Cristina Pascual

Successful discontinuation of eltrombopag after complete remission in patients with primary immune thrombocytopenia

Eltrombopag is effective and safe in immune thrombocytopenia (ITP). Some patients may sustain their platelet response when treatment is withdrawn but the frequency of this phenomenon is unknown. We retrospectively evaluated 260 adult primary ITP patients (165 women and 95 men; median age, 62 years) treated with eltrombopag after a median time from diagnosis of 24 months. Among the 201 patients who achieved a complete remission (platelet count >100 × 109/l), eltrombopag was discontinued in 80 patients. Reasons for eltrombopag discontinuation were: persistent response despite a reduction in dose over time (n = 33), platelet count >400 × 109/l (n = 29), patients request (n = 5), elevated aspartate aminotransferase (n = 3), diarrhea (n = 3), thrombosis (n = 3), and other reasons (n = 4). Of the 49 evaluable patients, 26 patients showed sustained response after discontinuing eltrombopag without additional ITP therapy, with a median follow‐up of 9 (range, 6–25) months. These patients were characterized by a median time since ITP diagnosis of 46.5 months, with 4/26 having ITP < 1 year. Eleven patients were male and their median age was 59 years. They received a median of 4 previous treatment lines and 42% were splenectomized. No predictive factors of sustained response after eltrombopag withdrawal were identified. Platelet response following eltrombopag cessation may be sustained in an important percentage of adult primary ITP patients who achieved CR with eltrombopag. However, reliable markers for predicting which patients will have this response are needed. Am. J. Hematol. 90:E40–E43, 2015.

Prognostic impact of minimal residual disease analysis by flow cytometry in patients with acute myeloid leukemia before and after allogeneic hemopoietic stem cell transplantation

Allogeneic stem cell transplantation (allo‐SCT) has become the treatment of choice in patients with intermediate‐risk and high‐risk acute myeloid leukemia (AML). The quality of response to treatment, assessed in terms of detection of minimal residual disease (MRD), has been consistently associated with prognosis and clinical outcome in patients with AML. The aim of the present study was to evaluate the prognostic impact of analyzing MRD in bone marrow using 4‐color multiparametric flow cytometry (MFC) in 29 patients with AML before and after allo‐SCT. Eighteen patients who were shown to be MRD‐negative [≤0.1% leukemia‐associated immunophenotypes (LAIPs)] by MFC at transplantation and underwent allo‐SCT had lower rates of relapse (15% vs. 66%, P = 0.045), better overall 1‐yr survival (83% vs. 52%, P = 0.021) and a lower cumulative incidence of relapse (P = 0.032) than patients who were MRD‐positive (>0.1%). All post‐transplant MRD‐positive patients underwent a therapeutic intervention after transplant (tapering of immunosuppression, donor lymphocyte infusion, or re‐transplant) with the intention of preventing relapse. Disease was controlled and MRD disappeared in five of these patients. Disease recurred in the other seven patients. We can conclude that follow‐up with MFC for the detection of MRD in AML before and after SCT is useful for predicting relapse. In the post‐transplant setting, monitoring of MRD by MFC could be a key preemptive intervention.

Amelioration of the severity of heparin-binding antithrombin mutations by posttranslational mosaicism

The balance between actions of procoagulant and anticoagulant factors protects organisms from bleeding and thrombosis. Thus, antithrombin deficiency increases the risk of thrombosis, and complete quantitative deficiency results in intrauterine lethality. However, patients homozygous for L99F or R47C antithrombin mutations are viable. These mutations do not modify the folding or secretion of the protein, but abolish the glycosaminoglycan-induced activation of antithrombin by affecting the heparin-binding domain. We speculated that the natural β-glycoform of antithrombin might compensate for the effect of heparin-binding mutations. We purified α- and β-antithrombin glycoforms from plasma of 2 homozygous L99F patients. Heparin affinity chromatography and intrinsic fluorescence kinetic analyses demonstrated that the reduced heparin affinity of the α-L99F glycoform (K(D), 107.9 ± 3nM) was restored in the β-L99F glycoform (K(D), 53.9 ± 5nM) to values close to the activity of α-wild type (K(D), 43.9 ± 0.4nM). Accordingly, the β-L99F glycoform was fully activated by heparin. Similar results were observed for recombinant R47C and P41L, other heparin-binding antithrombin mutants. In conclusion, we identified a new type of mosaicism associated with mutations causing heparin-binding defects in antithrombin. The presence of a fully functional β-glycoform together with the activity retained by these variants helps to explain the viability of homozygous and the milder thrombotic risk of heterozygous patients with these specific antithrombin mutations.

Use of eltrombopag after romiplostim in primary immune thrombocytopenia

The thrombopoietin receptor agonists (THPO‐RAs), romiplostim and eltrombopag, are effective and safe in immune thrombocytopenia (ITP). However, the value of their sequential use when no response is achieved or when adverse events occur with one THPO‐RA has not been clearly established. Here we retrospectively evaluated 51 primary ITP adult patients treated with romiplostim followed by eltrombopag. The median age of our cohort was 49 (range, 18–83) years. There were 32 women and 19 men. The median duration of romiplostim use before switching to eltrombopag was 12 (interquartile range 5–21) months. The reasons for switching were: lack of efficacy (n = 25), patient preference (n = 16), platelet‐count fluctuation (n = 6) and side‐effects (n = 4). The response rate to eltrombopag was 80% (41/51), including 67% (n = 35) complete responses. After a median follow‐up of 14 months, 31 patients maintained their response. Efficacy was maintained after switching in all patients in the patient preference, platelet‐count fluctuation and side‐effect groups. 33% of patients experienced one or more adverse events during treatment with eltrombopag. We consider the use of eltrombopag after romiplostim for treating ITP to be effective and safe. Response to eltrombopag was related to the cause of romiplostim discontinuation.

Eltrombopag safety and efficacy for primary chronic immune thrombocytopenia in clinical practice

Eltrombopag is effective and safe in chronic immune thrombocytopenia (ITP). However, clinical trials may not accurately reflect what happens in clinical practice. We evaluated the efficacy and safety of eltrombopag in primary chronic ITP in a real‐world setting.

Sustained response after discontinuation of short-and medium-term treatment with eltrombopag in patients with immune thrombocytopenia

Abstract Eltrombopag is effective and safe in chronic immune thrombocytopenia (ITP) patients not responding to previous therapy. However, when eltrombopag is discontinued, platelet counts usually return to baseline within 2 weeks. Here, we describe the clinical characteristics of the, to the best of our knowledge, largest case series of patients with ITP, who presented sustained responses after discontinuing eltrombopag (n = 12). The median time from diagnosis to eltrombopag initiation was 24 months (range, 1–480). The median number of prior therapies was 5 (range, 1–7), and the median duration of eltrombopag treatment was 5 months (range, 1–13). Three patients received eltrombopag for only 1 month. The treatment was well-tolerated. The median (range) follow-up of this case series was of 7 months (6–20), during which all patients maintained a safe platelet count without the need for anti-ITP treatment. The communication of such cases may support the conduction of new studies to investigate which predictive factors could identify ITP patients with sustained responses after discontinuing eltrombopag without additional therapy. The need of long-term use of eltrombopag should be re-examined.

Inhibitory killer cell immunoglobulin-like receptor (iKIR) mismatches improve survival after T-cell-repleted haploidentical transplantation

Alloreactivity triggered by interaction between killer cell immunoglobulin‐like receptors (KIRs) and natural killer (NK) cells plays a role in the graft‐versus‐tumor effect after hematopoietic stem cell transplantation (SCT). Our aim in this study was to evaluate this role in the setting of T‐cell‐repleted haploidentical SCT with postinfusion high‐dose cyclophosphamide (PT‐Cy). We included 33 patients. Among patient–donor pairs with at least 1 inhibitory KIR (iKIR) gene mismatch, event‐free survival (EFS) and cumulative incidence of relapse 1 year after transplant were significantly better (85% vs. 37% [P = 0.008] and 18% vs. 46% [P = 0.041], respectively). A subanalysis in 12 patients with Hodgkins lymphoma (HL) showed an improvement in EFS 1 year after transplant in those patients with KIR ligand mismatch (100% vs. 25%, P = 0.012), although overall survival (OS) was not affected (85% vs. 80%, P = 0.2). Eight of 12 patient–donors pairs presented iKIR mismatches. Of note, this outcome was better in the small subgroup, both for EFS (100% vs. 25%, P = 0.012) and for OS (100% vs. 37%, P = 0.004). Our data suggest that in the setting of T‐cell‐repleted haploidentical SCT with PT‐Cy, iKIR mismatch is associated with improved survival, with particularly good results for both iKIR and KIR ligand mismatches in patients with HL.

Transient hemolysis due to anti‐D and anti‐A1 produced by engrafted donor's lymphocytes after allogeneic unmanipulated haploidentical hematopoietic stem cell transplantation

Development of de novo alloantibodies against recipients red blood cell (RBC) antigens by engrafted donors lymphocytes is a known phenomenon in the setting of allogeneic hematopoietic stem cell transplantation (HSCT). This situation is usually clinically insignificant. We report a case of early clinically relevant hemolytic anemia in a blood group A1 D+ patient, due to a limited production of anti‐D and anti‐A1 produced by nonpreviously sensitized newly engrafted donors immune system.

Trasplante de médula ósea en pacientes con anemia falciforme. Experiencia en un centro

INTRODUCTION Sickle cell disease (SCD), despite the improvement in the medical management, is still associated with severe morbidity and decreased survival. Allogenic hematopoietic stem cell transplantation (Allo-HSCT) currently provides the only curative therapy. A report is presented on our experience in children with SCD, who underwent Allo-HSCT in a single centre. MATERIAL AND METHOD A single centre descriptive study was conducted on patients with SCD who underwent a bone marrow transplant from an HLA-identical sibling donor between January 2010 and December 2014. Epidemiological, clinical and analytical parameters were collected with a follow-up to December 2015. Data are presented as frequencies, percentages, and medians (range). RESULTS Allo-HCST was performed in 11 patients (8 males) with a median age of 7 years (2-13), all of them with comorbidity prior to the HCST. A stable graft was achieved in 10 out of 11 patients, 9 of them with complete donor chimerism, and one patient with stable mixed chimerism after 1 year of allo-HSCT. One patient has secondary graft failure with re-appearance of symptoms associated with SCD on day 180. Complications of Allo-HSCT are: arterial hypertension 7/11, acute renal failure 3/11, CMV reactivation 9/11, neurological complications 4/11 (subarachnoid haemorrhage, seizure), and acute graft versus host disease (aGVHD) of the skin 6/11, one of whom developed grade iv intestinal aGVHD, causing his death (day 51). None of the patients developed chronic GVHD. The overall survival and event-free survival was 90.9% and 81.9%, respectively, with a median follow-up of 3.1 (1-5.7) years. CONCLUSIONS Allo-HSCT, the only curative therapy, remains associated with morbidity. There was a transplant related mortality in our study, consistent with multicentre studies (1/11), and with aGVHD being the main cause. Other problems still include graft failure (1/11), and neurological complications (4/11), although the permanent sequelae are mild.

Role on antithrombin deficiency and thrombotic risk of the beta glycoform: a post-translational mosaicism for heparin binding mutations

The balance between actions of procoagulant and anticoagulant factors protects organisms from bleeding and thrombosis. Thus, antithrombin deficiency increases the risk of thrombosis, and complete quantitative deficiency results in intrauterine lethality. However, patients homozygous for L99F or R47C antithrombin mutations are viable. These mutations do not modify the folding or secretion of the protein, but abolish the glycosaminoglycan-induced activation of antithrombin by affecting the heparin-binding domain. We speculated that the natural β-glycoform of antithrombin might compensate for the effect of heparin-binding mutations. We purified α- and β-antithrombin glycoforms from plasma of 2 homozygous L99F patients. Heparin affinity chromatography and intrinsic fluorescence kinetic analyses demonstrated that the reduced heparin affinity of the α-L99F glycoform (K(D), 107.9 ± 3nM) was restored in the β-L99F glycoform (K(D), 53.9 ± 5nM) to values close to the activity of α-wild type (K(D), 43.9 ± 0.4nM). Accordingly, the β-L99F glycoform was fully activated by heparin. Similar results were observed for recombinant R47C and P41L, other heparin-binding antithrombin mutants. In conclusion, we identified a new type of mosaicism associated with mutations causing heparin-binding defects in antithrombin. The presence of a fully functional β-glycoform together with the activity retained by these variants helps to explain the viability of homozygous and the milder thrombotic risk of heterozygous patients with these specific antithrombin mutations.