The fibrinogen prothrombin time-derived method is not useful in patients anticoagulated with low molecular weight heparins or rivaroxaban

Essentials Fibrinogen prothrombin time-derived (FIBPT-d) behavior in anticoagulated patients is under studied. FIBPT-d method overestimates fibrinogen in rivaroxaban and low molecular weight heparin samples. Unfractionated heparin and dabigatran samples showed similar bias to the control group. Rabbit brain and human recombinant thromboplastin behavior was different in rivaroxaban samples.

SUMMARY

Background The fibrinogen prothrombin time-derived (FIBPT-d) method with photo-optical coagulometers is easy and economical. However, there are few reports on the behavior of this test on samples from patients anticoagulated with direct oral anticoagulants or low molecular weight heparin (LMWH). Objective To compare fibrinogen results obtained with the Clauss (FIB C) method and the FIBPT-d method with two thromboplastins in anticoagulated patients. Population The study population comprised 295 consecutive anticoagulated patients: 99 treated with vitamin K antagonists (VKAs), 49 treated with unfractionated heparin (UFH), 47 treated with LMWH, 50 treated with rivaroxaban, 50 treated with dabigatran, and 100 normal controls (NCs). Methods Dabigatran samples were analyzed by the use of FIB C with HemosIL Fibrinogen C or 100 NHI thrombin units mL-1 reagents; rabbit brain and human recombinant thromboplastins with HemosIL PTFibrinogen HS plus (HS) and Recombiplastin 2G (RP) were used for FIBPT-d method. Heparin and rivaroxaban levels were assessed with HemosIL Liq antiXa with specific calibrators; dabigatran levels were determined with the HemosIL Direct Thrombin Inhibitor Assay. All assays were performed on the ACL TOP platform in two laboratories. Percentage biases for the FIBPT-d method versus the FIB C method were calculated by the use of Bland-Altman plots. Results Positive biases of the FIBPT-d method versus the FIB C method with both thromboplastins were seen in NC samples (13.7% and 18.9% for HS and RP, respectively), but biases with HS in rivaroxaban and VKA patient samples were higher than that in NC samples, at 31.9% and 34.0%, respectively. LMWH patient samples showed higher bias than NC samples: 26.5% and 29.3.0% with HS and RP, respectively. UFH and dabigatran patient samples showed similar bias as NC samples. Conclusion The FIBPT-d method should not be used in anticoagulated patients, because the FIBPT-d mathematical algorithm has been validated only in normal subjects, so overestimation could occur in these patients.

Subcutaneous alemtuzumab in patients with refractory/relapsed B-CLL after a fludarabine-based regimen

6600

Background: Alemtuzumab is the only immunotherapy that is effective as a single agent in patients with B-CLL who are refractory to, or who have relapsed after, fludarabine therapy. The optimized schedule for alemtuzumab that achieves maximal efficacy with manageable toxicity is still being explored. We report the first interim analysis of a new, less intensive schedule of alemtuzumab SC to patients with refractory/relapsed B-CLL. Methods: Alemtuzumab was dose escalated from 10 to 20 mg during the first week, 30 mg bid during the second and third weeks, and 30 mg once weekly during weeks 4, 6, 8, 10, 12, 16, 20, 24, 28, 34, and 40. Antiviral prophylaxis included TMP/SMX bid 3 times a week and acyclovir 200 mg tid. Results: Patients (N = 36) with refractory (19%) or relapsed (81%) B-CLL had a median age of 67 years (range, 43–86 years), 28 were male, 61%/39% had Binet stage B/C disease, and 2 had B-cell prolymphocytic transformation. The median number of prior therapies was 1 (range, 1–4). The median duration of treatment was 7 weeks (range, 2–24 weeks), with a median cumulative alemtuzumab dose of 412 mg (range, 150–1,080 mg). Thirty-two patients were evaluable for response. The overall response rate of 93%: complete response (CR), 34%; unconfirmed CR, 6%; partial response (PR), 53%. Two patients (7%) did not respond to therapy. Of the 7 refractory patients, 5 had a PR, 1 did not respond, and 1 was not yet evaluable. Median overall survival was 10 months, which correlated with response and pretreatment status. Minimal residual disease (MRD) was measured by flow cytometry in 5 patients who achieved a CR: 3 patients had <0.5% of CD5/CD19/CD23+ cells, 1 patient had <5% of CLL cells, and 1 patient had <10% CLL cells. According to WHO toxicity criteria, 5 patients experienced grade 3/4 infection; 2 patients had grade 3 granulocytopenia/thrombocytopenia; 1 patient had cytomegalovirus (CMV) reactivation without CMV disease; and 1 patient developed Epstein-Barr Virus with prolonged bone marrow hypoplasia. Conclusions: Results of this interim analysis suggest that a less intense regimen of alemtuzumab is feasible, effective, and safe for patients with refractory/relapse B-CLL after fludarabine therapy.

No significant financial relationships to disclose.

[Bone marrow transplantation for severe aplastic anemia]

Severe aplastic anemia is a hematological disease with a high mortality rate, for which bone marrow transplantation is the treatment of choice, specially in children and young adults. The number of transfusions undergone before the transplant is the most important factor to predict the possibility of graft failure. Twenty patients with severe aplastic anemia, most of them already multiple transfused, were transplanted utilizing cyclophosphamide combined with antilymphocyte globulin as a conditioning regiment. All the evaluable patients engrafted and there were no episodes of graft failure. Three patients died, and 17 (85%) are alive with hematopoietic recovery at a median of 27.7 months post-transplant. Bone marrow transplantation was an excellent therapeutic option in this series of patients with severe aplastic anemia and the conditioning regiment appeared to be sufficiently myeloablative and immunosuppressive to avoid early or late graft failure.

Acute megakaryoblastic leukemia with massive myelofibrosis: complete remission and reversal of marrow fibrosis with allogeneic bone marrow transplantation as the only treatment

We report results of allogeneic bone marrow transplantation in an 8-year-old boy with acute megakaryoblastic leukemia characterized by intense fibrosis together with 20% blast cells in the bone marrow, who was transplanted without preceding chemotherapy for remission induction. Conditioning comprised cytosine arabinoside, cyclophosphamide and total body irradiation. The donor was his HLA-identical sister. The patient is well with minor chronic graft-versus-host disease and normal hematologic values 670 days post-transplant.