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  • 1
    Publication Date: 2015-12-03
    Description: Background Improving strategies for patients (pts) with relapsed/refractory (R/R) Hodgkin lymphoma (HL) who fail stem cell transplantation (SCT) or are unsuitable for the procedure remains an essential need. Lenalidomide and bendamustine are active and well tolerated as single agents in recurrent HL, with overall response rates (ORR) of 30% to 53% [Fenhinger, 2012; Corazzelli, 2012; Moskowitz, 2012].These agents independently frame different targets on tumor and microenvironment cells and may cooperate to override disturbed immunologic pathways and circumvent drug resistance in HL. In a Bayesian, multi-center, open label phase 1/2 study, we investigated for safety and efficacy the combination of continuous lenalidomide with weekly bendamustine (ClinicalTrials.gov # NTC01412307). Methods The study aimed at defining the optimal daily dose of continuous lenalidomide (10, 15, 20 or 25 mg) as combined, in a 28-day cycle, to weekly fixed-dose bendamustine (60 mg/m2; d 1, 8, 15). The dose-finding algorithm proceeded in cohorts of 3 pts, based on anticipated efficacy and toxicity pairs of probability (Thall & Cook, Biometrics 2004). Trade-offs between response [Cheson 2007 criteria] and dose-limiting toxicity [CTCv3.0 grade (G) 〉3 lasting 〉2 weeks] were assessed after 2 cycles (day +56) and pts were planned to receive up to 6 total courses, unless progression or unacceptable toxicity occurred. ORR and progression-free survival (PFS) were additional endpoints. Results Thirty-six pts (69% male) with a median age of 31 yrs (r 19-75) were enrolled. The median number of prior therapies was 4 (r 1-9) and the median time from upfront treatment was 24 mo.s (r 7-118). Twenty-six pts (72%) had primary refractory disease after ABVD, 16 pts (44%) failed prior SCT [single (n=7) or tandem (n=3) ASCT, tandem ASCT/alloSCT (n=6)]. Fifteen pts (42%) had previously received a median of 5 cycles (r 2-8) of brentuximab vedotin (BV) and 3 pts were already given bendamustine (〉3 courses). Overall, 23 pts (64%) were refractory to most recent therapy. Eff/Tox trade-offs at cycle 2 showed that 73% of pts had response w/o toxicity, 19% had no response w/o toxicity, 6% had response with toxicity and 2% had no response with toxicity. With such Eff/Tox profiles, the study algorithm did not prompt any dose escalation for lenalidomide after the first 18 pts and the initial dose level (10 mg) was adopted for the expansion phase. A total of 156 LeBen cycles were administered, and pts received a median of 4 courses (r 1-6). Overall, 16 cycles were delayed due to G3/G4 thrombocytopenia (n=6), G4 neutropenia (n=3), G3 pneumonia (n=3), G3 respiratory infection (n=2), G2 phlebitis (n=1), G2 supraventricular arrhythmia (n=1). Two patients discontinued treatment, while in PR and CR after 4 courses, due to protracted (〉2 weeks) thrombocytopenia. No G4 extra-hematological toxicity was observed. The complete response (CR) rate was 44% (16/36) with an ORR of 75% (27/36; 95% CI, 59-86). Notably, substantial CR and PR rates were achieved after LeBen regardless of primary refractoriness, SCT and BV failure (Table). Most CRs (14/16) were obtained within the first 4 cycles; 6 responders (4 CRs and 2 PRs) underwent SCT. Median PFS was 3.2 mo.s (r 1.5-5.4) for pts with progressive (PD) or stable disease (SD) and 11.4 mo.s (r 4-31) for those achieving CR/PR. Median overall survival for the entire cohort was 24 mo.s. Overall, complete responders (including 6 pts consolidated with SCT) had a 2-year disease-free survival of 41% (median, 14.3 mo.s). Conclusions The innovative schedule of the Leben combination is safe, yields high response rates in heavily pretreated and primary refractory HL pts, including SCT and BV failures, and steps over the 'single agent' activity of its components. Due to its immunomodulatory potential the Leben platform is amenable to further upgrading through lenalidomide maintenance, combination with immune checkpoint inhibitors and BV. Table 1. Efficacy results Responsesno. (%) All pts Refractory to upfront therapy Refractory to most recent therapy Failure after SCT Failure after ASCT Failure after AlloSCT Failure after BV Failure after SCT and BV Failure after bendamustine No BV (n=36) (n=26) (n=23) (n=16) (n=10) (n= 6) (n=15) (n=8) (n=3) (n=21) CR 16 (44) 11 (42) 8 (35) 8 (50) 6 (60) 2 (33) 5 (33) 3 (37) 0 11 PR 11 8 9 4 2 2 4 2 0 7 SD 2 2 2 1 0 1 1 1 1 1 PD 7 5 4 3 2 1 5 2 2 2 CR+PR 27 (75) 19 (73) 17 (74) 12 (75) 8 (80) 4 (66) 9 (60) 5 (62) 0 18 (86) Disclosures Pinto: Takeda, Celgene, Roche, TEVA: Honoraria; Takeda: Research Funding. Zinzani:Takeda: Membership on an entity's Board of Directors or advisory committees; J&J: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees.
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  • 2
    Publication Date: 2015-12-03
    Description: Background: The highly unfavorable outcome of patients with recurrent HL, who progress after stem cell transplantation or are ineligible for such procedure make the development of new active agents an impellent medical need in this clinical setting. EDO-S101 is fusion molecule combining the DNA damaging effects of bendamustine (BDM) with the pan-histone deacetylase (HDAC) inhibitor, vorinostat. Given that BDM and HDAC inhibitors are active agents in recurrent HL we investigated the preclinical activity of EDO-S101 in this malignancy. Methods: We assessed the patterns of EDO-S101 cytotoxicity (0.39 to 50 µmol/L) in a panel of HL-derived cell lines (L1236, L428, KMH2, HDLM2, L540) and its regulatory effects on genes involved in DNA-damage/repair response, apoptosis and cell cycle checkpoints. As a further model we exploited an L1236 cell clone (R100) selected for resistance (R) to BDM through continuous exposure to increasing concentrations of the agent. R100 cells display a growth pattern indistinguishable from parental L1236 cells when cultured in the presence of BDM (100 µmol/L). Clonal identity of R100 cells with parental L1236 was confirmed by sequencing of V3-21 (FR2/FR3) and JH3-JH4 Ig DNA regions. Results: EDO-S101 induced a significant time- and dose-dependent inhibition of growth and survival in all HL cell lines. L1236 cells displayed the highest sensitivity to the agent with an IC50, at 48 hrs, of 1.88 µmol/L, as opposed to KMH2, L428, L540 and HDLM2 cells with IC50 of 2.06, 2.53, 2.26 and 16.2 µmol/L, respectively. These values were about 10-fold lower than the IC50 of BDM in the same cell lines. While exposure of L1236 cells to EDO-S101 caused cell accumulation in S-phase, qRT-PCR disclosed that cell death was mainly dependent on triggering of apoptosis, as shown by the early (24 hrs) and sustained (48 hrs) upregulation of NOXA, p21 and p27 genes. Data were confirmed by the significant increase (〉150%) of Annexin V-expressing L1236 cells. In contrast, expression levels of PLK1, AKA and cyclin B1 genes remained unchanged or were increased. This excluded induction of the mitotic catastrophe (MC) as a major determinant of cytotoxic activity for EDO-S101 in L1236 cells. Exposure to EDO-S101 induced a strong DNA stress/repair response as shown by the activation of pATR/pATM and increase of the downstream DNA damage checkpoint proteins pCHK1-/-2 and CCNB1, along with the upregulation of the EXO1 gene. Most intriguingly, BDM-resistant L1236 cells (R100) were highly sensitive to EDO-S101, with an IC50 of only 4.56 µmol/L, but less responsive to vorinostat (IC50: 6.17 µmol/L) than parental L1236 cells (IC50: 0.58 µmol/L). Differently from native cells, EDO-S101 induced a late downregulation of transcripts for PLK1 and AKA genes and of cyclin B1 gene and protein in R100 cells, along with the early induction of NOXA and p21, but not p27 genes. In both L1236 and R100 cells, expression of MC-genes was unaffected by exposure to vorinostat. This suggests a more complex mechanism for EDO-S101 in BDM-resistant HL cells involving activation of the both apoptotic and MC pathways. Notably, we documented that EDO-S101 corrected the constitutive ATM/ATR unbalance of R100 cells by triggering the early (24 hrs) upregulation of ATR and a late (48 hrs) downregulation of ATM transcripts and proteins, along with increased levels of EXO1 and MGMT at 24 hrs. Vorinostat induced a similar effect. Finally, while baseline expression levels of HDAC isoforms were comparable among HL cell lines, EDO-S101 caused a significant (〉40%) late downregulation of transcripts for all HDAC isoforms (HDAC-1 to -8) in R100 cells but only of HDAC-6 in native L1236. This pattern diverged from results obtained in both L1236, i.e. increase of all HDAC isoform transcripts except HDAC-6, and R100 cells, i.e. upregulation of all isoforms and reduction of HDAC-6, with vorinostat and BDM as single agents. Conclusions: We have described for the first time that EDO-S101 is effective in preclinical models of HL including cells resistant to BDM. The combined functions of in one molecule of a bifunctional alkylator and panHDAC inhibitor confer this agent unique antitumor property different from both of its single drug components. Following a strong DNA damage response, triggering of apoptosis and/or MC may take place in HL cells according to their sensitivity status to BDM. A phase 1/2 study in recurrent HL, including patients pretreated with BDM, is next to be launched. Disclosures Mehrling: 4Mundipharma-EDO GmbH, Basel, Switzerland: Employment. Pinto:Takeda, Celgene, Roche, TEVA: Honoraria; Takeda: Research Funding.
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  • 3
    Publication Date: 2012-11-16
    Description: Abstract 2763 Patients with HL recurring after stem cell transplantation (SCT) are mostly incurable. Therefore development of new agents and strategies is an impellent medical need in this setting. BDM is a hybrid purine analogue/bi-functional alkylator active in B-cell tumors. Despite preliminary evidences of efficacy in refractory HL, the molecular mechanisms underlying the potential activity of BDM towards malignant H-RS cells were never explored. We investigated patterns of BDM cytotoxicity (12.5 to 100 mmol/L) in a panel of HL-derived cell lines (L1236, L428, KMH2, HDLM2, L540) and its time-dependent (8, 24, 48, 72 hrs) effects on genes involved in DNA-damage stress and repair response, apoptosis and cell cycle checkpoints by Q-RT-PCR. BDM induced a significant time- and dose-dependent inhibition of growth and survival in all cell types. L1236 cells displayed the highest sensitivity to the agent with an IC50, at 48 hrs, of 10.7 mmol/L, as opposed to KMH2, L428, L540 and HDLM2 cells with IC50 of 11.1, 12.4, 14.8 and 16.2 mmol/L, respectively. BDM elicited a dose-dependent increase of apoptosis (30% to 50% at 72 hrs) in all cell lines, as shown by Annexin-V/propidium iodide staining. The exquisite sensitivity to BDM of L1236 cells was confirmed by clonogenic assays, since these cells, after a 24 hr exposure, showed the lowest IC50 for secondary colony formation (0.7± 0.06 mmol/L) as compared to all other cell lines (IC50 range: 3.1 ± 0.28 to 15.0 ± 1.27 mmol/L). Most notably, however, BDM, within the same concentration range, activated different cell death subroutines among the various cell lines. Q-RT-PCR disclosed that BDM-induced cell death in L1236 was mainly dependent on triggering of apoptosis, as shown by the early (8–24 hrs) up regulation of the proapoptotic genes NOXA and p21, but not p27, without appreciable changes in expression levels of genes related to activation of the mitotic catastrophe process, i.e. PLK1, Aurora A kinase (AAK), and cyclin B1. In contrast, induction of mitotic catastrophe was a main determinant of BDM action on KMH2, L428 and L540 cells, as shown by early (8 hrs) and sustained (48 hrs) down-regulation of PLK1, AAK and cyclin B1 genes, without early changes in NOXA and p21 expression levels. This was confirmed by highly aberrant mitosis and further multinucleation. Interestingly, BDM induced the sequential activation of both these cell death pathways in HDLM2 cells only. In this cells, the early (8–24 hrs) down regulation of PLK1, AAK and cyclin B1 genes, was later (48–72 hrs) followed by a significant induction of NOXA, p21 and p27 genes. The highest sensitivity of L1236 cells to BDM correlated with the delayed (72 hrs) induction of the DNA-repair genes EXO-1 and ATR, but not ATM, as opposed to the earlier (24 hrs) and sustained up regulation of these DNA-repair genes, and of ATM, in all other cell types. Accordingly, only after 72 hrs from exposure to BDM, the proliferation-related genes C-MYC, E2F2 and cyclins (D1, D2) were up regulated in surviving L1236 cells, along with a 〉70% reduction in G0/G1 cells, a significant (48%) increase of cells in the G2 phase of the cell cycle and a 20% increment of those in S phase. Conversely, in the other cell lines, S phase accumulation (35% to 60.5% increase) and up regulation of proliferation-related genes in surviving cells occurred, as early as 24 hrs after exposure to BDM. Overall, these results indicate that BDM affects different cell death pathways among HL-derived cell lines. Specifically, in L1236 cells the agent induces the early up regulation of proapototic genes and G2 arrest, accompanied by a delayed activation of DNA repair genes. This changes may lead to cell death through apoptosis rather than mitotic catastrophe which, conversely, appeared the predominant cell death pathway activated by BDM in the other cell lines. Notably, while determinants of BDM toxicity in ‘bona fide’ HL cell lines consistently overlap with those described for tumor B-cells of non-Hodgkin lymphomas (mitotic catastrophe), L1236 cells display a different response pattern to the agent, more reminiscent of BDM action on myeloma tumor cells. Since only L1236 cells are clonotypically related to primary H-RS cells from which were derived, our results suggest that optimal BDM dosing and scheduling in HL may be different from those adopted for other B-cell tumors. In this sense, a lower BDM dosing through a weekly schedule is currently being tested at our institution in refractory HL. Disclosures: No relevant conflicts of interest to declare.
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  • 4
    Publication Date: 2009-11-20
    Description: Abstract 267 Introduction: The tumor cells of HL, the Hodgkin and Reed-Sternberg (H-RS) cells, derive from germinal center B-cells with a deranged B-cell transcription program due to epigenetic silencing and acquired genetic lesions. Tissue H-RS cells are surrounded by a preponderant infiltrate of mixed non-malignant reactive cells, including B-lymphocytes, which provide essential signals for their survival and proliferation. Small percentages of B-cells, clonally related to H-RS cells, were found in the blood of HL patients (pts), suggesting they may represent putative HL-initiating cells (Jones, 2009). Since the serum free light chain (sFLC) assay detects and quantifies monoclonal and polyclonal B-cell populations expanding in lymphohemopoietic tissues, we exploited the sFLC testing to further explore the biologic significance of B-lymphocytes in HL. Patients and Methods: Frozen (-80°C) serum samples from 119 untreated cHL pts (48% males), with normal renal function and serum immunochemistry, were assayed by immunonephelometry (Freelite, The Binding Site, Ltd., UK). After quantization of free κ and λ concentrations (normal ranges, κ: 3.3-19.4 mg/L; λ: 5.71-26.3 mg/L), sFLC κ/λratio was calculated (reference range 0.26-1.65). The median age was 31 years (r, 15–70), with 22% aged ≥ 45 years. Histology was nodular sclerosis in 85 pts (71.4%) and 72 (60.5%) were in stage I–II. According to GHSG criteria, 16% had early favorable, 29% early unfavorable and 55% advanced disease. The International Prognostic Score (IPS) was of 0-2 and ≥ 3 in 66.4% and 33.6% of pts, respectively. Following ABVD (4-6 courses ± RT), the median Event-free survival (EFS) was 78 mo.s [95% CI, 68-88] for the entire population and 75 mo.s [95% CI, 60-90] and 64 mo.s [95% CI, 50-77] for pts in early and advanced stage, respectively. Results: Elevated κor λsFLC concentrations were found in 47% (median 29.55 mg/L; r, 19.44 - 64.70) and 29.4% (median 32.70 mg/L; r, 26.60 - 79.77) of pts, respectively. In 30 pts (25.2%) levels of polyclonal κ and λ sFLC were concurrently elevated. The sFLC κ/λratio was abnormal in only 7.5% of pts (clonal λ: 8/119; clonal λ: 1/119). The presence of high sFLC levels correlated with lymphopenia (〈 0.6 × 109/L; p= 0.04), leukocytosis (WBC 〉 15 × 109/L; p=0.03), ESR (〉 50; p=0.04) and unfavorable IPS (≥ 3; p=0.03), but not with EBV status and risk factors such as stage, B symptoms, bulky and extra nodal disease, LDH and albumin. The association with leukocytosis may in part result from inhibition of spontaneous neutrophils apoptosis exerted by FLC (Cohen, 2003). Most interestingly, while we found no significant association with response rate, baseline elevation in sFLC predicted for EFS in 51 evaluable pts with early stage disease. Patients were divided into tertiles and best break point value for predicting EFS coincided with the upper limit of the highest tertile for both κ (〉25.53 mg/L) or λsFLC (〉26.66 mg/L) (Figure 1). The pts in the top tertile had the worst outcome compared with the 2 lower tertiles (κ, p=0.015; λ, p=0.002). Outcomes for the 2 lower tertiles were comparable. Data remained significant after stratification for the IPS. In contrast, baseline sFLC levels, κ or λ, were not predictive for EFS in pts with advanced disease. Interestingly, sFLC levels in a control group of 30 pts in continuous CR from 2 years, were within the normal ranges. Conclusions: We have shown that about 50% of cHL pts displays elevated levels of sFLC mirroring the presence of a consistent polyclonal B-cell expansion at diagnosis. The role of reactive B-cells in HL is poorly understood. While some data indicate that high intratumoral B-cell counts may predict for a better outcome, the activity of rituximab in cHL, regardless of CD20 expression on H-RS cells, was suggested to result by depletion from the HL microenvironment of normal B lymphocytes required for tumor cell growth (Younes, 2003). Our study support that elevated sFLC levels may reflect an increased polyclonal B cell activity in cHL microenvironment which appears to negatively influence the outcome of pts in early stage disease. This effect is lost in advanced disease, suggesting that rituximab might result more active for pts in early than advanced stages. That putative HL-initiating small B-cells may emerge from the expanded polyclonal B-cell population present from the early phases of disease development, is an intriguing possibility. Disclosures: Marchei: Radim, Italy: Employment. Amoroso:The Binding Site, Ltd: Consultancy.
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  • 5
    Publication Date: 2015-12-03
    Description: Background: Given the consistent antitumor activity and favorable toxicity profile in heavily pretreated patients, BDM represents a suitable platform for combination with target-based agents in the setting of recurrent HL. The anti-CD30 antibody-monomethyl auristatin E (MMAE) conjugate brentuximab vedotin (BV) appears a most valuable candidate by coupling an impressive clinical activity with the lack of serious overlapping toxicities with BDM. While the combination of BDM and BV is being evaluated in Phase II studies, no information is available as to possible mechanisms through which BDM may regulate the antitumor efficacy of BV towards HL cells. Methods: We evaluated the effects of acute and extended exposure to BDM on CD30 expression and sensitivity to the cytotoxic activity BV in the HL cell line L1236. Cells were cultured in the presence of BDM at its IC50 for different time points of acute exposure. Through continuous exposure to increasing concentrations (25.0, 50.0, 75.0, 100 micromol/L) of BDM, we then performed a serial in vitro selection for BDM-resistant (R) L1236 cell clones and determined their CD30 expression by flow cytometry, qRT-PCR, and Western analysis. Results: Acute exposure to BDM (48 to 72 hrs) of L1236 cells led to a sizeable upregulation of CD30 as shown by flow cytometry. This effect was unsustained since CD30 intensity returned to baseline levels upon culturing in BDM-free medium for one week. Expression of other surface antigens, i.e. HLA-DR, was unaffected by BDM while acute exposure to doxorubicin and other cytotoxic drugs did not modify the CD30 expression. We established four L1236-derived cell clones (R25, R50, R75 and R100) able to proliferate across the different concentrations of BDM with growth/viability curves superimposable to native cells. Clonal identity among clones and with parental cells was confirmed by sequencing of V3-21 (FR2/FR3) and JH3-JH4 Ig DNA regions. All R-clones displayed an up to 900% increase in CD30 median fluorescence intensity, relative to native L1236 cells (Figure 1A). The sustained CD30 upregulation was confirmed by qRT-PCR and Western blotting since R-clones expressed up to 10-fold higher levels of CD30-specific mRNA and CD30-specific 120 kDa components as compared to parental cells. To rule out a general upregulation of surface molecules as a result of the chronic exposure to BDM we evaluated the expression of other surface antigens. As opposed to CD30, HLA-DR and PDL-1 relative transcript levels and cell surface expression were significantly reduced in R-cells. Intriguingly, BDM-induced CD30 upregulation was specific to L1236 cells since extended exposure to BDM did not modify expression levels of CD30 in other lymphoma cell types (SUDHL1, JEKO). BDM-induced CD30 overexpression significantly enhanced the sensitivity of HL cells to the cytotoxic effects of BV. MTS assay showed the IC50 of R100 cells to BV shifted to 0.21 ± 0.06 mcg/mL (48 hrs) and 0.19 ± 0.05 mcg/mL (72 hrs) vs. 3.16 ± 0.75 mcg/mL (48 hrs) and 3.87 ± 0.68 mcg/mL (72 hrs) of parental cells, a 15- and 20-fold increase, respectively (p
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  • 6
    Publication Date: 2011-11-18
    Description: Abstract 5168 Background: Myeloproliferative neoplasms (MPNs) are a group of diseases characterized by clonal expansion of single or multiple lineages of myeloid subset (i.e. granulocytic, erythroid, megakaryocytic and mast cell). Since 2008, the WHO included the detection of JAK2 mutations (the common V617F and the less common exon 12 mutations), into the diagnostic criteria of MPNs. The specific pathogenic implication of JAK2 mutations in MPNs is still under investigation. Preliminary data emerging from the treatment of Idiopathic Myelofibrosis patients with JAK2 inhibitors have shown only clinically significant benefits (improvement of splenomegaly and constitutional symptoms) but not a clear evidence of disease-modifying activity. Several techniques (e.g. ASO-PCR, ARMS-PCR, Direct sequencing, HRM, DHPLC, etc) have been used to detect the JAK2 V617F mutation, but all of them were low sensitive and time-consuming. We developed a PNA-clamping competitive PCR assay able to detect JAK2 V617F mutation with a very high level of sensitivity and specificity. Methods: In order to promote the selective amplification of the JAK2 V617F mutant allele, a specific PNA oligonucleotide, full matching with the wild-type (wt) sequence of the portion of JAK2 gene containing the V617F mutation, was designed to compete with the reverse primer used in the PCR assay. It was experimentally demonstrated that a PNA concentration of 6 μmol/L occurred for the complete clamping of 100 ng of wt genomic DNA used as template for the PCR reaction. The sensitivity of the assay was determined by a serial dilution (100% through 0.01%) of genomic DNA containing JAK2 V617F mutation, obtained from HEL cell line, with wt DNA obtained from healthy donors. The specificity of PCR products was assessed by sequencing in both forward and reverse directions. The thermal dissociation profile of PNA/DNA and DNA/DNA duplexes was studied by monitoring the Enthalpy as function of the temperature (range 20–100°C), with an heating/cooling rate of 1°C/min. Results: PNA-clamping competitive PCR was able to detect JAK2 V617F mutation with a sensitivity of 0.01%. Thermodynamic studies clearly showed that the melting temperature (Tm) of fully matched PNA/DNA duplex is always higher than Tm of the corresponding DNA/DNA duplex. The enthalpy values for the hybrid PNA/DNA are always greater than the corresponding DNA/DNA duplex and a single mismatch has an energetic cost higher in a PNA/DNA than in DNA/DNA duplex. This energetic cost is more evident in the melting temperature with a ΔTm of 16°C and 7°C for the PNA/DNA and DNA/DNA duplex, respectively. In the PCR assay the PNA complementary to the JAK2 wild type sequence strongly compete with the primer resulting in a complete knock out of the wild type allele. In a blind screening of samples obtained from 308 MPN patients, PNA clamping competitive PCR was able to detect JAK2 V617F mutation in 61.4% cases of Polycythemia Vera, 54.4% of Essential Thrombocythemia, 57.9% of Idiopathic Myelofibrosis and in 21.4% of Ph negative-MPNs, respectively. In 40 unselected patients, PNA clamping PCR results were confirmed by other techniques such as ASO-PCR, ARMS-PCR and direct sequencing. Conclusions: The PNA-clamping competitive PCR assay could be used as convenient, high-sensitive and reliable diagnostic test for detection of JAK2 V617F mutation both on genomic DNA and cDNA samples. As suggested from the thermodynamic studies, a similar technique could be developed for the detection of any known single point mutation, widely contributing to the improvement of molecular diagnostic tests usable in clinical practice. Disclosures: No relevant conflicts of interest to declare.
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