FMS-like tyrosine kinase 3 (FLT3) is a receptor tyrosine kinase family member. Mutations in
, as well known, represent the most common genomic alteration in acute myeloid leukemia (AML), identified ...in approximately one-third of newly diagnosed adult patients. In recent years, this has represented an important therapeutic target. Drugs such as midostaurin, gilteritinib, and sorafenib, either alone in association with conventional chemotherapy, play a pivotal role in AML therapy with the mutated
gene. A current challenge lies in treating forms of AML with extramedullary localization. Here, we describe the general features of myeloid sarcoma and the ability of a targeted drug, i.e., gilteritinib, approved for relapsed or refractory disease, to induce remission of these extramedullary leukemic localizations in AML patients with
mutation, analyzing how in the literature, there is an important development of cases describing this promising potential for care.
Lung cancer remains the leading cause of cancer deaths worldwide. International societies have promoted the molecular analysis of MET proto-oncogene, receptor tyrosine kinase (
) exon 14 skipping for ...the clinical stratification of non-small cell lung cancer (NSCLC) patients. Different technical approaches are available to detect
exon 14 skipping in routine practice. Here, the technical performance and reproducibility of testing strategies for
exon 14 skipping carried out in various centers were evaluated. In this retrospective study, each institution received a set (
= 10) of a customized artificial formalin-fixed paraffin-embedded (FFPE) cell line (Custom
ex14 skipping FFPE block) that harbored the
exon 14 skipping mutation (Seracare Life Sciences, Milford, MA, USA), which was previously validated by the Predictive Molecular Pathology Laboratory at the University of Naples Federico II. Each participating institution managed the reference slides according to their internal routine workflow.
exon 14 skipping was successfully detected by all participating institutions. Molecular analysis highlighted a median Cq cut off of 29.3 (ranging from 27.1 to 30.7) and 2514 (ranging from 160 to 7526) read counts for real-time polymerase chain reaction (RT-PCR) and NGS-based analyses, respectively. Artificial reference slides were a valid tool to harmonize technical workflows in the evaluation of
exon 14 skipping molecular alterations in routine practice.
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Background. Minimal residual disease (MRD) is the strongest prognostic factor in both children and adults with acute lymphoblastic leukemia (ALL). Currently, it is most widely monitored by ...molecular methods based on real-time-quantitative-PCR (RQ-PCR). Digital-droplet-PCR (ddPCR) and next-generation-sequencing (NGS) represent advanced tools that have the potential to overcome some limitations of standard approaches and potentially provide additional benefits. We analyzed adult ALL follow-up (FU) samples by RQ-PCR, ddPCR and NGS in order to better define the discriminating power of these novel methods.
Patients and Methods. Thirty adult ALL patients enrolled in the GIMEMA LAL 1913 protocol and their 83 FU bone marrow (BM) samples were studied. All patients received homogeneous induction/early consolidation chemotherapy, with concurrent MRD analysis at four time-points, to optimize risk classification and support risk/MRD-oriented therapy. RQ-PCR analyses followed the EuroMRD Consortium guidelines (van der Velden, 2007), ddPCR was performed as published (Della Starza, 2016; Cavalli, 2017) and NGS, as previously described (Faham, 2012; Kotrova M, 2017).
Results. By MRD RQ-PCR analysis, 19/83 samples were positive and quantifiable (Q), 9/83 were positive not-quantifiable (PNQ) and 55/83 were negative (NEG). By MRD ddPCR analysis, 27/83 samples were Q, 1/83 sample was PNQ and 55/83 proved NEG. Comparing the results of the two methods, we observed that MRD detection was concordantly positive or negative in 81% (67/83) of FU samples, while 19% (16/83) samples were classified as discordant. Most of the discordances occurred in samples with low levels of disease, i.e. PNQ or NEG: 9/83 were RQ-PCR PNQ, 4 of which were Q by ddPCR and 5 were ddPCR NEG. In the remaining 7 discordant FU samples, 5 were RQ-PCR NEG/ddPCR Q, 1 sample was RQ-PCR Q /ddPCR NEG and 1 sample was RQ-PCR NEG/ddPCR PNQ. The use of ddPCR significantly reduced the proportion of PNQ samples if compared to RQ-PCR - 1/83 (3%) vs 9/83 (15%) - respectively (p=0.0179), increasing the proportion of Q samples: 27/83 (33%) vs 19/83 (23%). It is worth noting that ddPCR also quantified the levels of disease in 9% (5/55) of samples, that were RQ-PCR NEG (Table 1).
MRD analysis was also performed by NGS in 41 samples from 15 patients: 18/41 samples proved Q and 23/41 were NEG. Comparing the MRD detection obtained by both ddPCR and NGS, we observed a concordant result in 98% (40/41) of samples; only 1 sample was ddPCR NEG and NGS Q with a MRD level of 1x10-5. The concordance between RQ-PCR and NGS was 78% (32/41 samples). Moreover, among these 41 samples 9 (from 7 patients) were discordant between RQ-PCR and ddPCR in the first comparative analysis: in 4 RQ-PCR-NEG FU samples, 3 were Q by both ddPCR and NGS, 1 was ddPCR NEG and NGS Q, with a MRD level of 10- 5; 1 subsequent relapse was observed; 4 FU samples that were RQ-PCR-PNQ/ddPCR-Q, were Q also by NGS; 1 subsequent relapse was observed. Finally, 1 RQ-PCR-PNQ sample was negative by both ddPCR and NGS, and no recurrence has so far been observed. Moreover, in the cohort of samples analyzed only by RQ-PCR and ddPCR, in 1 RQ-PCR NEG/ddPCR Q sample a relapse was observed, while the only case that was RQ-PCR Q/ddPCR NEG has so far not relapsed. Notably, 2 of the 3 relapses were documented in patients who were, at decisional treatment TPs, RQ-PCR PNQ or NEG and ddPCR/NGS Q.
Conclusions. When MRD levels are very low, it can be difficult to dissect if the not-quantifiable signal observed by PCR is due to few residual leukemic cells or to a non-specific amplification of normal DNA. The superior sensitivity and accuracy of ddPCR and NGS could be instrumental to univocally define these samples, which presently represent a problematic gray area in the clinical practice of MRD-driven protocols and might be associated with clinical relapse: indeed, among 83 FU samples analyzed we observed 3 relapses, whose FU samples were classified as PNQ or NEG by RQ-PCR, but proved Q by ddPCR and/or NGS. At variance, no relapses were recorded in patients whose FU samples were defined RQ-PCR-PNQ, but proved ddPCR/NGS NEG. Moreover, in 2/3 relapsed cases the change of MRD status (PNQ or NEG vs Q) could have led to a switch in risk classification and therefore in a treatment change. Further studies with a larger number of discrepant cases and a longer FU time will allow to conclusively define the clinical application and implication of these new methods.
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Chiaretti:Shire: Consultancy; Pfuzer: Consultancy; Amgen: Consultancy; Incyte: Consultancy. Foà:NOVARTIS: Speakers Bureau; ROCHE: Other: ADVISORY BOARD, Speakers Bureau; CELTRION: Other: ADVISORY BOARD; ABBVIE: Other: ADVISORY BOARD, Speakers Bureau; CELGENE: Other: ADVISORY BOARD, Speakers Bureau; JANSSEN: Other: ADVISORY BOARD, Speakers Bureau; INCYTE: Other: ADVISORY BOARD; AMGEN: Other: ADVISORY BOARD; GILEAD: Speakers Bureau.
Circulating tumor DNA (ctDNA) has become the most investigated analyte in blood. It is shed from the tumor into the circulation and represents a subset of the total cell-free DNA (cfDNA) pool ...released into the peripheral blood. In order to define if ctDNA could represent a useful tool to monitor hematologic malignancies, we analyzed 81 plasma samples from patients affected by different diseases. The results showed that: (i) the comparison between two different extraction methods Qiagen (Hilden, Germany) and Promega (Madison, WI) showed no significant differences in cfDNA yield, though the first recovered higher amounts of larger DNA fragments; (ii) cfDNA concentrations showed a notable inter-patient variability and differed among diseases: acute lymphoblastic leukemia and chronic myeloid leukemia released higher amounts of cfDNA than chronic lymphocytic leukemia, and diffuse large B-cell lymphoma released higher cfDNA quantities than localized and advanced follicular lymphoma; (iii) focusing on the tumor fraction of cfDNA, the quantity of ctDNA released was insufficient for an adequate target quantification for minimal residual disease monitoring; (iv) an amplification system proved to be free of analytical biases and efficient in increasing ctDNA amounts at diagnosis and in follow-up samples as shown by droplet digital PCR target quantification. The protocol has been validated by quality control rounds involving external laboratories. To conclusively document the feasibility of a ctDNA-based monitoring of patients with hematologic malignancies, more post-treatment samples need to be evaluated. This will open new possibilities for ctDNA use in the clinical practice.
Highlights • Generation of miR-155 network on FLT3-ITD+ AML utilizing data from multiple sources. • Connections among miR-155 and master myeloid transcription factor in FLT3-ITD+ AML. • Inhibition of ...FLT3-ITD decreases p-JUN and miR-155 and increases miR-155 targets. • Inverse correlation between miR-155 and TFs (PU.1 and CEBP-beta) in FLT3-ITD+ AML. • In vitro functional experiments of miR-155 mimic and silencing confirm our model.
Relapsed/refractory AML patients have a poor prognosis; allogeneic hematopoietic stem cell transplantation (HSCT) is the only chance in this setting to achieve long-term disease-free survival (1). ...It was previously established the activity of clofarabine plus cytarabine in AML relapse (clofarabine dosed once daily for 5 days with 40 mg/m2 followed 4 hours later by ara-C at 1 g/m2 per day)(2).However, modifications of this combination in AML therapy of relapsed/refractory patients warrant further evaluation. Therefore, our goal was to determine the efficacy and safety of clofarabine at lower dosage followed by cytarabine (Ara-C) in adult patients with relapsed or refractory acute myeloid leukemia (AML) and to evaluate the capacity of this regimen as a bridge for HSCT.
Patients aged 18-65 years with refractory/relapsed AML were treated at the dose of clofarabine 30 mg/mq on days 1-5 and cytarabine 1000 mg/mq gg on days 1-5. We evaluated the complete remission rate (CRR), duration of remission (DOR) and overall survival (OS). Minimal residual disease (MRD) by molecular targeting was considered in all patients.
Twenty-five (25) patients aged 29-64 years (median 47), who were fit for allogenetic HCT, received one cycle of 30 minutes infusion of clofarabine 30 mg/mq, followed 4 hours later by 3 hours infusion of intermediate dose cytarabine 1000 mg/mq days 1-5. Only in the first three patients this schedule was followed by gentuzumab. Nine (36%) patients had refractory disease (seven after one induction regimen, one after two previous regimes, one after a prior hematopoietic stem cell transplant (HSCT); 16 (64%) patients were in their first (12 patients) or second relapse (4 patients); among the 12 patients in first relapse, 5 were from an allogeneic stem cell transplant. Fourteen patients (56%) achieved a complete remission (CR), seven (28%) was refractory and 4 (16%) died of treatment related mortality. Eleven (44%) patients underwent (9 in CR) to allogeneic transplants or DLI infusion (3 patients refractory, and 8 patients relapsed), only one patient underwent to autologous transplant. One patient, who was relapsed after prior HSCT, obtained a CR but he developed acute graft vs host disease after therapy and died in molecular CR*. Among all patients underwent HSCT after Clofa/Ara-c salvage, six patients (50%) are still alive and in complete remission, six patients (50%) died because of HSCT complications or AML relapse. The complete remission rate (CRR) was (56,00 %), the median Overall Survival was 5 months for all patients (range 1-38 M), 11 Months for those underwent to tranplantation and 1,5 Months for non transplanted group. Treatment was complicated by neutropenic fever (n=17), grade III-IV mucositis (n=2) , skin rush (n=4) grade II- III, hepatic transaminase elevations (n=2). Two (n=5) patient died before their disease status could be evaluated.
These preliminary results suggest that combination treatment with clofarabine 30 mg/mq and ARA-C 1000 mg/mq is effective in this particularly poor prognosis category of patients, resulting in an ORR very favorably, representing a potential “bridge” toward bone marrow transplant procedures (among the 14 patients who achieved a CR, twelve (85%) proceeded to HSCT, and six are still alive). The safety profile is acceptable in this relapsed/refractory population, and our results are very similar to previous regimes using higher clofarabine dosages. More studies with this combination in adults are warranted.
1 Estey E. Treatment of relapsed and refractory acute myeloid leukemia. Leukemia. 2000;14:476-479. 2. Faderl S et al, “Results of a pase 1-2 study of clofarabine in combination with cytarabine (ara-C)”Blood 2005
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No relevant conflicts of interest to declare.
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