Lawrence Rice

Efficacy of romiplostim in patients with chronic immune thrombocytopenic purpura: a double-blind randomised controlled trial

BACKGROUND Chronic immune thrombocytopenic purpura (ITP) is characterised by accelerated platelet destruction and decreased platelet production. Short-term administration of the thrombopoiesis-stimulating protein, romiplostim, has been shown to increase platelet counts in most patients with chronic ITP. We assessed the long-term administration of romiplostim in splenectomised and non-splenectomised patients with ITP. METHODS In two parallel trials, 63 splenectomised and 62 non-splenectomised patients with ITP and a mean of three platelet counts 30x10(9)/L or less were randomly assigned 2:1 to subcutaneous injections of romiplostim (n=42 in splenectomised study and n=41 in non-splenectomised study) or placebo (n=21 in both studies) every week for 24 weeks. Doses of study drug were adjusted to maintain platelet counts of 50x10(9)/L to 200x10(9)/L. The primary objectives were to assess the efficacy of romiplostim as measured by a durable platelet response (platelet count > or =50x10(9)/L during 6 or more of the last 8 weeks of treatment) and treatment safety. Analysis was per protocol. These studies are registered with ClinicalTrials.gov, numbers NCT00102323 and NCT00102336. FINDINGS A durable platelet response was achieved by 16 of 42 splenectomised patients given romplostim versus none of 21 given placebo (difference in proportion of patients responding 38% [95% CI 23.4-52.8], p=0.0013), and by 25 of 41 non-splenectomised patients given romplostim versus one of 21 given placebo (56% [38.7-73.7], p<0.0001). The overall platelet response rate (either durable or transient platelet response) was noted in 88% (36/41) of non-splenectomised and 79% (33/42) of splenectomised patients given romiplostim compared with 14% (three of 21) of non-splenectomised and no splenectomised patients given placebo (p<0.0001). Patients given romiplostim achieved platelet counts of 50x10(9)/L or more on a mean of 13.8 (SE 0.9) weeks (mean 12.3 [1.2] weeks in splenectomised group vs 15.2 [1.2] weeks in non-splenectomised group) compared with 0.8 (0.4) weeks for those given placebo (0.2 [0.1] weeks vs 1.3 [0.8] weeks). 87% (20/23) of patients given romiplostim (12/12 splenectomised and eight of 11 non-splenectomised patients) reduced or discontinued concurrent therapy compared with 38% (six of 16) of those given placebo (one of six splenectomised and five of ten non-splenectomised patients). Adverse events were much the same in patients given romiplostim and placebo. No antibodies against romiplostim or thrombopoietin were detected. INTERPRETATION Romiplostim was well tolerated, and increased and maintained platelet counts in splenectomised and non-splenectomised patients with ITP. Many patients were able to reduce or discontinue other ITP medications. Stimulation of platelet production by romiplostim may provide a new therapeutic option for patients with ITP.

The Clinical Behavior of Localized and Multicentric Castleman Disease

Since it was originally described in 1956 [1], Castleman disease has been well established as a distinct clinicopathologic entity [2-4]. It is also known as angiofollicular lymph node hyperplasia, giant lymph node hyperplasia, lymphoid hamartoma, benign lymphoma, and follicular lymphoreticuloma. Histologically, it is an example of the so-called atypical lymphoproliferative disorders [4], a lymphoid proliferation not clearly recognizable as either purely reactive or fully neoplastic in nature. Because it is characterized by lymphadenopathy with or without constitutional symptoms, the disease clinically resembles malignant lymphoma. In their review of 81 cases, Keller and colleagues [3] found that all patients with localized Castleman disease had a benign clinical course. Complete local surgical excision totally eliminated the systemic symptoms present at diagnosis, with only occasional local recurrences. About 80% of cases of localized Castleman disease were hyaline vascular, and 20% were plasma-cell; only an occasional case of mixed disease was reported. Most patients with localized plasma-cell disease were children or young adults, and they presented with abdominal or mediastinal masses (peripheral masses were rare). Some had constitutional symptoms and laboratory abnormalities, such as anemia, hypoalbuminemia, hypergammaglobulinemia, and elevated erythrocyte sedimentation rates [3, 5]. Gaba and associates [6] reported the first case of multicentric Castleman disease in 1978. Most multicentric cases subsequently described have been of the plasma-cell type, although hyaline vascular and mixed cases have occasionally been reported [7-9]. The multicentric plasma-cell form of the disease is histologically similar to the localized plasma-cell type, but the two have major clinical differences. In contrast to the localized form, multicentric Castleman disease is a systemic illness with disseminated lymphadenopathy; its aggressive and usually fatal course is associated with infectious complications and risk for malignant tumors, such as lymphoma or Kaposi sarcoma [10, 11]. Multicentric Castleman disease has also been described in association with HIV infection [11]. Because limited information is available about therapy for the multicentric form of the disease, we analyzed the clinical features, management, and outcome of patients in whom Castleman disease was diagnosed at our institutions. Methods We reviewed the medical reports on 17 consecutive patients who 1) received a histologic diagnosis of Castleman disease at Texas Medical Center, Houston, Texas, between March 1977 and October 1995 and 2) had information on clinical follow-up available. The histologic material was reviewed by two pathologists who were blinded to clinical findings and the clinical course of the patients, and agreement was reached for each patient. In 15 of the 17 patients, the diagnosis of Castleman disease was confirmed; the other 2 patients had nonspecific histologic changes and were excluded from our analysis. Eight of the patients were identified from the files of the University of Texas M.D. Anderson Cancer Center, and 7 were identified from the files of hospitals affiliated with Baylor College of Medicine: Methodist Hospital, St. Lukes Episcopal Hospital, Ben Taub Hospital, and the Veterans Affairs Medical Center. Clinical information was obtained from a review of patient charts and from the attending pathologists and clinicians. In this paper, we describe the clinical features at presentation, clinicopathologic correlations, treatments, and outcomes of the 15 patients. As earlier investigators have done, we classified the patients as having one of two distinct clinical presentations: localized or multicentric. Patients were defined as having localized disease if they presented with only one group of lymph nodes histologically involved by Castleman disease; they were defined as having multicentric disease if they presented with involvement of two or more lymph node groups. The definition of extranodal involvement required a biopsy result that showed the features of Castleman disease in the involved organ. Systemic symptoms were attributed to Castleman disease if no other cause was found. Because the histologic features of plasma-cell Castleman disease may be found in patients with many reactive lymph node conditions, such as rheumatoid arthritis, syphilis, or skin diseases, and in patients with nodes draining malignancies and patients with the Wiskott-Aldrich syndrome [12], we excluded these possibilities before diagnosing plasma-cell Castleman disease. Results Localized Castleman Disease Diagnosis Of the 15 patients in our series, 7 met the criteria for localized Castleman disease. These patients were analyzed according to the histologic type of disease present (Table 1). No erythrocyte sedimentation rate at diagnosis was available for any of these patients. Table 1. Treatment and Evolution of Localized Castleman Disease* Four (57%) of the patients with localized disease had histologic evidence of the hyaline vascular type of disease. None of these four patients had constitutional symptoms at diagnosis. This histologic type of disease was not associated with mediastinal node involvement in any patient. Two patients had histologic evidence of the plasma-cell type of disease; both presented with constitutional symptoms. One patient had histologic evidence of mixed-type disease. Initial Treatment The primary treatment for all seven patients with localized disease was complete surgical resection. All of these patients are currently alive with no evidence of recurrence. The location of the lymphadenopathy did not influence outcome. Multicentric Castleman Disease Diagnosis Eight patients met the criteria for multicentric disease. These patients were analyzed according to the histologic type of disease present (Table 2). All of these patients, regardless of the histologic type of disease, had constitutional symptoms and laboratory abnormalities at presentation. One patient had hyaline vascular disease, four (50%) had plasma-cell disease, and three (37%) had mixed disease. Table 2. Treatment and Evolution of Multicentric Castleman Disease* Initial Treatment The initial therapy for patients 10, 13, and 15, all of whom had multicentric disease, was combination chemotherapy (Table 2). Patient 10 received cyclophosphamide, vincristine, doxorubicin, and dexamethasone; patient 15 received cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP); and patient 13 received chlorambucil and prednisone. Patient 10 attained a partial radiologic response but still had stable residual retroperitoneal adenopathy. Because no biopsy was done, it is not known whether this represented residual tumor or scar tissue. Patient 10 developed mediastinal adenopathy 3 years after diagnosis of Castleman disease, and a biopsy result was diagnostic of sarcoidosis. Patients 8 and 11 had surgery as initial therapy. Patient 8 underwent debulking surgery, and systemic symptoms improved. Disease recurred in the same area 2 years later and was treated with prednisone for a few weeks without response; this treatment was discontinued after an episode of severe upper gastrointestinal bleeding. At that time, patient 8 developed new weakness in the left hand that failed to resolve despite several courses of intravenous immunoglobulin. He became progressively weaker and continued to lose weight. He then received four cycles of CHOP without response. His last course was complicated with pneumonia and sepsis, and he received no further chemotherapy. He died 34 months after initial diagnosis and 1 year after his relapse. Patient 11 underwent complete surgical resection for abdominal and axillary adenopathy. He had a recurrence of Castleman disease in the submaxillary area 8 years later, which was treated with complete surgical excision. Ten months after his relapse, he developed peripheral T-cell non-Hodgkin lymphoma that was resistant to several chemotherapy regimens. The patient died 13 years (156 months) after initial diagnosis and 5 years after his relapse. In both patient 8 and patient 11, the initial disease and the relapses were of the plasma-cell type. Patients 12 and 14 received prednisone, 1 mg/kg of body weight per day, as initial treatment. Although both patients achieved complete clinical remission while receiving steroids, lymphadenopathy recurred after tapering. Maintenance therapy with prednisone, 20 to 30 mg/d, was required. Both patients remain alive 8 and 35 months after diagnosis. Patient 9 received no specific treatment during observation and had spontaneous regression of symptoms and palpable lymphadenopathy several months after initial diagnosis. No results of follow-up imaging procedures were available for this patient, and she remains alive and symptom-free 57 months after initial diagnosis. Discussion Clinical Findings Castleman disease is a rare disorder. Only three series of the localized form, describing a total of 174 patients [2, 3, 5], and three series of the multicentric form, describing a total of 38 cases [7-9], have been published. After comparing our data with those from other series [2, 3, 5, 7-9], we conclude that the localized and multicentric forms of Castleman disease are two distinct conditions that have similar histologic features but different clinical features, natural history, and responses to treatment. In the seven patients with localized Castleman disease in our series, the median age at diagnosis was 35 years (range, 15 to 45 years). This is not significantly different from data in previous reports [3, 5]. Similarly, no sex predilection was seen. Constitutional symptoms and laboratory abnormalities were seen almost exclusively in patients with plasma-cell disease; this finding is consistent with previous reports [3, 5]. The systemic manifestations of localized disease seemed to be less florid than those in multicentric disease,

Antibody inhibitors to von Willebrand factor metalloproteinase and increased binding of von Willebrand factor to platelets in ticlopidine-associated thrombotic thrombocytopenic purpura.

Ticlopidine, a potent antiplatelet agent used to maintain patency after coronary artery stenting and to prevent strokes in high-risk persons (1), has been associated with thrombotic thrombocytopenic purpura (TTP) (2-5). Thrombotic thrombocytopenic purpura, first described by Moschcowitz (6), is characterized by extensive platelet thrombi in the arterioles and capillaries. Abnormalities in von Willebrand factor multimers, including the presence of unusually large multimers and disappearance of the large multimers found in normal plasma, have been detected in many cases of the disease (7, 8). Furthermore, von Willebrand factor is abundant in the thrombi of patients with TTP (9), and flow cytometric studies have demonstrated that the factor is bound to platelets in the circulation of these patients during the most thrombocytopenic phase of the disease (10). The von Willebrand factor, a glycoprotein critical in mediating platelet deposition at sites of vessel injury, is synthesized and secreted by endothelial cells as a disulfide-linked polymer composed of a 2050amino acid monomer (11). Upon release into the circulation, it is cleaved by a plasma metalloproteinase in a shear-dependent manner (11) at the peptide bond between tyrosine-842 and methionine-843 (12). This cleavage decreases the size of the von Willebrand factor polymer, generates a series of multimers found in normal plasma, and produces dimers of 176-kD and 140-kD fragments (11). In the absence of the proteinase, large and unusually large von Willebrand factor multimers accumulate in the plasma. When unfolded by shear stress (13), these multimers exhibit an increased capacity to support platelet aggregation (14). Indeed, a deficiency of the proteinase has been reported in idiopathic TTP (15, 16). We investigated whether von Willebrand factor is involved in ticlopidine-associated TTP. Methods Patients Seven consecutive patients who developed TTP after initiation of ticlopidine therapy and were treated at the participating institutions from 1 January 1996 to 31 December 1998 were investigated. The criteria for the diagnosis of TTP were those described elsewhere (10, 16). We also determined proteinase activity in 17 controls: 7 consecutive, unselected patients without thrombocytopenia (age range, 62 to 81 years; 5 men and 2 women) who donated blood samples at routine follow-up examinations after 3 to 5 weeks of ticlopidine therapy prescribed for cardiac stents, and 10 randomly selected hospitalized patients not taking ticlopidine. Blood samples were obtained by venipuncture or at the time of plasmapheresis. The investigational protocol was approved by the institutional review boards of the participating centers. von Willebrand Factor Studies Platelet-bound von Willebrand factor, von Willebrand factor multimers, von Willebrand factorcleaving metalloproteinase activity, and the inhibitory activity of IgG to the von Willebrand factorcleaving metalloproteinase were measured as described elsewhere (10, 16). The von Willebrand factor bound to single platelets in EDTA-anticoagulated whole-blood samples was quantified by flow cytometry. Proteinase activity was expressed as a percentage of that in the pooled normal plasma control. Results The initial clinical and laboratory findings of the patients are summarized in the Table. The duration of ticlopidine therapy before diagnosis of TTP ranged from 2 to 7 weeks (median, 3 weeks). None of the patients had a history of autoimmune disorders, and none were receiving penicillins, antineoplastic chemotherapy, or oral contraceptives before onset of the disease. In all patients, remission occurred after ticlopidine therapy was discontinued and daily plasma exchange was instituted. The median number of plasma exchanges received by the patients was 10 (range, 5 to 30). None of the patients had relapse after plasma exchange was discontinued. Table. Clinical and Laboratory Findings von Willebrand Factor Binding to Single Platelets Binding of von Willebrand factor to platelets was studied in patients 1 to 3; the test was not available for the other 4 patients. Platelet-bound von Willebrand factor was 7.5, 4.5, and 4.5 arbitrary units, respectively (normal value<2.1 arbitrary units) in the initial blood samples; these values returned to normal when patients received plasma exchange and platelet counts increased. von Willebrand Factor Multimers In all seven patients, the largest multimers, which are found in normal plasma, were missing in the initial plasma samples. For patient 1, von Willebrand factor multimeric patterns in three of seven subsequent plasma samples were abnormal; one sample lacked the largest von Willebrand factor multimers, and two contained unusually large multimers. The initial plasma sample (obtained on day 1) for patient 3 was missing the largest multimers. The next two samples (obtained on days 2 and 4) contained unusually large multimers. The multimers were normal in the subsequent two samples (obtained on days 8 and 9). For patients 1, 2, and 6, plasma samples obtained upon remission were available for investigation; all samples showed normal multimeric patterns. von Willebrand Factor Metalloproteinase Activity For patient 1, only plasma samples obtained on days 4 to 6 after admission (when his platelet counts were 77 109/L, 70 109/L, and 76 109/L) were available for the study. These samples contained 28%, 17%, and 14%, respectively, of the proteinase activity found in plasma from normal controls. Proteinase activity was 0% in the initial plasma samples of patients 2 to 4 and 7%, 12%, and 4%, respectively, in patients 5 to 7. However, the plasma samples of these three patients were obtained from the plasmapheresis bags in amounts of 200 to 250 mL during the initial plasma exchanges. For patient 2, the protease activity increased to 100% on day 3, when the platelet count was 260 109/L. For patient 3, protease activity increased to 6%, 10%, 81%, and 77%, respectively, on days 2, 4, 8, and 9, when platelet counts were 25 109/L, 130 109/L, 280 109/L, and 325 108/L. Plasma proteinase levels in patient 5 increased to 23% and 55% on days 4 and 6, respectively, when platelet counts were 140 109/L and 180 109/L. A plasma sample obtained from patient 6 on day 5, when the platelet count had increased to 277 109/L, contained 94% proteinase activity. The mean (SD) plasma proteinase activity in the 7 controls receiving ticlopidine for 3 to 5 weeks was 114% 36%, which did not differ from the activity in the 10 randomly selected controls who were not treated with ticlopidine (97% 17%). In a previous study (16), 74 randomly selected patients without TTP had proteinase activity of 103% 23%. Inhibitors of von Willebrand Factor Proteinase To explore the causes of proteinase deficiency, the initial plasma sample of patient 2 was mixed with normal control plasma after treatment at 56 C for 30 minutes. The von Willebrand factor metalloproteinase activity in the mixture was suppressed to 23% of the activity found in a control mixture of heated normal pooled plasma and normal control plasma. Plasma samples from patients 3 to 7 were sufficient in volume for studies to determine whether their immunoglobulins inhibited the proteinase. The IgG isolated from patient 3 on day 1 exhibited a concentration-dependent inhibition of proteinase activity in normal control plasma. The concentration of the IgG molecules required to inhibit 50% of the protease activity in the mixture (IC50) was 2.2 mg/mL. The IgG isolated from the same patient on day 9 was not inhibitory. The IC50 of the IgG isolated from initial plasma samples of patients 4 to 7 was 5.5, 2.2, 4.4, and 2.2 mg/mL, respectively. In tests comparing susceptibility to inhibition, von Willebrand factor metalloproteinase in plasma from the normal controls and that in the plasma samples from controls who received ticlopidine were equally sensitive to inhibition by IgG isolated from patients with ticlopidine-associated TTP (data not shown). The inhibitory activity of IgG was abolished when it was incubated with antibodies to IgG Fab (data not shown). Discussion In two series of single-episode and intermittent idiopathic TTP (15, 16), inhibition of plasma von Willebrand factor proteinase by IgG autoantibodies was found to be characteristic. In support of a role of von Willebrand factor proteinase deficiency in the pathogenesis of platelet thrombosis, the deficiency was not observed in persons who did not have the disease. Furthermore, shear stress was found to increase the capacity of von Willebrand factor to support platelet aggregation (16). We now describe seven patients with ticlopidine-associated TTP who also had severely decreased levels of von Willebrand factor proteinase 2 to 7 weeks after initiation of ticlopidine therapy. The durations of ticlopidine therapy before the diagnosis of TTP are similar to the 2 to 12 weeks observed in 98 cases of TTP in a recently described series (17). The deficiency in our patients resolved after ticlopidine therapy was discontinued and plasmapheresis was instituted. The deficiency was not observed in randomly selected patients who had been receiving ticlopidine for similar durations but did not develop the disease. The absence or severe reduction of von Willebrand factor metalloproteinase was accompanied by binding of von Willebrand factor to platelets. Concurrently, the large von Willebrand factor multimers were missing. The level of von Willebrand factor proteinase activity required to prevent or decrease binding of von Willebrand factor to platelets and thrombosis was low (approximately 10% to 15%). Thus, even a slight increase in the proteinase activity was sufficient to suppress the values of platelet-bound von Willebrand factor. At this low level of proteinase activity, von Willebrand factor proteolysis remained defective. This explained the presence of unusually large von Willebrand factor multimers in the plasma. The decrease in von Willeb

The negative regulation of red cell mass by neocytolysis: Physiologic and pathophysiologic manifestations

We have uncovered a physiologic process which negatively regulates the red cell mass by selectively hemolyzing young circulating red blood cells. This allows fine control of the number of circulating red blood cells under steady-state conditions and relatively rapid adaptation to new environments. Neocytolysis is initiated by a fall in erythropoietin levels, so this hormone remains the major regulator of red cell mass both with anemia and with red cell excess. Physiologic situations in which there is increased neocytolysis include the emergence of newborns from the hypoxic uterine environment and the descent of polycythemic high-altitude dwellers to sea level. The process first became apparent while investigating the mechanism of the anemia that invariably occurs after spaceflight. Astronauts experience acute central plethora on entering microgravity resulting in erythropoietin suppression and neocytolysis, but the reduced blood volume and red cell mass become suddenly maladaptive on re-entry to earth’s gravity. The pathologic erythropoietin deficiency of renal disease precipitates neocytolysis, which explains the prolongation of red cell survival consistently resulting from erythropoietin therapy and points to optimally efficient erythropoietin dosing schedules. Implications should extend to a number of other physiologic and pathologic situations including polycythemias, hemolytic anemias, ‘blood-doping’ by elite athletes, and oxygen therapy. It is likely that erythropoietin influences endothelial cells which in turn signal reticuloendothelial phagocytes to destroy or permit the survival of young red cells marked by surface molecules. Ongoing studies to identify the molecular targets and cytokine intermediaries should facilitate detection, dissection and eventual therapeutic manipulation of the process.

The HIT Expert Probability (HEP) Score: a novel pre‐test probability model for heparin‐induced thrombocytopenia based on broad expert opinion

Summary.  Background: The diagnosis of heparin‐induced thrombocytopenia (HIT) is challenging. Over‐diagnosis and over‐treatment are common. Objectives: To develop a pre‐test clinical scoring model for HIT based on broad expert opinion that may be useful in guiding clinical decisions regarding therapy. Patients/methods: A pre‐test model, the HIT Expert Probability (HEP) Score, was constructed based on the opinions of 26 HIT experts. Fifty patients referred to a reference laboratory for HIT testing comprised the validation cohort. Two hematology trainees scored each patient using the HEP Score and a previously published clinical scoring system (4 T’s). A panel of three independent experts adjudicated the 50 patients and rendered a diagnosis of HIT likely or unlikely. All subjects underwent HIT laboratory testing with a polyspecific HIT ELISA and serotonin release assay (SRA). Results: The HEP Score exhibited significantly greater interobserver agreement [intraclass correlation coefficient: 0.88 (95% CI 0.80–0.93) vs. 0.71 (0.54–0.83)], correlation with the results of HIT laboratory testing and concordance with the diagnosis of the expert panel (area under receiver‐operating curve: 0.91 vs. 0.74, P = 0.017) than the 4 T’s. The model was 100% sensitive and 60% specific for determining the presence of HIT as defined by the expert panel and would have allowed for a 41% reduction in the number of patients receiving a direct thrombin inhibitor (DTI). Conclusion: The HEP Score is the first pre‐test clinical scoring model for HIT based on broad expert opinion, exhibited favorable operating characteristics and may permit clinicians to confidently reduce use of alternative anticoagulants. Prospective multicenter validation is warranted.

Assessment of tissue iron overload by nuclear magnetic resonance imaging.

PURPOSE The ability of stored intracellular iron to enhance magnetic susceptibility forms the basis by which tissue iron can be detected by nuclear magnetic resonance (NMR) imaging. We used this technique to assess myocardial, spleen, and liver iron content in patients with known or suspected iron overload disorders. PATIENTS AND METHODS Spin echo NMR images were obtained in 30 patients; 20 had chronic anemias treated by multiple blood transfusions, five had idiopathic hemochromatosis, and five had non-hemochromatotic liver disease with elevated serum ferritin levels and no stainable iron on liver biopsy. The acquisition of oblique images through the short axis of the left ventricle permitted assessment of left ventricular function, while demonstrating the liver and spleen on the same image. Iron content was assessed using a signal intensity ratio of organ (spleen, liver, or myocardium) to skeletal muscle. RESULTS In patients with multiple blood transfusions, iron content was highest in liver, followed by the spleen. Significant iron overload was detected in the myocardium of only one patient. Left ventricular systolic wall thickening was normal in patients receiving multiple blood transfusions. Two patients with treated idiopathic hemochromatosis had normal signal intensity ratios, and three untreated patients had evidence of significant deposits of iron in the liver and spleen as indicated by a reduction in signal intensity ratios (0.2 +/- 0.01 and 0.9 +/- 0.01, respectively). Five patients with non-hemochromatotic liver disease and high serum ferritin levels had normal signal intensity ratios by NMR imaging. CONCLUSION NMR imaging is a useful method of detecting tissue iron and distinguishing disease due to iron overload. Myocardial iron deposition is a late event, occurring after accumulation of iron in the spleen and liver.

Improved quality of life for romiplostim-treated patients with chronic immune thrombocytopenic purpura: results from two randomized, placebo-controlled trials

Health‐related quality of life (HRQoL) is a major concern for adults with chronic immune thrombocytopenic purpura (ITP) due to the symptoms associated with the disease and its treatment. This study utilized the ITP‐patient assessment questionnaire (ITP‐PAQ), a specialized HRQoL questionnaire for ITP, to investigate the humanistic burden of ITP and the impact of romiplostim therapy on HRQoL in two, placebo‐controlled, phase 3 clinical trials of splenectomized and non‐splenectomized patients. ITP‐PAQ was self‐administered to ITP patients at baseline, and weeks 4, 12 and 24 of treatment. Splenectomized patients had lower baseline HRQoL scores than non‐splenectomized patients in seven of 10 scales (P < 0·05). After 24 weeks of romiplostim therapy, splenectomized patients showed significant improvements over placebo in four of 10 ITP‐PAQ Scales (Symptoms, P = 0·0337; Bother, P = 0·0126; Social Activity, P = 0·0145; and Women’s Reproductive Health, P = 0·0184). Non‐splenectomized patients demonstrated significant improvement over placebo in the Activity Scale (P = 0·0458). Data pooled from the two trials, adjusted for splenectomy status, showed significant improvement for romiplostim‐treated patients in six scales; Symptoms, Bother, Activity, Fear, Social Activity and Women’s Reproductive Health. These results suggest that adult patients with chronic ITP have improved HRQoL following romiplostim therapy.

Increased von Willebrand Factor Binding to Platelets in Single Episode and Recurrent Types of Thrombotic Thrombocytopenic Purpura

Extensive microvascular platelet aggregation is characteristic of thrombotic thrombocytopenic purpura (TTP). Previous studies have indicated that abnormalities of von Willebrand factor (vWf) are often present in TTP patient plasma. There has not been previously any direct evidence linking these abnormalities to the process of intravascular platelet aggregation in TTP. We used flow cytometry to analyze the binding of vWf to single platelets, and the presence of platelet aggregates, in the blood of 4 children with chronic relapsing (CR) TTP and 5 adults with single episode or recurrent TTP. vWf on the single platelets of CRTTP patients at all time points studied was significantly increased compared to controls, and was increased further as platelet counts decreased to levels below 40,000/μl. The single episode and recurrent adult TTP patients had platelet aggregates in the blood, as well as increased vWf on single platelets, before therapy commenced and thereafter until recovery was in process. In the one unresponsive single episode TTP patient, vWf on single platelets remained elevated, and platelet aggregates persisted, until her death. The platelet α‐granular protein, P‐selectin, was not increased on the single platelets of most TTP blood samples, suggesting that it is vWf from plasma (rather than from α‐granules) that attaches to platelet surfaces in association with platelet aggregation. These results suggest that vWf‐platelet interactions are involved in the platelet clumping process that characterizes TTP. Am. J. Hematol. 57:293–302, 1998.

Neocytolysis contributes to the anemia of renal disease.

Neocytolysis is a recently described physiological process affecting the selective hemolysis of young red blood cells in circumstances of plethora. Erythropoietin (EPO) depression appears to initiate the process, providing the rationale to investigate its contributions to the anemia of renal disease. When EPO therapy was withheld, four of five stable hemodialysis patients showed chromium 51 (51Cr)-red cell survival patterns indicative of neocytolysis; red cell survival was short in the first 9 days, then normalized. Two of these four patients received oral 13C-glycine and 15N-glycine, and there was a suggestion of pathological isotope enrichment of stool porphyrins when EPO therapy was held, again supporting selective hemolysis of newly released red cells that take up the isotope (one patient had chronic hemolysis indicated by isotope studies of blood and stool). Thus, neocytolysis can contribute to the anemia of renal disease and explain some unresolved issues about such anemia. One implication is the prediction that intravenous bolus EPO therapy is metabolically and economically inefficient compared with lower doses administered more frequently subcutaneously.

Responses to human CD40 ligand/human interleukin-2 autologous cell vaccine in patients with B-cell chronic lymphocytic leukemia.

Purpose: Human CD40 ligand activates the malignant B-cell chronic lymphocytic leukemia cells and enhances their capacity to present tumor antigens. Human interleukin-2 further potentiates the immunogenicity of human CD40 ligand in preclinical murine models. Experimental Design: We prepared autologous B-cell chronic lymphocytic leukemia cells that expressed both human CD40 ligand (>90% positive) and human interleukin-2 (median secretion, 1,822 pg/mL/106 cells; range, 174-3,604 pg). Nine patients were enrolled in a phase I trial, receiving three to eight s.c. vaccinations. Results: Vaccinations were administered without evidence of significant local or systemic toxicity. A B-cell chronic lymphocytic leukemia–specific T-cell response was detected in seven patients. The mean frequencies of IFN-γ, granzyme-B, and IL-5 spot-forming cells were 1/1,230, 1/1,450, and 1/4,500, respectively, representing a 43- to 164-fold increase over the frequency before vaccine administration. Three patients produced leukemia-specific immunoglobulins. Three patients had >50% reduction in the size of affected lymph nodes. Nonetheless, the antitumor immune responses were observed only transiently once immunization ceased. High levels of circulating CD4+/CD25+/LAG-3+/FoxP-3+ immunoregulatory T cells were present before, during and after treatment and in vitro removal of these cells increased the antileukemic T-cell reactivity. Conclusions: These results suggest that immune responses to B-cell chronic lymphocytic leukemia can be obtained with human CD40 ligand/human interleukin-2–expressing s.c. vaccines but that these responses are transient. High levels of circulating regulatory T cells are present, and it will be of interest to see if their removal in vivo augments and prolongs the antitumor immune response.