Hemolysis Warning Added to WinRho SDF Labeling

Kate Traynor

BETHESDA, MD 10 March 2010—FDA today announced the addition of a boxed warning to the labeling of WinRho SDF because the product has been associated with sometimes-deadly cases of intravascular hemolysis (IVH) in patients with immune thrombocytopenic purpura (ITP).

The warning and other labeling changes are described in a "Dear Healthcare Professional" (PDF) letter from Cangene, the manufacturer of the i.v. immune globulin product, and Baxter Healthcare Corp., which markets WinRho SDF in the United States.

The boxed warning does not apply to patients treated with WinRho to prevent Rh isoimmunization, according to the letter.

According to the boxed warning, patients who receive the immune globulin product for the treatment of ITP should be closely monitored, in a health care setting, for a minimum of eight hours after the drug is administered.

The monitoring should include "dipstick" urinalysis at baseline, two and four hours after administration and before the end of the monitoring period. Patients should also be evaluated for indications of IVH, which include back pain, shaking, chills, fever, discolored urine, or hematuria, the warning states.

If IVH is suspected, additional testing should be performed, including urinalysis and measurements of plasma hemoglobin, haptoglobin, lactate dehydrogenase, and bilirubin, according to the warning.

Other changes to WinRho's labeling (PDF) include warnings about cases of severe anemia, acute renal insufficiency, kidney failure, and disseminated intravascular coagulation in patients treated with the immune globulin product.

The product is contraindicated in patients with autoimmune hemolytic anemia, preexisting hemolysis, or a high risk for the condition, or with immunoglobulin A (IgA) deficiency and anti-IgA antibodies. Patients whose hemoglobin level is less than 8g/dL are at risk for worsening anemia and should not use WinRho, the labeling states.