Reduced-toxicity conditioning with treosulfan and fludarabine in allogeneic hematopoietic stem cell transplantation for myelodysplastic syndromes: final results of an international prospective phase II trial.

BACKGROUND: An alternative reduced-toxicity conditioning regimen for allogeneic transplantation, based on treosulfan and fludarabine, has recently been identified. The rationale for this study was to investigate the efficacy and safety of this regimen prospectively in patients with a primary myelodysplastic syndrome. DESIGN AND METHODS: A total of 45 patients with primary myelodysplastic syndromes were conditioned with 3×14 g/m(2) treosulfan and 5×30 mg/m(2) fludarabine followed by allogeneic hematopoietic stem cell transplantation. Subtypes of myelodysplastic syndromes were refractory anemia with excess blasts-2 (44%), refractory cytopenia with multilineage dysplasia (27%), refractory anemia (9%), refractory anemia with ringed sideroblasts (4%), refractory cytopenia with multilineage dysplasia and ringed sideroblasts (4%), refractory anemia with excess blasts-1 (2%), and myelodysplastic syndrome with isolated del (5q) (2%). The myelodysplastic syndrome was unclassified in 7% of the patients. Forty-seven percent of the patients had a favorable karyotype, 29% an unfavorable one, and 18% an intermediate karyotype. Patients were evaluated for engraftment, adverse events, graft-versus-host disease, non-relapse mortality, relapse incidence, overall survival and disease-free survival. RESULTS: All but one patient showed primary engraftment of neutrophils after a median of 17 days. Non-hematologic adverse events of grade III-IV in severity included mainly infections and gastrointestinal symptoms (80% and 22% of the patients, respectively). Acute graft-versus-host disease grade II-IV developed in 24%, and extensive chronic graft-versus-host disease in 28% of the patients. After a median follow-up of 780 days, the 2-year overall and disease-free survival estimates were 71% and 67%, respectively. The 2-year cumulative incidences of non-relapse mortality and relapse were 17% and 16%, respectively. CONCLUSIONS: Our safety and efficacy data suggest that treosulfan-based conditioning therapy is a promising treatment option for patients with myelodysplastic syndromes. clinicaltrials.gov identifier: NCT01062490.

Treatment of active secondary progressive multiple sclerosis with treosulfan.

OBJECTIVE: To study the safety and efficacy of treosulfan, a cytotoxic alkylating agent, in patients with active secondary progressive multiple sclerosis. BACKGROUND: Treosulfan (L-threitol-1,4-bis(methanesulfonate)) is a bifunctional alkylating agent with a favorable profile of side effects, approved for the treatment of ovarian cancer. Treosulfan has previously been shown to reduce the severity of experimental allergic encephalomyelitis under pre-therapeutic and therapeutic conditions. In human peripheral blood mononuclear cells, treosulfan reduces proliferative capacity and increases apoptosis. STUDY DESIGN: This is a nonrandomized, open label study conducted in two centers. Eleven patients with active secondary progressive MS that failed to or did not qualify for approved disease modifying drugs were treated with treosulfan for 1 year. Patients received intravenous infusions of 7 g/m(2) every 4 weeks for 3 months (cycles 1-4, induction phase) with a predefined one-step dose escalation, thereafter every 3 months for the following 9 months (cyles 5-7, maintainance phase). Cranial MRI was performed every 3 months, EDSS and MSFC as well as physical examination were assessed at each clinical visit. RESULTS: Treatment with treosulfan was safe and well tolerated. Nine of 11 patients remained on study drug over the complete treatment period and showed clinical stabilisation or improvement as determined by EDSS and MSFC. Two patients discontinued study drug because of leukocytopenia and withdrawal of consent, respectively. No clinical relapses were observed during the treatment period. Thus, the median number of relapses per year was reduced signifi- cantly by 1.5 (range -3 to 0), p < 0.016, compared to prestudy. Therapy with treosulfan lead to a clear reduction of MRI activity as revealed by a reduced number of Gd + enhancing lesions on T1 weighted images. The mean number and volume of T2 lesions remained unchanged over 1 year. Four out of 9 patients under treosulfan showed no detectable disease activity (no Gd enhancing lesions, no new or newly enlarging T2 lesions). CONCLUSIONS: Application of treosulfan in MS was safe and well tolerated. Further studies are warranted to evaluate the efficacy of this treatment in secondary progressive MS.

Allogeneic hematopoietic stem-cell transplantation in patients with hematologic malignancies after dose-escalated treosulfan/fludarabine conditioning.

PURPOSE: Treosulfan was introduced recently as a conditioning agent for allogeneic blood stem-cell transplantation. The favorable nonhematologic toxicity profile at 3 x 10 g/m(2) was the basis for dose escalation in this prospective, multicenter trial. PATIENTS AND METHODS: Fifty-six patients with various hematologic malignancies who were not eligible for standard conditioning were treated with one of three doses: 10 g/m(2), 12 g/m(2), or 14 g/m(2) of intravenous treosulfan, which was administered on days -6 to -4 combined with fludarabine 30 mg/m(2) on days -6 to -2. Patients in complete remission (CR; 42%) or non-CR (58%) received grafts from matched related (47%) or matched unrelated (51%) donors; one patient had a mismatched related donor (2%). RESULTS: No engraftment failure occurred. Overall, extramedullary toxicity and the nonrelapse mortality rate at 2 years (20%) were low and did not increase with dose. Cumulative incidence of relapse/progression reached 31%. The overall survival and progression-free survival rates were 64% and 49%, respectively, in the total study population. An inverse dose dependency of relapse incidence was indicated in the subgroup receiving transplantations from matched related donors (P = .0568). CONCLUSION: Treosulfan-based conditioning was feasible at all three doses. The 3 x 14 g/m(2) dose was selected for additional studies, because it combines desired characteristics of low toxicity and a low relapse rate.