FROM THE JOURNAL OF CLINICAL ONCOLOGY
Defibrotide improved survival at 100 days after hematopoietic stem cell transplantation (HSCT) in patients with hepatic veno-occlusive disease, based on an open-label trial that compared trial participants with historical controls.
Of the 102 patients in the defibrotide group, 39 were alive 100 days after HSCT (38.2%), compared with 8 of 32 (25.0%) in the historical control group. The propensity-adjusted, between-group difference was 23.0% (95.1% confidence interval, 5.2%-40.8%; P = .0109). At 180 days post-HSCT, the difference in survival between the groups was not significant (Blood. 2016 Feb 3. doi: 10.1182/blood-2015-10-676924 ).
Defibrotide has Fast Track designation from the FDA and the new drug application is currently under Priority Review with a decision expected by March 31, 2016. A potentially fatal complication of HSCT, hepatic veno-occlusive disease is characterized by hepatomegaly, jaundice, rapid weight gain, fluid retention, and ascites. There are no approved therapies.
“In this context, defibrotide provides a promising treatment option for patients with a high unmet medical need,” wrote Dr. Paul G. Richardson of Dana-Farber Cancer Institute in Boston and his colleagues.
At day 100 post-HSCT, complete response was seen in 25.5% of the defibrotide group and in 12.5% of the historical control group. The propensity-adjusted, between-group difference was 19% (95.1% CI, 3.5-34.6%; P = .0160). The complete response was durable in 22 of the 26 patients. In the control group, complete response was limited in two patients, impossible to assess in one patient, and durable in one patient.
The multicenter, open-label, phase III trial prospectively enrolled 102 patients with hepatic veno-occlusive disease from 2006 to 2008. Defibrotide was administered intravenously at 25 mg/kg/day in 4 divided doses for a minimum of 21 days. Treatment continued beyond 21 days until resolution of veno-occlusive disease or until the patient was discharged from the hospital.
To identify the historical controls, 6,867 medical charts of HSCT patients hospitalized from 1995 to 2007 were reviewed, and 32 historical control patients were selected. Most (21 of 32) were diagnosed with during 2000-2006, and 11 were diagnosed before 2000. The historical controls were selected by an independent medical review committee, and met the same entry criteria as the defibrotide group.
Because recruiting for the defibrotide group and screening for historical controls occurred at the same institutions during similar time periods, patient management and supportive care were likely similar for the two groups. Propensity scores were included in the analysis to adjust for prognostic factors that were unbalanced between treatment and control groups, including ventilator and dialysis dependency at study entry, age greater or less than 16 years, prior HSCT (0 vs. 1), and allogeneic or autologous transplant.
Hypotension was the most common adverse event reported in the defibrotide and control groups (39% and 50%, respectively), followed by diarrhea (23.5% and 37.5%, respectively). The defibrotide and control groups had similar incidences of common hemorrhagic adverse events (64% and 75%, respectively). Fatal adverse events occurred in 64% of the defibrotide group and 69% of the control group, and fatal hemorrhagic events occurred in 14.7% of the defibrotide group and 6.3% of the control group.
Approved by the European Union, defibrotide is a single-stranded, deoxyribonucleic acid derivative that stabilizes damaged endothelial cells and prevents further endothelial cell damage.
Dr. Richardson reported consulting or advisory roles with Gentium/Jazz Pharmaceuticals, the maker of defibrotide.