Pracinostat plus azacitidine in older patients with newly diagnosed acute myeloid leukemia: results of a phase 2 study.

Pracinostat, a potent oral pan-histone deacetylase inhibitor with modest single-agent activity in acute myeloid leukemia (AML), has shown synergistic antitumor activity when combined with azacitidine. This single-group, multicenter phase 2 study assessed the safety and efficacy of pracinostat combined with azacitidine in patients who were at least 65 years old with newly diagnosed AML and who were ineligible for standard induction chemotherapy. Patients received pracinostat 60 mg/d, 3 d/wk, for 3 consecutive weeks, plus azacitidine 75 mg/m2 daily for 7 days in a 28-day cycle. Primary endpoints were complete remission (CR), CR with incomplete count recovery (CRi), and morphologic leukemia-free state (MLFS) rates of the combination. Secondary endpoints included safety, progression-free survival (PFS), and overall survival (OS) of the regimen. Fifty patients (33 de novo, 12 secondary, and 5 therapy-related AML) were enrolled. Twenty-six patients (52%) achieved the primary endpoint of CR (42%), CRi (4%), and MLFS (6%). Median OS and PFS were 19.1 months (95% confidence interval [CI], 10-26.5 months) and 12.6 months (95% CI, 10-17.7 months), respectively, with a 1-year OS rate of 62%. Forty-three patients (86%) experienced at least 1 grade 3 or worse treatment-emergent adverse event with the combination, with infections (52%), thrombocytopenia (46%), and febrile neutropenia (44%) reported as the most common toxicities. The 30- and 60-day all-cause mortality rates were 2% and 10%, respectively. DNA sequencing revealed somatic mutations at baseline, and clearance rates correlated with response to treatment. Pracinostat plus azacitidine is a well-tolerated and active regimen in the frontline treatment of older patients with AML unfit for intensive therapy. A larger controlled trial is ongoing. This trial was registered at www.clinicaltrials.gov as #NCT01912274.

Urothelial cell intracytoplasmic inclusions after treatment of promyelocytic leukemia with arsenic trioxide.

Intramitochondrial inclusions containing arsenite that occur within urothelial cells have been previously described in mice exposed to high concentrations of arsenic but not in rats. In epidemiology studies, similar urothelial cell inclusions have also been observed in the urine of humans exposed to high concentrations of arsenic in the drinking water; however, these inclusions were mistakenly identified as micronuclei. To further examine the urothelial cell inclusions that occur in inorganic arsenic-exposed humans, we evaluated two patients with a history of acute promyelocytic leukemia treated for disease relapse with a combination of all-trans retinoic acid and arsenic trioxide. Posttreatment examination of the patients' urine cytology specimens by light and electron microscopy demonstrated cytoplasmic inclusions in exfoliated superficial urothelial cells similar to those seen in mice. The inclusions were present in decreasing quantities at 3 and 7 months after completion of treatment. No comparable inclusions were detected in exfoliated urothelial cells in urine from six individuals not treated with arsenic trioxide. Based on the results of the examination by light and electron microscopy, we have determined that urothelial cell inclusions in the urine of humans previously identified as micronuclei are instead intracytoplasmic inclusions similar to those found in arsenic-treated mice.

Revisiting use of growth factors in myelodysplastic syndromes.

Myelodysplastic syndromes (MDS) represent a heterogeneous group of clonal hematologic neoplasms characterized by morphologic dysplasia, aberrant hematopoiesis and peripheral blood refractory cytopenias. MDS is recognized to be associated with an increased risk of symptomatic anemia, infectious complications and bleeding diathesis, as well as a risk of progression to acute myeloid leukemia, particularly in patients with a high IPSS score. The advent of use of hematopoietic growth factors such as granulocyte colony-stimulating factor (G-CSF) and recombinant erythropoietin (EPO) has improved symptoms in MDS patients in addition to some data that suggest there might be an improvement in survival. G-CSF is an effective therapeutic option in MDS patients, and it should be considered for the management of refractory symptomatic cytopenias. G-CSF and EPO in combination can improve outcomes in appropriate MDS patients such as those with lower-risk MDS and refractory anemia with ring sideroblasts (RARS) . This article reviews use of growth factors for lower-risk MDS patients, and examines the data for G-CSF, EPO and thrombopietic growth factors (TPO) that are available or being developed as therapeutic modalities for this challenging disease.