Francesco Buccisano

Idiopathic thrombocytopenic purpura: current concepts in pathophysiology and management.

Idiopathic thrombocytopenic purpura (ITP) is characterized by a low platelet count, which is the result of both increased platelet destruction and insufficient platelet production. Although the development of autoantibodies against platelet glycoproteins remains central in the pathophysiology of ITP, several abnormalities involving the cellular mechanisms of immune modulation have been identified. Conventional treatments for ITP aim at reducing platelet destruction, either by immunosuppression or splenectomy. Two new thrombopoietic agents, AMG 531 and eltrombopag, have been used in clinical trials to stimulate platelet production in ITP patients not responsive to standard treatments. These new molecules bear no structural resemblance to thrombopoietin, but still bind and activate the thrombopoietin receptor. This review will focus on the pathophysiology and treatment of ITP in adults, highlighting recent advances in both fields.

The efficacy of imatinib mesylate in patients with FIP1L1-PDGFRα-positive hypereosinophilic syndrome. Results of a multicenter prospective study

Background and Objectives The hypereosinophilic syndrome (HES) may be associated with the fusion of the platelet derived growth factor receptor α (PDGFRα) gene with the FIP1L1 gene in chromosome 4 coding for a constitutively activated PDGFRα tyrosine kinase. These cases with FIP1L1-PDGFRα rearrangement have been reported to be very sensitive to the tyrosine kinase inhibitor imatinib mesylate. Design and Methods A prospective multicenter study of idiopathic or primary HES was established in 2001 (Study Protocol Registration no. NCT 0027 6929). One hundred and ninety-six patients were screened, of whom 72 where identified as having idiopathic or primary HES and 63 were treated with imatinib 100 to 400 mg daily. Results Twenty-seven male patients carried the FIP1L1-PDGFRα rearrangement. All 27 achieved a complete hematologic remission (CHR) and became negative for the fusion transcripts according to reverse transcriptase polymerase chain reaction (RT-PCR) analysis. With a median follow-up of 25 months (15–60 months) all 27 patients remain in CHR and RT-PCR negative, and continue treatment at a dose of 100 to 400 mg daily. In three patients imatinib treatment was discontinued for few months, the fusion transcript became rapidly detectable, and then again undetectable upon treatment reassumption. Thirty-six patients did not carry the rearrangement; of these, five (14%) achieved a CHR, which was lost in all cases after 1 to 15 months. Interpretation and Conclusions All patients meeting the criteria for idiopathic or primary HES should be screened for the FIP1L1-PDGFRα rearrangement. For all patients with this rearrangement, chronic imatinib treatment at doses as low as 100 mg daily ensures complete and durable responses.

Low-Dose Thalidomide Ameliorates Cytopenias and Splenomegaly in Myelofibrosis With Myeloid Metaplasia: A Phase II Trial

PURPOSE A phase II dose-escalation trial was conducted to ascertain low-dose thalidomide safety and response in patients with advanced myelofibrosis with myeloid metaplasia (MMM). PATIENTS AND METHODS Thalidomide was administered together with current therapy to 63 patients, starting at 50 mg daily and increasing to 400 mg as tolerated. RESULTS Half of the patients sustained daily doses more than 100 mg and the drop-out rate was 51% at 6 months: the drop-out rate was lower in patients with high baseline fatigue score. At efficacy analysis, anemia was ameliorated in 22% of the patients and transfusions were eliminated in 39% of transfusion-dependent patients. Platelet count increased by 50 x 10(9)/L or more in 22% of patients with an initial count lower than 100 x 10(9)/L. Splenomegaly decreased by more than 50% of the initial size in 19% of patients. Reduction of an overall disease severity score occurred in 31% of patients and was associated with a significant reduction of fatigue. Disease severity amelioration was independently predicted by a high baseline myeloproliferative index (ie, large splenomegaly, thrombocytosis, or leukocytosis). CONCLUSION Low-dose thalidomide displays an acceptable toxicity profile and provides an objective and subjective advantage to a relevant portion of MMM patients.

Toward Optimization of Postremission Therapy for Residual Disease–Positive Patients With Acute Myeloid Leukemia

PURPOSE Despite the identification of several baseline prognostic indicators, the outcome of patients with acute myeloid leukemia (AML) is generally heterogeneous. The effects of autologous (AuSCT) or allogeneic stem-cell transplantation (SCT) are still under evaluation. Minimal residual disease (MRD) states may be essential for assigning patients to therapy-dependent risk categories. PATIENTS AND METHODS By multiparametric flow cytometry, we assessed the levels of MRD in 142 patients with AML who achieved complete remission after intensive chemotherapy. RESULTS A level of 3.5 x 10(-4) residual leukemia cells (RLCs) after consolidation therapy was established to identify MRD-negative and MRD-positive cases, with 5-year relapse-free survival (RFS) rates of 60% and 16%, respectively (P < .0001) and overall survival (OS) rates of 62% and 23%, respectively (P = .0001). Of patients (n = 77) who underwent a transplantation procedure (56 AuSCT and 21 SCT procedures); 42 patients (55%) were MRD positive (28 patients who underwent AuSCT and 14 patients who underwent SCT) and 35 patients (45%) were MRD negative (28 patients who underwent AuSCT and seven who underwent SCT). MRD-negative patients had a favorable prognosis, with only eight (22%) of 35 patients experiencing relapse, whereas 29 (69%) of 42 MRD-positive patients experienced relapse (P < .0001). In this high-risk group of 42 patients, we observed that 23 (82%) of 28 of those who underwent AuSCT experienced relapse, whereas six (43%) of 14 who underwent SCT experienced relapse (P = .014). Patients who underwent SCT also had a higher likelihood of RFS (47% v 14%). CONCLUSION A threshold of 3.5 x 10(-4) RLCs postconsolidation is critical for predicting disease outcome. MRD-negative patients have a good outcome regardless of the type of transplant they receive. In the MRD-positive group, AuSCT does not improve prognosis and SCT represents the primary option.

Modulation of VLA-4 and L-selectin expression on normal CD34+ cells during mobilization with G-CSF

We have evaluated the immunophenotype, functional activity and clonogenic potential of CD34+ cells from peripheral blood (PB) of normal donors before and after 4 and 6 days of G-CSF administration. The percentage and absolute number of CD34+ cells significantly increased at days 4 and 6 of G-CSF administration, compared to the steady-state level (P < 0.0001). two-colour fluorescence analysis showed, at days 4 and 6, a lower proportion of cd34+/c-kit+ compared to the steady-state level (P < 0.0001), but a similar expression of cd13, cd33, cd38, hla-dr and thy-1 antigens on cd34+ cells. The expression of adhesion molecules on CD34+ cells revealed a significant reduction of CD11a (P = 0.009), CD18, CD49d and CD62L (P < 0.0001) at days 4 and 6, compared to the baseline level. three-colour staining showed a reduction of the more immature compartment (34+/DR−/13−) and an increase of the more differentiated compartment (34+/DR+/13+). Downregulation of VLA-4 during mobilisation was seen almost exclusively on more committed cells (34+/13+); downregulation of CD62L, on the contrary, was observed on both early progenitors (34+/13−) and more committed cells (34+/13+). The expression of 34+/VLA-4+ decreased on both c-kit+ and c-kit− cells, while the expression of 34+/62L+ decreased on the c-kit+ cells only. In vivo administration of G-CSF reduced the adherence capacity of CD34+ cells to normal BM stroma; in vitro incubation with SCF or IL-3 enhanced the expression of CD49d on CD34+ cells, while GM-CSF reduced the expression of CD62L. SCF was the only cytokine able to induce a significant increase of CD34+ cell adherence to preformed stroma. Pre-incubation with the blocking β2 integrin monoclonal antibody caused a reduction of CD34+ cell adherence. In conclusion, the decrease of CD49d expression on mobilized CD34+ cells correlates with a poor adhesion to BM stroma; CD34+ cells incubated in vitro with SCF showed, conversely, a higher expression of CD49d and a greater adherence capacity on normal preformed stroma.

Simultaneous detection of NPM1 and FLT3-ITD mutations by capillary electrophoresis in acute myeloid leukemia

Mutations in the Nucleophosmin (NPM1) gene have been recently described to occur in about one-third of acute myeloid leukemias (AML) and represent the most frequent genetic alteration currently known in this subset. These mutations generate an elongated NPM1 protein that localizes aberrantly in the cytoplasm. In analogy with Flt3 alterations, NPM1 mutations are mostly detectable in AML with normal karyotype and their recognition may be relevant to identify distinct response to treatment. Hence, in addition to conventional karyotyping and RT-PCR of fusion genes, combined analysis of both Flt3 and NPM1 mutations will be increasingly relevant in the genetic diagnosis work-up of AML. We developed a multiplex RT-PCR assay followed by capillary electrophoresis to simultaneously analyze NPM1 and Flt3 gene alterations (NFmPCR assay). The assay was validated in leukemic cell RNAs extracted from 38 AML patients, which had been previously characterized for Flt3 status by conventional RT-PCR. Direct sequencing of NPM1 RT-PCR products was carried out in 15 cases to verify results obtained by capillary electrophoresis. Both NPM1 sequencing and conventional RT-PCR Flt3 results showed 100% concordance with the results of the NFmPCR assay. We suggest that this assay may be introduced in routine analysis of genetic alterations in AML.

Azacitidine for the treatment of patients with acute myeloid leukemia: report of 82 patients enrolled in an Italian Compassionate Program.

The efficacy of azacitidine for the treatment of high‐risk myelodysplastic syndromes has prompted the issue of its potential role even in the treatment of acute myeloid leukemia (AML).

Consolidation and maintenance immunotherapy with rituximab improve clinical outcome in patients with B-cell chronic lymphocytic leukemia†

Rituximab in sequential combination with fludarabine (Flu) allowed patients with B‐cell chronic lymphocytic leukemia (B‐CLL) to achieve higher remission rates and longer response duration. Based on their recent experience in indolent non‐Hodgkin lymphomas, in this study, the authors attempted to demonstrate whether consolidation/maintenance therapy with rituximab could prolong the response duration in this patient population.

Valproic Acid at Therapeutic Plasma Levels May Increase 5-Azacytidine Efficacy in Higher Risk Myelodysplastic Syndromes

Purpose: Epigenetic changes play a role and cooperate with genetic alterations in the pathogenesis of myelodysplastic syndromes (MDS). We conducted a phase II multicenter study on the combination of the DNA-methyltransferase inhibitor 5-azacytidine (5-AZA) and the histone deacetylase inhibitor valproic acid (VPA) in patients with higher risk MDS. Experimental Design: We enrolled 62 patients with MDS (refractory anemia with excess blasts, 39 patients; refractory anemia with excess blasts in transformation, 19 patients; and chronic myelomanocytic leukemia (CMML), 4 patients) and an International Prognostic Scoring System (IPSS) rating of Intermediate-2 (42 patients) or high (20 patients). VPA was given to reach a plasma concentration of >50 μg/mL, then 5-AZA was added s.c. at 75 mg/m2 for 7 days in eight monthly cycles. Results: The median overall survival was 14.4 months. At a median follow-up of 12 months (range, 0.7-21.0), the disease progressed in 20 patients, with 21% cumulative incidence of progression. Of 26 patients who completed eight cycles, 30.7% obtained complete or partial remission, 15.4% had a major hematologic improvement, whereas 38.5% showed stable disease. Drug-related toxicity was mild. Favorable prognostic factors for survival were IPSS Intermediate-2 and plasma VPA of ≥50 μg/mL (log rank = 0.013 and 0.007, respectively). Analysis of polymorphisms important for the metabolism of the drugs used in the trial showed that carriers of the CYP2C19*2 variant of cytochrome P450 required higher VPA doses to achieve the target VPA plasma concentration of 50 μg/mL on day 1 of 5-AZA treatment (P = 0.0021). Conclusion: Our data show that the 5-AZA/VPA combination is active and safe in patients with MDS with a poor prognosis. Achievement of VPA therapeutic levels may indeed increase 5-AZA efficacy.

Cytogenetic and molecular diagnostic characterization combined to postconsolidation minimal residual disease assessment by flow cytometry improves risk stratification in adult acute myeloid leukemia

A total of 143 adult acute myeloid leukemia (AML) patients with available karyotype (K) and FLT3 gene mutational status were assessed for minimal residual disease (MRD) by flow cytometry. Twenty-two (16%) patients had favorable, 115 (80%) intermediate, and 6 (4%) poor risk K; 19 of 129 (15%) carried FLT3-ITD mutation. Considering postconsolidation MRD status, patients with good/intermediate-risk K who were MRD(-) had 4-year relapse-free survival (RFS) of 70% and 63%, and overall survival (OS) of 84% and 67%, respectively. Patients with good- and intermediate-risk K who were MRD(+) had 4-year RFS of 15% and 17%, and OS of 38% and 23%, respectively (P < .001 for all comparisons). FLT3 wild-type patients achieving an MRD(-) status, had a better outcome than those who remained MRD(+) (4-year RFS, 54% vs 17% P < .001; OS, 60% vs 23%, P = .002). Such an approach redefined cytogenetic/genetic categories in 2 groups: (1) low-risk, including good/intermediate K-MRD(-) with 4-year RFS and OS of 58% and 73%, respectively; and (2) high risk, including poor-risk K, FLT3-ITD mutated cases, good/intermediate K-MRD(+) categories, with RFS and OS of 22% and 17%, respectively (P < .001 for all comparisons). In AML, the integrated evaluation of baseline prognosticators and MRD improves risk-assessment and optimizes postremission therapy.