NeoGenomics Laboratories Research Articles

Validation of Clinical Prognostic Models and Integration of Genetic Biomarkers of Drug Resistance in CLL Patients Treated with Ibrutinib

Introduction:We previously reported a prognostic scoring system in CLL using pre-treatment factors in patients treated with ibrutinib [Ahn et al, 2016 ASH Annual Meeting]. Here we present long-term follow-up results and validation of the prognostic models in a large independent cohort of patients. We also determine the incidence of resistance-conferring mutations in BTK and PLCG2 genes in different clinical risk groups.Methods and Patients:The discovery cohort comprised 84 CLL patients on a phase II study with either TP53 aberration (deletion 17p or TP53 mutation) or age ≥65 years (NCT01500733). The validation cohort comprised 607 patients pooled from four phase II and III studies for ibrutinib in treatment-naïve or relapsed/refractory CLL (NCT01105247; NCT01578707; NCT01722487; NCT01744691). All patients received single-agent ibrutinib 420mg once daily. We used Cox regression models to identify independent predictors of PFS, Kaplan-Meier method to estimate probabilities of PFS, log-rank test to compare PFS, and Cochran-Armitage trend test to compare the incidence of mutation among subgroups. We used R version 3.5.0 or SAS® version 9.3 for statistical analyses. For biomarker correlation, we tested cellular DNA or cell-free DNA collected from patients in the discovery cohort with the targeted sequencing of BTK and PLCG2 genes.Result:At a median follow-up of 5.2 years, 28 (33.3%) of 84 patients in the discovery cohort progressed or died. 52 (61.9%) patients had treatment-naïve CLL. Independent factors of PFS on univariate analysis were; TP53 aberration, prior treatment, and β-2 microglobulin (B2M) >4mg/L (P<0.05 for all tests). Unmutated IGHV and advanced Rai stage (III/IV) showed a trend toward inferior outcome without reaching statistical significance. Because higher levels of B2M were associated with relapsed/refractory CLL, we performed two multivariate Cox regression models to assess B2M and prior treatment status separately. Risk groups were determined by the presence of TP53 aberration, advanced Rai stage, and B2M >4mg/L for Model 1, and TP53 aberration, advanced Rai stage, and relapsed/refractory CLL for Model 2 (Table 1). The high-risk group had all three adverse risk factors; the intermediate-risk group had two risk factors; and the low-risk group, none or one. The median PFS of the high-risk group was 38.9 months for Model 1 and 38.4 months for Model 2, and was significantly shorter than those of intermediate and low-risk groups.In the validation cohort, 254 (41.8%) of 607 patients progressed or died at a median follow-up of 4.2 years. 167 (27.5%) patients had treatment-naïve CLL. Both models showed statistically significant differences in PFS by risk groups (Table 1). For the high-risk group, 4-year PFS was 30.2% in Model 1 and 30.5% in Model 2, which were inferior to those of intermediate (53.4 and 52.4%) and low-risk groups (68.7 and 73.7%). Model 1 classified 20% of patients and Model 2 classified 28% of patients to the high-risk group.BTK and PLCG2 mutations are common genetic drivers of ibrutinib resistance in CLL. To determine whether the incidence of these mutations correlates with prognostic risk groups, we performed targeted sequencing of BTK and PLCG2 of samples collected from patients in the discovery cohort. We used cell-free DNA for patients who received long-term ibrutinib (≥3 years) and had low circulating tumor burden, and cellular DNA, for samples collected within 3 years on ibrutinib or at progression. Of 84 patients, 69 (82.1%) were tested at least once, and 37 (44.0%) were tested at least twice. The frequency of testing was similar across the risk groups by two models (P>0.05). The cumulative incidences of mutations at 5 years in the low-, intermediate-, and high-risk groups were: 21.4%, 44.8% and 50%, respectively, by Model 1 (P=0.02); and 22.6%, 41.4% and 66.7%, respectively, by Model 2 (P=0.01).Conclusion:We developed and validated prognostic models to predict the risk of disease progression or death in CLL patients treated with ibrutinib. Risk groups classified by three commonly available pre-treatment factors showed statistically significant differences in PFS. The clinically-defined high-risk disease was linked to higher propensity to develop clonal evolution with BTK and/or PLCG2 mutations, which heralded ibrutinib resistance. DisclosuresAlbitar:Neogenomics Laboratories: Employment. Ma:Neogenomics Laboratories: Employment. Ipe:Pharmacyclics, an AbbVie Company: Employment, Other: Travel; AbbVie: Equity Ownership. Tsao:Pharmacyclics LLC, an AbbVie Company: Employment. Cheng:Pharmacyclics LLC, an AbbVie Company: Employment. Dean:CTI BioPharma Corp.: Employment, Equity Ownership; Pharmacyclics LLC, an AbbVie Company: Employment, Equity Ownership. Wiestner:Pharmacyclics LLC, an AbbVie Company: Research Funding.

Venetoclax in Combination with FLAG-IDA Chemotherapy (FLAG-V-I) for Fit, Relapsed/Refractory AML Patients: Interim Results of a Phase 1b/2 Dose Escalation and Expansion Study

Venetoclax in Combination with FLAG-IDA Chemotherapy (FLAG-V-I) for Fit, Relapsed/Refractory AML Patients: Interim Results of a Phase 1b/2 Dose Escalation and Expansion Study

Abstract 4015: A comparative study of PD-L1 IHC 22C3 and 28-8 FDA-approved diagnostic assays in cancer

Abstract Background: Higher levels of PD-L1 expression at the surface of tumor cells have been associated with increased response to anti-PD-1 therapies (Santabarbara G et al. Ann Transl Med. 2016;4:215; Borghaei H et al. N Engl J Med. 2015;373:1627-1639; Brahmer J et al. N Engl J Med. 2015;373:123-135). The FDA has 2 approved tests associated with the use of these agents. The Dako PD-L1 IHC 22C3 kit is approved as a companion diagnostic for the use of pembrolizumab in the first- and second-line non-small-cell lung cancer (NSCLC) settings, where diagnostic testing is required for its use. The Dako PD-L1 IHC 28-8 kit is approved as a complementary diagnostic for nivolumab therapy in second-line NSCLC, where testing is not required for its use. NeoGenomics Laboratories stained a subset of the samples received for PD-L1 testing with both 22C3 and 28-8 on the same biopsy specimen. This dataset presents an opportunity to explore real-world concordance testing for 22C3 and 28-8 antibodies. Methods: The analysis was performed on a dataset obtained from Symphony Health Solutions describing the PD-L1 biomarker test results and annotations reported by NeoGenomics Laboratories between Oct 7, 2015, and Aug 31, 2016. A total of 5217 biomarker test results were available for 4528 patients afflicted by diverse malignancies. Concordance testing was performed on 556 unique patients that had a single 22C3/28-8 pairing collected from the same biopsy specimen. All staining was performed using the FDA-approved in vitro diagnostic assay using the 22C3 antibody or the 28-8 antibody on the Dako Link 48. Cases were reviewed and scored randomly across multiple pathologists, who received special training and certification in scoring. All statistical analyses were performed in SAS. Results: Paired biopsy specimens stained with both 22C3 and 28-8 displayed high degrees of correlation (Spearman’s correlation co-efficient = 0.97). In addition, Bland-Altman analysis revealed that the mean difference in the percentage of tumor cells positively stained for PD-L1 between the paired 22C3 and 28-8 assay findings was 0.48% [95% prediction limit (-12.41% to 13.37%)]. Across expression levels both antibodies displayed a similar probability of being interpreted as greater than one another (43 of 556 where 28-8&amp;gt;22C3 and 40 of 556 where 22C3&amp;gt;28-8), with no clear direction of a single antibody displaying greater sensitivity. When analyzed at the ≥ 1%, ≥ 5%, ≥ 10%, ≥ 25% and ≥ 50% thresholds, the overall rate of agreement was between 96.8% and 98.2% and associated with a level of agreement (Cohen’s kappa) between 0.92 and 0.96. Conclusion: Both the 22C3 and 28-8 diagnostic assays show strong agreement in a single central laboratory real-world setting. These data, in conjunction with recent findings from analytical comparability studies reported elsewhere, support the potential interchangeability of these assays for diagnostic interpretation. Citation Format: Cory Batenchuk, Maher Albitar, Sucha Sudarsanam, Vladislav Chizhevsky, Chelsea Jin, Virginia A. Burns. A comparative study of PD-L1 IHC 22C3 and 28-8 FDA-approved diagnostic assays in cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4015. doi:10.1158/1538-7445.AM2017-4015

Development and Validation of Automated Flow Cytometry System for the Diagnosis and Prediction of Molecular Abnormalities in Myelodysplastic Syndrome

Background: Diagnosis of myelodysplastic syndrome (MDS) is not clear-cut based on morphology or flow cytometry, especially when blast count is not increased. Cytogenetics and molecular profiling remains the most important means for confirming the diagnosis of MDS. Numerous studies have attempted to use flow cytometry-based scores for the diagnosis of MDS. However, most of these scores involve subjective parameters that are difficult to standardize. We developed a flow cytometry software with a capability to automatically capture additional parameters of each gated cell population and used the generated metadata for developing an algorithm for the diagnosis and prediction of molecular abnormalities in MDS then integrated this algorithm as a feature of the software for routine analysis.Methods and Results: This new smart software automatically captures and saves the following parameters from each quadrant from each gate: percentage of cells, mean intensity, dispersion in this quadrant (variance) for each antibody on the X and Y axis, and the correlation coefficient between the X and Y dispersions. Using a standard 23 antibodies panel for leukemia and lymphoma evaluation and conventional gating leads to capturing on the average a 2623 different data points.Using this smart software, we analyzed 294 bone marrow samples referred for suspected diagnosis of MDS due to cytopenia and captured the metadata. All samples had molecular evaluation by NGS using 54 gene panel and majority had cytogenetic data. Patients classified as having MDS if molecular studies or cytogenetic data showed one or more abnormality associated with MDS.Univariate analysis showed that 103 variables to be statistically significant in distinguishing MDS with adjusted P-values less than 0.05 after controlling for false discovery rate (FDR). In multivariate analysis we first used a lasso logistic regression model and selected 40 variables. Using these variables, we developed a predictive model using a support vector machine (SVM) to identify MDS. Upon testing this model using the leave-one-out procedure, the area under the ROC curve was 91.6%. For further validation of this algorithm after integration into the software, we tested blindly additional cohort of 115 patients that had bone marrow submitted for ruling out MDS. The algorithm correctly distinguished between MDS and non-MDS in 104 (90.4%) of these patients using a cut-of point at 0.55 and predicted the presence of cytogenetic abnormality or the presence of one or more genes mutated. Mutations at allele frequency ≥20% are considered adequate for the diagnosis of MDS. Upon correlating the algorithm score with the number of mutated genes as a reflection of the severity of the disease, there was statistically significant (P< 0.0001) correlation between the score and the number of mutated genes (figure).Conclusion: We developed a system in flow cytometry analysis that captures new parameters reflecting dispersion of staining in each gated subpopulation and the correlation between the dispersion of staining antibodies. These new parameters have been proven to be very useful in the diagnosis and prediction of the diagnosis of MDS allowing us to develop automated and reliable algorithm for the diagnosis of MDS and the prediction of level of molecular abnormalities. [Display omitted] DisclosuresAlbitar:Neogenomics Laboratories: Employment, Equity Ownership. Shahbaba:University of California, Irvine: Employment. Agersborg:Neogenomics Laboratories: Employment, Equity Ownership. Chang:Neogenomics Laboratories: Employment. Albitar:Neogenomics Laboratories: Employment. Uyeji:Neogenomics Laboratories: Employment. Luchetta:Neogenomics Laboratories: Employment. Su:Armstrong State University: Employment. Zhang:Armstrong State University: Employment.

Interclonal and Intraclonal Heterogeneity in Patients with IDH1/2 Mutation

Abstract Background: DNA methylation in AML/MDS plays a major role in the pathogenesis of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). The major genes involved in DNA methylation in AML/MDS are IDH1 and 2, TET2 and DNMT3A. Mutations in IDH1/2 result in the production of an aberrant metabolite, 2-hydroxyglutarate, which acts as a competitive inhibitor of a-ketoglutarate and inhibits TET2 oxidation of 5-methylcytosine to 5-hydroxymethylcytosine (5hmC). Mutations in TET2 or IDH1/2 are associated with reduced levels of 5hmC and genomic hypermethylation. TET2 mutations and IDH1/IDH2 mutations are believed to be mutually exclusive. In addition, DNMT3A as a DNA methyltransferase enzyme is commonly mutated in AML/MDS and its mutation is believed to lead to hypomethylation. Understanding the interaction between these genes may influence therapy with IDH1/2 inhibitors. Toward better understanding of interaction between these genes, we analyzed the mutation profile of these genes in patients with AML/MDS. Methods: A total of 1182 bone marrow (BM) aspirate samples were tested by the commercially available TruSight Myeloid Next Generation Sequencing Panel (Illumina, San Diego, CA). We extracted DNA from bone marrow aspirate using the QIAamp DNA Mini Kit. This NGS panel covers hot spot mutations in 54 genes. The average depth of sequencing was 10,000X. Results: IDH1/2 mutations were detected in 201 of the 1182 (17%). IDH1 was detected in 87 (7.4%) and IDH2 was detected in 120 (10.1%). This included 6 patients who had mutations in both IDH1 and IDH2. Variant (mutant) allele frequency (VAF) was significantly higher (P=0.01) in IDH2 as compared to IDH1 (median of 43.35% vs 35.0%, respectively). Thirteen patients (6.5%) had mutant VAF &gt;50% suggesting homozygosity, 11 of which had IDH2 mutation. Two of the 6 patients with both IDH1 and IDH2 mutations had VAF &lt;20%, raising the possibility of two independent clones. TET2 mutations were detected in 15 (7.5%) of the patients with IDH1/2 mutations. There was significant difference (P=0.03) in VAF between IDH1/2 and TET2. Nine of these patients showed comparable VAF while the other 6 patients showed completely different VAF, suggesting subclonal heterogeneity. In addition, 58 (29%) patients showed mutations in IDH1/2 and DNMT3A. While there was no significant difference in VAF between IDH1/2 and DNMT3A, VAF in IDH1/2 was &gt;50% in 6 of these patient and in DNMT3A in 3 patients. Twenty four patients had TP53 mutation, of which 16 had IDH1 mutation and 8 had IDH2 mutation, which is disproportional with the prevalence of IDH1 mutation. There was no statistically significant difference in VAF between TP53 and IDH1/2, but 4 of these patients had both DNMT3 and IDH2 mutations and one had both IDH1 and IDH2 mutations. None of the patients with TP53 mutation had TET2 mutation. Conclusions: IDH2 mutations may coexist with IDH1 and TET2 mutations. This co-mutation appears to be in the same clone in some patients and in a separate clone in others. The presence of VAF&gt;50% in 6.5% of patients, which suggests homozygosity, along with co-presence of IDH1 and IDH2 and TET2 mutations suggests possible dosage effects in the biology of MDS/AML. The high rate (29%) of co-presence of DNMT3A with IDH/1/2 mutations also suggests cooperation between the two mechanisms in influencing DNA methylation and leukemogenesis. The relatively high incidence of TP53 mutation in IDH1 patients suggests that IDH1 mutation might be associated with more aggressive disease than IDH2. This data suggests that there is interaction and significant interclonal and intraclonal heterogeneity in DNA methylation genes in AML/MDS. Complete profiling of these genes is necessary for better understanding and proper prediction of clinical behavior particularly when patients treated with DNA methylation inhibitors. Figure Figure. Disclosures Ma: Neogenomics Laboratories: Employment. Thangavelu:Neogenomics Laboratories: Employment. De Dios:Neogenomics Laboratories: Employment. Funari:Neogenomics Laboratories: Employment. Albitar:Neogenomics Laboratories: Employment, Equity Ownership.

Higher Mutation Rate in Patients with Aplastic Anemia Using Peripheral Blood cfDNA As Compared with Bone Marrow Cells

Background:We have reported that peripheral blood cell-free DNA (cfDNA) is reliable for detecting bone marrow molecular abnormalities in patients with hematologic neoplasms. However, not clear is whether cfDNA is sufficient to detect mutations present at low variant allele frequency (VAF). Since patients with aplastic anemia (AA usually have relatively small clones in blood and bone marrow (BM), we compared mutations detected in BM cells with those detected in peripheral blood cfDNA from patientswith this disease.Methods: A total of 120 paired BM aspirate and PB plasma samples were tested by the commercially available TruSight Myeloid Sequencing Panel (Illumina; San Diego, CA). We extracted DNA from bone marrow aspirate using the QIAamp DNA Mini Kit. We used NucliSenS EasyMAG automated platform for extracting total nucleic acid from PB plasma collected in EDTA. All paired BM and plasma samples were tested by the commercially available TruSight Myeloid Sequencing Panel (Illumina; San Diego, CA), which covers hot spot mutations in 54 genes. The average depth of sequencing was 10,000X.Results: One hundred twenty paired BM and cfDNA samples from 96 patients with aplastic anemia were tested. Of the 96 patients, 33 (34%; equivalent to 48 samples, 40%) had one or more mutations. We identified 54 different somatic mutations in these patients, of which 45 were unique. There was no significant difference (P=0.71, Sign test) in allele frequency between cfDNA and BM. The median mutant allele frequency was 10.9% in cfDNA and 12.6% in BM cells, and 40 of the 54 mutations had allele frequency ≤20% in BM cells, while 45 samples had allele frequency ≤20 in cfDNA. Six of the 33 patients with somatic mutations (18%) showed mutations in plasma cfDNA but not in BM. In contrast, 2 patients (6%) showed mutations in BM cells and not in cfDNA. One of these two patients had a mutation in ASXL1 gene detected in BM cells but not in cfDNA and a subsequent sample showed the same ASXL1mutation in BM cells and not in cfDNA, and a second clone with a different ASXL1 mutation detected in both BM cells and cfDNA. Overall concordance between BM cells and cfDNA in the 120 samples was 92% and there was no statistically significant difference between the two sample types (P=0.6).Summary and Conclusions: Seven samples (from 7 patients) of the 120 tested samples showed mutations in cfDNA and not in BM cells while 3 samples (from 2 patients) showed mutations in BM and not in cfDNA. VAF of mutations in cfDNA were similar to those in BM cells. Therefore, peripheral blood cfDNA should be tested in addition to BM cells for detecting mutations in patients with AA. Peripheral blood cfDNA can be used as a reliable means for monitoring patients with AA. cfDNA testing can be used as an alternative testing to bone marrow even when mutant allele frequency in bone marrow is <20%. cfDNA may be an especially valuable source of mutation detection in marrow failure, in which marrow aspirates may not contain sufficient cells for accurate mutation analysis. DisclosuresAlbitar:Neogenomics Laboratories: Employment. Townsley:Novartis: Research Funding. Ma:Neogenomics Laboratories: Employment. De Dios:Neogenomics Laboratories: Employment. Funari:Neogenomics Laboratories: Employment. Young:GSK/Novartis: Research Funding. Albitar:Neogenomics Laboratories: Employment, Equity Ownership.

Using Next Generation Sequencing of Peripheral Blood cfDNA As a Clinical Test in Screening for Hematologic Neoplasms

Background: The recent advances in molecular techniques and the adaptation of next generation sequencing (NGS) in routine clinical testing increased our ability to use molecular approaches in the diagnosis and classification of most hematologic diseases. Bone marrow aspiration and biopsy remains necessary for initial confirmation of diagnosis of neoplastic processes in bone marrow, but significant literature suggests that screening or monitoring patients by testing peripheral bloodcfDNAmight be a reliable alternative to marrow biopsy and might reduce the need for a painful bone marrow procedure. Here we report the results of routine clinical testing ofcfDNAthat is ordered by practicing hematologist in the context of the presence or the suspicion of the presence of hematologic neoplasm.Methods: A total of 227 peripheral blood samples were submitted for screeningcfDNAfor mutations in a 54 gene focusedMyeloidpanel using NGS sequencing. DNA was extracted from plasma usingNucliSenSEasyMAGautomated platform and then assayed using theTruSightMyeloid Sequencing Panel (Illumina; San Diego, CA) with an average sequencing depth of 10,000X. The average age patients was 71 (18-96) years. The reason for submitting samples wasruling out MDS in 199 and ruling out AML or other hematologic neoplasms in 28 samples. Of these samples, 12 patients had a follow up testing of bone marrow aspiration sample.Results: Of the 227 tested samples (Figure 1), 126 (55%) showed no evidence of mutation in any of the tested genes. Based on our previous data (see ASH abstract by Albitar et al, 2016), this suggested that MDS can be ruled out in these patients and bone marrow biopsy could be avoided and not recommended. In contrast, 101 (45%) had mutations in one or more genes. Twenty-nine (~12.8%) contained a mutation in a single gene with variant allele frequency (VAF) <20% in one gene and were considered not diagnostic for the presence of clinically significant hematologic neoplasm, but follow up was recommended. Of these patients, one had a mutation in JAK2 at VAF of 6% and a second had a mutation in CALR gene at VAF of 7%, which most likely suggest the presence of early evolvingmyeloproliferativeneoplasms. Seventy-four patients (33%) had mutations in two or more genes or in one gene but with VAF≥20% and considered diagnostic for the presence of hematologic neoplasm and bone marrow morphologic evaluation was recommended. The most commonly mutated gene in these patents was TET2, detected in 30 samples, of which 8 also showed a second mutation in TET2, followed by ASXL1, and DNMT3A mutated in 24 and 26 samples, respectively. Samples containing a TET2 mutation were more likely to have a second mutation in TET2 or another gene, in contrast other genes that were frequently mutated did not show this trend (see Figure). TP53 gene was mutated in 16 samples, 7 of which as a single abnormality with VAF <20% therefore was reported as of unknown significance and recommended ruling out neoplasms in hematologic (lymphoid and myeloid) as well as solid tumors. SF3B1 gene mutations were detected in 19 samples and recommended ruling out refractory anemia with ringsideroblasts(RARS). Despite the small sampling (12 samples), follow up usingcfDNAtesting reliably recapitulated original bone marrow Biopsy’s findings. In one patient, additionalsubcloneswere detected incfDNAthat were not detected in the bone marrow aspirate.Conclusions:cfDNAtesting is reliable approach to screen for the presence of Hematologic neoplasm and potentially could avoid the need for bone marrow biopsy in almost half the patients expected to have MDS or otherhematopoeticneoplasms. Positive diagnosis can be confirmed in additional 45% of patients and only 12.8% of patients will be reported with questionable results. Except for those with TP53 mutations, the rest of the 12.8% cases can be classified as Clonal Hematopoiesis of Indeterminate Potential (CHIP). While bone marrow is still the gold standard, our real world experience shows liquid biopsies can be sensitive and non-invasive approach to rule out MDS or other hematological diseases. [Display omitted] DisclosuresFunari:NeoGenomics Laboratories: Employment. Ma:Neogenomics Laboratories: Employment. Thangavelu:Neogenomics Laboratories: Employment. De Dios:Neogenomics Laboratories: Employment. Albitar:Neogenomics Laboratories: Employment, Equity Ownership.

Myeloid Neoplasm Gene Somatic Mutations in Patients with Severe Aplastic Anemia Treated with Eltrombopag and Standard Immunosuppression

▪The major complication of severe aplastic anemia is clonal evolution, defined as any new cytogenetic abnormality or progression to MDS/AML, which occurs in about 15% of SAA patients, usually many months to years after the diagnosis. Eltrombopag, a thrombopoietin receptor agonist, appears capable of stimulating hematopoietic stem cell proliferation in patients with bone marrow failure. Addition of eltrombopag to standard immunosuppressive treatment (IST) with horse antithymocyte globulin (hATG) and cyclosporine (CsA) markedly increases hematologic response rates in treatment-naive SAA, with overall response rates up to 90% and complete response rates approaching 60% (Townsley DM et al, ASH 2015, clinicaltrials.gov NCT01623167). In comparison, IST alone achieves 60% overall response rates, of which 10% are complete (Scheinberg Blood 2012). Somatic mutations in myeloid cancer candidate genes are present in one-third of patients after IST alone (Yoshizato T et al, NEJM 2015). Specific subsets of mutations were associated with clinical outcomes: a group including ASXL1 and DNMT3A with a poor response to IST, inferior survival, and clonal evolution, while BCOR and PIGA were associated with good response and favorable outcomes. Monosomy 7, the most prevalent cytogenetic abnormality defining clonal evolution, can develop in the absence of gene mutations, underscoring the non-determinative and complex role mutations play in clonal evolution (Dumitriu B et al, Blood 2015). Of patients with disease refractory to IST who were subsequently treated with single-agent eltrombopag, 19% (8/43) developed cytogenetic abnormalities, usually within the first year of treatment, but only rarely with morphologic changes consistent with MDS/AML (Desmond R et al, Blood 2014). The frequency of somatic mutations following treatment with eltrombopag added to IST in treatment-naïve SAA patients is unknown.We used amplicon-based next-generation sequencing to assess mutations in 54 candidate genes recurrently mutated in myeloid neoplasms. Bone marrow cells of 90 subjects who had been treated with IST/eltrombopag were obtained at 6 months following treatment initiation, or at the time of clonal evolution. At least one detectable mutation was identified in 21 (23%) subjects. All 21 patients had exhibited a hematologic response to treatment by 6 months; of those patients with somatic mutations, 14 of 19 (74%) had a complete hematologic response. In comparison, of the 69 patients who lacked mutations, 20 (29%) had a complete response. Nine different genes were mutated in total, with the most frequent genes being ASXL1 and BCOR. BCOR was associated with more robust responses (6 of 7 had a complete response) and younger age (range 12 - 49 years; Table). One subject with a longstanding history of JAK2-positive essential thrombocytosis and myelofibrosis at baseline had two additional mutations detectable following treatment, TET2 and ASXL1.With a median follow up of 21 months, clonal cytogenetic evolution occurred in 7/90 (8%) subjects. Three of seven patients also had a mutation in a myeloid cancer gene (two with DNMT3A and one with ASXL1/RUNX1); in the other four, no somatic mutation was detected, either at the 6-month time point or at time of cytogenetic evolution. Four patients had monosomy or partial deletion of chromosome 7: one patient had complex (t(3;3)(q21;q26), -7), one patient had deletion 13q that later disappeared, and one patient had trisomy 6 and trisomy 15 in 2 metaphases. The patient with complex cytogenetics did not have somatic mutations detected at evolution, and she later died due to relapsed AML following transplant.The rates of somatic mutations in myeloid cancer genes and of cytogenetic evolution in patients treated with IST/eltrombopag do not appear to be higher than we and others have reported in aplastic anemia treated with standard IST, without eltrombopag (Kulasekararaj AG et al, Blood 2014). The distribution of genes mutated and the allelic frequency of these mutations also were similar to patients treated with standard IST. These results suggest that the benefits of a higher response rate and quality of response associated with the addition of eltrombopag to IST for the initial treatment of SAA are not associated with a higher risk of clonal progression. [Display omitted] DisclosuresTownsley:GSK/Novartis: Research Funding. Cooper:GSK/Novartis: Research Funding. Winkler:GSK/Novartis: Research Funding. Scheinberg:Novartis: Consultancy, Speakers Bureau. Rios:GSK/Novartis: Research Funding. Weinstein:GSK/Novartis: Research Funding. Desierto:GSK/Novartis: Research Funding. Fernandez Ibanez:GSK/Novartis: Research Funding. Dunbar:GSK/Novartis: Research Funding. Ma:Neogenomics Laboratories: Employment. Albitar:Neogenomics Laboratories: Employment, Equity Ownership. Young:GSK/Novartis: Research Funding.

Company Profile: NeoGenomics Laboratories, Inc.

NeoGenomics Laboratories, Inc. is a publicly traded high-complexity national clinical laboratory company that specializes in cancer diagnostic testing, focused on molecular and genomic approaches. NeoGenomics has been associated with innovation in providing world-class pathology and cancer genetic diagnostic services for pathologists, oncologists, urologists and gastroenterologists, as well as hospitals throughout the USA. The company mission also includes the integration of technical advances in molecular methodologies including computer-aided pattern-recognition mathematical algorithms in order to integrate data from multiple analytes and thereby develop precise (personalized) predictive tools for the diagnosis of disease, prognosis and response to therapy. The company has a unique business model in that it is committed to partnering with routine diagnostic laboratories, thereby providing them with the option of technical-component-only testing for esoteric biomarkers and allowing local control of the professional component, in the interpretation and the review of raw data. The company, through innovative research and development, is dedicated to the cost-effective delivery of leading-edge, high-quality patient care through the application of precise and personalized laboratory medicine.

Correlation Between Histologic Assessment and Fluorescence In Situ Hybridization Using MelanoSITE in Evaluation of Histologically Ambiguous Melanocytic Lesions

The 4-probe, multicolor, fluorescence in situ hybridization (FISH) panel targeting chromosomes 6 and 11 has shown promising sensitivity and specificity in distinguishing between benign nevi and malignant melanoma. Only a few studies have assessed the potential utility of FISH in classification of histologically ambiguous melanocytic lesions. In the United States, this assay is exclusively licensed to NeoGenomics Laboratories (Irvine, California), which provides the technical component and has developed an innovative service (MelanoSITE) allowing pathologists to interpret FISH results using a dedicated Web portal. Thus far, use of MelanoSITE as a diagnostic adjunct in the diagnosis of melanocytic lesions has not, to our knowledge, been reported in the literature. To analyze 1.5 years of experience with the MelanoSITE melanoma FISH assay in the evaluation of histologically ambiguous lesions in the context of second opinion and routine dermatopathology practice. A prospective histologic/FISH correlation study of 140 cases. Twenty-seven percent of abnormal FISH results were false-positive results because of tetraploidy. After correcting for known false-positive results, all lesions considered atypical nevi showed normal FISH signals. Abnormal FISH signals were reported in 30% of lesions considered histologically borderline and in 48% of lesions in which a diagnosis of melanoma was favored. Four-probe, multicolor FISH results for melanoma correlate with the microscopic assessments of histologically ambiguous lesions. Pathologists using MelanoSITE must be aware of the high rate of false-positive results from tetraploidy.