Andres Brainsky

Safety and efficacy of eltrombopag for treatment of chronic immune thrombocytopenia: results of the long-term, open-label EXTEND study

Patients with chronic immune thrombocytopenia may have bleeding resulting from low platelet counts. Eltrombopag increases and maintains hemostatic platelet counts; however, to date, outcome has been reported only for treatment lasting ≤ 6 months. This interim analysis of the ongoing open-label EXTEND (Eltrombopag eXTENded Dosing) study evaluates the safety and efficacy of eltrombopag in 299 patients treated up to 3 years. Splenectomized and nonsplenectomized patients achieved platelets ≥ 50 000/μL at least once (80% and 88%, respectively). Platelets ≥ 50 000/μL and 2 × baseline were maintained for a median of 73 of 104 and 109 of 156 cumulative study weeks, respectively. Bleeding symptoms (World Health Organization Grades 1-4) decreased from 56% of patients at baseline to 20% at 2 years and 11% at 3 years. One hundred (33%) patients were receiving concomitant treatments at study entry, 69 of whom attempted to reduce them; 65% (45 of 69) had a sustained reduction or permanently stopped ≥ 1 concomitant treatment. Thirty-eight patients (13%) experienced ≥ 1 adverse events leading to study withdrawal, including patients meeting protocol-defined withdrawal criteria (11 [4%] thromboembolic events, 5 [2%] exceeding liver enzyme thresholds). No new or increased incidence of safety issues was identified. Long-term treatment with eltrombopag was generally safe, well tolerated, and effective in maintaining platelet counts in the desired range.

Eltrombopag before Procedures in Patients with Cirrhosis and Thrombocytopenia

BACKGROUND Eltrombopag is an oral thrombopoietin-receptor agonist. This study evaluated the efficacy of eltrombopag for increasing platelet counts and reducing the need for platelet transfusions in patients with thrombocytopenia and chronic liver disease who are undergoing an elective invasive procedure. METHODS We randomly assigned 292 patients with chronic liver disease of diverse causes and platelet counts of less than 50,000 per cubic millimeter to receive eltrombopag, at a dose of 75 mg daily, or placebo for 14 days before a planned elective invasive procedure that was performed within 5 days after the last dose. The primary end point was the avoidance of a platelet transfusion before, during, and up to 7 days after the procedure. A key secondary end point was the occurrence of bleeding (World Health Organization [WHO] grade 2 or higher) during this period. RESULTS A platelet transfusion was avoided in 104 of 145 patients who received eltrombopag (72%) and in 28 of 147 who received placebo (19%) (P<0.001). No significant difference between the eltrombopag and placebo groups was observed in bleeding episodes of WHO grade 2 or higher, which were reported in 17% and 23% of patients, respectively. Thrombotic events of the portal venous system were observed in 6 patients who received eltrombopag, as compared with 1 who received placebo, resulting in the early termination of the study. The incidence and severity of other adverse events were similar in the eltrombopag and placebo groups. CONCLUSIONS Eltrombopag reduced the need for platelet transfusions in patients with chronic liver disease who were undergoing elective invasive procedures, but it was associated with an increased incidence of portal-vein thrombosis, as compared with placebo. (Funded by GlaxoSmithKline; ELEVATE ClinicalTrials.gov number, NCT00678587.).

Eltrombopag Increases Platelet Numbers in Thrombocytopenic Patients With HCV Infection and Cirrhosis, Allowing for Effective Antiviral Therapy

BACKGROUND & AIMS Thrombocytopenia is common among patients with hepatitis C virus (HCV) infection and advanced fibrosis or cirrhosis, limiting initiation and dose of peginterferon-alfa (PEG) and ribavirin (RBV) therapy. The phase 3 randomized, controlled studies, Eltrombopag to Initiate and Maintain Interferon Antiviral Treatment to Benefit Subjects with Hepatitis C-Related Liver Disease (ENABLE)-1 and ENABLE-2, investigated the ability of eltrombopag to increase the number of platelets in patients, thereby allowing them to receive initiation or maintenance therapy with PEG and RBV. METHODS Patients with HCV infection and thrombocytopenia (platelet count <75,000/μL) who participated in ENABLE-1 (n = 715) or ENABLE-2 (n = 805), from approximately 150 centers in 23 countries, received open-label eltrombopag (25-100 mg/day) for 9 weeks or fewer. Patients whose platelet counts reached the predefined minimal threshold for the initiation of PEG and RBV therapy (95% from ENABLE-1 and 94% from ENABLE-2) entered the antiviral treatment phase, and were assigned randomly (2:1) to groups that received eltrombopag or placebo along with antiviral therapy (24 or 48 weeks, depending on HCV genotype). The primary end point was sustained virologic response (SVR) 24 weeks after completion of antiviral therapy. RESULTS More patients who received eltrombopag than placebo achieved SVRs (ENABLE-1: eltrombopag, 23%; placebo, 14%; P = .0064; ENABLE-2: eltrombopag, 19%; placebo, 13%; P = .0202). PEG was administered at higher doses, with fewer dose reductions, in the eltrombopag groups of each study compared with the placebo groups. More patients who received eltrombopag than placebo maintained platelet counts of 50,000/μL or higher throughout antiviral treatment (ENABLE-1, 69% vs 15%; ENABLE-2, 81% vs 23%). Adverse events were similar between groups, with the exception of hepatic decompensation (both studies: eltrombopag, 10%; placebo, 5%) and thromboembolic events, which were more common in the eltrombopag group of ENABLE-2. CONCLUSIONS Eltrombopag increases platelet numbers in thrombocytopenic patients with HCV and advanced fibrosis and cirrhosis, allowing otherwise ineligible or marginal patients to begin and maintain antiviral therapy, leading to significantly increased rates of SVR. Clinical trial no: NCT00516321, NCT00529568.

Selective validation of the WHO Bleeding Scale in patients with chronic immune thrombocytopenia.

Abstract Objective: To evaluate the World Health Organization’s (WHO) Bleeding Scale in two studies of eltrombopag in adults with chronic immune thrombocytopenia (ITP). Research design and methods: Validated scales assessing bleeding in adults with ITP are lacking. Data from two long-term, phase 3 clinical trials (RAISE: NCT00370331; EXTEND: NCT00351468) that assessed eltrombopag in adults with chronic ITP were analyzed to evaluate the performance of the WHO Bleeding Scale. Results: In RAISE, effect size (0.71), standardized response (0.75), and responsiveness statistics (0.57) were moderate for bleeding and bruising assessments. In EXTEND, effect size (0.62) and responsiveness statistics (0.59) were moderate; the standardized response statistic was 0.487. Intraclass correlation for test–retest reliability was 0.75 in RAISE and 0.71 in EXTEND. A positive correlation was observed between the WHO Bleeding Scale and the ITP Bleeding Scale. Bleeding scores and quality-of-life measures were inversely correlated (p < 0.05 for all). Minimal important differences for the WHO Bleeding Scale were 0.33–0.40 at baseline and last on-treatment assessment in both studies. Limitations: The majority of bleeding in these studies was mild to moderate, so this analysis cannot provide strong evidence of the validity of the WHO Bleeding Scale in patients with more severe bleeding. Potential limitations to the WHO Bleeding Scale itself include dependence on clinician interpretation of patient recall, inability to distinguish among bleeding events occurring at different anatomical sites, and an inherent assumption of linear increases in severity of bleeding across the response categories. Conclusions: These findings suggest potential usefulness of the WHO Bleeding Scale in adult patients with chronic ITP for standardizing grading of bleeding across research studies and in clinical practice.

Risk of thrombosis in patients with primary immune thrombocytopenia and antiphospholipid antibodies: A systematic review and meta-analysis.

Antiphospholipid antibodies (aPL) are common in ITP, but their role for the occurrence of ITP-related thrombosis is controversial. We performed a systematic review and a meta-analysis to investigate the risk of thrombosis associated with lupus anticoagulant (LA), anticardiolipin (aCL) and anti-β2GP-I antibodies in primary ITP. The literature search was run on Medline, Cochrane and ISI Web of Science from January 1st 1980 to December 31st 2014. Unpublished studies were searched in meeting abstracts. The main analysis assessed the risk of all thromboses (arterial or venous) associated with the presence of LA, aCL or anti-β2GP-I antibodies. Random-effect models were used to calculate odds ratios (OR) and their 95% confidence intervals (CI). Searches in electronic databases retrieved 776 citations. Twelve additional studies from unpublished literature were added. Eventually, 10 cohort studies totalizing 1574 patients were included in the analysis. The pooled OR for the risk of all thromboses associated with LA was 6.11, 95% CI [3.40-10.99]; it was 2.14, 95% CI [1.11-4.12] with aCL. The ORs were similar when stratifying on the type of thrombosis (arterial vs. venous). Only two studies assessed the risk of thrombosis associated with anti-β2GP-I antibody positivity; consequently, no pooled OR was computed for these antibodies. This meta-analysis highly suggests that LA positivity, and to a less extent aCL antibodies, are associated with an enhanced risk of thrombosis in primary ITP patients. Further prospective studies are needed to identify the factors associated with the risk of thrombosis among LA patients before assessing prevention strategies.

Efficacy of eltrombopag in management of bleeding symptoms associated with chronic immune thrombocytopenia.

Bleeding is of particular clinical importance in the management of chronic immune thrombocytopenia (ITP), which involves impaired platelet production and accelerated destruction. We report the first comprehensive analysis of the impact of eltrombopag on bleeding in five clinical studies of adult chronic ITP: two 6-week phase 2 (TRA100773A) and phase 3 (TRA100773B) studies; a 6-month phase 3 study (RAISE); a phase 2 repeat-dose study (REPEAT); and a phase 3 extension study (EXTEND). Bleeding was assessed using the World Health Organization Bleeding Scale and categorized as no bleeding (grade 0), any bleeding (grades 1–4), and clinically significant bleeding (grades 2–4). Bleeding was also assessed using National Cancer Institute Common Terminology Criteria for Adverse Events v3.0. Across all studies, bleeding at baseline ranged from 50 to 73% for eltrombopag-treated patients; by week 2, bleeding had decreased, ranging from 26 to 39%. This trend was maintained throughout treatment. Similar results were observed for clinically significant bleeding. No such trend was seen in placebo-treated patients for any bleeding or clinically significant bleeding. For TRA100773B and RAISE, the odds of any bleeding across the entire treatment period were 51 and 76% lower for eltrombopag-treated versus placebo-treated patients (P = 0.021, P < 0.001). The odds of clinically significant bleeding in RAISE were 65% lower (P < 0.001). In conclusion, analysis of prospective data from five clinical studies demonstrates that eltrombopag significantly reduces bleeding in adult patients with chronic ITP.

Dental procedures in 24 patients with chronic immune thrombocytopenia in prospective clinical studies of eltrombopag

Abstract Primary immune thrombocytopenia (ITP) is an autoimmune disease characterized by chronically low peripheral blood platelet counts. Eltrombopag is an oral, non-peptide, thrombopoietin-receptor agonist that increases platelet production. This report examines peri-procedural platelet counts and bleeding complications among chronic ITP patients requiring dental procedures while participating in clinical studies with eltrombopag. A total of 494 patients participated in five clinical studies of eltrombopag in chronic ITP. Information about dental procedures was collected prospectively in four studies and retrospectively in one study. Twenty-four patients (22 eltrombopag, 2 placebo) underwent 32 dental procedures (dental cleaning, tooth repair, artificial crown, dental prosthesis, tooth extraction, dental or wisdom teeth extraction, dental root extraction, and endodontic procedures, among others) during study treatment or up to 10 days later. Supplemental ITP therapy (e.g., corticosteroids, platelet transfusions) was given before the dental procedure to increase platelet counts in three eltrombopag-treated patients and both placebo-treated patients. The mean pre-procedure platelet count ± standard deviation for all procedures in the overall population of patients, eltrombopag group, and placebo group prior to undergoing dental procedures was 96 000 ± 81 069/µl,103 517 ± 81 522/µl, and 23 333 ± 9291/µl, respectively. Two patients in each group had platelet counts below 30 000/µl before the procedure. No patient who had a dental procedure experienced a bleeding adverse event. Among patients with chronic ITP who required a dental procedure during clinical studies of eltrombopag, supplemental ITP treatment was required for both patients who received placebo but was not required for most patients who received eltrombopag. No bleeding complications were reported. These data imply that patients with chronic ITP who receive eltrombopag and experience increases in platelet counts fulfill current pre-procedural platelet count recommendations to undergo invasive dental procedures, and may have a lower risk of bleeding complications and a reduced need for supplemental ITP treatment.

Hemostatic challenges in patients with chronic immune thrombocytopenia treated with eltrombopag

Chronic immune thrombocytopenia (ITP) is an autoimmune disease that results in chronically low platelet counts. Treatment guidelines recommend a platelet count of at least 50 000/µl before minor surgery and at least 80 000/µl before major surgery. This retrospective analysis explored invasive non-dental procedures associated with the risk of bleeding (hemostatic challenges) among patients with chronic ITP in five phase 2/phase 3 studies of the thrombopoietin-receptor agonist, eltrombopag. Data collection for patients who underwent hemostatic challenges included demographics, study medication, timing of the procedure, platelet counts at last assessment before and first assessment after the procedure, supplemental ITP treatment, and bleeding events. Among 494 patients who participated in the studies, 87 hemostatic challenges were recorded. Median platelet counts before 44 major procedures in 32 patients were 100 000/µl and 18 500/µl among patients who received eltrombopag and placebo, respectively; before 43 minor procedures in 38 patients, median platelet counts were 82 000/µl and 20 000/µl among patients who received eltrombopag and placebo, respectively. A minority of patients required supplemental ITP treatment. Only 2 of 87 hemostatic challenges were associated with bleeding events; both patients received eltrombopag and pre-procedural platelet counts were 83 000/µl and 2000/µl. Although the number of patients who did not undergo procedures due to thrombocytopenia was not captured, these data suggest a majority of patients with chronic ITP who receive eltrombopag and experience increases in platelet counts meet current pre-procedural platelet count recommendations. The potential role of eltrombopag in supporting preparation of chronic ITP patients for surgical procedures still needs to be clinically established.

Thrombophilia in patients with chronic immune thrombocytopenia.

Abstract An increased risk of thromboembolic events among patients with chronic immune thrombocytopenia has been reported but is still not fully understood. A thrombophilia panel (factors suspected/known to denote a thrombophilic state or indicate activation of the clotting cascade) was measured in previously treated patients with chronic immune thrombocytopenia enrolled in an eltrombopag trial to assess potential thrombophilia risk markers. Of 167 patients, 136 (81%) had abnormal levels of at least 1 known or suspected thrombosis risk marker or coagulation cascade activation marker. Six patients reported thromboembolic events, and all of these patients had at least two abnormal analytes in the thrombophilia panel. The presence of multiple baseline thrombophilia risk markers support the theory that chronic immune thrombocytopenia is a pro-thrombotic disease.

A comment on Boyers et al.: "eltrombopag for the treatment of chronic immune or idiopathic thrombocytopenic purpura: a NICE single technology appraisal".

Dear Editor In their publication of the National Institute for Health and Clinical Excellence (NICE) single technology appraisal of eltrombopag, Boyers et al. [1] report the results of the indirect treatment comparison (ITC) of eltrombopag and romiplostim, conducted by GlaxoSmithKline (GSK) [the manufacturer of eltrombopag] and made available to NICE as part of the single technology appraisal of eltrombopag. Subsequent to the appraisal process, GSK identified and corrected a methodological error in this analysis (available at http://www.gsk-clinicalstudyregister.com [study ID: 114014]). NICE were made aware of this error in November 2010. This correction was not published as part of the original assessment of eltrombopag and is not used in the Boyers et al. publication [1]. GSK would like to alert the readers of PharmacoEconomics to the corrected data and interpretation of this analysis. The nature of the error, the corrected results and the impact on the conclusions of the article are outlined below.