ALBERT

Description: An elevated level of nucleophosmin (NPM) is often found in actively proliferative cells including human tumors. To identify the regulatory role for NPM phosphorylation in proliferation and cell cycle control, a series of mutants targeting the consensus cyclin-dependent kinase (CKD) phosphorylation sites was created to mimic or abrogate either single-site or multi-site phosphorylation. Cells expressing the phosphomimetic NPM mutants showed enhanced proliferation and G2/M cell-cycle transition; whereas nonphosphorylatable mutants induced G2/M cell-cycle arrest. Simultaneous inactivation of two CKD phosphorylation sites at Ser10 and Ser70 (S10A/S70A, NPM-AA) induced phosphorylation of Cdk1 at Tyr15 (Cdc2Tyr15) and increased cytoplasmic accumulation of Cdc25C. Strikingly, stress-induced Cdk1Tyr15 and Cdc25C sequestration were completely suppressed by expression of a double phosphomimetic NPM mutant (S10E/S70E, NPM-EE). Further analysis revealed that phosphorylation of NPM at both Ser10 and Ser70 sites were required for proper interaction between Cdk1 and Cdc25C in mitotic cells. Moreover, the NPM-EE mutant directly bound to Cdc25C and prevented phosphorylation of Cdc25C at Ser216 during mitosis. Finally, NPM-EE overrided stress-induced G2/M arrest, increased peripheral-blood blasts and splenomegaly in a NOD/SCID xenograft model, and promoted leukemia development in Fanconi mouse hematopoietic stem/progenitor cells. Thus, these findings reveal a novel function of NPM on regulation of cell-cycle progression, in which Cdk1-dependent phosphorylation of NPM controls cell-cycle progression at G2/M transition through modulation of Cdc25C activity.

Description: Introduction Efforts to improve the survival of non-Hodgkin lymphoma (NHL) patients with recurrent disease have focused primarily on the use of consolidative myeloablative autologous hematopoietic stem cell transplantation (HSCT). However, the major limitation of HSCT for NHL is the high incidence of relapse, even at maximally tolerated preparative regimen intensities. In a series of phase I studies designed to improve HSCT longterm remission rates, we have assessed the safety and feasibility of cellular immunotherapy utilizing ex vivo expanded autologous central memory (Tcm)-enrichedT cells that are genetically modified to express CD19-specific chimeric antigen receptors (CD19CAR), given in conjunction with standard of care myeloablative HSCT. Methods Here we present results from the first two studies investigating different starting cell populations and CAR constructs. The NHL1 trial utilized a starting population of CD8+ Tcm and transduced with a lentiviral vector encoding the 1st-generation CD19CAR (CD19R:zeta), consisting of a CD19-specific scFv linked to a CD3-zeta (CD19R:zeta) signaling domain. The NHL2 trial used a bulk Tcm population including both CD4+ and CD8+cells, which were transduced with lentiviral vectors encoding a 2nd-generation CD19CAR that added a CD28 costimulatory domain (CD19R:CD28:zeta) and a selectable marker for cell tracking (EGFRt). Engineered Tcm-derived CD19CAR T cells were infused 2 days after HSCT at dose levels of 25-200 x10^6 CAR T cells (dose levels in table), and all participants were followed for dose limiting toxicity (DLT) for 28 days. Both phase I studies utilized the target equivalence range design, which defines the dose escalation and de-escalation rules for determining maximum tolerated dose based on a target range of acceptable toxicity. Results NHL1 protocol (NCT01318317): Eight participants were consented and received CD8+ Tcm -derived CD19R:zeta T cell therapy. Seven patients had a diagnosis of diffuse large B cell lymphoma (DLBCL) and 1 had mantle cell lymphoma (MCL). Four of the 8 were female, and 3/8 were ≥ age 65 years. The mean age was 62 years (50-75). The median number of prior chemo/immunotherapy regimens was 3 (2-4). Two of the 8 (25%) participants had prior radiation. Five of 8 (63%) participants on NHL1 achieved a best response of CR or continuing CR. Four of 8 (50% 95% CI [16%, 84%]) participants have progressed. The progression free survival (PFS) at both 1 and 2 years is 50%, 95% CI[16%,84%] with a median follow-up of 24.7 (min=24.0, max=26.7) months. There were 2 deaths, both from disease progression. NHL2 protocol (NCT 01815749): Eight participants were consented and received Tcm-derived CD19R:CD28:zeta/EGFRt T cell therapy. Four patients had MCL, 4 had DLBCL, 3/8 were female, 2/8 were ≥ age 65 years. The mean age was 58 years (23-71). The median number of prior chemo/immunotherapy regimens was 2 (1-3). All eight NHL2 participants achieved a best response of CR or continuing CR. The PFS at 6 months is 100%, 95% CI[63%, 100%] with a median follow-up of 12.2 (min=10.0, max=14.1) months. To date 2 participants of the 8 (25%, 95% CI [3%, 65%]) have progressed (one at 6.4 months and one at 12.6 months). There was 1 death from disease progression. Both NHL1 and NHL2 trials demonstrated safety and feasibility. There were no DLTs, delayed hematopoietic reconstitution, or non-relapse mortality on either study. In NHL2, we employed bulk Tcm including both CD4+ and CD8+ cells in the CAR transduction and also added a CD28 co-stimulatory domain in the CAR design, to enhance persistence and antitumor activity. NHL2 exhibited better CAR T cell persistence compared to NHL1 T cell therapy based on area under the curve of log10copies/µg of genomic DNA from day 1 to 25 post infusion (mean difference = 14.8, 95% CI [7.4, 22.3], P

Description: Abstract 255 Despite proven efficacy in clinical trials, hydroxyurea (HU) has not been uniformly adopted into the care of children with sickle cell disease (SCD). In 2008, the NIH Consensus Development Conference on Hydroxyurea Treatment for Sickle Cell Disease postulated that barriers to HU use may occur at the provider level. Limited evidence exists on barriers to the use of HU, and prior studies have largely focused on use in adults. HU use is rapidly expanding to different indications, to use in patients with less common hemoglobin genotypes and to young children. Initial data from the Pediatric Hydroxyurea Phase III Trial (BABY HUG) in very young children (ages 9–18 months) is also now becoming available. To better understand current provider barriers to effective translation of efficacy trial results into “real-world” clinical care of children with SCD, we surveyed pediatric hematology providers within several regional consortiums of pediatric hematology programs in the eastern US. The objectives of our study were to: 1) describe practice patterns related to HU use among providers of children and adolescents with SCD; 2) identify provider level barriers to HU use among SCD children; and 3) solicit provider recommendations to overcome the perceived barriers. A close-ended, self-administered web-based survey was sent to 230 pediatric hematology providers in June 2010. Provider demographics, practice characteristics, clinical indications to prescribe HU, concerns related to HU use and suggestions to improve HU use were assessed by this survey. Forty-two percent (N=97) of 230 surveys were completed by hematologists (84%), nurse practitioners (12%) and physician assistants (3.7%). The number of SCD patients in provider practices ranged from 2 to 1,200 patients. 57% of respondents were female. 42% of respondents were in practice for more than 20 years. The majority (72%) of providers were white. Many providers (83%) were somewhat/very familiar with the NHLBI guidelines about HU use in SCD. Among those surveyed, the most frequent indications to start HU were: 1) history of 3 painful episodes, 2) acute chest syndrome, 3) chronic pain use requiring narcotics, 4) priapism and 5) symptomatic anemia. A majority of providers (82%) reported using HU in children ages 3–5 years of age, with 41% of providers indicated using HU in children less than 3 years of age. Fewer than half of providers (28%) prescribe HU to patients with Hgb SC or other Hgb S variants. Only 74% of providers attempted to titrate HU to maximal tolerated dose. This goal dose ranged from 20 to 40mg/kg/day among our respondents. Major provider concerns about HU in children are: 1) patient compliance with taking HU, 2) compliance with attending drug monitoring visits, 3) compliance with taking contraception, 4) effects of HU on fertility and 5) long term side effects. Almost 50% of clinicians were concerned about the age of the patient when starting HU: 48.5% of clinicians considered patients less than 1 years of age too young to start HU, while 40% of clinicians felt patients' ages 1–2 years were too young. Some providers (39%) had concerns about the efficacy of HU in patients with Hgb SC, while 24.1% were concerned about efficacy in patients with Hgb S variants. Providers' suggestions to improve HU use included: 1) developing updated evidence based practice guidelines for HU use (89%), 2) developing culturally appropriate patient educational materials about HU (84%), 3) extending FDA approval for HU to children (80%), and 4) developing a national registry of patients on HU to monitor clinical outcomes and adverse events (74%). Our survey highlights that HU use varies among pediatric providers with respect to: 1) the broader clinical indications for HU use, 2) optimal maximal tolerated dose of HU, 3) appropriate lower age limit to prescribe HU, and 4) sickle cell genotype in which to use HU. Updated national evidence- based guidelines to assist clinicians in using HU in pediatric sickle cell care are indicated given the efficacy of HU for SCD over a wide range of indications, the logistical limits and tempo of clinical studies, the paucity of other widely available treatments, and persistent barriers to HU use at the provider level. Additional studies are warranted to examine alternative indications for HU, HU use in younger ages, optimum dosing, potential impact on fertility, teratogenicity and possible carcinogenicity, and use of HU for other sickle cell genotypes. Disclosures: Off Label Use: Hydroxyurea has not been FDA approved for use in children and adolescents with sickle cell disease, the topic of the submitted abstract.

Description: Abstract 4276 Introduction: Hematopoietic stem cell transplantation (HSCT) from an HLA matched donor is the only curative therapy for sickle cell disease (SCD), with sibling donor survival rates approaching 95%. Referral from the primary hematologist for transplant evaluation is a key step in the process. Study aims were to assess pediatric SCD providers for: 1) Current perspectives and referral patterns; 2) Whether perspectives differ for those practicing at a transplant center. Methods: All pediatric hematology providers at the designated newborn screening hemoglobinopathy centers within the seven state New York-Mid-Atlantic Consortium (NYMAC) were anonymously surveyed. Descriptive statistics and chi squared test or Fisher's exact test were used for analysis. Results: Of 197 pediatric SCD providers contacted through the NYMAC listserv, 104 (53%) responded, predominantly hematologists. Half (53%) of responders practice at sites performing HSCT for pediatric SCD. Overall, transplant centers had larger SCD patient populations (p

Description: Abstract 1089 Poster Board I-111 Fanconi anemia (FA) is a human genomic instability syndrome that is uniquely sensitive to oxidative stress. Members of the FA protein family are involved in repair of genetic damage caused by DNA cross-linkers. The molecular pathway in which the FA proteins function in oxidative stress response has not been defined. Here we report functional interaction between the FA protein FANCD2 and the forkhead transcription factor FOXO3a in response to oxidative stress. FOXO3a was colocalized to FANCD2 foci in cells subjected to oxidative stress. The FANCD2-FOXO3a complex was not detected in cells deficient for the FA core complex component FANCA, but could be restored after complementation with a functional FANCA. Consistent with this, a non-monoubiquitinated FANCD2 mutant failed to bind FOXO3a. While both DNA cross-linker mitomycin C and ionizing radiation induced monoubiquitination of FANCD2, neither was able to induce the association of FANCD2 and FOXO3a. This indicates that the FOXO3a-FANCD2 interaction is oxidative stress specific. Overexpression of FOXO3a reduced abnormal accumulation of reactive oxygen species, enhanced cellular resistance to oxidative stress, and increased antioxidant gene expression in corrected but not mutant FA-D2 cells. The novel oxidative stress response pathway converging FANCD2 and FOXO3a identified in this study is likely to contribute to cellular anti-oxidant defense. Disclosures No relevant conflicts of interest to declare.

Description: Introduction: Treatment of adults with relapsed/refractory (R/R) B-ALL using CD19-targeted chimeric antigen receptor (CAR) T cells has achieved remarkable remission rates, both in pediatric and adult populations. There are multiple CAR constructs and T cell manufacturing platforms in use, and both aspects of the therapy may impact efficacy and toxicity. Park et al. report that 83% of adult patients (pts) achieve complete response (CR) to their CD19 CAR T cells with a CD28 costimulatory domain (NEJM; 3785: 449), using an unselected peripheral blood (PBMC) manufacturing platform. Unfortunately, therapy-associated toxicities in adult and pediatric ALL pts are problematic, with grade 3/4 cytokine release syndrome (CRS) ranging from 26-49 % and neurotoxicity 18-42%. Here we report preliminary data from one arm of a phase 1 clinical trial (NCT02146924) in adult pts with R/R B-ALL testing a memory-enriched T cell starting population engineered to express a CD19-specific, CD28-costimulatory CAR (CD19:28z-CAR). All pts achieved CR or CRi with a low incidence of severe cytokine release syndrome (CRS) and neurotoxicity. Unique to this study is our Tn/mem-enriched manufacturing platform, a naïve/memory T cell-enriched T cell product that is lentivirally transduced to express our CD19:28z-CAR. The manufacturing process starts with patient PBMC, depletes the CD14+ monocytes and CD25+ Tregs, and selects for CD62L+ T cells. The resultant T cell population for CAR transduction includes both the central memory and stem cell memory populations along with naïve T cells. Preclinical studies in mice had suggested that using a more uniform T cell product with a less-differentiated T cell phenotype improved antitumor activity. This Tn/mem manufacturing platform is the same as our Tcm-derived platform (Blood;127:2980) except that CD45RA depletion was omitted. Patients and Methods: This phase I study used the activity constrained for toxicity (ACT) design, an extension of the toxicity equivalence range (TEQR) design of Blanchard and Longmate (Contemp Clin Trials; 32:114), that dose escalates based on lack of activity, while constraining the dose for toxicity. The primary objectives of this study were to test the safety and activity of Tn/mem-enriched CD19:28z CAR T cells, and to determine the phase 2 recommended dose. The primary endpoints were toxicity and disease response. Sixteen pts were consented and received a lymphodepleting regimen (LDR) of 1.5-3 gm/m2 cyclophosphamide over 2-3 days and 25-30 mg/m2 fludarabine for 3 days. Three pts received LDR, but did not receive T cells due to infection or lack of CD19+ disease. Patients received a flat dose of 200 million (M) CD19:28z-CAR T cells: 11 autologous and 2 allogeneic donor products. Of the 13 that received 200 M CAR+ T cells, 2 pts were deemed ineligible for dose escalation / disease response evaluation, as 1 received

Description: Autologous stem cell transplantation (ASCT) remains an important consolidative therapy for patients with recurrent non-Hodgkin lymphoma (NHL), but is limited by the high incidence of NHL relapse. We report a Phase I clinical trial of ASCT followed by CD19-specific CD28-costimulatory chimeric antigen receptor (CD19:28z-CAR) T cells, with the goal of reducing NHL relapse rates. Safety and feasibility were the primary objectives, with CAR T cell persistence and expansion in the myeloablative ASCT setting as secondary objectives. This study examines safety and feasibility for two manufacturing platforms that differed in the T cell subset composition used for CAR engineering. Initially, the T cell population for CAR transduction was central memory (Tcm)-enriched: participants' peripheral blood mononuclear cells (PBMC) were depleted for CD14+ monocytes, CD25+ Tregs, and CD45RA+ naïve and stem-memory T cells, after which they were selected for CD62L+ Tcm (Wang et al. Blood;127:2980). Based on comparative preclinical data, a second arm was added to the trial to evaluate a Tn/mem-derived manufacturing platform that enriched central memory, naïve, and stem memory T cells (no CD45RA+ depletion). Either Tcm- or Tn/mem-enriched T cells were activated with CD3/CD28 beads, transduced with lentiviral vector encoding the CD19:28z-CAR, and expanded ex vivo. This phase I trial used the toxicity equivalence range design (Blanchard and Longmate. Contemp Clin Trials; 32;114) with an equivalence range for DLTs of 0.20-0.35 and a target toxicity rate of 0.25. The first 3 participants on each arm were followed one at a time, with later accrual in cohorts of 3. Twenty-three participants underwent ASCT and received CD19:28z-CAR T cells 2 days post stem cell infusion at the assigned dose level (DL): 17 on the Tcm arm (DL 50 million [M] CAR+ T cells [n=3], 200 M [n=5], 600 M [n=9]); 6 on the Tn/mem arm (DL 200 M). Participants were followed for dose limiting toxicity (DLT) for 28 days. Table 1 shows results by arm and DL. Both arms demonstrated safety and feasibility. There was no delayed hematopoietic reconstitution on either arm. On the Tcm arm, the only DLT was at DL 600 M (1 of 9 at 600 M). The Tn/mem arm was opened at 200 M and 6 participants were treated with no DLTs. The dose was not escalated as the protocol management team had seen activity at the 200M level in 2 other trials using the Tn/mem product. Tcm Arm: Fourteen of 17 participants (82%) had a diagnosis of diffuse large B-cell lymphoma (DLBCL) and 3 had mantle cell lymphoma. The mean age of the participants on the Tcm arm was 57 (35-75). The median number of prior chemotherapy regimens was 2 (1-5). The median progression-free survival (PFS) was 34.6 months 95% CI [21.8, undefined]. Seven of 17 participants (41%) have progressed, 1 died in remission of unrelated intracranial hemorrhage (6%), 7 (41%) remain in CR and are still in follow-up, and 2 are lost to follow-up (12%). All 17 participants achieved a CR or a continuing CR after ASCT and T cells. Tn/mem arm: Five of 6 participants (83%) had a DLBCL diagnosis, and 1 was NHL not otherwise specified. The mean age of the participants was 50 (40-72). The median number of prior chemotherapy regimens was 2.5 (1-3). The median follow-up time for the Tn/mem arm was 12 months, with median PFS not yet reached. One of 6 (17%) has progressed, 4 (66%) remain in CR and are still in follow-up, and 1 is lost to follow-up (17%). Five of 6 (83%) participants achieved a best response of CR or continuing CR after therapy. Several differences were observed between the manufacturing platforms. Since the Tn/mem production platform has fewer depletion steps, it resulted in a higher product yield, which shortened the ex vivo expansion period by 4.1 days (95% CI [1.5%, 6.6%]) from 18.9 days (15-24) for Tcm to 14.8 days (12-18) for Tn/mem (P

Description: Abstract 2194 Poster Board II-171 Imatinib mesylate (IM) is effective in inducing remission and improving survival in CML patients. However IM-treated patients continue to harbor residual leukemia stem cells (Blood 101:4701, 2003). Most patients relapse if treatment is discontinued, and it is generally recommended that treatment with IM be continued indefinitely. The inability of IM to cure CML, the potential for side effects and the financial burden of life-long treatment provide an impetus to develop approaches to eliminate residual leukemia stem cells. We have shown in preclinical studies that treatment with the HDAC inhibitor LBH589 (LBH) combined with IM effectively eliminates CML stem cells resistant to IM alone. The safety and MTD of LBH589 in combination with Imatinib has not been previously evaluated. We have initiated a phase I, open label clinical trial to determine the safety and tolerability of LBH589 given in combination with IM in CML patients, and to determine the MTD and dose-limiting toxicity (DLT). CML patients in chronic phase (CP) treated with IM 400mg/d for 〉1 year with major or complete cytogenetic response and residual disease on Q-PCR are eligible. LBH589 is administered in combination with IM 400mg PO daily in 28 day cycles, with successive cohorts of patients receiving escalating doses of LBH 3 times a week (level 1: 10mg; level 2: 15mg; level 3: 20mg). Treatment is scheduled for 6 cycles of 28 days each. Five patients have been enrolled thus far (Table). No dose limiting toxicity (DLT), defined as Grade 3 hematological or non-hematological toxicity in the first 28 days, was observed in 3 patients enrolled at dose level 1. DLT (Grade 3 thrombocytopenia) was observed in 1 of the 2 patients enrolled at dose level 2. Other toxicities included thrombocytopenia (Grade 3 [n=2]; Grade 1-2 [n=4]), hypophosphatemia (Grade 3 [n=1]; Grade 2 [n=2]), fatigue (Grade 1 [n=3]), hypocalcemia (Grade 1 [n=2] and Grade 1-2 GI symptoms (diarrhea [n=2]; nausea [n=3]; anorexia [n=2]; vomiting [n=3]; constipation [n=1]). Of note, significant QTc prolongation was not observed on intensive EKG monitoring. IM did not require to be held for any of these toxicities. Two patients have completed 6 cycles of treatment, with one opting to receive an additional 3 cycles, 2 are currently receiving treatment, and one withdrew after 1.5 cycles because of fatigue and GI symptoms. Bone marrow aspirates for assessment of BCR-ABL status were performed at the end of cycles 3 and 6 of treatment. Q-PCR analyses showed reduction in BCR-ABL levels in patient #2 (LBH 10mg) after 3 months, which was not sustained at 6 months. Patient #4 (LBH 15mg), followed for 5 months so far, had undetectable BCR-ABL after 3 months of treatment. These results suggest that LBH589 can be safely administered in combination with IM. Reduction in BCR-ABL levels was seen in two patients but the durability is unclear as yet. We are continuing accrual of patients to define the MTD and safety of this combination. Disclosures: Bhatia: Novartis: Consultancy, Research Funding. Snyder:Novartis: Consultancy, Honoraria, Speakers Bureau. Deininger:Novartis: Consultancy. Radich:Novartis: Consultancy, Honoraria, Research Funding.

Description: Introduction: Therapy-related Myeloid Neoplasms (TRMN) arise after cytotoxic chemotherapy and/or radiotherapy administered for a prior neoplasm and have dismal outcome. Inherited predisposition or direct induction of fusion transcripts can be responsible of TRMN. Recent evidence suggests that patient with Clonal Hematopoiesis of Indeterminate Potential (CHIP) may have an increased risk of TRMN. In gynecological and breast cancers, CHIP mutations have been described in around 25 % of patients (Coombs et al., Cell Stem Cell 2017). In this setting, we aimed to identify the impact of CHIP-associated mutations in overall survival of TRMN. Methods: In this retrospective study, we included patients with TRMN diagnosed and/or treated at Gustave Roussy Cancer Center between January 2004 and December 2018 if they had a previous breast or gynecological cancer, DNA samples available at TRMN diagnosis and a signed informed consent. We performed a targeted 77 genes mutational analysis using Next Generation Sequencing (NGS), using Haloplex technique (Agilent), sequencing on MiSeq (Illumina). If any somatic mutation associated with hematological malignancies could define CHIP, the most frequent genes mutated in original CHIP papers are: ASXL1, ASXL2, ATM, BCOR, CBL, CHEK2, DNMT3A, IDH1, IDH2, JAK2, PPM1D, SF3B1, SRSF2, TET2 and TP53. These will define "CHIP-associated mutations" at TRMN diagnosis. According to results, patients were classified into "CHIP-associated mutations" or "no-CHIP" categories (no mutations detected or all the other mutations detected at TRMN diagnosis). Moreover, patients were also classified into 3 subgroups according to a modified genetic ontogeny-based classifier (Lindsley et al., Blood 2015): "P53/PPM1D" subgroup, "MDS and AML with MDS mutations" subgroup, and "de novo/pan-AML" subgroup. Survival analyses were performed using GraphPad software. Results: 77 patients were identified: 49 therapy-related AML (t-AML) (64%) and 28 therapy-related MDS (t-MDS) (36%). Median age at TRMN diagnosis was 62 years [36-86] and median time interval between primary cancer and TRMN was 5.1 years. Primary cancers were breast (70%), ovarian (23%), endometrial (4%) and cervical (3%) cancers. Patients were treated with radiotherapy alone (13%), cytotoxic agent alone (19%), or chemotherapy/radiotherapy (68%). The most frequently mutated genes at TRMN diagnosis were: TP53 (31%), DNMT3A (19%), NRAS (13%), TET2 (12%), NPM1 (10%), PPM1D (9%), PTPN11 (9%) (Fig1A). 10% of patients had no gene mutation detected. According to 2017 ELN risk stratification, genetic risk for t-AML was favorable, intermediate and adverse in 19 (39%), 14 (28%) and 16 patients (33%), respectively. According to IPSS score, 86% of the t-MDS patients were classified as High risk/Intermediate 2 and 14% as Intermediate 1/Low risk. Treatment options included best supportive care for 16 patients (21%), low dose chemotherapy for 26 patients (34%), or intensive chemotherapy/allogenic transplant for 34 patients (45%). Based on Lindsley's modified classifier median overall survival for "P53/PPM1D", "MDS" and "de novo/pan-AML" subgroups were 12, 17 and 25 months, respectively (p=0.009) (Fig1B). "CHIP-associated mutations" were detected in 53 patients (69%) with no significant impact on overall survival (Fig1C). Interestingly, age at TRMN diagnosis in patients with "CHIP-associated mutations" vs patients with "no-CHIP" was higher (65 vs 56 years old, p=0.002) and the time interval between cancer diagnosis and TRMN was longer (6.6 [0.9-38.1] vs 2.9 [1.2-8.5] years, p〈 0.001) (Fig1D). CHIP emergence was not correlated with type of cancer's treatment or with number of treatment lines. "P53/PPM1D" subgroup was more frequent in patients treated with 2 lines or more for their primary cancer than in patients who received only 1 line of treatment (50% and 25% respectively, p=0.03). Conclusion: TRMN occurring after gynecological or breast cancers are of bad prognosis, especially for P53 and PPM1D mutated patients. Our results show that CHIP related mutations are found in a large percentage of patients and could be responsible for emergence of TRMN, especially in older patients. Figure 1 Disclosures de Botton: Forma: Consultancy, Research Funding; Bayer: Consultancy; Daiichi: Consultancy; Novartis: Consultancy; Astellas: Consultancy; Abbvie: Consultancy; Pierre Fabre: Consultancy; Syros: Consultancy; Agios: Consultancy, Research Funding; Janssen: Consultancy; Pfizer: Consultancy; Servier: Consultancy; Celgene: Consultancy, Speakers Bureau. Micol:AbbVie: Consultancy; Jazz Pharmaceuticals: Consultancy.