Modupe Elebute

Long-term safety and efficacy of sustained eculizumab treatment in patients with paroxysmal nocturnal haemoglobinuria.

Paroxysmal nocturnal haemoglobinuria (PNH) is characterized by chronic, uncontrolled complement activation resulting in elevated intravascular haemolysis and morbidities, including fatigue, dyspnoea, abdominal pain, pulmonary hypertension, thrombotic events (TEs) and chronic kidney disease (CKD). The long‐term safety and efficacy of eculizumab, a humanized monoclonal antibody that inhibits terminal complement activation, was investigated in 195 patients over 66 months. Four patient deaths were reported, all unrelated to treatment, resulting in a 3‐year survival estimate of 97·6%. All patients showed a reduction in lactate dehydrogenase levels, which was sustained over the course of treatment (median reduction of 86·9% at 36 months), reflecting inhibition of chronic haemolysis. TEs decreased by 81·8%, with 96·4% of patients remaining free of TEs. Patients also showed a time‐dependent improvement in renal function: 93·1% of patients exhibited improvement or stabilization in CKD score at 36 months. Transfusion independence increased by 90·0% from baseline, with the number of red blood cell units transfused decreasing by 54·7%. Eculizumab was well tolerated, with no evidence of cumulative toxicity and a decreasing occurrence of adverse events over time. Eculizumab has a substantial impact on the symptoms and complications of PNH and results a significant improvement in patient survival.

Long-term effect of the complement inhibitor eculizumab on kidney function in patients with paroxysmal nocturnal hemoglobinuria†‡

Paroxysmal nocturnal hemoglobinuria (PNH) is a debilitating and life‐threatening disease in which lysis of PNH red blood cells frequently manifests with chronic hemolysis, anemia, and thrombosis. Renal damage in PNH is associated with chronic hemosiderosis and/or microvascular thrombosis. We determined the incidence of renal dysfunction or damage, defined by stages of chronic kidney disease (CKD), in a large cohort of PNH patients and evaluated the safety and efficacy of the complement inhibitor eculizumab in altering its progression. Renal dysfunction or damage was observed in 65% of the study population at baseline with 21% of patients with later stage CKD or kidney failure (glomerular filtration rate [GFR] ≤60 ml/min/1.73 m2; Stage 3, 4, or 5). Eculizumab treatment was safe and well‐tolerated in patients with renal dysfunction or damage and resulted in the likelihood of improvement as defined as categorical reduction in CKD stage (P < 0.001) compared with baseline and to placebo (P = 0.04). Improvement in renal function was more commonly seen in patients with baseline CKD Stages 1–2 (67.1% improvement, P < 0.001) although improvement was also observed in patients with CKD Stages 3–4 (P = 0.05). Improvements occurred quickly and were sustained for at least 18 months of treatment. Patients categorized at CKD Stages 3–5 did not worsen during treatment with eculizumab. Overall, 40 (21%) of 195 patients who demonstrated renal dysfunction or damage at baseline were no longer classified as such after 18 months of treatment. Administration of eculizumab to patients with renal dysfunction or damage was well tolerated and was usually associated with clinical improvement. Am. J. Hematol. 85:553–559, 2010.

Prospective study of rabbit antithymocyte globulin and cyclosporine for aplastic anemia from the EBMT Severe Aplastic Anaemia Working Party

Rabbit antithymocyte globulin (rATG; thymoglobulin, Genzyme) in combination with cyclosporine, as first-line immunosuppressive therapy, was evaluated prospectively in a multicenter, European, phase 2 pilot study, in 35 patients with aplastic anemia. Results were compared with 105 age- and disease severity-matched patients from the European Blood and Marrow Transplant registry, treated with horse ATG (hATG; lymphoglobulin) and cyclosporine. The primary end point was response at 6 months. At 3 months, no patients had achieved a complete response to rATG. Partial response occurred in 11 (34%). At 6 months, complete response rate was 3% and partial response rate 37%. There were 10 deaths after rATG (28.5%) and 1 after subsequent HSCT. Infections were the main cause of death in 9 of 10 patients. The best response rate was 60% for rATG and 67% for hATG. For rATG, overall survival at 2 years was 68%, compared with 86% for hATG (P = .009). Transplant-free survival was 52% for rATG and 76% for hATG (P = .002). On multivariate analysis, rATG (hazard ratio = 3.9, P = .003) and age more than 37 years (hazard ratio = 4.7, P = .0008) were independent adverse risk factors for survival. This study was registered at www.clinicaltrials.gov as NCT00471848.

Eculizumab, a terminal complement inhibitor, improves anaemia in patients with paroxysmal nocturnal haemoglobinuria

In paroxysmal nocturnal haemoglobinuria (PNH), chronic destruction of PNH red blood cells (RBCs) by complement leads to anaemia and other serious morbidities. Eculizumab inhibits terminal complement‐mediated PNH RBC destruction by targeting C5. In the phase III, double‐blind, placebo‐controlled, TRIUMPH study, eculizumab reduced haemolysis, stabilized haemoglobin levels, reduced transfusion requirements and improved fatigue in patients with PNH. Herein, we explored the effects of eculizumab on measures of anaemia in patients from the TRIUMPH study and the open‐label SHEPHERD study, a more heterogeneous population. Eculizumab reduced haemolysis regardless of pretreatment transfusion requirements and regardless of whether or not patients became transfusion‐dependent during treatment (P < 0·001). Reduction in haemolysis was associated with increased PNH RBC counts (P < 0·001) while reticulocyte counts remained elevated. Eculizumab‐treated patients demonstrated significantly higher levels of haemoglobin as compared with placebo in TRIUMPH and relative to baseline levels in SHEPHERD (P < 0·001 for each study). Eculizumab lowered transfusion requirement across multiple pretreatment transfusion strata and eliminated transfusion support in a majority of both TRIUMPH and SHEPHERD patients (P < 0·001). Patients who required some transfusion support during treatment with eculizumab showed a reduction in haemolysis and transfusion requirements and an improvement in fatigue. Eculizumab reduces haemolysis and improves anaemia and fatigue, regardless of transfusion requirements.

Transfusion of prion‐filtered red cells does not increase the rate of alloimmunization or transfusion reactions in patients: results of the UK trial of prion‐filtered versus standard red cells in surgical patients (PRISM A)

This study, conducted for the UK Blood Transfusion Services (UKBTS), evaluated the clinical safety of red cells filtered through a CE‐marked prion removal filter (P‐Capt™). Patients requiring blood transfusion for elective procedures in nine UK hospitals were entered into a non‐randomized open trial to assess development of red cell antibodies to standard red cell (RCC) or prion‐filtered red cell concentrates (PF‐RCC) at eight weeks and six months post‐transfusion. Patients who received at least 1 unit of PF‐RCC were compared with a control cohort given RCC only. About 917 PF‐RCC and 1336 RCC units were transfused into 299 and 291 patients respectively. Twenty‐six new red cell antibodies were detected post‐transfusion in 10 patients in each arm, an overall alloimmunization rate of 4·4%. Neither the treatment arm [odds ratio (OR) 0·93, 95% confidence interval (CI) 0·3, 2·5] nor number of units transfused (OR 0·95, 95% CI 0·8, 1·1) had a significant effect on the proportion of patients who developed new alloantibodies. No pan‐reactive antibodies or antibodies specifically against PF‐RCC were detected. There was no difference in transfusion reactions between arms, and no novel transfusion‐related adverse events clearly attributable to PF‐RCC were seen. These data suggest that prion filtration of red cells does not reduce overall transfusion safety. This finding requires confirmation in large populations of transfused patients.

Evaluation of the haemopoietic reservoir in de novo haemolytic paroxysmal nocturnal haemoglobinuria

Summary. Paroxysmal nocturnal haemoglobinuria (PNH) is an acquired clonal disorder of the haemopoietic stem cell (HSC). The pathogenetic link with bone marrow failure is well recognized; however, the process of clonal expansion of the glycosylphosphatidylinositol (GPI)‐deficient cells over normal haemopoiesis remains unclear. We have carried out detailed analysis of the stem cell population in 10 patients with de novo haemolytic PNH using the long‐term culture‐initiating cells (LTC‐IC) assay in parallel with measurements of CD34+ cells and mature haemopoietic progenitors, granulocyte–macrophage colony‐forming unit (CFU‐GM) and CFU‐erythroid [burst‐forming units erythroid (BFU‐E) + CFU granulocyte/erythroid/macrophage/megakaryocyte (GEMM)]. All patients had hypercellular bone marrows with erythroid hyperplasia, normal blood counts or mild peripheral blood cytopenias, increased reticulocyte counts and evidence of deficient GPI‐anchored proteins. We found a significant reduction in the LTC‐IC frequency in the CD34+ compartment of PNH patients (mean 2, range 1·3–3·0; n = 6) compared with normal donors (mean 13, range 5·2–45·5; n = 21) (P < 0·0001). Furthermore, there was a significant reduction in the erythroid compartment [CFU‐E/105 bone marrow mononuclear cells (BMMC) and CFU‐E/105 CD34+ cells] of PNH patients, but no significant difference in the granulocyte–monocyte precursors (CFU‐GM/105 BMMC or CFU‐GM/105 CD34+ cells) compared with normal donors, suggesting that there is a defect in the early stem cell pool in PNH patients without clinical or haematological evidence of bone marrow failure.

Differential apoptosis and Fas expression on GPI-negative and GPI-positive stem cells: a mechanism for the evolution of paroxysmal nocturnal haemoglobinuria.

Summary. Paroxysmal nocturnal haemoglobinuria (PNH) has a dual pathogenesis. PIG‐A mutations generate clones of haemopoietic stem cells (HSC) lacking glycosylphosphatidylinositol (GPI)‐anchored proteins and, secondly, these clones expand because of a selective advantage related to bone marrow failure. The first aspect has been elucidated in detail, but the mechanisms leading to clonal expansion are not well understood. We have previously shown that apoptosis and Fas expression in HSC play a role in bone marrow failure during aplastic anaemia. We have now investigated apoptosis in PNH. Ten patients were studied. Apoptosis, measured by flow cytometry, was significantly higher among CD34+ cells from patients compared with healthy controls. Fas expression was also increased. Cells that were stained for CD34, CD59 and apoptosis showed a significantly lower apoptosis in CD34+/CD59− compared with CD34+/CD59+ cells from the same patient. In three patients, staining for CD34, CD59 and Fas revealed lower Fas expression on CD34+/CD59− cells. Differential apoptosis of CD34+/CD59− HSC may be sufficient in itself to explain the expansion of PNH clones in the context of aplastic anaemia. In addition to demonstrating a basic mechanism underlying PNH clonal expansion, these results suggest further hypotheses for the evolution of PNH, based on the direct or indirect resistance of GPI‐negative HSC to pro‐inflammatory cytokines.