Clinical findings with the first generation of thrombopoietic agents

Recombinant human thrombopoietin promotes platelet recovery in DCAG-treated patients with intermediate-high-risk MDS/hypoproliferative AML

BACKGROUND

This study aimed to explore the effects of recombinant human thrombopoietin (rhTPO) on platelet recovery in decitabine, cytarabine, aclarubicin, and G-CSF (DCAG)-treated patients with intermediate-high-risk myelodysplastic syndrome/hypo proliferative acute myeloid leukemia.

METHODS

Recruited patients were at a ratio of 1:1 into 2 groups: the rhTPO group (DCAG + rhTPO) and control group (DCAG). The primary endpoint was the time for platelets to recover to ≥ 20 × 109/L. The secondary endpoints were the time for platelets to recover to ≥ 30 × 109/L and ≥ 50 × 109/L, overall survival (OS), and progression-free survival (PFS).

RESULTS

The time required for platelet recovery to ≥ 20 × 109/L, ≥30 × 109/L, and ≥ 50 × 109/L in the rhTPO group was significantly shorter (6.5 ± 2.2 vs 8.4 ± 3.1 days, 9.0 ± 2.7 vs 12.2 ± 3.9 days, 12.4 ± 4.7 vs 15.5 ± 9.3 days, respectively; all P < .05 vs controls). The amount of platelet transfusion in the rhTPO group was smaller (4.4 ± 3.1 vs 6.1 ± 4.0 U, P = .047 vs controls). The bleeding score was lower (P = .045 vs controls). The OS and PFS were significantly different (P = .009 and P = .004). The multivariable analysis showed that age, karyotype, and time for PLT recovery to ≥ 20 × 109/L were independently associated with OS. Adverse events were similar.

CONCLUSIONS

This study suggests that rhTPO leads to a faster platelet recovery after DCAG treatment, reduces the risk of bleeding, reduces the number of platelet transfusions, and prolongs the OS and PFS.

Efficacy and safety of recombinant human interleukin-11 in the treatment of acute leukaemia patients with chemotherapy-induced thrombocytopenia: A systematic review and meta-analysis

RATIONALE, AIMS, AND OBJECTIVES

Current meta-analysis was conducted aiming to assess the efficacy and safety of recombinant human interleukin-11 (rhIL-11) in the treatment of acute leukaemia (AL) patients with chemotherapy-induced thrombocytopenia (CIT).

METHODS

We searched PubMed, Embase, Chinese National Knowledge Infrastructure database (CNKI), Cochrane Library, and Wan Fang Database on 4 July 2018.

RESULTS

Ten randomized controlled trials (RCTs) and two observational studies were included, which involved 754 AL patients with CIT. Pooled analysis demonstrated that rhIL-11 was beneficial on CIT: recovery time of platelet count to 50 × 10⁹ /L [weight mean difference (WMD) = -4.19 days; 95% CI: -5.01, -3.37], recovery time of platelet count to 100 × 10⁹ /L (WMD = -4.45 days; 95% CI: -4.85, -4.06), platelet transfusion volume (WMD = -6.14 U; 95% CI: -9.20, -3.09), and the rate of haemorrhage (RR = 0.46; 95% CI: 0.36 to 0.61). Most adverse events associated with rhIL-11 were mild to moderate.

CONCLUSION

Our findings suggest that rhIL-11 is effective and safe in the treatment of CIT in patients with AL.

Thrombopoietin receptor agonists for prevention and treatment of chemotherapy-induced thrombocytopenia in patients with solid tumours

BACKGROUND

Chemotherapy-induced thrombocytopenia (CIT) is defined as a peripheral platelet count less than 100×109/L, with or without bleeding in cancer patients receiving myelosuppressive chemotherapy. CIT is a significant medical problem during chemotherapy, and it carries the risk of sub-optimal overall survival and bleeding. Alternative interventions to platelet transfusion are limited. Different stages of preclinical and clinical studies have examined the thrombopoietin receptor agonists (TPO-RAs) for CIT in patients with solid tumours.

OBJECTIVES

To assess the effects of TPO-RAs to prevent and treat CIT in patients with solid tumours:(1) to prevent CIT in patients without thrombocytopenia before chemotherapy, (2) to prevent recurrence of CIT, and (3) to treat CIT in patients with thrombocytopenia during chemotherapy.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, to 28 September 2017), MEDLINE (from 1950 to 28 September 2017), as well as online registers of ongoing trials (Clinical Trials, Chinese Clinical Trial Register, Australian New Zealand Clinical Trial Registry, WHO ICTRP Search Portal, International Standard Randomised Controlled Trial Number registry, GlaxoSmithKline Clinical Study Register, and Amgen Clinical Trials) and conference proceedings (American Society of Hematology, American Society of Clinical Oncology, European Hematology Association, European Society of Medical Oncology, and Conference Proceedings Citation Index-Science, from 2002 up to September 2017) for studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing TPO-RAs alone, or in combination with other drugs, to placebo, no treatment, other drugs, or another TPO-RAs for CIT in patients with solid tumours.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the results of the search strategies, extracted data, assessed risk of bias, and analysed data according to standard methodological methods expected by Cochrane.

MAIN RESULTS

We identified six trials eligible for inclusion, of which two are ongoing, and one awaiting classification study. The three included trials were conducted at many different sites in Europe, America, and Asia. All of the three studies recruited adult and elder participants (no children were included) with solid tumours, and compared TPO-RAs with placebo. No studies compared TPO-RAs alone, or in combination with other drugs, to no treatment, or other drugs, or another TPO-RAs.We judged the overall risk of bias as high as we found a high risk for detection bias. We assessed the risk of bias arising from inadequate blinding of outcome assessors as high for number and severity of bleeding episodes (one of the primary outcomes).To prevent CIT: We included two trials (206 participants) comparing TPO-RAs (eltrombopag, multiple-dose oral administration with chemotherapy) with placebo. The use of TPO-RAs may make little or no difference to the all-cause mortality at 33 weeks of follow-up (RR 1.35, 95% CI 0.53 to 3.45; one trial, 26 participants; low quality of evidence). There is not enough evidence to determine whether TPO-RAs reduce the number of patients with at least one bleeding episode of any severity (RR 0.62, 95% CI 0.22 to 1.78; two trials, 206 participants; very low quality of evidence). There is not enough evidence to determine whether TPO-RAs reduce the number of patients with at least one severe/life-threatening bleeding episode (RR 0.36, 95% CI 0.06 to 2.06; two trials, 206 participants; very low quality of evidence). No studies were found that looked at overall survival (one of the primary outcomes), the number of treatment cycles with at least one bleeding episode, the number of days on which bleeding occurred, the amount of bleeding, or quality of life.To prevent recurrence of CIT: We included one trial (62 participants) comparing TPO-RAs (romiplostim, single-dose subcutaneous administration with chemotherapy) with placebo. There is not enough evidence to determine whether TPO-RAs reduce the number of patients with at least one bleeding episode of any severity (RR 2.80, 95% CI 0.17 to 47.53; one trial, 62 participants; very low quality of evidence). There is not enough evidence to determine whether TPO-RAs reduce the number of patients with at least one severe/life-threatening bleeding episode (no severe/life-threatening bleeding episodes; one trial, 62 participants; very low quality of evidence). No studies were found that looked at overall survival (one of the primary outcomes), the number of treatment cycles with at least one bleeding episode, the number of days on which bleeding occurred, the amount of bleeding, or quality of life. We found one ongoing study (expected recruitment 74 participants), it is planned to give TPO-RAs (romiplostim, subcutaneous administration with chemotherapy) to participants, but to date this trial has not reported any outcomes.To treat CIT: We found one ongoing study (expected recruitment 83 participants), which is planned to give TPO-RAs (eltrombopag, seven days orally) to participants when their platelet counts are less than 75×109/L during chemotherapy. This trial was originally planned to complete in March 2017, however, the completion date has passed and no results are reported.The one awaiting classification study included patients without thrombocytopenia before chemotherapy (to prevent CIT), patients with thrombocytopenia during chemotherapy (to prevent recurrence of CIT), and other patients during chemotherapy (uncertain whether CIT had happened). There was no evidence for a difference in the number of patients with at least one bleeding episode of any severity (RR 0.27, 95% CI 0.07 to 1.02; one trial, 75 participants). There was no evidence for a difference in the number of patients with at least one severe/life-threatening bleeding episode (RR 0.44, 95% CI 0.03 to 6.77; one trial, 75 participants). This study did not address overall survival or quality of life.

AUTHORS' CONCLUSIONS

No certain conclusions can be drawn due to the lack of strong evidence in the review. The available weak evidence did not support the use of TPO-RAs for preventing CIT or preventing recurrence of CIT in patients with solid tumours. There was no evidence to support the use of TPO-RAs for treating CIT in patients with solid tumours.

From chronic immune thrombocytopenia to severe aplastic anemia: recent insights into the evolution of eltrombopag

Thrombopoietin (TPO) is the most potent cytokine stimulating thrombopoiesis. Therapy with exogenous TPO is limited by the formation of antibodies cross-reacting with endogenous TPO. Mimetics of TPO are compounds with no antigenic similarity to TPO. Eltrombopag is an orally-active nonpeptide small molecule that binds to the transmembrane portion of the TPO receptor MPL. Initial trials of eltrombopag have centered on immune thrombocytopenia (ITP), which is due to both increased destruction and decreased production of platelets. Eltrombopag at 25-75 mg/day has been shown to be highly effective in raising the platelet count in ITP with suboptimal response to immunosuppression and splenectomy. These successful results led to the exploration of eltrombopag in other thrombocytopenic disorders. In hepatitis C viral infection, eltrombopag raises the platelet count sufficiently enough to allow treatment with ribavirin and pegylated interferon. Because MPL is expressed on hematopoietic cells, eltrombopag use in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) might enhance leukemic proliferation. Clinical trials of eltrombopag in MDS and AML, however, have shown amelioration of thrombocytopenia without promoting disease progression. In severe aplastic anemia (SAA) not responding to immunosuppression with anti-thymocyte globulin (ATG) and cyclosporine, eltrombopag as a single agent at 150-300 mg/day results in an overall response rate of 40-70%. At high doses, adverse effects including pigmentation, gastrointestinal upset and hepatic derangement have become evident. Current studies have examined the first-line use of eltrombopag in combination with ATG in SAA. In a recent study, eltrombopag used at 150 mg/day with horse ATG resulted in an overall response rate of 90% in newly diagnosed SAA patients, with a complete response rate of about 50%. Clonal karyotypic aberrations are, however, found in 10-20% of SAA patients treated with eltrombopag. The safety and efficacy of eltrombopag in SAA require further evaluation, particularly when it is used with less intensive immunosuppression.

Use of eltrombopag in thrombocytopenia of liver disease

Second generation thrombopoietin agonists including eltrombopag and romiplostim act on the thrombopoietin receptor to increase the megakaryocyte production. These agents were needed as use of first generation recombinant products was associated with formation of autoantibodies. Eltrombopag is an oral thrombopoietin agonist found effective in raising platelet counts in patients with immune thrombocytopenia. The drug has now been found to be useful in raising platelet counts in thrombocytopenia related to liver disease including cirrhosis and chronic viral hepatitis. Although the drug may help enable adequate interferon therapy in patients with HCV infection and help carry out invasive procedures in patients with cirrhosis, concerns have been raised of possible thrombotic complications including portal vein thrombosis. Randomized trials have shown that use of eltrombopag concomitant with pegylated interferon and ribavirin increased the chances of sustained virologic response while decreasing the dose reductions of interferon. The data on use of romiplostim in these clinical indications is also emerging. However, in the future, availability of interferon free regimens is likely to decrease the use of eltrombopag for enabling antiviral therapy. The review discusses the role of eltrombopag in management of liver disease related thrombocytopenia in wake of recent data as also the dosage, precautions and adverse effects associated with its use.