Risk Of Therapy-related Myeloid Neoplasms Research Articles

Sex-Based Differences in Risk of Therapy-Related Myeloid Neoplasms.

Therapy-related myeloid neoplasm (t-MN) is a life-threatening complication of autologous peripheral blood stem cell (PBSC) transplantation for non-Hodgkin lymphoma (NHL). Previous studies report an association between clonal hematopoiesis (CH) in PBSC and risk of t-MN, but small samples precluded examination of risk within specific subpopulations. Targeted DNA sequencing was performed to identify CH mutations in PBSC from a retrospective cohort of 984 patients with NHL (median age at transplant, 57 years; range, 18-78). Fine-Gray proportional subdistribution hazard regression models estimated association between number of CH mutations and t-MN, adjusting for demographic, clinical, and therapeutic variables. Secondary analyses evaluated the association between CH and t-MN among males and females. CH was identified in PBSC from 366 patients (37.2%). t-MN developed in 60 patients after a median follow-up of 5 years. Presence of ≥2 mutations conferred increased t-MN risk (adjusted hazard ratio [aHR], 2.10; 95% CI [1.08 to 4.11]; P = .029). CH was associated with increased t-MN risk among males (aHR, 1.83 [95% CI, 1.01 to 3.31]) but not females (aHR, 0.56 [95% CI, 0.15 to 2.09]). Although the prevalence and type of CH mutations in PBSC were comparable, the 8-year cumulative incidence of t-MN was higher among males vs. females with CH (12.4% v 3.6%) but was similar between males and females without CH (4.9% v 3.9%). Expansion of CH clones from PBSC to t-MN was seen only among males. presence of CH mutations in PBSC confers increased risk of t-MN after autologous transplantation in male but not female patients with NHL. Factors underlying sex-based differences in risk of CH progression to t-MN merit further investigation.

Risk of secondary leukemias in patients with germline PALB2 pathogenic variants after chemotherapy exposure.

10598 Background: Pathogenic variants in germline cancer-predisposing genes (e.g. BRCA1/2, PALB2) confer an increased risk for solid tumors but not de novomyeloid malignancies. Many of these genes are related to DNA repair pathways. It is not known whether exposure to genotoxic therapy increases the risk of secondary hematologic malignancies. Here, we report the incidence of hematologic malignancy after a solid tumor diagnosis among patients with a germline PALB2 pathogenic variant. Methods: Patients were identified at the Massachusetts General Hospital Center for Cancer Risk Assessment among individuals seeking counseling and/or testing for hereditary cancer risk genes. Analyses were conducted using R version 4.2.2 “tidyverse” and “gtsummary” packages. Results: Of the 176 charts reviewed, 102 (57%) had a history of malignancy, of which 68 (66%) received genotoxic chemotherapy. The median follow-up after chemotherapy was 59mo (IQR =17,109). The most common malignancy and chemotherapy were breast cancer (n=76, 75%) and doxorubicin, cyclophosphamide, and paclitaxel (n = 21, 31%). We compared patient outcomes by receipt of chemotherapy or not. There was no difference in race, age at cancer diagnosis, surgery rate, treatment with hormone therapy, or secondary malignancy between the two groups (p > 0.05). There was higher incidence of radiation treatment in those receiving genotoxic therapy compared to those who did not (65% vs 41%, p = 0.024), but no difference Gray or in follow up after radiation. Mortality in the genotoxic therapy group was 15% (n=10) vs. 9% (n=2) in the no genotoxic therapy group (p =0.33). Two subjects developed a hematologic malignancy (one case each of CLL and CML); both had prior chemotherapy and radiation exposure (Table). Conclusions: Cancer survivors with a germline PALB2 pathogenic variant and subsequent exposure to genotoxic therapy appear to have low risk of secondary hematologic malignancy. Although two subjects in the chemotherapy group developed leukemias, given the cases seen it is unlikely that these relate to the treatment exposure. Given the small sample size and retrospective nature of this study, more investigation is necessary to fully quantify the risk of therapy-related myeloid neoplasm in patients with germline PALB2 pathogenic variants. [Table: see text]

Dynamics of clonal hematopoiesis under DNA-damaging treatment in patients with ovarian cancer

Clonal hematopoiesis (CH) driven by mutations in the DNA damage response (DDR) pathway is frequent in patients with cancer and is associated with a higher risk of therapy-related myeloid neoplasms (t-MNs). Here, we analyzed 423 serial whole blood and plasma samples from 103 patients with relapsed high-grade ovarian cancer receiving carboplatin, poly(ADP-ribose) polymerase inhibitor (PARPi) and heat shock protein 90 inhibitor (HSP90i) treatment within the phase II EUDARIO trial using error-corrected sequencing of 72 genes. DDR-driven CH was detected in 35% of patients and was associated with longer duration of prior PARPi treatment. TP53- and PPM1D-mutated clones exhibited substantially higher clonal expansion rates than DNMT3A- or TET2-mutated clones during treatment. Expansion of DDR clones correlated with HSP90i exposure across the three study arms and was partially abrogated by the presence of germline mutations related to homologous recombination deficiency. Single-cell DNA sequencing of selected samples revealed clonal exclusivity of DDR mutations, and identified DDR-mutated clones as the origin of t-MN in two investigated cases. Together, these results provide unique insights into the architecture and the preferential selection of DDR-mutated hematopoietic clones under intense DNA-damaging treatment. Specifically, PARPi and HSP90i therapies pose an independent risk for the expansion of DDR-CH in a dose-dependent manner.

The crossroads of cancer therapies and clonal hematopoiesis

The intricate interplay between Clonal Hematopoiesis (CH) and the repercussions of cancer therapies has garnered significant research focus in recent years. Previously perceived as an age-related phenomenon, CH is now closely linked to inflammation (“Inflammaging”) and cancer, impacting leukemogenesis, cancer progression, and treatment responses. This review explores the complex interplay between CH and diverse cancer therapies, including chemotherapy, targeted treatments, radiation, stem cell transplants, CAR-T cell therapy, and immunotherapy, like immune checkpoint inhibitors. Notably, knowledge about post-chemotherapy CH mutation/acquisition has evolved from a de novo incident to more of a clonal selection process. Chemotherapy and radiation exposure, whether therapeutic or environmental, increases CH risk, particularly in genes like TP53 and PPM1D. Environmental toxins, especially in high-risk environments like post-disaster sites or space exploration, are associated with CH. CH affects clinical outcomes in stem cell transplant scenarios, including engraftment, survival, and t-MN development. The presence of CH also alters CAR-T cell therapy responses and impacts the efficacy and toxicity of immunotherapies. Furthermore, specific mutations like DNMT3A and TET2 thrive under inflammatory stress, influencing therapy outcomes and justifying the ongoing tailored interventions in clinical trials. This review underscores the critical need to integrate CH analysis into personalized medicine, enhancing risk assessments and refining treatment strategies. As we progress, multidisciplinary collaboration and comprehensive studies are imperative. Understanding CH's impact, especially concerning genotoxic stressors, will inform screening, surveillance, and early detection strategies, decreasing the risk of therapy-related myeloid neoplasms and revolutionizing cancer treatment paradigms.

Abstract 5747: Chemotherapy-related mutational signatures reveal the origins of therapy-related myeloid neoplasms

Abstract Patients treated with chemotherapy (CT) and/or autologous stem-cell transplantation (ASCT) are at risk for therapy-related myeloid neoplasms (tMN). Certain cytotoxic agents introduce mutations within distinct trinucleotide contexts resulting in a unique barcode for each exposed cell. We leveraged mutational signatures to investigate the role of CT in the genomic landscape of tMN with respect to antecedent clonal hematopoiesis (CH). We analyzed 32 tMN and 2 tALL from 33 patients and interrogated for copy number abnormalities (CNA), structural variants (SV), single nucleotide variants (SNV), and mutational signatures. For 7 patients with tMN post-melphalan/ASCT, we investigated antecedent CH using targeted sequencing on pre-melphalan samples, including autograft products. CH variants that became clonal in tumor were seen in 5/7 pre-melphalan/ASCT samples (TP53, RUNX1, NCOR1, NF1, CREBBP, DNMT3A, and PPM1D). Complex SV were seen in 7 tMNs; including chromothripsis in 6 (19.4%). In 4 cases, chromothripsis involved chromosome 19 with hyper-amplification of the SMARCA4 locus (≥5 copies). Mutational signature analysis revealed 6 known single base substitution (SBS) signatures in tMN including melphalan (SBS-MM1) and platinum signatures (SBS31, SBS35, and E-SBS37). TMNs with CT signatures had higher mutation burden than those without (p = 0.004). 17 patients with exposure to agents other than melphalan/platinum did not have increased mutational burden with respect to de novo AML (TCGA; NEJM, 2013). All patients with prior platinum exposure (including tALL, n=9) had platinum SBS signatures while only 2 of 7 patients with prior melphalan/ASCT had a melphalan signature (SBS-MM1). Detection of CT signatures in bulk sequencing relies on one cell, with its barcode of mutations, to expand to clonal dominance. Given pre-existent CH, including in 3/3 autograft products, absence of a CT signature despite melphalan exposure implies progression by a clone that escaped CT exposure with stem-cell collection and reinfusion. Conversely, all platinum-exposed tAML had signature evidence of exposure confirming existence of CH prior to exposure and supporting post-CT single-cell expansion. TMNs from 3 patients exposed to sequential platinum and melphalan/ASCT had platinum but not melphalan signatures confirming single-cell expansion of the pre-tMN CH clone post-platinum but with escape from exposure to melphalan via leukapheresis. Chromothripsis events bore only non-duplicated CT-induced mutations, indicative of acquisition prior to, and not directly caused by, CT exposure. These disparities suggest that ASCT provides a mechanism for CH clones to escape CT and re-engraft with transplant. Coupled with driver events accrued prior to CT, this suggest that CT-induced mutagenesis may be less important than other factors, such as CT-induced immunosuppression, in the expansion of pre-TMN CH clones. Citation Format: Benjamin Diamond, Bachisio Ziccheddu, Eileen M. Boyle, Kylee Maclachlan, Justin Taylor, Justin M. Watts, Sydney X. Lu, David G. Coffey, Niccolo Bolli, Elli Papaemmanuil, Kelly Bolton, Jae H. Park, Heather Landau, Karuna Ganesh, Mikkael A. Sekeres, Stephen Nimer, David J. Chung, Caleb H. Ho, Mikhail Roshal, Alexander Lesokhin, Gareth Morgan, Ola Landgren, Francesco Maura. Chemotherapy-related mutational signatures reveal the origins of therapy-related myeloid neoplasms [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 5747.

Clinical Significance of Clonal Hematopoiesis in the Setting of Autologous Stem Cell Transplantation for Lymphoma

Clinical Significance of Clonal Hematopoiesis in the Setting of Autologous Stem Cell Transplantation for Lymphoma

Chemotherapy-Related Mutational Signatures Reveal the Origins of Therapy-Related Myeloid Neoplasms

Chemotherapy-Related Mutational Signatures Reveal the Origins of Therapy-Related Myeloid Neoplasms

Mutant PPM1D and TP53 populate the hematopoietic compartment after peptide receptor radionuclide therapy (PRRT) exposure.

10605 Background: Mutations in TP53 and PPM1D are putative drivers associated with therapy related-myeloid neoplasm (T-MN) and have been identified in pre-treatment blood samples obtained at the time of primary malignancy, predating clinically evident T-MN. Genomic analysis of patients(pts) who undergo leukemogenic therapies will help understand T-MN biology and devise risk mitigation strategies. PRRT (Lu 177) for neuroendocrine tumors is associated with enhanced risk of T-MNs. The mechanism for T-MN induced by PRRT is largely elusive due to the novelty of this drug. Methods: We analyzed initial (n=13) and serial blood samples (n=4) prior to and following PRRT for clonal mutations in order to elucidate the role of PRRT in exerting selective pressures on HSCs. Genomic DNA was analyzed using a targeted myeloid 100-gene panel and a variant allele frequency (VAF) cutoff 1% was used to call clonal hematopoiesis (CH). Results: Fifty-four percent pts had CH, despite relatively young age of cohort (median age 58 years, range 41-75) and minimal chemo-radiotherapy exposure; baseline characteristics and molecular profile of cohort is published [Singh et al. Blood 2020; 136 (Supplement 1): 35–36]. Serial sample analysis in 4 pts (Table 1) demonstrates that PRRT exposure is associated with clonal evolution and accompanying cytopenias in 75% (3/4) pts. Pt-1 (age 67) with normal baseline hemogram developed persistent cytopenias after PRRT, accompanied by emergence and expansion of mutant- PPM1D (m PPM1D; VAF 20%). These data suggest that cytopenias result from repopulation of the HSC compartment by m PPM1D cells. In Pts 2 and 3 (age 74 and 75), we note expansion of m TP53 and m PPM1D clones respectively, also associated with the development of cytopenias. Pt-4 was younger (age 59) and developed no cytopenias. Exposure to PRRT was associated with loss of m TET2 and m DDX41, possibly due to lack of clonal fitness of m TET2/DDX41 clones and the relatively young HSC microenvironment. Conclusions: We conclude that mutations in PPM1D and TP53 are clinically relevant, contribute to clonal cytopenias and may increase risk of future T-MN. The temporal association of m TP53 and m PPM1D expansion with PRRT exposure in our analysis suggests selection of these clones in response to PRRT-induced stress, outcompeting wild type and less therapy-resistant HSCs. Our study along with others will inform future efforts to strategize methods of surveillance and early detection for clonality assessment and chemoprevention, to reduce adverse effects of leukemogenic therapies.[Table: see text]

Autologous stem cell transplantation finds a place in acute promyelocytic leukaemia.

Autologous stem cell transplantation finds a place in acute promyelocytic leukaemia.

Clonal Hematopoiesis Is Associated with Increased Risk for Therapy-Related Myeloid Neoplasms in Chronic Lymphocytic Leukemia Patients Treated with Chemo(immuno)Therapy

Clonal haematopoiesis of indeterminate potential (CHIP) is defined by the detection of somatic mutations in genes recurrently mutated in myeloid neoplasms (MNs), in the blood of healthy individuals with normal blood values and lack of morphological evidence of MN. Recent studies have highlighted the potential association between CHIP and the development of MN, in particular therapy-related MN (t-MN) in patients with lymphoma treated with chemotherapy and/or autologous stem-cell transplantation. In the present study, we investigated whether the presence of CHIP is associated with a higher risk for the development of t-MN in patients with chronic lymphocytic leukemia (CLL) treated with chemo(immuno)therapy, including fludarabine and cyclophosphamide combinations. To this end, we studied 9 patients with CLL who developed a t-MN [acute myeloid leukemia (AML): n=6, myelodysplastic syndrome (MDS): n=3] after the administration of chemo(immuno)therapy (FCR: n=7, other, n=2), with available samples collected both before CLL treatment and at diagnosis of t-MN. The median interval between the two samples was 26 months (range: 9-38months). NGS was performed on DNA extracted from bone marrow mononuclear cells (MNCs) at t-MN diagnosis, using the Trusight Myeloid Sequencing Panel (n=4) and the Archer VariantPlex Myeloid kit (n=5). Backtracking of the variants detected at the t-MN phase was performed by NGS of DNA extracted from peripheral blood MNCs (n=8) or CD19+ selected cells (n=1) in the samples from the CLL phase. In case no variants were detected in the t-MN phase, targeted digital droplet PCR (ddPCR) was also performed in paired CLL samples to confirm the presence of the variants. Moreover, using the Trusight Myeloid Sequencing Panel, we evaluated the prevalence of CHIP in a population cohort of 285 patients with CLL at the time of diagnosis. The variant allele frequency (VAF) cut-off for the detection of the variants was set to 5%. Variants were reported if meeting the following criteria: (i) located within an exonic or splicing region; (ii) be non-synonymous; (iii) not listed in the gnomAD database, if not also recurrently reported in Cosmic v85. Overall, 16 variants were detected in 7/9 cases analyzed at the time of t-MN [NRAS (n=4), DNMT3A (n=3), TET2 (n=2), EH2 (n=2), TP53 (n=2), KRAS (n=1), U2AF1 (n=1) and SF3B1 (n=1)], while no variants were detected in 2 t-MN samples. In 6/7 cases with detectable variants at t-MN diagnosis, the same variants were present at the CLL phase with either lower (n=4) or similar (n=2) VAF. Overall, CHIP was detectable in 6/9 (66.7%) CLL patients who later developed a t-MN. Among the untreated CLL patients, 45 CHIP-related variants were detected in 35/285 cases (12%) as 7 patients harbored more than one variant. The median VAF was 12.7% (5.1-58.6%) with 27/45 (60%) having a VAF<20%. The affected genes were: DNMT3A (n=9), ASXL1 (n=8), KRAS (n=7), BCOR (n=3), NRAS (n=3), TET2 (n=2), U2AF1 (n=2), PTPN11 (n=2), HRAS (n=2), JAK2 (n=1), CBL (n=1), CALR (n=1), IDH2 (n=1), MPL (n=1), PHF6 (n=1) and ETV6 (n=1). CHIP was not associated with advanced age. Subgroup-analysis amongst CHIP-patients revealed: (i) enrichment of additional CHIP-related variants, male gender and younger age in carriers of ASXL1 variants and (p=0.1, p=0.008 and p=0.06; (ii) a bias towards female gender in patients with DNMT3A variants (p=0.008). The difference in the prevalence of CHIP between patients with CLL developing a t-MN (6/7) and those in the untreated cohort (35/285) was statistically significant (p<0.001). In conclusion, CHIP is significantly enriched in patients with CLL developing t-MNs after the administration of chemo(immuno)therapy, with obvious therapeutic implications especially in the era of targeted agents. The significance of CHIP in CLL should be further evaluated in the context of large clinical studies. MTV and TP contributed equally. EF and PB contributed equally. Disclosures Voso: Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Scarfo:Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AstraZeneca: Honoraria; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees. Ghia:ArQule: Consultancy, Honoraria; BeiGene: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Acerta/AstraZeneca: Consultancy, Honoraria; Adaptive, Dynamo: Consultancy, Honoraria; Novartis: Research Funding; Janssen: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Sunesis: Consultancy, Honoraria, Research Funding; MEI: Consultancy, Honoraria; Lilly: Consultancy, Honoraria; Celgene/Juno: Consultancy, Honoraria. Stamatopoulos:AstraZeneca: Honoraria; Janssen, Gilead, Abbvie: Honoraria, Research Funding.

Abstract LB-304: Oncologic therapy for solid tumors alters the risk of clonal hematopoiesis

Abstract Solid tumor patients often suffer from cytopenias and are at risk for therapy-related myeloid neoplasms (tMN). Somatic mutations in leukemia-associated genes can occur in normal healthy individuals, referred to as clonal hematopoiesis (CH). CH is associated with cytopenias, risk of leukemia and cardiovascular disease. We and others have shown that CH is frequent in cancer patients. Characterization of the relationship between exposure to specific oncologic regimens and CH and how these relate to cytopenias and tMN risk would inform treatment decisions and tMN prevention strategies. To determine the relationship between CH and oncologic therapy we interrogated CH in a cohort of 9045 solid tumor patients. Subjects were sequenced using a targeted panel of cancer-associated mutations used to screen tumor samples against a blood control sample. Mutation detection was performed on blood-derived sequencing data using the matched tumor as a comparator and accounted for background sequencing error rates. CH was identified in 23% of patients. In multivariate regression analyses adjusted by age, CH was more often found in current smokers (OR=1.20, 95%CI=1.07-1.35, p<0.001) and less often found in Asians compared to Whites (OR=0.72, 95%CI=0.56-0.89, p<0.001). Smoking was associated with CH mutations in ASXL1 (OR=3.75, 95%CI=2.73-5.17, p<0.001). There was a higher proportion of patients with CH among those who had received chemotherapy (OR=1.14, 95%CI=1.02-1.26, p=0.02) and those who had received external beam radiation therapy (OR=1.45, 95%CI=1.28-1.63, p<0.001) prior to blood collection. Mutations in the DNA repair/cell cycle pathway (including TP53, PPM1D and CHEK2) were more common among patients who received chemotherapy and radiation therapy prior to IMPACT testing compared to those who were treatment naïve (p<0.001). Exposure to prior cytotoxic chemotherapy (OR=1.20, 95%CI=1.02-1.30; p=0.007) and radiation therapy (OR=1.6, 95%CI=1.4-1.9, p<0.001) was associated with having CH while exposure to immunotherapy and targeted therapy was not. Increasing cumulative dose of chemotherapy overall and cytotoxic therapy was associated with a higher likelihood of CH (p=0.015 and p=0.007 respectively). There was evidence of specific gene, treatment and dosage effects. To further examine the relationship between oncologic therapy and clonal evolution of CH, we collected 375 sequential samples at least 18 months apart. T mean change in VAF of CH mutations per year was found to increase by 0.17% in patients who did not receive further therapy during the follow-up time and 0.49% in those who were exposed to cytotoxic chemotherapy. A subset of patients with CH were consented to germline testing for cancer predisposition genes (N=6368). We observe a higher rate of CH among patients with a germline mutation in the cell cycle/DNA repair pathway (i.e. TP53) when compared to patients without germline mutations (OR=3.7, 95% CI: 1.35-9.35, p-value=0.01). CH is frequent in solid tumor patients and can be reliably detected when a matched tumor normal targeted gene sequencing approach is performed. Beyond age, CH is strongly associated with race, smoking and importantly prior exposure to oncologic therapy with evidence of specific treatment effects. Screening of CH in cancer cohorts is critical to the development of future clinical guidelines and risk-adapted prevention strategies for tMN. Note: This abstract was not presented at the meeting. Citation Format: Kelly Bolton, Ryan Ptashkin, Lior Braunstein, Teng Gao, Sean M. Devlin, Daniel Kelly, Catherine Coombs, Minal Patel, Matahi Moarii, Elsa Bernard, Antonin Berthon, Laura Boucai, Dominik Glodzik, Axel Martin, Zsofia Stadler, Michael Walsh, Diana Mandelker, Akshar Patel, Jessica Schulman, Gunes Gundem, Aijazuddin Syed, Maria Arcila, David B. Solit, Mark E. Robson, Marc Ladanyi, Choonsik Lee, John Philip, Dean Bajorin, Montserrat Garcia-Closas, Stuart Gardos, David Hyman, Martin Tallman, Mariko Yabe, Kenneth Offit, Howard Scher, Virginia Klimek, Luis Diaz, Nilanjan Chatterjee, Michael F. Berger, Lindsay Morton, Ross Levine, Ahmet Zehir, Elli Papaemmanuil. Oncologic therapy for solid tumors alters the risk of clonal hematopoiesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-304.

Clinical Impact of Clonal Hematopoiesis after Autologous Stem Cell Transplantation for Lymphoma: A National Population-Based Cohort Study

▪Background:Somatic driver mutations in hematopoietic cells may lead to clonal hematopoiesis of indeterminate potential (CHIP). In patients with lymphoma CHIP has been associated with increased risk of therapy-related myeloid neoplasms (tMN) and inferior survival after autologous stem cell transplantation as demonstrated in a large single center study and in a case-control study (Gibson CJ et al., JCO 2017 and Berger G et al., Blood 2018). Here, we investigated the clinical impact of clonal hematopoiesis in a nation-wide population-based cohort of Danish lymphoma patients undergoing autologous transplant with prospective data from four national patient registries.Methods:Patients with lymphoma who had undergone leukapheresis at all danish transplant centers from 2000 to 2012 were identified. DNA and RNA was extracted from mobilized peripheral blood products. Targeted sequencing of all samples was performed using an Illumina TruSeq Custom Amplicon panel (Illumina, San Diego, CA, USA) designed to cover >95% of mutations associated with CHIP (ASXL1, ASXL2, BCOR, BRCC3, CBL, CREBBP, DNMT3A, ETV6, GNB1, IDH1, IDH2, JAK2, KRAS, NRAS, PPM1D, RAD21, SF3B1, SRSF2, TET2, TP53). To allow detection of low-level mutations and secure variant calling, unique molecular identifiers (UMI's) were used. Filtering of variants was done by stringent criteria consistent with earlier studies. Assessment of mutations was performed blinded to the patients' clinical data.Prospective clinical patient data was obtained for all patients from four national registries, including the Danish Lymphoma Registry (diagnosis, involvement, lymphoma treatment, relapse and death), the Danish National Patient Registry (hospital admission diagnoses and treatments), the Danish Cancer Registry (primary and secondary cancer diagnoses) and the Danish Pathology Database (histopathological examinations and diagnoses), respectively.Results:Samples from 574 patients were included. The median age was 55.5 years (IQR: 45.3 - 62.2) and the median follow-up time for survivors was 9.2 years (IQR: 7.1 - 11.2). The lymphoma subtypes were typical of patients selected for autologous transplantation; diffuse large B-cell lymphoma (191 pts), follicular lymphoma (102 pts), mantle cell lymphoma (88 pts), Hodgkin's lymphoma (80 pts), peripheral T-cell lymphoma (77 pts) and other histologies (36 pts). Of the 574 patients analyzed, 191 (33.3%) of the patients had somatic mutations meeting CHIP criteria (total mutations called=210). The most commonly mutated genes were DNMT3A (n=59, 28%), TET2 (n=48, 23%), PPM1D (n=34, 16%), ASXL1 (n=21, 10%) and TP53 (n=18, 8%). As expected CHIP mutations were more frequent in patients above 60 years (p=0.002). Prevalence of CHIP was associated with an inferior overall survival (p=0.004) and event-free survival (p=0.03). It was also associated with increased risk of biopsy-confirmed tMN (p=0.03) and higher probability of receiving blood transfusions after autologous transplant (p=0.027).Especially patients with mutations in DNA damage response genes PPM1D and TP53 (found in 48 pts, 8.3%) had a significantly increased risk of adverse outcomes. Both overall survival and event-free survival were significantly poorer with the presence of DNA damage pathway mutations (p<0.0001 for both, Figure 1A), as well as risk of tMN (p=0.01). In addition, PPM1D/TP53 mutations were associated with increased rates of any secondary cancer (p=0.004), including non-hematological cancer, and hospital admissions with severe infections (p=0.01, Figure 1B).The impact of low-level mutations and statistical modelling of interactions between parallel outcomes will be presented at the meeting.Conclusion:To our knowledge this is the first population-based study of clonal hematopoiesis in patients with lymphoma. We find that CHIP and particularly mutations in DNA damage response genes (PPM1D/TP53) are associated with increased mortality, which confirms findings from single center studies. These data support the evaluation of CHIP for risk assessment in lymphoma patients before high-dose chemotherapy. Our study also identifies increased rates of several clinically relevant adverse outcomes (severe infections, blood transfusions and secondary cancers) in lymphoma patients with clonal hematopoiesis. DisclosuresGrønbæk:Janssen Pharma: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Otsuka Pharma: Membership on an entity's Board of Directors or advisory committees.

Age-related clonal hematopoiesis: implications for hematopoietic stem cell transplantation.

Over the past decade, advances in hematopoietic stem cell transplantation (HSCT) have enabled older individuals to undergo the procedure as well as to serve as donors. Recently, aging has been linked with the development of age-related clonal hematopoiesis (ARCH), defined as the gradual clonal expansion of hematopoietic stem and progenitor cells (HSPC) carrying recurrent disruptive genetic variants in individuals without a diagnosis of hematologic malignancy. Here we will review the implications of ARCH in the context of HSCT. ARCH is highly prevalent in the general population and commonly involves genes that are recurrently mutated in hematologic malignancies. Nevertheless, the vast majority of individuals with ARCH will not develop overt hematologic disease in their lifetime. The presence of ARCH may increase the risk of therapy-related myeloid neoplasms (t-MN) in individuals undergoing autologous HSCT. In the setting of allogeneic HSCT, ARCH present in the donor may contribute to adverse outcomes such as unexplained cytopenias posttransplant and donor cell leukemia. A better understanding of the hematopoietic milieu of HSCT recipients and of the importance of ARCH in the context of the replicative pressures imposed on transplanted HSPCs is needed in order to optimize conditioning regimens, donor selection and clinical outcomes post-HSCT.

Preleukaemic clonal haemopoiesis and risk of therapy-related myeloid neoplasms: a case-control study

BackgroundTherapy-related myeloid neoplasms (t-MNs) are often fatal secondary malignancies. Risk factors for t-MNs are not well understood. Recent studies suggested that individuals with clonal hematopoiesis have higher risk of developing hematological malignancies. We hypothesized that cancer patients with clonal hematopoiesis have increased risk of developing t-MNs.MethodsWe conducted a retrospective case-control study to compare the prevalence of clonal hematopoiesis between patients who developed t-MNs (cases) and who did not develop t-MNs (control). For cases, we studied14 patients with various types of cancers who developed t-MNs and whose paired samples of t-MN bone marrow (BM) and peripheral blood (PB) that were previously obtained at the time of primary cancer diagnosis were available. Fifty four patients with lymphoma who received combination chemotherapy and did not develop t-MNs after at least 5 years of follow up were studied as a control. We performed molecular barcode sequencing of 32 genes on the pre-treatment PB samples to detect clonal hematopoiesis. For the t-MN cases, we also performed targeted gene sequencing on t-MN BM samples and investigated clonal evolution from clonal hematopoiesis to t-MNs. To confirm association between clonal hematopoiesis and t-MN development, we also analyzed prevalence of clonal hematopoiesis in a separate cohort of 74 patients with lymphoma. All of these patients were treated under the prospective randomized trial of frontline chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) with or without melatonin and 5 (7%) of them had developed t-MNs.FindingsIn 14 patients with t-MNs, we detected pre-leukemic mutations in 10 of their prior PB samples (71%). In control, clonal hematopoiesis was detected in 17 patients (31%), and the cumulative incidence of t-MNs at 5 years was significantly higher in patients with clonal hematopoiesis (30% [95% CI: 16% – 51%] vs. 7% [95% CI: 2% – 21%], P = 0.016). In the separate cohort, 5 patients (7%) developed t-MNs and 4 (80%) of them had clonal hematopoiesis. The cumulative incidence of t-MNs at 10 years was significantly higher in patients with clonal hematopoiesis (29% [95% CI: 8%–53%] vs. 0% [95% CI: 0%–0%], P = 0.0009). Multivariate Fine and Gray model showed that having clonal hematopoiesis significantly increased the risk of t-MN development (HR = 13.7, P = 0.013).InterpretationPre-leukemic clonal hematopoiesis is frequently detected in patients with t-MNs at the time of their primary cancer diagnosis and before patients were exposed to chemotherapy/radiation therapy. Detection of clonal hematopoiesis significantly increased the risk of t-MN development in patients with lymphoma. These data suggest potential approaches of screening clonal hematopoiesis in cancer patients to identify patients at risk of t-MNs and warrants a validation in prospective trial investigating a role of clonal hematopoiesis as a predictive marker for t-MNs.

Characteristics and outcomes of patients with multiple myeloma who develop therapy-related myelodysplastic syndrome, chronic myelomonocytic leukemia, or acute myeloid leukemia.

Patients with multiple myeloma (MM) have had significant improvements in outcomes. An increased risk of therapy-related myeloid neoplasms (t-MNs) has also developed. Little is known about the characteristics and outcomes of these patients. Patients with MM treated at our institution from 1993 to 2011 were reviewed. Forty-seven patients were diagnosed with t-MN. Our primary objective was to evaluate the interval to t-MN, response to treatment, and overall survival (OS). The median patient age at the MM diagnosis was 65 years. Of the 47 patients, 32 (68.0%) initially received conventional chemotherapeutic agents, 7 (14.9%), novel agents (eg, lenalidomide, thalidomide, bortezomib), and 8 (17.0%), a combination. Twenty patients (42.6%) underwent high-dose chemotherapy and autologous hematopoietic stem cell transplantation. The median interval from the MM diagnosis to t-MN was 7 years (95% CI, 5.0-28.0). Of the 47 patients, 33 (70.2%) developed therapy-related myelodysplastic syndrome (t-MDS), 11 (23.4%) acute myeloid leukemia (t-AML), and 3 (6.4%) chronic myelomonocytic leukemia (t-CMML). The median age at the t-MN diagnosis was 65 years. Of the 47 patients, 26 (78.8%) with t-MDS, 9 (81.8%) with t-AML, and 1 (33.3%) with t-CMML had complex/high-risk cytogenetics. The median OS for all 47 patients after the t-MN diagnosis was 6.3 months (95% CI, 4.0-8.7). The development of t-MN in patients with MM is associated with poor outcomes. These patients, in general, have complex cytogenetic abnormalities and short complete remission and OS times. A better understanding of the disease biology and novel therapeutic approaches are warranted.

The BCL2L10 Leu21Arg variant and risk of therapy-related myeloid neoplasms and de novo myelodysplastic syndromes

Therapy-related myeloid neoplasms (t-MNs) are an increasingly recognized complication in patients previously treated with radiotherapy and/or chemotherapy for cancer or autoimmune disease. Single nucleotide variants (SNVs) in genes involved in the cellular pathways of detoxification, DNA repair and apoptosis may modify the individual risk of developing a t-MN. We studied the frequency of the SNVs of six genes involved in xenobiotic detoxification (CYP3A4, NQO1, GSTA1, GSTM1, GSTP1 and GSTT1), two DNA repair genes (RAD51 and XRCC3) and one key regulator of apoptosis (BCL2L10) in a case–control study including 111 cases of t-MN and 259 controls. This is the first report on the prevalence of BCL2L10 Leu21Arg polymorphism in myeloid malignancies. In this line, we also tested 146 cases of de novo myelodysplastic syndrome (MDS) and 109 cases of de novo acute myeloid leukemia (AML). Our results showed a significantly lower frequency of the BCL2L10-21Arg allele in patients with t-MN and de novo MDS compared to controls (Leu/Arg + Arg/Arg: 50.6% vs. 65.9%, p = 0.017 and 45.8% vs. 65.9%, p = 0.0003, respectively). Carriers of the BCL2L10-21Arg variant have a reduced risk of developing t-MN and de novo MDS.

Long-Term Outcome of B-CLL Patients Treated in a Prospective Trial Evaluating Combination of Oral Fludarabine and Cyclophosphamide As Frontline Therapy

Abstract 1795 Introduction.The combination of fludarabine and cyclophosphamide (FC) has become the core combination of modern frontline chemotherapy for fit and young B-CLL patients (pts). Recently the association with rituximab to FC (IV administration) has been shown to increase the response and extend both progression free survival (PFS) and overall survival (OS) in untreated pts (Hallek et al., Lancet 2010). So far few data are available concerning the very long term outcome of pts treated by FC containing regimen. Methods. We previously reported a prospective phase II trial (Cazin et al., BJH 2008) of the oral combination of FC over 5 days in 75 patients with untreated B-CLL and less than 66 years old. The study was conducted between October 1999 and February 2001. Briefly, oral FC then demonstrated high efficacy with overall response rate (ORR) and complete response (CR) rate of 80% and 53% respectively despite the absence of rituximab in this regimen. We here propose to examine 10-year end points of progression-free survival (PFS), overall survival (OS), impact of genomic features, and risk of therapy-related myeloid neoplasm (t-MN) by updating survival data of all the pts incuded in this trial. Results. With a median follow-up of 10.7 years, the median 10-year OS was 51.7%. Responders presented better 10-year OS than non-responders (57% vs. 38%, p=0.031) but quality of response (CR vs. PR) did not significantly impact 10-year OS. A major prognostic impact of IGVH mutational status could be observed since 10-year OS was 81% for mutated patients vs. 44% for unmutated pts (p=0.012). The median 10-year PFS was 30% and clearly influenced by the mutational status (50% if mutated profile vs. 12% if unmutated profile, p=0.02). However there is no trend of a plateau and even long term responding patients still relapse with time. Finally, only one patient developed t-MN but 9 others presented solid neoplasms. Conclusion. Long-term follow-up of B-CLL patients prospectively treated in a phase II clinical trial demonstrates extended OS and PFS with oral FC without high risk of t-MN. Disclosures:No relevant conflicts of interest to declare.

5.32 Long-term Outcome of B-CLL Patients Treated in a Prospective Trial Evaluating Combination of Oral Fludarabine and Cyclophosphamide as Frontline Therapy

Abstract 1795 Introduction. The combination of fludarabine and cyclophosphamide (FC) has become the core combination of modern frontline chemotherapy for fit and young B-CLL patients (pts). Recently the association with rituximab to FC (IV administration) has been shown to increase the response and extend both progression free survival (PFS) and overall survival (OS) in untreated pts (Hallek et al., Lancet 2010). So far few data are available concerning the very long term outcome of pts treated by FC containing regimen. Methods. We previously reported a prospective phase II trial (Cazin et al., BJH 2008) of the oral combination of FC over 5 days in 75 patients with untreated B-CLL and less than 66 years old. The study was conducted between October 1999 and February 2001. Briefly, oral FC then demonstrated high efficacy with overall response rate (ORR) and complete response (CR) rate of 80% and 53% respectively despite the absence of rituximab in this regimen. We here propose to examine 10-year end points of progression-free survival (PFS), overall survival (OS), impact of genomic features, and risk of therapy-related myeloid neoplasm (t-MN) by updating survival data of all the pts incuded in this trial. Results. With a median follow-up of 10.7 years, the median 10-year OS was 51.7%. Responders presented better 10-year OS than non-responders (57% vs. 38%, p=0.031) but quality of response (CR vs. PR) did not significantly impact 10-year OS. A major prognostic impact of IGVH mutational status could be observed since 10-year OS was 81% for mutated patients vs . 44% for unmutated pts (p=0.012). The median 10-year PFS was 30% and clearly influenced by the mutational status (50% if mutated profile vs. 12% if unmutated profile, p=0.02). However there is no trend of a plateau and even long term responding patients still relapse with time. Finally, only one patient developed t-MN but 9 others presented solid neoplasms. Conclusion. Long-term follow-up of B-CLL patients prospectively treated in a phase II clinical trial demonstrates extended OS and PFS with oral FC without high risk of t-MN. Disclosures: No relevant conflicts of interest to declare.

Chemoimmunotherapy With Fludarabine and Rituximab Produces Extended Overall Survival and Progression-Free Survival in Chronic Lymphocytic Leukemia: Long-Term Follow-Up of CALGB Study 9712

The addition of rituximab to fludarabine-based regimens in chronic lymphocytic leukemia (CLL) has been shown to produce high response rates with extended remissions. The long-term follow-up of these regimens with respect to progression, survival, risk of secondary leukemia, and impact of genomic risk factors has been limited. We report the long-term follow-up of the chemoimmunotherapy trial CALGB 9712 from the Cancer and Leukemia Group B, for which treatment regimen was previously reported, to examine end points of progression-free survival (PFS), overall survival (OS), impact of genomic features, and risk of therapy-related myeloid neoplasm (t-MN). A total of 104 patients were enrolled on this study and now have a median follow-up of 117 months (range, 66 to 131 months). The median OS was 85 months, and 71% of patients were alive at 5 years. The median PFS was 42 months, and 27% were progression free at 5 years. An estimated 13% remained free of progression at almost 10 years of follow-up. Multivariable models of PFS and OS showed that immunoglobulin heavy chain variable region mutational status was significant for both, whereas cytogenetic abnormalities were significant only for OS. No patient developed t-MN before relapse. Long-term follow-up of CALGB 9712 demonstrates extended OS and PFS with fludarabine plus rituximab. Patients treated with fludarabine plus rituximab administered concurrently or sequentially have a low risk of t-MN. These long-term data support fludarabine plus rituximab as one acceptable first-line treatment for symptomatic patients with CLL.