pH Stability of Defibrase_ in Aqueous Solution Determined by En-zyme-linked Immunosorbent Assay

Stability of Defibrase in various pH buffer solutions was investigated. Enzyme-linked immuno-sorbent assay (ELISA) and coagulating time method were used to assess antigenic stability and coagulating stability, respectively. The change of antigenic activities and coagulating activities of Defibrase in the same buffer solutions (pH 6, 7 and 8, with the exception of pH 3.6) showed similar tendency to decline with the time. Concentrated Defi-brase was relatively stable at neutral pH 6~7, more than 95% of its initial activities (100BUmL-1) was kept after a 10-day storage at 40 oC, whereas in pH 3.6 and pH 9 buffer solutions, diluted Defibrase was very labile. Addition of Triton X-100 or bovine serum albumin could effectively prevent loss of Defibrase by minimizing adsorption of De-fibrase to plastic surface (P<0.005). Concentration of Defibrase could also affect its stability in aqueous solutions.

REASSESSMENT OF DEFIBRASE IN TREATMENT OF ACUTE CEREBRA LINFARCTION :A MULTICENTER ,RANDOMIZED ,DOUBLE-BLIND ,PLACEBO-CONTROLLED TRIAL

Objoctive To evaluate the efficacy and safety of defibrase in patients with acute cerebral infarction by a large sample, multicenter, randomized, double-blind, placebo-controlled clinical trial. Mothods Patients with acute cerebral infarction within 12 hours of stroke onset were randomly assigned to receive either an initial intravenous infusion of defibrase 15 U plus normal saline 250 mL or 250 mL of normal saline only. Subsequent infusions of defibrase 5 U or placebo (normal saline) were given on the 3rd, 5th, 7th, and 9th day, respectively. Both groups received standard care of acute cerebral infarction. The primary efficacy outcome was functional status (Barthel Index) at 3 months after treatment. Safety outcome were bleeding events and mortality rate. Secondary outcome included Chinese Stroke Scale (CSS) score at 14 days and recurrence rate of stroke at 1 year. A total of 1053 patients were enrolled at 46 centers from September 2001 to July 2003, and 527 patients were randomly assigned to receive defibrase and 526 to receive placebo. A similar proportion of patients in both groups completed a full course of treatment. There was a significantly greater proportion of favorable functional status (Barthel Index 1≥95) in defibrase group than in placebo group at 3 months (52.2% vs. 42.8%, P 〈 0.01), and the proportion of dependent functional status (Barthel Index ≤60) was a little lower in defibrase group compared with placebo group (27.7% vs. 32.4%). These differences were more obvious among patients who were treated within 6 hours of stroke onset. Patients in defibrase group had better improvement with respect to CSS score than those in placebo group at 14 days (P 〈 0.05). Recurrence rate of stroke at 1 year was lower in the defibrase group compared with placebo group (6.2% vs. 10.1%, P = 0.053). Patients in defibrase group had higher risk of extracranial bleeding events (4.7% vs. 1.5%, P 〈 0.01 ) and a tendency of higher risk of symptomatic intracranial hemorrhage. The hemorrhage incidence was higher in patients with fibrinogen level 〈 130 mg/dL than ≥ 130 mg/dL (10.6% vs. 3.8%, P 〈 0.05). Mortality rate at 3 months were slightly higher in defibrase group than placebo group (5.9% vs. 4.2%). Conclusions The defibrase is effective to improve neurological function and function of daily living for patients with acute cerebral infarction within 12 hours of symptom onset. The efficacy was even better for acute cerebral infarction within 6 hours of onset. The increased risks of intra- and extracranial hemorrhage during defibrase administration were related to the plasma fibrinogen level.

Dynamic changes in fibrinogen levels of patients with acute cerebral infarction after taking defibrase

BACKGROUND： At present, as a therapeutic drug mainly for reducing fibrinogen （FIB） levels, the dynamic influence of defibrase on the FIB levels of patients with acute cerebral infarction has not been clearly ascertained. OBJECTIVE： To observe the dynamic changes in FIB levels of patients with acute cerebral infarction at different time points after taking defibrase. DESIGN, TIME AND SETTING： Randomized controlled clinical trial. The study was conducted in the Department of Neurology, the Second Affiliated Hospital of Jinan University, from June to November 2006. PARTICIPANTS： Sixty patients with acute cerebral infarction, who had been treated by the Neurological Department of the Second Affiliated Hospital of Jinan University from June to November 2006, were selected, including 37 males and 23 females, aged 35-75 years. All cases met the diagnostic criteria formulated by the Fourth National Cerebrovascular Disease Conference within 12 hours of onset. All the patients were confirmed with definite hemiparesis and cerebral infarction without coma, and were randomly divided into two groups： a treatment group （n =40） and a control group （n =20）. Patients＇ families had the right to be informed and agree with the treatment, which had permission from the Hospital Ethics Committee. METHODS： Patients in the control group were given routine treatment with 30 mL fleabane and 0.75 g cytidine diphosphate added to 500 mL saline solution once a day for 14 consecutive days. Patients in the treatment group were given routine treatment and Haiwang defibrase injection （purchased from Changchu Guoao Bio-Pharmaceutical Co. Ltd., Approval document number H10983237） within 12 hours of infarction. Defibrase doses of 15, 12.5 and 10 U were given over 2 hours according to the patients＇ pre-treatment plasma FIB levels of ≥ 4.50 g/L, 3.50 4.49 g/L and 1.00 3.49 g/L, respectively. Plasma FIB levels in the treatment group were measured before, and once every six hours for 48 hours after administration of defibrase. Later, measurements were taken once every 12 hours and FIB levels were kept in a range of 0.5-1.3 g/L for one week. When the FIB level increased to over 1.3 g/L, a 5 U dose of defibrase was given again over two hours, FIB levels of the control group were measured once before treatment and once after one week of treatment MAIN OUTCOME MEASURES： （1） Dynamic changes of FIB levels in the defibrase treatment group. （2） Comparison of dynamic changes of FIB levels in the treatment group and control group before and after treatment for one week. RESULTS： All 60 patients were included in the final analysis. The treatment group＇s FIB levels quickly decreased to 0.5-1.3 g/L within 12 hours of taking the first dose of defibrase and reached a minimum in 24 hours. Later, they began to rise slowly into the therapeutic range （0.5-1.3 g/L） in 48 hours. The FIB levels of the treatment group increased slowly to over 1.3 g/L in 60 hours after the first dose of defibrase and then quickly decreased to the therapeutic range after the second dose of 5 U defibrase with a minimum level higher than after the first dose, and higher again after the third dose. After treatment, patients＇ FIB levels could be kept in the therapeutic range for about one week. The FIB levels in patients in the treatment group were significantly lower after taking defibrase for one week in comparison with the levels before treatment （P 〈 0.01）. There was no difference in the control group between the levels pre-treatment and one week after treatment （P 〉 0.05）. CONCLUSIONS： FIB levels in patients with acute cerebral infarction quickly decrease after taking the first dose of defibrase and reach a minimum in 24 hours. Later, they begin to rise slowly into the therapeutic range （0.5-1.3 g/L） in 48 hours. The FIB levels increase slowly to over 1.3 g/L in 60 hours. The effect of defibrase is weaker when the same dose of defibrase is used in patients repeatedly.

Meta-analysis of defibrase in treatment of acute cerebral infarction

Background Fibrinogen-depleting agents are promising in the treatment of cerebral ischemic disease. They were studied by many trials, and the outcomes were different because of different regimens and different doses. In this study, we assessed the efficacy and safety of defibrase on acute cerebral infarction in China. Methods A search using Chinese hospital knowledge database （CHKD） and MEDLINE database for randomized controlled trials was carded out. A CHKD （1994 June 2005） search was performed with the keyword ＂defibrase＂, then a second search for the keyword ＂acute cerebral infarction＂; a MEDLINE search （1950 June 2005） was performed with the following keywords： [（cerebral ischemia）, OR （acute cerebral infarction）, OR （stroke）], AND [defibrase]. Meta-analysis was performed with RevMan software 4.2. Results Included were 14 studies comparing the efficiency and safety of defibrase with other drugs in the treatment of acute cerebral infarction. Patients＇ records were pooled （total 646 patients; defibrase, n=328, no defibrase n=318）. Neurological deficit score （NDS） before treatment showed weighted mean differences （WMD）=0.95, 95% confidence interval （CI）= （-0.60, 2.50）, P=0.23; NDS after treatment showed WMD=- 2.20, 95% CI= （-4.21, -0.18）, P=0.03; Barthel index at 3 months showed WMD=4.45, 95% CI= （-0.13, 9.03）, P=0.06; the plasma fibrinogen level before treatment showed WMD=0.02, 95% CI= （-0.16, 0.19）, P=0.86; plasma fibrinogen level after treatment showed WMD=- 1.51, 95% CI= （- 1.88, - 1.15）, P〈0.00 001.Conclusions With the given dose and regimen of defibrase in China, defibrase may play a role of anticoagulation. It might inhibit the progression of stroke and prevent the recurrence of stroke.