Rational management approach to pure red cell aplasia

Pure red cell aplasia is an orphan disease, and as such lacks rationally established standard therapies. Most cases are idiopathic; a subset is antibody-mediated. There is overlap between idiopathic cases and those with T-cell large granular lymphocytic leukemia, hypogammaglobulinemia, and low-grade lymphomas. In each of the aforementioned, the pathogenetic mechanisms may involve autoreactive cytotoxic responses. We selected 62 uniformly diagnosed pure red cell aplasia patients and analyzed their pathophysiologic features and responsiveness to rationally applied first-line and salvage therapies in order to propose diagnostic and therapeutic algorithms that may be helpful in guiding the management of prospective patients, 52% of whom were idiopathic, while the others involved large granular lymphocytic leukemia, thymoma, and B-cell dyscrasia. T-cell-mediated responses ranged between a continuum from polyclonal to monoclonal (as seen in large granular lymphocytic leukemia). During a median observation period of 40 months, patients received a median of two different therapies to achieve remission. Frequently used therapy included calcineurin-inhibitors with a steroid taper yielding a first-line overall response rate of 76% (53/70). Oral cyclophosphamide showed activity, albeit lower than that produced by cyclosporine. Intravenous immunoglobulins were effective both in parvovirus patients and in hypogammaglobulinemia cases. In salvage settings, alemtuzumab is active, particularly in large granular lymphocytic leukemia-associated cases. Other potentially useful salvage options include rituximab, anti-thymocyte globulin and bortezomib. The workup of acquired pure red cell aplasia should include investigations of common pathological associations. Most effective therapies are directed against T-cell-mediated immunity, and therapeutic choices need to account for associated conditions that may help in choosing alternative salvage agents, such as intravenous immunoglobulin, alemtuzumab and bortezomib

A Multi-Center Open-Labeled Phase II Study of Intensive Salvage Therapy Followed By Enasidenib Maintenance for Patients with Relapsed/Refractory IDH2mutant AML

Introduction: Patients with relapsed/refractory acute myeloid leukemia (R/R AML) have limited therapeutic options and effective management remains clinical challenge. For medically fit patients, salvage therapy with an intensive chemotherapy regimen is the standard of care with remission rates of about 40-50%. Long-term survival is achievable only with disease control followed by allogeneic hematopoietic stem cell transplantation (HCT). A majority of patients with R/R AML who achieve a morphologic clinical remission with salvage chemotherapy frequently harbor detectable clonal events that act as a reservoir for disease relapse. Relapsed/refractory isocitrate dehydrogenase 2 (IDH2) mutant AML patients who undergo cytarabine based salvage chemotherapy will largely retain detectable IDH2 mutations and enasidenib maintenance therapy offers an attractive and tolerable approach to maintenance for such patients. Enasidenib (AG221) is a first-in-class, selective, potent inhibitor of the neomorphic activity of mutant IDH2 enzyme. It is FDA approved as monotherapy for R/R AML with a time to response of approximately 2 months, but there is limited data on the use of this agent following salvage chemotherapy. In the upfront setting, the combination of enasidenib with induction chemotherapy has demonstrated high response rates, providing rationale for this approach (and tolerability with the combination) in the R/R population. Methods: To understand the impact of tailored consolidation following salvage chemotherapy in fit R/R AML we designed a multi-center, phase II trial with 2 cohorts. Cohort assignment is based upon the investigators assignment of patients eligibility (cohort 1.) for allogeneic HCT or (cohort 2) no allogeneic HCT. The main inclusion criteria are, (a.) age over 18 years (b.) received salvage cytarabine based chemotherapy or venetoclax combined with hypomethylating agents (HMA) or 2 or more cycles of HMA for confirmed R/R AML (c.) achieved at least >50% reduction in blast percentage in a nadir marrow from salvage chemotherapy and (d.) adequate organ function and lack of acute life threatening illness. Patients will have received the investigator's choice of salvage therapy and subsequently undergo bone marrow assessment with protocol sampling. Patients confirmed to have obtained a remission will then begin enasidenib 100mg once a day starting between 14 and 60 days after starting salvage therapy. Patients in cohort 1 will receive 1-4 cycles of enasidenib and proceed with HCT; enasidenib can be re-initiated between D30-100 following HCT for a planned total of 24 cycles. Cohort 2 will continue enasidenib maintenance until progression/death or relapse (Schema: Fig 1). Study Endpoints: The primary endpoint of the study to determine the effect of enasidenib maintenance therapy following salvage induction therapy for IDH2 R/R AML, we will evaluate EFS at 12 months separately in the two cohorts of the study. Secondary endpoints include (1) Rate of successful HCT of the subjects enrolled on the study (2) Median duration of maintenance therapy in both the study arms & (3) Overall survival at 12 and 24 months in each cohort. The efficacy of the treatment will be assessed using Simon (1989) optimal two-stage, single arm, unblinded Phase II trials allowing for early termination for futility. This design has a 90% power to detect a 20% improvement rate compared to historical data, while controlling to 10% probability of erroneously findings. A total of 39 (C1) + 25 (C2) = 64 evaluable patients will be enrolled. Interim safety analysis will be done after enrollment of the first 28 patient in C1 and 17 patients in C2. Conclusion: This study is currently is open and enrolling patients at multiple collaborative institutions to answer the key question of efficacy of enasidenib maintenance following salvage chemotherapy. Correlative studies are being performed to understand minimal residual disease in IDH2 mutant AML and its clonal architecture. Disclosures Carraway: BMS: Consultancy, Other: Research support, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; ASTEX: Other: Independent Advisory Committe (IRC); Abbvie: Other: Independent Advisory Committe (IRC); Takeda: Other: Independent Advisory Committe (IRC); Stemline: Consultancy, Speakers Bureau; Jazz: Consultancy, Speakers Bureau. Griffiths:Novartis: Honoraria, Research Funding; Boston Biomedical: Honoraria; Genentech Inc: Research Funding; Astex Pharmceuticals: Research Funding; Alexion Pharmaceuticals: Honoraria, Research Funding; Celgene/BMS: Honoraria, Research Funding; AbbVie Inc: Honoraria; Persimmune: Research Funding

Comprehensive Identification Of Germline Alterations In Telomerase Complex Genes By Whole Exome Sequencing Of MDS and Related Myeloid Neoplasms

Abstract In addition to classical familiar forms of bone marrow failure, some cases of aplastic anemia (AA) have been linked to inherited germ line polymorphism/mutations of telomerase machinery, leading to excessive telomere shortening. Germline telomere maintenance machinery mutations have been also been found in a proportion of acute myeloid leukemia (AML) and Myelodysplastic syndromes (MDS) patients (pts). However, the molecular pathogenesis of adult MDS and AML is complex and determination of genetic risk factors in addition to established familial and congenital syndromes has been difficult. To date targeted sequencing has been used for mutational screens with the inherent limitations of limited exome coverage, empiric bias and labor intensity. New generation (NGS) whole genome approaches prioritize somatic mutations as initial discovery targets, but the availability of sequenced cohorts allows also for detection of germline lesions both in a targeted and an unbiased fashion. Using NGS we studied 136 pts (mean age, 68.8 years, range 41-85) with MDS and related myeloid neoplasms for the presence of non-synonymous polymorphisms (SNV), which could affect telomerase machinery. These genes included TERT, DKC1, SMG6, NOP10, POT1, WRAP53, NHP2, GAR1, TINF2. No somatic defects of the telomerase complex were detected. We focused on novel sequence alterations or those described in available databases with a population allelic frequency of less than 5%. We identified 45 non-synonymous germline sequence alterations in 39 cases (32%). Most frequent SNV were found in TERT (n=15), DKC1 (n=7), SMG6 (n=6), NOP10 (n=4), POT1 (n=4), WRAP53 (n=4), while observations of NHP2 (n=3), GAR1 (n=1), TINF2 (n=1) were less prevalent. These variants were distributed in an almost mutually exclusive manner. Out of 3 variants in TERT, p.H412Y (n=3) and p.A279T (n=9) were reported to be pathogenic in bone marrow failure syndromes. In addition, p.A999T found in 8 cases in our cohort could also be pathogenic since it is less frequent in healthy controls. Similarly, p.441_442del (n=1), located in the N-terminal region, is a completely novel germline variant not detected in 6500 samples publicly available in ESP6500. In the pAML cohort (TCGA; n=197), the observations of germline variants for these telomerase complex genes were SMG6 (n=21), POT1 (n=19), NHP2 (n=1), NOP10 (n=1) GAR1 (n=1). Next, we analyzed clinical characteristics, including treatment responsiveness as assessed per modified 2006 IWG response criteria. The mean age of the 39 patients with germline telomerase machinery alterations was 67 years, 24% (9/39) were younger (age<60 years) compared to 12% (12/97) of wild type (WT; p=.12). Of note, 58% of these cases had a family history of solid tumors including breast, gastrointestinal and prostate and 8% (3/36) had a family history of myeloid malignancies. 41% (16/39) of the telomerase mutants had higher-risk MDS/sAML at presentation compared to 23% in WT cases (23/97; p=.19). A higher percentage of mutants also had complex cytogenetics compared to WT (35% vs. 13%; p=.01). Response rates to common therapies, including hypomethylating agents were similar, but we noted that none of the carrier cases (n=16) treated with lenalidomide showed therapeutic responses (0% vs. 37%). The mean overall survival of the carrier cases was lower compared to the WT (36 vs. 39 months, p=.10). When we studied cases with telomerase alterations for the presence of coinciding somatic mutations, using a targeted deep sequencing panel of the 100 most common mutations acquired in pts with germline telomerase complex alterations, we found most common the acquisition of DNMT3 (18% vs. 6%, p.10) and cohesin mutations (13% vs. 4%,p=.11). In sum, unbiased NGS sequencing approaches in MDS and related myeloid neoplasms allowed for identification of genetic germline alterations in telomerase maintenance machinery at higher rates than previously detected using targeted screening approaches, suggesting that such genetic defects may more frequently than previously thought contribute to cryptic and likely complex genetic predisposition to these diseases. Disclosures: Makishima: AA & MDS international foundation: Research Funding; Scott Hamilton CARES grant: Research Funding

Predictors of vascular disease in myelodysplastic syndromes

Abstract The escalating link between somatic mutations commonly seen in myelodysplastic syndromes (MDS) and atherosclerotic vascular disease has increased the interest in management and associations of these conditions. We present a retrospective study examining clinical and molecular variables associated with vascular disease in patients with MDS. This study included a comprehensive evaluation of 236 patients with MDS. Our study has multiple findings. Mutations in ASXL1 correlated with increased risk of vascular disease for the entire cohort (P = .013). Though this has been replicated in other studies, there are no guidelines at this time for preventing vascular events in these patients. Our study also showed that lower ferritin levels may be linked to increased vascular events (P = .043), therefore the optimal use of supportive red blood cell transfusions in patients with MDS and the overall impact of inflammatory markers such as erythrocyte sedimentation rate and c‐reactive protein should be re‐addressed. Furthermore, our study showed that patients with Trisomy 8 in the low‐risk MDS cohort (based on IPSS‐R scores) were protected from vascular events (P = .036). Our findings of lower ferritin being linked with increased risk of vascular events as well as patients with Trisomy 8 being protected from vascular events may impact patient care. There do not appear to be any prior studies with these findings. In addition, given the connection between MDS and atherosclerotic vascular disease, we believe guideline‐based management of cardiac risk factors among MDS patients may improve overall outcomes. Further studies with larger patient cohorts are needed to further investigate these findings

Genetic alterations of the cohesin complex genes in myeloid malignancies

Somatic cohesin mutations have been reported in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). To account for the morphologic and cytogenetic diversity of these neoplasms, a well-annotated cohort of 1060 patients with myeloid malignancies including MDS (n = 386), myeloproliferative neoplasms (MPNs) (n = 55), MDS/MPNs (n = 169), and AML (n = 450) were analyzed for cohesin gene mutational status, gene expression, and therapeutic and survival outcomes. Somatic cohesin defects were detected in 12% of patients with myeloid malignancies, whereas low expression of these genes was present in an additional 15% of patients. Mutations of cohesin genes were mutually exclusive and mostly resulted in predicted loss of function. Patients with low cohesin gene expression showed similar expression signatures as those with somatic cohesin mutations. Cross-sectional deep-sequencing analysis for clonal hierarchy demonstrated STAG2, SMC3, and RAD21 mutations to be ancestral in 18%, 18%, and 47% of cases, respectively, and each expanded to clonal dominance concordant with disease transformation. Cohesin mutations were significantly associated with RUNX1, Ras-family oncogenes, and BCOR and ASXL1 mutations and were most prevalent in high-risk MDS and secondary AML. Cohesin defects were associated with poor overall survival (27.2 vs 40 months; P = .023), especially in STAG2 mutant MDS patients surviving >12 months (median survival 35 vs 50 months; P = .017)

Germline Events In GFI1 In Myelodysplastic Syndrome

Abstract Germ line mutations in growth factor independent-1 (GFI1) have been described in a small subset of patients (pts) with severe congenital neutropenia. Subsequently, the GFI136N polymorphism, present in 3-5% of controls, has been found overrepresented (11%) in pts with primary (p) acute myeloid leukemia (AML), conveying 1.6 fold risk of development of AML. Mutant GFI136S and N variants lack affinity to HOXA9 (overrepresented in corresponding AML cases), shows increased proliferative potential in vitro and accelerates RAS-driven myeloproliferative neoplasm (MPN) disease in mice. Whole exome next generation (WE NGS) technology facilitates comprehensive screens for the presence of both somatic and germ line genetic alteration. In this study, we used NGS to search for germline variants of the GFI1 gene. We screened 140 pts (mean age 66.8 years, range 44-85) with MDS and related disorders (MDS/MPN and secondary (s) AML) for the presence of GFI1 variants. We found non-synonymous variants in 11 cases (8%), including the previously described pathogenic p.S36N (n=8), p.P107A (n=2), or p.L400F (n=1), while the corresponding frequencies for these alterations were .04 and .001, .002 in the general population. This frequency appears comparable or higher to those previously reported for pAML, but our screen of the TCGA AML cohort, perhaps due to very low coverage for this gene, did not reveal any GFI1 polymorphisms. We next focused on the clinical features of altered GFI1 carriers. A significant proportion of GFI1 cases were younger (age<60 years) 45% (5/11) compared to 19% (p=.05) for wild type (WT) and predominantly male (82% vs. 52%, p=.02). MDS and sAML and MDS/MPN were present in 4, 3 and 4 pts, respectively. Normal cytogenetics at presentation was present in 64% vs. 43% (p=0.22). The availability of the somatic mutational profile allowed us to investigate whether specific genes are more commonly mutated in GFI1 variant cases. Among the 100 most commonly mutated genes, somatic PTPN11 (18% vs. 2%, p=.09), ASXL1 (18% vs. 8% p=0.2), SF3B1 (18% vs. 9%, p=0.3) were the most frequently encountered. Response rate to therapy with hypomethylating agents amongst carriers of GFI1 variants was 50% compared to 35% among WT (p=.32). The mean overall survival of the GFI1mutants was also higher compared to WT (40 vs. 33.6m). In sum, our results demonstrate that potentially pathogenic GFI1 mutations are present in increased frequency in younger pts with MDS and thus may constitute a new predisposing factor for MDS and related myeloid neoplasms. Disclosures: Makishima: AA & MDS international foundation: Research Funding; Scott Hamilton CARES grant: Research Funding. Maciejewski:NIH: Research Funding; Aplastic anemia&MDS International Foundation: Research Funding