Louis M. Aledort

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.

A longitudinal study of orthopaedic outcomes for severe factor-VIII-deficient haemophiliacs

Abstract. Objective. Arthropathy is the major cause of morbidity in haemophilia. In an attempt to establish optimal therapeutic regimens for persons with haemophilia, we hypothesized that no direct relationship exists between increasing factor dosage and orthopaedic outcomes over time.

A Prospective Study of Human Immunodeficiency Virus Type 1 Infection and the Development of AIDS in Subjects with Hemophilia

We evaluated a multicenter cohort of 1219 subjects with hemophilia or related disorders prospectively, focusing on 319 subjects with documented dates of seroconversion to human immunodeficiency virus type 1 (HIV-1). The incidence rate of the acquired immunodeficiency syndrome (AIDS) after seroconversion was 2.67 per 100 person-years and was directly related to age (from 0.83 in persons 1 to 11 years old up to 5.66 in persons 35 to 70 years old; Ptrend = 0.00003). The annual incidence of AIDS ranged from zero during the first year after seroconversion to 7 percent during the eighth year, with eight-year cumulative rates (+/- SE) of 13.3 +/- 5.3 percent for ages 1 to 17, 26.8 +/- 6.4 percent for ages 18 to 34, and 43.7 +/- 16.4 percent for ages 35 to 70. Serial immunologic and virologic markers (total numbers of CD4 lymphocytes, presence of serum interferon or HIV-1 p24 antigen, and low or absent serum levels of anti-p24 or anti-gp120) predicted a high risk for the subsequent development of AIDS. Adults 35 to 70 years old had a higher incidence of low CD4 counts than younger subjects (P less than or equal to 0.005), whereas adolescents had a low rate of anti-p24 loss (P = 0.0007) and subjects 1 to 17 years old had a lower incidence of AIDS after loss of anti-p24 (P = 0.03). These findings not only demonstrate that the risk of AIDS is related directly to age but also suggest that older adults are disproportionately affected during the earlier phases of HIV disease, that adolescents may have a low replication rate of HIV, and that children and adolescents may tolerate severe immunodeficiency better because they have fewer other infections or because of some unmeasured, age-dependent cofactor or immune alteration in the later phase of HIV disease.

Comparative thrombotic event incidence after infusion of recombinant factor VIIa versus factor VIII inhibitor bypass activity

Summary.  Thrombosis is a rare but well‐recognized potential complication of Factor VIII Inhibitor Bypass Activity (FEIBA) infusion. Recombinant factor VIIa (rFVIIa) is increasingly used as an alternative to FEIBA; however, the thrombotic safety profile of rFVIIa remains incompletely characterized. To determine the incidence rates of thrombotic adverse events (AEs) after infusion of rFVIIa and FEIBA. Data from the MedWatch pharmacovigilance program of the US Food and Drug Administration, as supplemented by published case reports, were used in conjunction with estimated numbers of infusions available from manufacturers to assess comparative incidence of thrombotic AEs in patients receiving rFVIIa or FEIBA in the period from April 1999 through June 2002. Reported thrombotic AEs were rare, with incidence rates of 24.6 per 105 infusions (CI, 19.1–31.2 per 105 infusions) for rFVIIa and 8.24 per 105 infusions (CI, 4.71–13.4 per 105 infusions) for FEIBA. Thrombotic AEs were significantly more frequent in rFVIIa than FEIBA recipients (incidence rate ratio, 2.98; CI, 1.71–5.52). The most commonly documented single type of thrombotic AE after rFVIIa infusion was cerebrovascular thrombosis, while myocardial infarction was the most frequent type in patients receiving FEIBA. Contrasting AE reporting patterns between rFVIIa and FEIBA may have contributed to the observed difference in thrombotic event incidence. Nevertheless, this comprehensive pharmacovigilance assessment does not support superior thrombotic safety of rFVIIa and suggests that thrombotic AE risk may be higher in rFVIIa than FEIBA recipients.

Human Recombinant DNA–Derived Antihemophilic Factor (Factor VIII) in the Treatment of Hemophilia A

BACKGROUND Current treatment of hemophilia A, a hereditary disorder affecting approximately 1 in 10,000 males, relies on plasma-derived factor VIII concentrates. We tested the safety and efficacy of a recombinant factor VIII preparation for the treatment of this disorder. METHODS We conducted the investigation in three stages: comparing the pharmacokinetics of plasma-derived and recombinant factor VIII, assessing the efficacy of recombinant factor VIII for home therapy, and assessing its efficacy for major surgical procedures and hemorrhage. A total of 107 subjects with hemophilia, 20 of whom had not been treated previously, enrolled in the investigation. RESULTS The in vivo recovery and elimination half-lives of recombinant factor VIII equaled or exceeded those of plasma-derived factor VIII. Seventy-six subjects participated in a home-treatment program, using recombinant factor VIII for 69 to 807 days (median, 618); home diaries of 56 subjects treated for 5 months were analyzed. Of 540 bleeding episodes, 399 (73.9 percent) required only one treatment with recombinant factor VIII. The projected annual consumption of recombinant factor VIII was similar to that of plasma-derived factor VIII concentrate. Twenty-six subjects received recombinant factor VIII for 22 surgical procedures and 10 serious hemorrhages; hemostasis was excellent in all cases. De novo formation of inhibitors occurred in only 1 of 85 previously treated subjects. Inhibitor antibodies also developed in 6 of 21 children, 20 of whom had not previously been treated; 5 had low levels (less than or equal to 7.5 Bethesda units) despite continued treatment with recombinant factor VIII. There was no evidence of new formation of antibody to foreign proteins, and recombinant factor VIII was well tolerated. CONCLUSIONS Recombinant factor VIII has biologic activity comparable to that of plasma factor VIII and is safe and efficacious for the treatment of hemophilia A.

Nasal Spray Desmopressin (DDAVP) for Mild Hemophilia A and von Willebrand Disease

OBJECTIVE To evaluate the effect of a nasal spray preparation of desmopressin (DDAVP) on levels of factor VIII activity, ristocetin cofactor activity, and von Willebrand antigen as well as the length of bleeding time in patients with mild hemophilia A and von Willebrand disease; to determine whether effective hemostatic levels can be attained; and to compare the effect of this spray with that of standard intravenous desmopressin treatment. DESIGN Before-and-after trial in patients known to respond to intravenous desmopressin. SETTING Regional, comprehensive, hemophilia diagnosis and treatment center. PATIENTS A total of 22 patients, including 11 patients with von Willebrand disease, 8 patients with mild hemophilia A, and 3 symptomatic hemophilia carriers. INTERVENTIONS Patients were infused with desmopressin, 0.3 micrograms/kg body weight. At least 1 week later, they were taught to self-administer desmopressin nasal spray, 150 micrograms to each nostril. MEASUREMENTS In patients with hemophilia, the level of factor VIII activity was measured; in patients with von Willebrand disease, levels of factor VIII activity, ristocetin cofactor activity, and von Willebrand antigen as well as bleeding time were measured before and after each administration of desmopressin. MAIN RESULTS Desmopressin, when administered intravenously or intranasally, elevated levels of factor VIII, ristocetin cofactor, and von Willebrand antigen in both mildly hemophiliac patients and patients with von Willebrand disease when compared with baseline measures (P less than 0.05). Factor VIII levels adequate for hemostasis were achieved by 82% of the hemophiliac patients. An abnormal bleeding time was corrected in the majority (62%) of patients with von Willebrand disease. CONCLUSION A nasal spray preparation of desmopressin apparently was effective both in treating bleeding episodes and when used prophylactically for minor surgical procedures in several patients.

The economic impact of factor VIII inhibitors in patients with haemophilia.

Summary.  The impact on the cost of care for haemophilia patients with inhibitors is not well defined. To quantify the effect on health care expenditures associated with inhibitors to factor VIII (FVIII) or FIX, we conducted a retrospective cohort study examining product use and outcomes in adult and paediatric haemophilia patients with and without inhibitors. Twelve patients with inhibitors to FVIII or FIX (cases) identified in the haemophilia surveillance system (HSS) at two centres were matched on age, severity of haemophilia, and treatment centre to haemophilia patients without inhibitors. Patients with HIV or significant liver disease were excluded from the study. All eligible non‐inhibitor control patients were selected for inclusion in the study, resulting in a total of 28 controls. We then tracked product usage and hospitalizations from programme entry until 1998 or loss to follow‐up, producing a total database of 184 person‐years of experience. A descriptive matched analysis was conducted to examine annual differences in the cost of product used and hospitalizations. We found that the median cost for factor products among haemophilia patients with inhibitors was

Evaluation of bleeding and thrombotic events during long‐term use of romiplostim in patients with chronic immune thrombocytopenia (ITP)

55 853/year,

Emerging clinical concerns in the ageing haemophilia patient.

2760 less than comparable haemophilia patients without inhibitors. The median number of hospitalizations per year was 1.0 for both inhibitor and non‐inhibitor patients and the median number of days hospitalized was virtually the same. Although these findings do not appear to support the belief that there is a substantial increase in the cost of care for haemophilia patients with inhibitors, it does document that a few outlier patients can drive the cost of treatment for this disease. As the largest component of the cost of care is that of factor concentrate, it becomes imperative in the current health care environment to better define the true costs and benefits of treatments designed to eradicate or manage inhibitors. A careful cost accounting of immune tolerance induction (ITI) and other therapeutic strategies, taking into account successes and failures and duration and intensity of therapy, should help to better define the costs and benefits of such approaches. Methods to identify high cost inhibitor patients should be developed so that these strategies may be targeted to appropriate candidates.

Can B‐domain deletion alter the immunogenicity of recombinant factor VIII? A meta‐analysis of prospective clinical studies

Summary.  Background: Romiplostim is a peptibody protein that raises platelet counts during long‐term treatment of patients with chronic immune thrombocytopenia (ITP). Clinical outcomes related to increased platelet counts include a reduced risk of bleeding and a potential risk of thrombosis. Objective: To evaluate bleeding and thrombotic events occurring in chronic ITP patients during two phase 3, randomized, placebo‐controlled, 24‐week studies of romiplostim and during subsequent treatment in an open‐label extension study. Patients/Methods: In the phase 3 trials, 125 patients were randomized to romiplostim or placebo; romiplostim dose was adjusted to maintain platelet counts of 50–200 × 109 L−1. Patients who completed the phase 3 trials could enroll in the extension study in which all patients received romiplostim. Results: In the phase 3 trials, a significantly greater percentage of patients treated with placebo (34%) had bleeding adverse events of moderate or greater severity than did patients treated with romiplostim (15%, P = 0.018). In the extension study, the incidence of bleeding adverse events of moderate or greater severity decreased from 23% of patients in the first 24 weeks to 12% after 24–48 weeks, remaining ≤ 6% thereafter. The exposure‐adjusted incidence of thrombotic events was 0.1 per 100 patient‐weeks in the phase 3 studies, and 0.08 per 100 patient‐weeks in the extension study where patients received romiplostim for up to 144 additional weeks. Conclusions: The incidence and severity of bleeding was decreased in chronic ITP patients treated with romiplostim compared with placebo, and the incidence of thrombotic events was not different between the two groups.