Search

Ruxolitinib is a potent Janus kinase (JAK) 1/JAK2 inhibitor that has demonstrated rapid and durable improvements in splenomegaly and symptoms and a survival benefit in 2 phase 3 trials in patients with myelofibrosis. Ruxolitinib was well tolerated and effectively reduced splenomegaly and symptom burden in Asian patients with myelofibrosis in the Asian multinational, phase 2 Study A2202. We present a subset analysis of Japanese patients (n = 30) in Study A2202. At data cutoff, 22 patients were ongoing; 8 discontinued, mainly due to adverse events (n = 4). At week 24, 33 % of patients achieved ≥35 % reduction from baseline in spleen volume; 56.0 % achieved ≥50 % reduction from baseline in total symptom score, as measured by the 7-day Myelofibrosis Symptom Assessment Form v2.0. The most common adverse events were anemia (63 %), thrombocytopenia (40 %), nasopharyngitis (37 %), decreased platelet counts (30 %), and diarrhea (30 %). Dose reductions or interruptions due to hemoglobin decreases were more frequent in Japanese patients; no loss of efficacy and no discontinuations due to hematologic abnormalities were observed. Ruxolitinib was well tolerated in Japanese patients and provided substantial reductions in splenomegaly and myelofibrosis-related symptoms similar to those observed in the overall Asian population and phase 3 COMFORT studies.

Ruxolitinib, a potent JAK1/JAK2 inhibitor, improved splenomegaly and myelofibrosis-associated symptoms and prolonged survival compared with placebo and best available therapy in the phase 3 COMFORT studies. Although cytopenias were the most common adverse events associated with ruxolitinib treatment, a COMFORT-I analysis showed that they were managed effectively with dose modifications, without a negative impact on the efficacy of ruxolitinib. Subsequently, studies A2202 and AJP01 showed that ruxolitinib is an effective treatment for Japanese patients with myelofibrosis. We conducted a pooled analysis of these two studies (N = 81) to evaluate the association between ruxolitinib dose and changes in spleen volume or symptoms in Japanese patients. Most patients began treatment at 15 or 20 mg twice daily (BID); 70% received a final titrated dose ≥ 10 mg BID. Overall, 91% of patients exhibited spleen volume reductions; patients with final titrated doses ≥ 10 mg BID had larger spleen volume reductions. Similarly, 83% of patients showed improvements in symptom scores; those with a final titrated dose of 20 or 25 mg BID had the greatest reductions. Consistent with COMFORT-I, this pooled analysis indicates that, despite dose adjustments, ruxolitinib provides spleen and symptom control in Japanese patients, with higher doses associated with better responses.

We have demonstrated that adipose tissue-derived mesenchymal stem cells (ADSCs) from mice are capable of reconstituting the hematopoietic microenvironment, and facilitate hematopoiesis more effectively than bone marrow-derived mesenchymal stem cells (BMSCs) in mouse. The ready accessibility of fat tissue rich in MSCs and the higher hematopoiesis-supporting capacities of ADSCs suggest that ADSCs might represent a new therapeutic modality for the regeneration of impaired hematopoiesis. As a further step towards their use in clinical practice, we established human BMSCs and ADSCs from healthy volunteers of similar age, and compared their proliferation capacities, hematopoiesis-supporting properties, and safety. In vitro cell proliferation studies revealed that ADSCs have a higher population doubling number than BMSCs. In vitro co-culture assays showed that ADSCs not only support human CD34(+) peripheral blood stem cells (PBSCs), but also yield significantly more non-adherent hematic cells than BMSCs. In vitro progenitor assays revealed that ADSCs promote a higher frequency of early progenitors than do BMSCs. Interestingly, BM cellularity in irradiated mice that had received ADSCs tended to be higher than that of mice treated with BMSCs. When MSCs were injected into the BM cavity of tibiae, we observed no evidence of MSC-induced toxicity either during or after treatment. In addition, no microscopic abnormalities were observed in the bone marrow and major organs.

Hemophagocytic syndrome (HPS) induced by uncontrolled macrophage activation and subsequent graft failure is a frequent and prominent complication after allogeneic stem cell transplantation (allo-SCT), a cause of severe morbidity and death, and a therapeutic challenge. Liposome-incorporated dexamethasone, dexamethasone palmitate (DP), shows greater efficacy against macrophages as compared to dexamethasone sodium phosphate (DSP). Based on our findings that DP achieves significantly larger decrease than DSP on the viability of primary human macrophages compared in vitro, we tested the effects of DP in patients with HPS. A decrease in number of macrophages in the bone marrow and prevention of engraftment failure were observed in all patients without any severe complications. In conclusion, these data provide a rationale for testing DP as a first-line treatment for patients with HPS after allo-SCT.