Final Evaluation of a Clinical Phase III Trial Comparing Treosulfan to Busulfan-Based Conditioning Therapy Prior to Allogeneic Hematopoietic Stem Cell Transplantation of Adult Acute Myeloid Leukemia and Myelodysplastic Syndrome Patients Ineligible to Standard Myeloablative Regimens

Background Allogeneic hematopoietic stem cell transplantation (HCT) remains a challenge in elderly and comorbid AML and MDS patients. This patient population is at increased risk for non-relapse mortality (NRM) when treated with standard myeloablative conditioning and was selected to compare a newly developed treosulfan-based with a well-established reduced intensity busulfan-based preparative regimen in a prospective randomized clinical phase III trial. Methods Adult patients with AML in remission or MDS scheduled for HCT from matched related or unrelated donors, aged ≥50 years or with a comorbidity index (HCT-CI) of >2 were enrolled by a central stratified randomization procedure. Treatment arms consisted of intravenous (IV) treosulfan (10 g/m²/day [d-4 to d-2]) or IV busulfan (3.2 mg/kg/day [d-4 to d-3]), both combined with IV fludarabine (30 mg/m²/day [d-6 to d-2]). The primary objective was to compare event-free survival (EFS) at two years with relapse/progression of disease, graft failure, or death reported as events. Secondary endpoints were safety evaluation (according to CTCAE v4.03), engraftment, chimerism, overall survival (OS), relapse/progression incidence (RI), NRM and acute or chronic GvHD. After a previously conducted confirmatory interim analysis (based on 476 patients), which resulted in early termination of patient accrual due to significant non-inferiority of treosulfan treatment with improved EFS, NRM and OS (Beelen et al., ASH 2017), results of the final analysis of all 570 randomized patients including post surveillance data are provided here. Results Median age of the 551 patients (352 AML; 199 MDS) included in the full analysis set (268 treosulfan; 283 busulfan) was 60 years (range: 31, 70). Frequencies of early adverse events (d-6 to d+28) and incidences of acute and chronic GvHD were largely comparable between the two regimens, while extensive chronic GvHD was numerically in favor of treosulfan (19.7% vs. 26.7%; p=0.0750). Primary neutrophil recovery at day +28 was comparable, while the rate of complete donor-type chimerism (day +28) was higher after treosulfan (93.2% vs. 83.3%; p Conclusions Final evaluation of this phase III trial substantiates the previous confirmatory analysis resulting in significantly improved survival after treosulfan-based conditioning. Due to the reduction of NRM a major clinical benefit of the new treosulfan conditioning regimen was demonstrated in the selected AML/MDS patient population

Sequential allogeneic transplantation and ruxolitinib maintenance for a synchronous PCM1-JAK2 positive myeloid sarcoma and acute B-lymphoblastic leukemia

The translocation t(8;9)(p22;p24) results in the production of a chimeric PCM1-JAK2 fusion protein leading to the constitutive activation of the Janus Kinase 2 that renders this disease potentially sensitive to ruxolitinib. Here, we report an interesting case of PCM1-JAK2 myeloproliferative neoplasm evolving in myeloid sarcoma and B precursor ALL

Increased risk of recurrent thrombosis in patients with essential thrombocythemia carrying the homozygous JAK2 V617F mutation

Evidence suggests that the JAK2 V617F mutation is associated with an increased risk of first thrombosis in patients with essential thrombocythemia (ET). Whether this mutation is also a risk factor for recurrent thrombosis is currently unknown. To investigate the impact of the JAK2 V617F mutation on the risk of recurrent thrombosis in patients with ET, we carried out a multicentre retrospective cohort study. We recruited 143 patients with previous arterial (64.4%) or venous major thrombosis (34.8%) or both (0.8%); 98 of them (68.5%) carried the mutation. Thrombosis recurred in 43 of the patients (30%); overall, after adjustment for sex, age, presence of vascular risk factors, and treatment after the first thrombosis, the presence of the JAK2 mutation did not predict recurrence (multivariable hazard ratio, HR, 0.88, 95% CI 0.46-1.68). Indeed, the individuals homozygous for the JAK2 V617F (allele burden > 50%) mutation had an increased risk of recurrence in comparison with wild-type patients (HR 6.15, 95% CI 1.51-24.92). In conclusion, a homozygous JAK2 V617F mutation is an independent risk factor for recurrent thrombosis in patients with ET