Feasibility of Leukemia-Derived Exosome Enrichment and Co-isolated dsDNA Sequencing in Acute Myeloid Leukemia Patients: A Proof of Concept for New Leukemia Biomarkers Detection.

Exosomes are extracellular vesicles playing a pivotal role in the intercellular communication. They shuttle different cargoes, including nucleic acids from their cell of origin. For this reason, they have been studied as carriers of tumor markers in different liquid biopsy approaches, in particular for solid tumors. Few data are available concerning exosomes as markers of myeloid neoplasia. To better understand their real potential and the best approach to investigate leukemic exosomes, we present the results of a pilot feasibility study evaluating the application of next-generation sequencing analysis of dsDNA derived from exosomes isolated in 14 adult patients affected by acute myeloid leukemias. In particular, leukemia-derived exosome fractions have been analyzed. The concentration of dsDNA co-extracted with exosomes and the number and types of mutations detected were considered and compared with ones identified in the Bone Marrow (BM) and Peripheral Blood (PB) cells. Exosomal DNA concentration, both considering the cargo and the DNA surrounding the lipid membrane resulted in a linear correlation with leukemic burden. Moreover, exosomal DNA mutation status presented 86.5% of homology with BM and 75% with PB. The results of this pilot study confirmed the feasibility of a leukemia-derived exosome enrichment approach followed by exosomal dsDNA NGS analysis for AML biomarker detection. These data point to the use of liquid biopsy in myeloid neoplasia for the detection of active leukemic cells resident in the BM via a painless procedure.

Prognostic Relevance of NPM1 and FLT3 Mutations in Acute Myeloid Leukaemia, Longterm Follow-Up-A Single Center Experience.

The prognosis of acute myeloid leukemia depends on genetic aberrations, particularly NPM1 and FLT3-ITD mutations. The targeted drugs' availability has renewed interest in FLT3 mutations, but the impact of these genetic alterations using these treatments is yet to be confirmed. Our objective was to evaluate the results obtained with the intensified NILG-AML 01/00 protocol (ClinicalTrials.gov Identifier: NCT 00400673) in 171 unselected patients (median age, 54.5 years, range 15−74) carrying the FLT3 (ITD or TKD) and/or NPM1 mutations. The CR rate and 5-y survival were 88.3% and 58% +/− 4, respectively, significantly higher in the NPM1-mutated (CR 93.9%, p: 0.0001; survival 71% +/− 6, p: 0.0017, respectively). In isolated ITD patients, the CR was lower (66.7%, p: 0.0009), and the 3 years-relapse-free survival worse (24%, p: <0.0002). The presence of ITD, irrespective of the allelic ratio, or TKD mutation, did not significantly affect the survival or relapse-free survival among the NPM1-co-mutated patients. Our data indicate that a high dose of ARAC plus idarubicin consolidation exerts a strong anti-leukemic effect in NPM1-mutated patients both with the FLT3 wild-type and mutated AML, while in the NPM1 wild-type and FLT3-mutated, the therapeutic effect remains unsatisfactory. New strategies incorporating target therapy with second-generation inhibitors will improve these results and their addition to this aggressive chemotherapeutic program merits testing.

Malnutrition Prevention after Allogeneic Hematopoietic Stem Cell Transplantation (alloHSCT): A Prospective Explorative Interventional Study with an Oral Polymeric Formulation Enriched with Transforming Growth Factor Beta 2 (TGF-ß2).

Malnutrition is common after allogeneic Hematopoietic Stem Cell Transplantation (alloHSCT), and interventions directed to correct nutritional status are warranted to improve transplant outcomes. In this prospective study, an oral polymeric formulation enriched with TGF-ß2 (TE-OPF) was explored to correct malnutrition according to Patient-Generated Subjective Global Assessment (PG-SGA). TE-OPF was proposed to 51 consecutive patients who received transplants at our institution for hematological malignancies, and sufficient dose intake was established per protocol as at least 50% of the prescribed dose of TE-OPF: group A received adequate nutritional support; group B, inadequate. The study met the primary outcomes in terms of safety (no adverse events reported during TE-OPF intake except for its disgusting taste) and malnutrition (PG-SGA C 28 days after transplant): severely malnourished patients (PG-SGA C) accounted for 13% in group A and 88.9% in group B (p = 0.000). At the end of the study, after a median follow-up of 416 days, the estimated median Overall Survival (OS) was 734 days for well or moderately nourished patients (PG-SGA A/B) in comparison to 424 for malnourished patients (p = 0.03). Inadequate TE-OPF intake was associated with an increase in acute gastrointestinal Graft Versus Host Disease (GVHD) cumulative incidence (38% vs. 0% p = 0.006). A higher incidence of pneumonia was reported in group B (p = 0.006). IGF-1 levels at 14 and 28 days after transplant were significantly higher in group A and were associated with a lower incidence of acute GVHD (aGVHD). Higher subsets of B, T, and NK cells were found in group A, and a higher number of CD16+ NK cells was associated with a lower incidence of acute GVHD (p = 0.005) and increased survival at the end of the study (p = 0.023). Artificial neural network analysis suggested that inadequate TE-OPF intake, pneumonia, and sepsis significantly affected malnutrition 28 days after alloHSCT and survival 365 days after alloHSCT (normalized importance 100%, 82%, and 68%, respectively). In this exploratory and preliminary study, the use of TE-OPF appeared to reduce the incidence of malnutrition after alloHSCT, but larger and controlled studies are required.

Case Report: Late Onset of Myelodysplastic Syndrome From Donor Progenitor Cells After Allogeneic Stem Cell Transplantation. Which Lessons Can We Draw From the Reported Case?

BACKGROUND: Myelodysplastic syndromes and acute leukemias after allogeneic stem cell transplantation (allo-SCT) are mainly caused by recurrence of the primitive leukemic clones. More rarely, they originate from donor hematopoietic stem cells, developing the so-called donor cell leukemia (DCL) or myelodysplastic syndromes (DC-MDSs). DCL and DC-MDS can be considered as an in vivo model of leukemogenesis, and even if the pathogenetic mechanisms remain speculative, a genetic predisposition of donor progenitor cells, an altered host microenvironment, and the impairment of immune surveillance are considered the main causes. CASE PRESENTATION: We report a case of DC-MDS diagnosed 5 years after an allo-SCT from a matched related donor (patient's sister) in a patient with Philadelphia chromosome-positive B-cell acute lymphoblastic leukemia (Ph+ B-ALL). The sex-mismatch allowed us to identify the donor cell origin. At the onset, the DC-MDS was characterized by chromosome seven monosomy and NRAS, RUNX1, and BCOR mutations. Because of a familiar history of colorectal neoplasia and the variant allele frequency (VAF) of NRAS mutation at the onset, this mutation was searched on germline DNA in both the donor and the recipient, but the result was negative. Moreover, after transplant (+4 months), the patient developed severe and long-lasting chronic graft-versus-host disease (cGVHD), requiring multiple lines of treatments. Because of the severe immunosuppression, recurrent infections occurred and, lately, the patient died due to septic shock. CONCLUSION: This case report highlights the need, whenever possible, to evaluate the donor origin of the posttransplant myelodysplasia and acute leukemias. The potential key role of the impaired immune surveillance and of long-lasting immunosuppression appears to be emerging in the development of this case of DC-MDS. Finally, this case reminds the importance to investigate the familiar genetic predisposition in donors with a familiar history of neoplasia.

RT-qPCR versus Digital PCR: How Do They Impact Differently on Clinical Management of Chronic Myeloid Leukemia Patients?

Real-time quantitative PCR (RT-qPCR) is the gold standard to quantify the BCR-ABL1 transcript for molecular response monitoring in chronic myeloid leukemia (CML) patients, and it plays a pivotal role in clinical decision-making process, even if it presents technical limits. Increasing data suggest that digital PCR (dPCR) is more accurate and reliable than RT-qPCR in CML minimal residual disease monitoring and in patients' selection for treatment discontinuation. But what about the identification of treatment discontinuation failures? We present the case of a CML patient enrolled both in a study aiming to comparatively assess molecular response by RT-qPCR and dPCR and in the progressive arm of the OPTkIMA trial. This is a phase III trial including CML patients randomized to receive a fixed versus a progressive intermittent tyrosine kinase inhibitor regimen. At 24 months, because of two consecutive detections of MR2.0 by RT-qPCR, the patient resumed daily treatment. Conversely, dPCR revealed a stability of molecular response and even a slight decreasing of transcript over time. An additional specimen was sampled one month after the first MR2.0 detection because of clinical decision: RT-qPCR resulted MR3.0 and dPCR confirmed the transcript's stability. Nowadays, the resumption of therapy is RT-qPCR-driven despite its limits in detection and robustness. In this case, according to dPCR, the patient could have continued intermittent treatment and the stability of response was then confirmed by RT-qPCR. So, dPCR could be able to better identify peculiar clinical response to therapy.

Multidimensional geriatric assessment for elderly hematological patients (≥60 years) submitted to allogeneic stem cell transplantation. A French-Italian 10-year experience on 228 patients.

Nowadays, the evaluation of elderly patients' eligibility for allogeneic stem cell transplantation (allo-SCT) is crucial. We evaluated the feasibility and efficacy of a multidimensional geriatric assessment, the Fondazione Italiana Linfomi (FIL) score, on a cohort of 228 patients older than 60 years submitted to allo-SCT in Italy and France from 2008 to 2018. Based on FIL score, available in 215 patients, 125 (58%) patients were classified as "fit" and 90 as "unfit/frail." The hematopoietic cell transplantation-specific comorbidity index (HCT-CI) was measured in 222 patients (97%); 71 (32%) patients had HCT-CI 0, 75 (34%) patients scored 1-2, and 76 (34%) ≥3. A total of 121 (53%) patients died after a median follow-up of 36 months. FIL score was found to highly predict survival, due to an excess of NRM in unfit/frail group, and confirmed its independent prognostic role on OS (HR: 0.37; 95% CI: 0.25-0.55; p < 0.0001). On the contrary, the HCI-CI failed in allo-SCT outcome prediction (HR: 1.06; 95% CI: 0.96-1.16; p = 0.27). In summary, a comprehensive geriatric assessment with FIL score seems to add significant prognostic information in elderly patients submitted to allo-SCT. The pretransplant adoption of this easy-to-use tool could help the patients' selection and management.

Advances in CMV Management: A Single Center Real-Life Experience.

CMV infection is a major challenge in allogeneic stem cell transplantation (allo-SCT). The changing landscape in CMV management includes the introduction of letermovir in prophylaxis of high-risk patients and the source of CMV DNA monitoring (plasma-PL vs. whole blood-WB), for pre-emptive therapy (PET) initiation. We report here how our real-life experience in CMV management evolved, following letermovir registration. We focus on: (i) the effects of systematic use of letermovir for CMV prophylaxis in high-risk patients, (ii) the results of a longitudinal comparison of CMV DNAemia monitoring in PL and WB. From December 2018 to April 2020, 60 allo-SCTs have been performed in our center (LET ERA), of whom 45 received letermovir in prophylaxis from day 0 to day + 100, because of recipient positivity of anti CMV IgG. These patients were compared with a cohort of 41 allo-SCTs performed between November 2017 and November 2018 (NO LET ERA). Firstly, the incidence of CMV clinically significant infections, CMV disease, bacterial infections, proven/probable fungal infections, hospital re-admissions after allo-SCT by day + 100 in the two ERA were 8 vs. 44% (p = 0.0006), 2 vs. 12% (p = 0.02), 37 vs. 56% (p = 0.05), 8 vs. 19% (p = 0.09), and 23 vs. 39% (p = 0.09), respectively. By day + 180 these differences were 17 vs. 68% (p < 0.00001), 2 vs. 12% (p = 0.02), 45 vs. 78% (p = 0.09), 8 vs. 22% (p = 0.05), and 40 vs. 66% (p = 0.01), respectively. Secondly, from February to May 2019, we comparatively measured CMV DNA from WB and PL and we confirmed that there is a linear correlation between CMV DNA level in WB and PL (Spearman's test r = 0.86). Moreover, CMV DNAemia at the time of PET in the 12 patients with a clinically significant CMV infection was higher in WB vs. PL (5.202 vs. 4.981 copies/ml, p = 0.1). Our real-life experience confirms that: (i) letermovir is highly effective, leading to a significant drop in CMV clinically significant infections and CMV-related complications by day + 100 and + 180 after allo-SCT; (ii) WB may be an effective alternative to PL as a source for CMV DNA monitoring, as a linear correlation of DNAemia was confirmed between WB and PL, even if the CMV DNAemia at PET initiation was comparable in the two sources.

Feasibility of tumor­derived exosome enrichment in the onco­hematology leukemic model of chronic myeloid leukemia.

Due to the discovery of their role in intra­cellular communications, exosomes, which carry information specific to the cell of origin, have garnered considerable attention in cancer research. Moreover, there is evidence to suggest the possibility of isolating different exosome sub­populations based on target antigens at the cell surface. Philadelphia chromosome­positive (Ph+) chronic myeloid leukemia (CML) is a clonal myeloproliferative neoplasia characterized by the breakpoint cluster region­proto­oncogene 1 tyrosine­protein kinase (BCR­ABL1) fusion­gene, derived from the t (9;22) translocation. Tyrosine kinase inhibitors (TKIs) target BCR­ABL1 protein and induce major or deep molecular responses in the majority of patients. Despite the fact that several studies have demonstrated the persistence of leukemic cells in the bone marrow niche, even following treatment, TKIs prolong patient survival time and facilitate treatment­free remission. These characteristics render CML a plausible model for investigating the feasibility of tumor­derived exosome fraction enrichment. In the present study, patients in the chronic phase (CP) of CML were treated with TKIs, and the quantification of the BCR­ABL1 exosomal transcript was performed using digital PCR (dPCR). The possibility of tumor­derived exosomes enrichment was confirmed, and for the first time, to the best of our knowledge, the detection of the BCR­ABL1 transcript highlighted the presence of active leukemic cells in patients with CP­CML. According to these findings, tumor­derived exosomes may be considered a novel tool for the identification of active leukemic cells, and for the assessment of innovative monitoring focused on the biological functions of exosomes in CML.