside of clinical trials. Methods Newly-diagnosed patients with MPN-BP/AP treated with Ven+HMA at the Mayo Clinic, between March 2019 and May 2024, were retrospectively reviewed. Diagnostic criteria were according to the International Consensus Classification (Blood 2022;140:1200). Cytogenetic and molecular studies were performed by conventional karyotype and next-generation sequencing, respectively. All patients received at least one cycle of Ven+HMA (azacitidine 75 mg/m2 days 1-7 or decitabine 20 mg/m2 days 1-5). Response was assessed according to the 2022 European Leukemia Net criteria (Blood 2022;140:1345). Standard statistical analyses were performed using JMP Pro (Version 17.1.0). Results Patient characteristics 70 patients (median age 73 years, 59% males, 48% splenomegaly >14 cm, 4% isolated myeloid sarcoma) with newly-diagnosed MPN-BP (n=58) or AP (n=12) received Ven+HMA with (n=13) or without (n=57) concomitant JAK2 inhibitor. Driver mutation distribution was 69% JAK2, 21% CALR, 6% MPL, and 4% triple negative. Mutations involved ASXL1 (31%), TP53 (28%), TET2 (28%), RUNX1 (25%), SRSF2 (18%), IDH2 (12%), U2AF1 (11%), DNMT3A (9%), IDH1 (7%), and K/NRAS (7%). Karyotype was abnormal in 50 (76%) of 66 informative cases, of which 28 (56%) were complex (CK). Median TP53 mutation variant allele frequency (VAF) was 30% (8-96%) and all evaluable cases displayed CK (n=18). Response and Survival Complete remission (CR; 21%) or CR with incomplete count recovery (CRi; 19%) was documented in 28 (40%) patients with residual MPN in 18 (64%) patients. Median response duration was 5.5 months (1-60 months). After a median follow up of 7 months (1-62 months), 48 (69%) deaths, 13 relapses (46%), and 15 (21%) allogeneic stem cell transplants (ASCT; 12 in CR/CRi) were recorded. Median overall survival (OS) was 9 months and was superior with ASCT (median 22 vs. 8 months; p=0.01). In univariate analysis, transplant-censored survival was superior with CR/CRi (12 vs. 5 months; p<0.01) and IDH1 mutation (33 vs. 8 months; p=0.04) and inferior with CK (7 vs. 10 months; p=0.05), TP53 mutation (5 vs. 10 months; p<0.01), post polycythemia vera myelofibrosis (post-PV MF) (3 vs. 9 months; p=0.01), and splenomegaly >14 cm (5 vs. 16 months; p<0.01). Multivariable analysis confirmed the negative survival impact of not achieving CR/CRi (HR 3.8; p<0.01) and presence of TP53 mutation (HR 4.0; p<0.01); median survival (1/3-year survival rate) was 3 months (10%/0%) in TP53 mutated patients not achieving CR/CRi (n=11) vs. 27 months (65%/28%) in TP53 unmutated cases achieving CR/CRi (n=19) (p < 0.01). Median survival in patients with TP53 mutations or CK who achieved CR/CRi (n=7; 7 months) was inferior to that in treatment responders without TP53 mutations or CK (n=18; 23 months; p=0.01). CR/CRi rates in the presence vs. absence of TP53 mutations were 42% vs. 39% (p=0.80) and of CK (25% vs. 50% (p=0.04). Importantly, responses in the presence of TP53 mutations or CK were too short-lived to allow successful bridging to ASCT (median 2 vs. 9 months; p<0.01). Additional predictors of inferior treatment response included splenomegaly >14 cm (24% vs. 53%; p=0.01), and post-PV MF (0% vs. 46%; p<0.01) while SRSF2 (67% vs. 34%; p=0.04) and IDH2 mutations (75% vs. 35%; p=0.03) were associated with favorable response. In multivariable analysis, CK (p=0.04) and splenomegaly >14 cm (p=0.01) remained independent predictors of inferior response. The use of concomitant JAK2 inhibitor therapy did not impact treatment response (CR/CRi 46% vs. 39%; p=0.62) or survival (median 9 vs. 8 months; p=0.71). Conclusions TP53 mutations and CK undermine the value of Ven+HMA, with or without concomitant JAK2 inhibitor, in enabling successful bridging of newly-diagnosed MPN-BP/AP to ASCT. An alternative treatment approach is advised, in the particular scenario, while the observed 3-year survival rate of 28%, in treatment responders without TP53 mutations, is encouraging.

Background: Treatment of symptomatic splenomegaly in myelofibrosis (MF) was revolutionized by JAK2 inhibitors (JAKi), with ruxolitinib inducing a >35% spleen volume reduction in 42% of patients at 24 weeks (N Engl J Med 2012;366). However, the benefit is often transient with a median duration of spleen response of three years (N Engl J Med. 2011;365). Treatment modalities for the management of MF-associated splenomegaly resistant to JAKi treatment includes surgical resection and involved-field radiotherapy. In the current study, we describe our experience with the former. Methods: Study patients were retrospectively recruited from Mayo Clinic (USA) databases based on the following criteria: i) diagnosis according to the International Consensus Classification (Blood 2022;140:1200); ii) documentation of JAKi therapy exposure followed by splenectomy; iii) availability of information before and after splenectomy. Splenectomy was performed as an open (n=29) or laparoscopic (n=5) surgery. Conventional statistical methods were employed for data analysis (JMP Pro 17.0.0, SAS Institute, Cary, NC, USA). Results: A total of 34 patients (median age 62.5 years, range 43-79; 59% males) were identified with splenectomies performed between 2011-2024. Mutation distribution included JAK2 62%, CALR 26%, MPL 3%, and triple negative 9%. ASXL1 mutation was present in 37% and SRSF2 mutation was present in 26% of 19 informative cases. Karyotype was very high risk in 15% and unfavorable in 12%. Median time from diagnosis to JAKi initiation was 7.5 years (0-31). Majority (76%) were treated with one JAKi; 18% had been exposed to 2 different JAKi and 6% with three JAKi. JAKi included ruxolitinib (n=27), momelotinib (n=5), pacritinib (n=3), fedratinib (n=3), and BMS-911543 JAKi (n=5). Two patients underwent allogeneic stem cell transplant (ASCT) three and six months prior to splenectomy. Prior treatment included splenic radiation in 4 patients (median 0.6 years (0.2-1.2)). Pre-operative splenic embolization was performed in 4 patients on same day of splenectomy; one patient had embolization 10 months prior to splenectomy. Median interval from diagnosis to splenectomy was 10.3 years (1.0-35.4) and from initiation of JAKi therapy to splenectomy 1.8 years (0.03-12.1). Most patients had multiple indications for splenectomy including 76% with symptomatic splenomegaly, 50% with significant cytopenia, and 18% in preparation of ASCT. At time of splenectomy, median spleen size on imaging was 25.1 cm (14.7-36) and 55% were red cell transfusion-dependent (Revised international working group criteria). Postoperative complications were reported in 22 (65%) of patients. Major bleeding occurred in 11 (32%) (of which 7 (64%) required repeat surgical exploration) and thrombosis in 9 (26%); 5 patients experienced both major bleeding and thrombosis. Other complications included infection (n=5), renal injury (n=3), and pneumothorax (n=2). At a median follow up of 1.7 years (0.01-10.2) post-splenectomy, 12 (35%) ASCT were documented at a median of 2.3 years (1.5-26.4) post-procedure. Median post-splenectomy survival was 4.3 years (5-year survival 44%) and significantly longer in transplanted patients (median not reached vs 2.6 years; 5-year survival 65% vs 22%; p=0.02). Among patients without post-splenectomy ASCT (n=22), 12 (55%) deaths (including 2 from post-operative complications) and 3 leukemic transformations were recorded. Additionally, 13 of the 22 had transfusion-dependent anemia at splenectomy and subsequently 6 (46%) became transfusion-independent (TI) (≥12 weeks without transfusion) with median TI response duration of 2.8 years (0.3-7.1). In addition, among 5 non-transplanted patients with baseline thrombocytopenia (< 50 x 109/L (16-42 x 109/L)), 4 (80%) had platelet count > 100 x 109/L (median; 170 x 109/L, range: 119-279 x 109/L) within 3 months post-procedure. Conclusions: Splenectomy following JAKi-resistant or intolerant MF is associated with improvement of transfusion-dependent anemia (46% response), resolution of severe thrombocytopenia (80%), and may allow for successful transition to ASCT (35%). However, the procedure is associated with significant perioperative complications occurring in the majority of patients and underscores the need for future collaborative studies to develop selection criteria and evaluate alternative treatment modalities.

Introduction Oligomonocytic chronic myelomonocytic leukemia (OM-CMML) is defined by relative monocytosis ≥ 10% and an absolute monocyte count (AMC) between ≥ 0.5 and < 1.0 x109/L. The 5th ed WHO and International Consensus Classifications lowered the AMC threshold to ≥ 0.5 x10/9L for CMML diagnosis, thereby incorporating OM-CMML (Khoury, 2022; Arber, 2022). However, prior reports differ as to whether OM-CMML is a distinct CMML subtype. This multi-center study compares the clinical, molecular, and survival features of OM-CMML with myelodysplastic (MD, WBC < 13.0 x109/L) and myeloproliferative (MP, WBC ≥ 13.0 x109/L) CMML with an AMC ≥1.0. Methods After IRB approval, patients with CMML from Mayo Clinic (n = 400, 47%) and MD Anderson Cancer Center (n = 449, 53%) were identified retrospectively. Analyses considered clinical, laboratory, and next generation sequencing parameters at diagnosis or first referral (in chronic phase). Categorical variables were compared by Fisher exact or Pearson χ2 tests and continuous variables by Mann-Whitney U or ANOVA tests. Survival was assessed via the Kaplan-Meier method with outcomes censored at allogeneic stem cell transplantation (alloSCT). P < 0.05 was considered significant. Calculations used BlueSky Statistics (v10.3.1). Results A molecularly annotated cohort of 849 patients with CMML (median age 71 years, 32% female, 90% white, median follow up 31 months [mo]) was categorized as OM-CMML (n = 57, 7%), MD-CMML (n = 394, 46%), and MP-CMML (n = 391, 46%). There were no differences in age or sex across subtypes. No clinical differences were observed between OM-CMML and MD-CMML, with similar hematologic parameters, karyotype distributions, Mayo-Molecular (Patnaik, 2014) or CPSS-Molecular (Elena, 2016) risk stratifications, and rates of leukemic transformation (12% vs 12%, p = 0.98) and death (35% vs 43%, p = 0.27). Cases of OM-CMML had lower WBC counts (median 4.4 vs 24.7 x109/L, p < 0.0001), fewer circulating immature myeloid cells (23% vs 57%, p < 0.0001) and fewer marrow blasts (median 3% vs 4%, p = 0.0065) than MP-CMML. Comparatively, OM-CMML cases were overrepresented in the lower-risk groups of the CPSS-Molecular and Mayo-Molecular models (p < 0.0001). Leukemic transformation (12% vs 20%, p = 0.015) and death (35% vs 52%, p = 0.034) rates were higher in the MP-CMML cohort. Molecular profiles were similar between OM-CMML and MD-CMML, including median number of genes mutated (3 vs 3, p = 0.88). Frequencies of ASXL1 (39% vs 38%, p = 0.91), SRSF2 (48% vs 43%, p = 0.49), DNMT3A (7% vs 5%, p = 0.60), and SF3B1 (4% vs 7%, p = 0.48) mutations were also similar. TET2 mutation frequency was higher in OM-CMML (70% vs 55%, p = 0.031) and occurred in isolation more frequently (12% vs 6%, p = 0.048) compared to MD-CMML. Neither median number of TET2 mutations (1 vs 2, p = 0.87), nor TET2 variant allele fractions (41% vs 44%, p = 0.19) were different between the two groups. Compared to OM-CMML, patients with MP-CMML were more likely to have mutations in ASXL1 (39% vs 56%, p = 0.017), EZH2 (0% vs 9%, p = 0.019), JAK2 (0% vs 9%, p = 0.019), NRAS (7% vs 25%, p = 0.0024), and SETBP1 (2% vs 13%, p = 0.021). RAS family (CBL, BRAF, KRAS, NRAS, PTPN11; 25% vs 54%, p < 0.0001) and signaling pathway (CSF3R, FLT3, JAK2, SH2B3; 2% vs 14%, p = 0.0078) mutations were also more frequent whereas spliceosome mutations (SF3B1, SRSF2, U2AF1, ZRSR2; 61% vs 46%, p = 0.033) were less frequent in MP-CMML. The median (95% CI) overall survival (OS) of OM-CMML patients was 44 (38 - not reached) mo compared to 45 (34 - 60) mo in MD-CMML (p = 0.76) and 23 (20 - 29) mo in MP-CMML (p < 0.0032). Similar results were obtained when comparing the acute leukemia-free survival (LFS) of the OM-CMML (41 mo), MD-CMML (39 mo), and MP-CMML (19 mo) groups. At last follow up (medians 42 and 62 mo, respectively), 33% of evaluable OM-CMML patients had progressed to MD-CMML and 28% of MD-CMML patients had progressed to MP-CMML. No patient with OM-CMML progressed directly to MP-CMML. Conclusions These data show that OM-CMML and MD-CMML are a relatively homogenous subset of patients with similar clinicomolecular profiles and survival outcomes. Although OM-CMML patients are more likely to have TET2 mutations in comparison to other CMML subtypes, they have similar rates of disease progression as MD-CMML. This validates recent modifications to CMML classification criteria, in which OM-CMML cases are included as bona fide CMML.

Background A JAK2 mutation is detected in almost all patients with polycythemia vera (PV) and in ⁓50% of those with essential thrombocythemia (ET). The two diseases also share characteristic clinical and bone marrow morphological traits, suggesting they exist on a disease continuum rather than representing discrete entities. The objective of the current study was to compare clinical and genetic characteristics as well as long-term outcome between formally-defined PV vs. JAK2-mutated ET vs. JAK2-wild-type (WT) ET. Methods Study patients were retrospectively recruited from Mayo Clinic, USA databases (1967-2024). Diagnostic criteria were according to the International Consensus Classification (ICC; Blood 2022;140:1200). All study patients were fully annotated for JAK2, CALR, and MPL mutations while cytogenetic and additional next-generation sequencing (NGS)-derived mutation information was available in a subset of patients. Conventional statistical methods were employed for phenotypic comparisons and survival analysis. Results Among 2,010 study patients, 1,010 had PV, 617 (63%) JAK2-mutated ET, and 383 JAK2-WT ET (CALR 26%; MPL 3%; triple-negative 9%). Phenotypic comparisons revealed older age distribution in PV compared to JAK2-mutated ET (p=0.03) and the latter compared to JAK2-WT ET (p<0.01). Females were represented more in JAK2-mutated ET (69%), compared to both PV (49%; p<0.01) and JAK2-WT ET (54%; p<0.01). The frequencies of leukocytosis, palpable splenomegaly, constitutional symptoms, diabetes, hypertension, and abnormal karyotype were all significantly higher in PV, compared to both groups of ET, while JAK2-mutated compared to JAK2-WT ET displayed higher leukocyte count and incidence of hypertension. The incidences of arterial thrombosis at/prior to diagnosis were 14%, 16%, and 10% in PV, JAK2-mutated and WT ET, respectively (P=0.03), and venous thrombosis 14%, 13%, and 6% (p<0.01). After a median follow-up of 8.6 years, 632 (32%) deaths, 329 (16%) fibrotic progressions, 79 (4%) leukemic transformations, and 236 (12%) arterial and 202 (10%) venous thrombotic events were recorded, among all 2,010 study patients. Median overall survival was 19.3 years for PV vs. 17.8 years for JAK2-mutated ET vs. 23 years for JAK2-WT ET (p<0.01); however, the significant difference in favor of JAK2-WT ET was no longer apparent when analysis was adjusted for age and sex (p=0.15) and subsequently for other risk factors (p=0.86). All-inclusive multivariable analysis identified older age (p<0.01), male sex (p<0.01), higher leukocyte count (p<0.01), and arterial thrombosis history (p<0.01), but not the distinction between PV, JAK2-mutated, and JAK2-WT ET (p=0.9), to be independently associated with shortened survival. Leukemia-free survival was similar between PV and either JAK2-mutated (p=0.5) or JAK2-WT (p=0.1) ET. On the other hand, myelofibrosis-free survival was shorter in PV, compared to both JAK2-mutated (HR 1.8, 1.4-2.4; p<0.01) and JAK2-WT (HR 1.4. 1.0-1.8; p=0.03) ET. In multivariable analysis, older age (p<0.01), higher leukocyte count (p<0.01), PV vs. JAK2-mutated ET (HR 1.8; p<0.01), and JAK2-WT vs. JAK2-mutated ET (HR 1.6; p=0.01) were associated with a higher risk of fibrotic progression, with no difference noted between PV and JAK2-WT ET (p=0.4). Arterial thrombosis-free survival was similar between PV and JAK2-mutated ET (p=0.8). In univariate analysis, JAK2-WT ET vs. PV was associated with superior arterial thrombosis-free survival (p=0.02), but significance was lost when analysis was adjusted for arterial thrombosis history (p=0.1). Venous thrombosis-free survival favored JAK2-WT ET vs. PV (HR 0.3; p<0.01) and JAK2-mutated ET (HR 0.6; p=0.02) and the latter vs. PV (HR 0.6; p<0.01); the significant differences between PV and both groups of ET were sustained when analysis was adjusted for age, sex, and venous thrombosis history. Conclusions The current study highlights significant demographic and phenotypic differences between PV and JAK2-mutated ET. However, risk factor-adjusted overall, leukemia-free, and arterial thrombosis-free survival was not inferior in PV, compared to ET, regardless of the presence or absence of a JAK2 mutation in the latter. JAK2-WT ET was distinctly associated with a lower risk of venous thrombosis while JAK2-mutated ET appeared to be less vulnerable to fibrotic progression.

Background DISC-0974 is a monoclonal antibody that targets hemojuvelin, a co-receptor to BMP-SMAD signaling that stimulates hepcidin production. In healthy volunteers, DISC-0974 has been shown to be safe and induce dose-dependent decreases in serum hepcidin and corresponding increases in serum iron and absolute reticulocyte count (JCP 2024). Serum hepcidin level is abnormally elevated in myelofibrosis (MF) and is believed to contribute to iron-restricted erythropoiesis (AJH 2013:88:312). In an ongoing phase 1/2 study in MF (NCT05320198), DISC-0974 was well tolerated and associated with marked reduction in serum hepcidin levels and improvement in anemia (Blood 2023;142/DOI 10.1182). The current investigator-initiated laboratory correlative study examined the impact of mutations and baseline cytokine levels on anemia response to DISC-0974, in non-transfusion-dependent (nTD) patients with MF. Methods The current study was conducted under an institutional review board approved minimum risk protocol that allowed retrospective collection and analysis of data from Mayo Clinic patient records (Rochester, MN, USA). Study patients were selected from the aforementioned ongoing phase 1/2 study, based on availability of information on mutations and baseline cytokine levels. Definitions of nTD and anemia response criteria were according to the revised international working group (IWG) criteria (Blood 2024; in press): i) nTD was defined as the presence of ≤2 units transfused in the 12 weeks prior to enrollment; ii) a 12-week rolling average increase of hemoglobin by ≥1.5 or 1-1.4 g/dL is required for major and minor response, respectively. Mutation and cytokine analyses were performed according to institutional standard protocols; next-generation sequencing panel included 48 genes and cytokine panel 12 inflammatory cytokines. Results A total of 21 nTD patients with MF (median age 71 years; males 62%) were considered: 15 primary and 6 secondary. Driver mutation distribution was JAK2 52%, MPL 14%, and CALR-1 33%. DIPSS risk distribution was high (10%) and intermediate-2 (90%). Baseline median (range) values were 8.0 g/dL (range 7.1-9.5) for hemoglobin, 266 (41-1221) for serum ferritin, 79 (32-130) for serum iron, 32 (13-49) for transferrin saturation, and 59 (10-913) for serum erythropoietin. Karyotype was favorable (N=18) or unfavorable (N=2). Other mutations, included ASXL1 (N=5), SF3B1 (N=4), SRSF2 (N=1), U2AF1 (N=1), and “none of the above” (N=5). Elevated cytokines at baseline included TNF (90%), IL-18 (43%), IL-2R alpha (34%), IL-6 (24%), and MCP-1 (14%). DISC-0974 dose levels were 28 mg (N=2), 50 mg (N=7), 75 mg (N=7), and 100 mg (N=5). Twelve (60%) patients were on DISC-0974 monotherapy while 9 (40%) received concomitant ruxolitinib (N=5), pacritinib (N=1), or hydroxyurea (N=3). At median follow-up of 6 months (range 2-14), one (5%) patient has discontinued DISC-0974 for lack of response. Details on drug safety are summarized in another abstract (Gangat et al. ASH 2024). Per IWG criteria, 9 (43%) patients achieved major (MR) and 3 (14%) minor responses, resulting in an overall response (OR) rate of 57%. Two additional patients have surpassed the hemoglobin threshold for major response (≥1.5 g/dL) but have not yet met IWG criteria. OR and MR rates were higher in patients receiving DISC-0974 as monotherapy (OR 75% and MR 58%) vs. combined with JAK2 inhibitor or hydroxyurea (OR 33% and MR 22%) (p=0.05 for OR and 0.09 for MR), ASXL1 wild-type (N=15; OR 67% and MR 53%) vs. mutated (N=6; OR 33% and MR 17%) (p=0.16 for OR and 0.11 for MR), no ASXL1/SRSF2/U2AF1/SF3B1 (N=5; OR 100% and MR 80%) vs. at least one mutated (N=16; OR 44% and MR 31%) (p<0.01 for OR and 0.05 for MR). OR was also higher in the presence of elevated MCP-1 (p=0.05) or elevated IL-2R alpha (p=0.05) and MR in the presence of elevated IL-2R alpha (71% vs. 29%; p=0.06). Conclusions: The current study suggests that ASXL1 mutation might attenuate but not abrogate anemia response to DISC-0974, in MF. Elevated inflammatory cytokines in MF are often associated with increased hepcidin levels (AJH 2013:88:312) and this might explain their association with a higher response rate to DISC-0974, observed in the current study. Regardless, it is important to note that these observations represent preliminary data from a subset of patients from an ongoing clinical trial.

Background Absolute basophil count (ABC) might be increased in patients with myeloproliferative neoplasms and has been associated with poor prognosis in chronic myeloid leukemia (CML) and, possibly, primary myelofibrosis (PMF, Front. Oncol 2019;9:872). In a Mayo Clinic survey of 382 patients with BCR::ABL1-negative leukocytosis and ABC ≥0.09 x 109/L, 191 (50%) were associated with myeloid neoplasms, including 104 (27%) with CML, 23 (6%) essential thrombocythemia, 21 (6%) polycythemia vera (PV), and 18 (5%) PMF (AJH 2020;95:E216). Herein, we tapped into a well-characterized cohort of patients with PV, in order to describe the prevalence of basophilia, at specific ABC thresholds, and corresponding clinical, molecular, and prognostic correlates. Methods Study patients were retrospectively recruited from Mayo Clinic (USA) databases, after approval from IRB. Diagnostic criteria were according to the International Consensus Classification (Blood 2022;140:1200). Study inclusion criteria included the availability of information on ABC and absolute eosinophil count (AEC). Mayo Clinic institutional reference range for ABC was 0.01 to 0.08 x 109/L and for AEC 0.03 to 0.48 x 109/L. “Eosinophilia” was defined as an AEC of ≥0.6 x 109/L. Basophilia was evaluated both at an ABC of ≥0.1 x 109/L and ABC of ≥0.3 x 109/L, the latter representing 3 x the upper limit of the normal reference range. Cytogenetic information obtained within one year of diagnosis was available in 270 patients. Next-generation sequencing information collected before disease transformation was available in 99 patients. Conventional statistical methods were employed for comparisons of groups and survival analysis (JMP Pro 17.0.0 software SAS Institute, Cary, NC, USA). Results Information on ABC and AEC, obtained within one year of diagnosis, was available in 478 patients (median age 66 years; males 51%). Median values at presentation were 10.6 x 109/L for leukocyte count, 453 x 109/L platelet count, and 17.3 g/dL hemoglobin level. Presenting symptoms included palpable splenomegaly 24%, pruritus 31%, arterial thrombosis 12%, and venous thrombosis 17%. Median and range values for ABC and AEC were 0.12 x 109/L (0-3.2) and 0.27 x 109/L (0-6.5), respectively. ABC was ≥0.3 x 109/L in 80 (17%) patients and ≥0.1 x 109/L in 315 (66%). AEC was ≥0.6 x 109/L in 68 (14.6%) patients. ABC≥0.3 x 109/L was associated with AEC ≥0.6 x 109/L (p<0.01), leukocytosis (p<0.01), and palpable splenomegaly (p=0.02), but not platelet count, pruritus, smoking history, diabetes, or arterial or venous thrombosis; in multivariable analysis, the association with leukocytosis, but not that with splenomegaly, was confirmed. At a median follow-up of 5.7 years (range 0.03-32.8), 132 (28%) deaths, 17 (3.6%) leukemic and 40 (8.4%) fibrotic progressions were documented. Post-diagnosis events also included arterial (7%) and venous (9%) thrombosis. In univariate analysis, neither ABC (p=0.8, 0.7, and 0.96) nor AEC (p=0.7, 0.6, and 0.8), evaluated as continuous variables, affected overall (OS), leukemia-free (LFS), or myelofibrosis-free (MFFS) survival, respectively. Similarly, eosinophilia at AEC ≥0.6 x 109/L did not appear to influence OS (p=0.99), LFS (p=0.6) or MFFS (p=0.5). On the other hand, although basophilia at ABC≥0.3 x 109/L did not affect OS (p=0.27), it was significantly associated with inferior LFS (HR 6.5, 95% CI 2.3-18.0; p<0.01) and MFFS (HR 2.3, 95% CI 1.2-4.5; p=0.01); the corresponding p values for ABC≥0.1 x 109/L were 0.7, 0.1, and 0.17. The detrimental impact of basophilia (ABC≥0.3 x 109/L) on LFS was confirmed (P<0.01) with multivariable analysis that included other clinical variables, including leukocytosis (NS), platelet count (NS), basophil percentage (NS), age (p<0.01), and palpable splenomegaly (p<0.01). Results were similar during multivariable analysis for MFFS with palpable splenomegaly (p<0.01), ABC≥0.3 x 109/L (p=0.03), and age (p=0.05) sustaining independent predictive value. The number of informative cases was too small to evaluate prognostic interaction with mutations and karyotype. Conclusions: Basophilia in PV is associated with palpable splenomegaly and leukocytosis and independently predicts leukemic and myelofibrotic transformation. Additional studies are needed to confirm these observations and examine prognostic interaction with mutations and karyotype.

Background: Age-related clonal hematopoiesis (ARCH) is a precursor state to blood cancers and is associated with epigenetic age acceleration (EpiAgeAccel) (Aging Cell, 2021). While ARCH in combination with AgeAccel has the highest risk for all cause mortality and cardiovascular disease, not much is known about context-relevant clonal hematopoiesis (CRCH) - CH occurring in the context of prior chemo/radiation, bone marrow failure and germline predisposition syndromes. CRCH has a unique mutational signature enriched in genes in DNA damage response and repair (TP53 and PPM1D). To answer this question, we assessed EpiAge in a prospective cohort of patients with both ARCH and CRCH. Methods: Patients were prospectively recruited for CH and EpiAge assessment from the Mayo Clinic CH clinic between 2022 and 2024. Demographic and clinical data including chronologic age, BMI, sex, blood counts, and medical history were recorded at the time of enrollment. CH status was determined using error corrected sequencing on peripheral blood (PB) DNA. All somatic variants with a variant allele frequency (VAF) ≥0.5% were considered as CH. For EpiAge analysis PB DNA was analyzed using the Illumina MethylationEPIC array. The resulting beta values were used to obtain epigenetic age estimates using Horvath's clock (Genome Biol., 2013), Hannum's Clock (Mol Cell., 2013), PhenoAge (Aging, 2018), DunedinPACE (eLife, 2022), and predicted telomere length (Aging, 2019). Results: 106 (62%) of 170 patients assessed were found to have CH, with the most frequent mutations being TET2 (19%), PPM1D (17%), DNMT3A (16%), ASXL1 (9%), and TP53 (6%); median VAF 9.5%. Except for a higher median chronologic age (68 vs 60 years, p<0.001) in the CH group, baseline characteristics including BMI, comorbidities, baseline blood counts, sex and tobacco use history were similar between the two groups. The CH group demonstrated significant EpiAgeAccel by all three clocks: Horvath (p=0.001), Hannum (p<0.001), and PhenoAge (p<0.001); with an increase in biological age of 4.9 years (95% CI 2-7.7) by Horvath clock, 4.8 years (95% CI 2.2-7.5) by Hannum clock, and 7 years (95% CI 2.9-10.5) by PhenoAge, after adjusting for chronologic age, sex, smoking status, and cancer history. CH was also associated with increased DunedinPACE of aging by 0.13 biological year per chronologic year (bioyear/chronoyear) (95% CI 0.06-0.2, p<0.001), and shortened telomere lengths by 0.24kb (95% CI 0.11-0.35, p<0.001) after adjusting for chronologic age and excluding patients with telomere biology disorders. CH patients were then further classified into ARCH-63 (59%) and CRCH-43 (41%). While the median chronological age (69 vs 67 years) was similar between the 2 groups, CRCH patients had lower Hgb [10.9g/dL vs. 13g/dL (p=0.0001)] , lower platelet [146x109/L vs. 192x109/L (p=0.0132)] and lower WBC [4.4x109/L vs. 5.2x109/L (p=0.0345)]. The median BMI, comorbidities, and tobacco use history were similar between the 2 groups. The 3 most common ARCH mutations were TET2 (20%), DNMT3A (19%), and ASXL1 (14%), while, PPM1D (27%), TET2 (18%), and DNMT3A (14%) were frequent in CRCH. There was no significant difference found in median EpiAge via Horvath (68 vs 67.5years p=0.2826), Hannum (65 vs 66 years p=0.9333), or PhenoAge (55 vs 56 years p=0.618) between ARCH and CRCH. However, DunedinPACE of aging was higher in CRCH (1.27 vs 1.18 bioyear/chronoyear p=0.0148) and median telomere length was shorter in CRCH (6.35 vs 6.49kb p=0.0247), in comparison to ARCH. Multivariable regression analysis was completed for both ARCH and CRCH compared to non-CH, adjusting for chronologic age, smoking status, and male sex. While both ARCH and CRCH demonstrated EpiAgeAccel via Horvath(5.8years p=0.0001, 3.4 years p=0.051), Hannum(5years p=0.001, 4.5 years p=0.007), and PhenoAge (6.7years p=0.002, 7.6 years p=0.002) clocks, CRCH more than doubled DunedinPACE (0.2 bioyear/chronoyear, p<0.001) of aging compared to ARCH (0.08 bioyear/chronoyear, p=0.026). CRCH also demonstrated double the decrease in telomere length (0.34kb, p<0.001) compared to ARCH (0.17kb, p=0.015). Conclusion: Our prospective CH cohort study validates the association between CH and EpiAgeAccel using several different methylation clocks and for the first time, highlights increased pace of aging and shorter telomere lengths in CRCH versus ARCH. Correlations with cardiovascular disease and mortality outcomes are ongoing.

Abstract This phase 2 trial assessed high-dose IV ascorbic acid in TET2 mutant clonal cytopenia. Eight of 10 patients were eligible for response assessment, with no responses at week 20 by International Working Group Myelodysplasia Syndromes/Neoplasms criteria. This trial was registered at www.clinicaltrials.gov as #NCT03418038.