Thrombopoietin receptor agonists, which raise platelet counts in patients with chronic immune thrombocytopenia, may be associated with increases in bone marrow (BM) reticulin. Patients with chronic immune thrombocytopenia participating in the Eltrombopag Extended Dosing (EXTEND) study underwent BM biopsies to identify clinically relevant BM fibrosis-related increases. Specimens were centrally reviewed by 2 hematopathologists. Two hundred thirty-two biopsy specimens were collected from 117 patients treated for ≤5.5 years. Moderate to marked reticulin fibrosis was found in 2 patients. After withdrawing from the study, the biopsy of 1 patient reverted to normal. There were no other pathologic changes identified among on-treatment specimens, and no pattern of abnormal reticulin deposition associated with eltrombopag treatment was evident.

To determine the efficacy and safety of eltrombopag (E-PAG) combined with intensive immunosuppressive therapy (IST) for the treatment of pediatric patients with severe aplastic anemia (SAA). A total of 57 pediatric patients with newly diagnosed severe aplastic anemia were enrolled in this study. Thirty nine patients were treated with IST alone, consisting of porcine anti-human thymocyte globulin (30 mg/kg/day × 5 days) and cyclosporine A (CsA) (treated for 2 years, with a trough concentration maintained at 200-250 ng/mL), and 18 patients were treated with IST + E-PAG (12.5-50 mg/day, maintained for 6 months). We found no statistical difference between the response rates at 3 months for the two groups (CR: 12.8% vs. 22.2% p > 0.05

, ORR:

56.4% vs. 77.7% p > 0.05). However, we found a statistical difference between the response rates at 6 months for the two groups (CR: 17.9% vs. 50% p < 0.05

, ORR:

69.2% vs. 94.4% p < 0.05). The main side-effect during treatment with E-PAG was having a slightly to moderately elevated bilirubin level, which was temporary and controllable, accounting for approximately 66.6% (12/18) of patients in the IST + E-PAG group vs. 20.5% (8/39) of those in the IST group (p < 0.05). IST + E-PAG therapy appears to be more effective than IST alone for the treatment of pediatric SAA, with good tolerability and compliance. This approach deserves further exploration.

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BACKGROUND:

The objective of this Phase I dose escalation study was to explore the safety and tolerability of eltrombopag, an oral, nonpeptide, thrombopoietin receptor agonist, in patients with advanced soft tissue sarcoma (STS) and thrombocytopenia due to treatment with doxorubicin and ifosfamide (AI) combination chemotherapy.

METHODS:

Patients aged 18 or older with histologically confirmed, locally advanced or metastatic STS were treated with 1 cycle of AI followed by AI with eltrombopag starting at Cycle 2, using 2 different dosing schedules. The study design included an eltrombopag dose escalation phase starting at 75 mg daily to determine the optimal biological dose (OBD).

RESULTS:

Eighteen patients were enrolled and 15 received at least 1 dose of chemotherapy; 3 patients withdrew prior to receiving eltrombopag. Seven, 4, and 1 patients received 75 mg, 100 mg, and 150 mg eltrombopag daily, respectively. No dose-limiting toxicities were reported. Due to slow recruitment, the study was closed prior to identifying an OBD. The most common hematologic adverse events (AEs) were thrombocytopenia (80%), neutropenia (73%), and anemia (67%). The most common nonhematologic AEs were fatigue (53%), alanine aminotransferase increased, constipation, and nausea (47% each). Eleven of 12 patients who received eltrombopag completed at least 2 chemotherapy cycles; all had increased platelet counts on Day 1 of Cycle 2 (cycle with eltrombopag) compared to Day 1 of Cycle 1 (cycle without eltrombopag).

CONCLUSIONS:

Although data are limited, safety data were consistent with the known toxicities of AI combination chemotherapy or the side effect profile of eltrombopag seen in other studies. Available data suggest a potential pre- and post-chemotherapy dosing scheme for eltrombopag when administered with AI chemotherapy, and support further investigation of eltrombopag treatment in patients with chemotherapy-induced thrombocytopenia.

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Myelodysplastic Syndrome (MDS) is a disease of the bone marrow characterized by anemia,neutropenia, and thrombocytopenia (low red blood cell, white blood cell, and platelet counts). MDS patients with thrombocytopenia who fail standard therapies require regular platelet transfusions which are expensive and inconvenient, and are a risk for further serious bleeding complications. The new treatment of MDS using azacitidine has shown to increase the survival rate of MDS patients including to improve platelet production over time. However,in the early cycles of treatment with azacitidine,the low platelet counts tend to exacerbate before they provide any clinical benefit.

Eltrombopag is a drug designed to activate the thrombopoietin receptor. Eltrombopag has been able to increase platelet counts in healthy Thrombocytopenia Purpura (ITP), a disease where patients destroy their own platelets very rapidly and thus develop thrombocytopenia.

Eltrombopag is administered orally and is Therapeutic Goods Administration (TGA) approved for the treatment of thrombocytopenia in patients with chronic ITP who failed to respond to standard treatment.

This study is a single arm pilot study to evaluate the safety and tolerability of Eltrombopag in the treatment of low platelet counts in adult subjects with MDS treated using azacitidine This study also incorporates a correlative laboratory component designed to determined the mechanism of action of 5-azacitidine +/- Eltrombopag and to determine a baseline profile which may predict those most responsive. These studies will incorporate gene methylation and expression, and immunoprofiling.

Myelodysplastic syndromes (MDS) prevail in elderly patients and are characterized by inefficient erythropoiesis and peripheral cytopenias. Supportive care still represents the main therapeutic option in most patients. Quality of life is deteriorated mostly by anemia and by limitations due to dependence on transfusions, thrombocytopenia, and neutropenia. The only treatment available for severe thrombocytopenia consists of PLT transfusions, mainly in the presence of bleeding.

In patients with low and intermediate-1 risk MDS with an isolated deletion 5q cytogenetic abnormality, red blood cell (RBC) transfusion-dependence is a prevalent condition. For these latter patients reaching transfusion-dependence, lenalidomide, an immunomodulatory drug, has been approved by FDA and EMA. It has been shown that the drug induces significant erythroid (about 65%) and cytogenetic responses which have been associated with a survival benefit. In patients with MDS with del5q and serum erythropoietin levels \> 500 miU/L, lenalidomide dosing of 10 mg/day for 21 days every 28, rather than 5 mg dosing, induces higher rates of transfusion-independence and cytogenetic responses with a trend to survival advantage. As a consequence, the recommended starting dose of lenalidomide is 10 mg orally once daily on days 1-21 of repeated 28-day cycles. Lenalidomide treatment must not be started if the Absolute Neutrophil Counts (ANC) \< 0.5 Gi/L and/or PLT counts \< 25 Gi/L.

For patients who are dosed initially at 10 mg and who experience thrombocytopenia \< 25 Gi/L (45-75%), it is recommended to interrupt lenalidomide treatment until PLT count returns to ≥ 25 Gi/L on at least 2 occasions for ≥ 7 days or when the PLT count recovers to ≥ 50 Gi/L at any time, to resume lenalidomide at 50% dose reduction.

Eltrombopag is an orally bioavailable agonist of the thrombopoietin receptor. It has been shown that in patients affected by MDS and by acute myeloid leukemia, Eltrombopag neither increases the proliferation, nor the clonogenic growth capacity of bone marrow blasts. Furthermore, Eltrombopag induces an increase in the megakaryocytic differentiation and in the formation of normal megakaryocytic colonies. These results provide the rationale for pursuing further research on Eltrombopag for the treatment of thrombocytopenia in case of MDS.

Preliminary results of an ongoing randomized trial, EQoL-MDS, for the evaluation of efficacy, safety of eltrombopag for thrombocytopenia of low and intermediate-1 IPSS risk MDS has shown that eltrombopag is able to significantly raise PLT counts in about 65% of patients without additional toxicity Furthermore, the combination of lenalidomide and eltrombopag resulted in significant inhibitory effects on the growth of leukemic colonies in the majority of primary MDS and AML samples. Most importantly, eltrombopag was able to reverse the anti-megakaryopoietic effects of lenalidomide in primary MDS patient samples. These results provide a preclinical rationale for the use of this combination in MDS and AML

<b>

BACKGROUND:

</b>Eltrombopag is an oral thrombopoietin receptor agonist that stimulates thrombopoiesis and shows higher exposure in East Asian patients than in non-Asian patients. We evaluated the pharmacokinetics, efficacy, and safety of eltrombopag in Japanese patients with thrombocytopenia associated with chronic liver disease (CLD).<b>

METHODS:

</b>Thirty-eight patients with CLD and thrombocytopenia (platelets <50,000/μL) were enrolled in this phase II, open-label, dose-ranging study that consisted of 2 parts. In the first part, 12 patients received 12.5 mg of eltrombopag once daily for 2 weeks. After the evaluation of safety, 26 patients were randomly assigned to receive either 25 or 37.5 mg of eltrombopag once daily for 2 weeks in the second part.<b>

RESULTS:

</b>Pharmacokinetics showed that the geometric means of the maximum plasma concentration (C(max)) and the area under the curve (AUC) in the 12.5 mg group were 3,413 ng/mL and 65,236 ng h/mL, respectively. At week 2, the mean increases from baseline in platelet counts were 24,800, 54,000, and 60,000/μL in the 12.5, 25, and 37.5 mg groups, respectively. The median platelet counts increased within 2 weeks of the beginning of administration in all groups, and remained at the same level throughout the 2-week post-treatment period in the 12.5 mg group, whereas the platelet counts peaked a week after the last treatment in both the 25 and 37.5 mg groups. Most adverse events reported were grade 1 or 2; 2 patients in the 37.5 mg group had drug-related serious adverse events.<b>

CONCLUSIONS:

</b>Eltrombopag ameliorated thrombocytopenia in Japanese patients with CLD and thrombocytopenia. The recommended dose for these patients is 25 mg daily for 2 weeks.

Thrombocytopenia occurs frequently in patients with myelodysplastic syndromes (MDS), and the survival of patients after failure of hypomethylating agents (HMAs) is poor. We conducted a trial of eltrombopag in patients with MDS, MDS/myeloproliferative neoplasm (MPN) or acute myeloid leukemia (AML) with 20-30% myeloblasts after HMA failure and mean baseline platelet count ≤ 50 × 109/L. Eltrombopag was escalated from 50 mg daily up to 200 mg daily. The primary objective was to determine the maximally tolerated dose (MTD). 37 patients were enrolled, and MTD was not reached. Responses were observed in 9 patients (24%), 2 achieving marrow CR with hematologic improvement (HI), 1 marrow CR without HI, and 6 HI. Median overall survival was 7.5 months. Eltrombopag was well-tolerated and yielded modest responses in heavily treated, predominantly higher-risk MDS patients after HMA failure. Future studies should focus on determining characteristics that predict response.