FDA Announces New Boxed Warning for WinRho SDF


March 10, 2010

March 10, 2010 — Rho(D) immune globulin intravenous (WinRho SDF) will now bear a boxed warning about the risks of treating patients with immune thrombocytopenic purpura (ITP) after reports of some patients dying from intravascular hemolysis (IVH), the US Food and Drug Administration (FDA) announced today.

Some ITP patients treated with the immunoglobulin have developed IVH, which can lead to clinically compromising anemia and multisystem organ failure, including acute respiratory distress syndrome, according to an alert sent today by MedWatch, the FDA's safety information and adverse event reporting program.

Other serious complications reported after administration of WinRho SDF are severe anemia, acute renal insufficiency, renal failure, and disseminated intravascular coagulation, according to the FDA.

The most deaths resulting from IVH complications have occurred in patients older than 65 years with comorbid conditions.

WinRho SDF is made by Cangene, based in Winnipeg, Canada. It is distributed in the United States by Baxter Healthcare, based in Deerfield, Illinois.

The boxed warning that Cangene is adding to WinRho SDF warns clinicians that ITP patients treated with the immunoglobulin must be closely monitored in a healthcare setting for at least 8 hours after administration. A dipstick urinalysis should be performed 4 times during this monitoring period — at baseline, at the 2-hour mark, at the 4-hour mark, and at the end of the monitoring period.

The boxed warning also instructs clinicians to tell patients to look out for signs and symptoms of IVH such as back pain, shaking chills, fever, and discolored urine or hematuria. Absence of these signs and symptoms within the 8-hour monitoring period does not mean that IVH will not emerge later.

If patients exhibit these signs or symptoms or if IVH is suspected after treatment, clinicians should perform laboratory tests, including plasma hemoglobin, urinalysis, haptoglobin, lactate dehydrogenase, and both direct and indirect plasma bilirubin, according to the boxed-warning instructions.

In a letter to healthcare professionals posted on the FDA Web site, Cangene and Baxter Healthcare state that the new boxed warning strengthens earlier warnings about the risk of ITP patients developing IVH. The companies add that their letter does not apply to patients receiving WinRho SDF for the suppression of Rh isoimmunization.

For more information, visit the FDA's MedWatch Web site.

To report adverse events related to WinRho SDF, contact MedWatch by telephone at 1-800-FDA-1088, by fax at 1-800-FDA-0178, online at http://www.fda.gov/medwatch, or by mail to 5600 Fishers Lane, Rockville, Maryland 20852-9787.


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