Mechanism of action in ITP
Some decline in hemoglobin is to be expected based on the postulated mechanism of action 1-3
• In four clinical trials of patients treated with the recommended initial intravenous dose of 250 IU/kg (50 μg/kg)‡ the mean maximum decrease in hemoglobin was 1.70 g/dL (range: +0.40 to –6.1g/dL)1
‡Clinical trials of subjects (n=161) with childhood ITP, adults and children with chronic ITP, and adults with ITP secondary to HIV treated with WinRho
WinRho SDF Liquid is Bioequivalent to WinRho SDF Lyophilized1
In two comparative pharmacokinetic studies (n=101), the formulations were bioequivalent following IV administration based on the area under the curve to 84 days and had comparable pharmacokinetics following IM administration. Both formulations also had similar elimination half-lives. WinRho SDF must be administered via the intravenous route for the treatment of ITP.
* Clinical trials of subjects (n=161) with childhood ITP, adults and children with chronic ITP, and adults with ITP secondary to HIV treated with WinRho/WinRho SD
WARNING: INTRAVASCULAR HEMOLYSIS (IVH)
Intravascular hemolysis (IVH) leading to death has been reported in patients treated with WinRho® SDF for immune thrombocytopenic purpura (ITP).
IVH can lead to clinically compromising anemia and multi-system organ failure including acute respiratory distress syndrome (ARDS).
Serious complications including severe anemia, acute renal insufficiency, renal failure and disseminated intravascular coagulation (DIC) have also been reported.
Closely monitor patients treated with WinRho® SDF for ITP in a healthcare setting for at least eight hours after administration. A dipstick urinalysis to monitor for hematuria and hemoglobinuria is to be performed at baseline and then after administration at 2 hours, 4 hours and prior to the end of the monitoring period. Alert patients and monitor the signs and symptoms of IVH including back pain, shaking chills, fever, and discolored urine or hemoglobinuria. Absence of these signs and/or symptoms of IVH within eight hours do not indicate IVH cannot occur subsequently. If signs and/or symptoms of IVH are present or suspected after WinRho® SDF administration, post-treatment laboratory tests should be performed including plasma hemoglobin, haptoglobin, LDH, and plasma bilirubin (direct and indirect).
Please see WinRho SDF Prescribing Information for full prescribing details
Reference: 1. WinRho SDF Prescribing Information, December 2010. 2. Cines DB, Blanchette VS. Immune thrombocytopenic purpura. N Engl J Med. 2002;346:995-1008. 3. Sandler SG, Tutuncuoglu SO. Immune thrombocytopenic purpura-current management practices. Expert Opin Pharmacother. 2004;5:2515-2527.