Intravascular haemolysis associated with WinRho® SDF injection

HSA would like to bring to the attention of healthcare professionals the potential risk of intravascular haemolysis (IVH) and its complications associated with Rh_o (D) Immune Globulin (Human) (WinRho® SDF) when used to treat Immune Thrombocytopenia Purpura (ITP).

WinRho® SDF is the gamma globulin (IgG) fraction of human plasma containing antibodies to the Rh_o(D) antigen (D antigen). It is indicated for the prevention of Rh immunisation in Rh_o (D) negative women at risk of developing Rh antibodies; prevention of alloimmunisation in Rh_o (D) negative individuals transfused with Rh_o (D) positive red blood cells (RBCs) or blood components with Rho (D) positive RBCs and for the treatment of ITP. It has been registered for use locally since 2008 and is available in three strengths: 600IU, 1500IU and 5000IU.

Global post-marketing reports of intravascular haemolysis (IVH)

From March 1995 to March 2009, Cangene Corporation (the manufacturer of WinRho® SDF) reported a total of 180 serious post-marketing reports of suspected and/or confirmed cases of IVH associated with the use of WinRho® SDF worldwide. Of the 180 serious cases, 58 (32%) were considered definite IVH, 59 (33%) were probable IVH and 47 (26%) were possible IVH. Seventeen of the 58 definite IVH cases (29%) reported fatal outcomes, of which 13 patients were over the age of 65 years and 15 patients had a history of serious underlying co-morbid diseases that were considered to have induced or exacerbated pathological conditions leading to fatal outcomes.

A disproportionate number of IVH cases has also been reported in patients with ITP secondary to haematological malignancies such as leukaemia or lymphoma, or active viral infections with Hepatitis C virus (HCV) and Epstein-Barr virus (EBV).

IVH can lead to clinically compromising anaemia and multi-system organ failure including acute respiratory distress syndrome. Serious complications such as severe anaemia, acute renal insufficiency, renal failure and disseminated intravascular coagulation have also been reported. Fatal outcomes associated with IVH and its complications have occurred most frequently in patients of advanced age (> 65 years) with co-morbid conditions.

Local regulatory actions

The local package insert (PI) for WinRho® SDF has been updated on the risk of IVH in patients treated for ITP, including new contraindications and conditions for use of WinRho® SDF in the treatment of ITP.

The new contraindications include patients with evidence of autoimmune haemolytic anemia or systemic lupus erythematosus or anti-phospholipid antibody syndrome; who are elderly with co-morbidities predisposing to acute haemolytic reactions or its complications; who are IgA deficient or who have ITP secondary to conditions such as leukemia, lymphoma, or active viral infections with EBV or HCV.

New conditions for use include recommendations that patients treated with WinRho® SDF for ITP should be closely monitored for at least eight hours after administration together with a dipstick urinalysis at baseline, 2, 4 and 8 hours after administration. Absence of signs and/or symptoms of IVH within 8 hours do not indicate IVH cannot occur subsequently.

A Dear Healthcare Professional Letter was issued by Pharmaforte Singapore Pte Ltd on 27 May 2010 to all purchasers of WinRho® SDF to inform them of the above-mentioned safety concerns as well as the updates made to the local PI. This letter can also be accessed via the HSA's websiteand the MOH Healthcare Professional Portal (HPP). ^1,2

Physicians are advised to be vigilant for signs and symptoms of IVH, including back pain, shaking chills, fever, and discoloured urine or haematuria in patients being treated with WinRho® SDF.

To date, HSA has not received any local adverse reaction reports associated with WinRho® SDF. Healthcare professionals are encouraged to report any suspected adverse drug reactions associated with WinRho® SDF to the Vigilance Branch of HSA.

References

1. HSA website. Dear Healthcare professional Letters (DHCPL)
   https://www-hsa-gov-sg.cwp.sg/announcements/Dear-Healthcare-Professional-Letters
2. MOH-Health Professionals Portal:
   http://www.hpp.moh.gov.sg

Published: 16 Aug 2010

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