Treatment of chemotherapy-induced thrombocytopenia in patients with non-hematologic malignancies.

Chemotherapy-induced thrombocytopenia (CIT) is a common complication of the treatment of non-hematologic malignancies. Many patient-related variables (e.g., age, tumor type, number of prior chemotherapy cycles, amount of bone marrow tumor involvement) determine the extent of CIT. CIT is related to the type and dose of chemotherapy, with regimens containing gemcitabine, platinum, or temozolomide producing it most commonly. Bleeding and the need for platelet transfusions in CIT are rather uncommon except in patients with platelet counts below 25x109/L in whom bleeding rates increase significantly and platelet transfusions are the only treatment. Nonetheless, platelet counts below 70x109/L present a challenge. In patients with such counts, it is important to exclude other causes of thrombocytopenia (medications, infection, thrombotic microangiopathy, post-transfusion purpura, coagulopathy and immune thrombocytopenia). If these are not present, the common approach is to reduce chemotherapy dose intensity or switch to other agents. Unfortunately decreasing relative dose intensity is associated with reduced tumor response and remission rates. Thrombopoietic growth factors (recombinant human thrombopoietin, pegylated human megakaryocyte growth and development factor, romiplostim, eltrombopag, avatrombopag and hetrombopag) improve pretreatment and nadir platelet counts, reduce the need for platelet transfusions, and enable chemotherapy dose intensity to be maintained. National Comprehensive Cancer Network guidelines permit their use but their widespread adoption awaits adequate phase III randomized, placebo-controlled studies demonstrating maintenance of relative dose intensity, reduction of platelet transfusions and bleeding, and possibly improved survival. Their potential appropriate use also depends on consensus by the oncology community as to what constitutes an appropriate pretreatment platelet count as well as identification of patient-related and treatment variables that might predict bleeding.

An alternative intermittent eltrombopag dosing protocol for the treatment of chronic immune thrombocytopenia.

Eltrombopag, an oral thrombopoietin receptor agonist, is dosed daily to treat chronic immune thrombocytopenia (ITP). As it has a half-life of 26-35 h in ITP patients and requires patents to abide by strict dietary restrictions that may impair quality of life and reduce compliance, we developed an alternative intermittent (AI) eltrombopag dosing protocol for ITP, with dosing less frequent than once daily. Ten patients were treated with AI dosing for a median of 94 (range: 29-156) weeks, with most patients treated with 2-4 weekly doses for extended durations. During AI dosing, 95%, 84% and 71% of all platelet counts were ≥20 × 109 l-1 , ≥50 × 109 l-1 and ≥100 × 109 l-1 , respectively. Five patients required rescue treatment for thrombocytopenia and World Health Organization grade 1 mucocutaneous bleeding, and there were no thromboembolic events. In summary, intermittently dosed eltrombopag was efficacious in treating chronic ITP in a small cohort, with rates of platelet response and rescue treatment comparable with rates in studies evaluating daily dosing.

Hereditary hemorrhagic telangiectasia: diagnosis and management from the hematologist's perspective.

Hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is an autosomal dominant disorder that causes abnormal blood vessel formation. The diagnosis of hereditary hemorrhagic telangiectasia is clinical, based on the Curaçao criteria. Genetic mutations that have been identified include ENG, ACVRL1/ALK1, and MADH4/SMAD4, among others. Patients with HHT may have telangiectasias and arteriovenous malformations in various organs and suffer from many complications including bleeding, anemia, iron deficiency, and high-output heart failure. Families with the same mutation exhibit considerable phenotypic variation. Optimal treatment is best delivered via a multidisciplinary approach with appropriate diagnosis, screening and local and/or systemic management of lesions. Anti-angiogenic agents such as bevacizumab have emerged as a promising systemic therapy in reducing bleeding complications but are not curative. Other pharmacological agents include iron supplementation, antifibrinolytics and hormonal treatment. This review discusses the biology of HHT, management issues that face the practising hematologist, and considerations of future directions in HHT treatment.

Miglustat therapy in type 1 Gaucher disease: clinical and safety outcomes in a multicenter retrospective cohort study.

We evaluated clinical and safety outcomes in adult patients with type 1 Gaucher disease receiving miglustat in clinical practice settings. An observational, retrospective cohort study was conducted in centers across the EU and the USA. Medical chart data were collected from consecutive patients between the 20th November 2002 and 31st December 2008. A total of 115 patients were included; 34 (30%) were enzyme replacement therapy-naïve ('naïve') and 81 (70%) were enzyme pretreated ('pretreated'). Median (range) miglustat exposures in these groups were 15.1 (0.6-52.9)months and 15.2 (0.3-62.1)months, respectively. Low numbers of patients were anemic (10/101) or thrombocytopenic (21/101) at initiation of miglustat therapy. The median (range) hemoglobin concentration at miglustat initiation was 12.8 (10.2-16.4)g/dl in naïve patients and 13.6 (7.3-17.4)g/dl in pretreated patients; median (range) changes in hemoglobin were 0.3 (-2.5-3.6) and -0.3 (-4-4.6)g/dl, respectively. The median (range) platelet counts at miglustat initiation were 101 (37-730)×10(9)/l in naïve patients and 173 (43-382)×10(9)/l in pretreated patients; median (range) changes in platelet count were 8 (-77-145)×10(9)/l and -10 (-144-434)×10(9)/l, respectively. Plasma chitotriosidase was substantially reduced in naïve but not in pretreated patients. Organ volumes were not routinely monitored. Forty-nine (43%) patients discontinued miglustat; most due to gastrointestinal manifestations and some due to tremor. Overall, hemoglobin and platelet counts tended to increase in naïve patients treated with miglustat, and to remain stable or decrease slightly in pretreated patients. The profile of safety and tolerability observed with miglustat in the current study is similar to previous studies.