FAQs

Q.  What is ITP?
A.  ITP is immune thrombocytopenic purpura , an autoimmune bleeding disorder that causes thrombocytopenia, a condition in which blood doesn't clot as it should due to a low number of blood cells called platelets or thrombocytes. A patient with thrombocytopenia has a blood platelet count below 100,000 per microliter. A normal platelet count ranges from 150,000 to 400,000 per microliter.

ITP creates a defect in the body's immune system, in which antibodies are created that destroy blood platelets as if they were invaders in the body, causing thrombocytopenia. The exact reason for this autoimmune response is unknown; for this reason, ITP is often known as idiopathic thrombocytopenic purpura, with "idiopathic" meaning "unknown." (The word "purpura" in the name refers to purplish bruises caused by the bleeding under the skin that often results from ITP.)

Most cases of ITP are acute— i.e., they last less than 6 months—and occur in children, often stemming from a viral infection. If ITP lasts over 6 months, it is considered chronic and generally requires long-term treatment. Chronic ITP generally cannot be tied to an infection or other medical event and usually occurs in adults.

It is important to note that a patient with thrombocytopenia will not necessarily have ITP—in fact, ITP is diagnosed by eliminating other possible causes of thrombocytopenia. One form of non-ITP thrombocytopenia is a relatively rare inherited condition in which the blood platelets are supplied but do not function properly. ITP is not an inherited condition.

Another non-ITP cause of thrombocytopenia is a malfunction of the bone marrow, which produces the blood platelets. This could stem from bone marrow failure or even leukemia, and is often evidenced by such symptoms as anemia or bone pain. In addition, severe infections and sudden blood loss can also cause a malfunction (usually temporary) in the bone marrow's ability to produce platelets. Thrombocytopenia can also be caused by an inability of the spleen to release sufficient platelets into the bloodstream.

For more information, see About ITP.

Q.  What are the incidence and prevalence of ITP? 
A.  Approximately 200,000 individuals in the US are thought to have ITP. In adults, about three times more women than men have the disease. (In children, distribution is fairly even between boys and girls.) About 30,000 new cases occur in the United States every year, about half of these in children.

Q.  What are the symptoms or consequences of ITP?
A.  Effects of ITP can vary considerably from patient to patient. Hemorrhage is the most serious complication, particularly intracranial hemorrhage, which although rare is often fatal. The mortality rate from hemorrhage is approximately 1% in children and 5% in adults. The rate of bleeding-related mortality increases with age. In patients with severe thrombocytopenia, mortality rates from bleeding are significantly raised in patients more than 60 years of age (13% per year) versus patients less than 40 years of age (0.4% per year).

Q.  How is ITP diagnosed?
A.  ITP is diagnosed after eliminating other possible causes of thrombocytopenia. Several laboratory tests are used to rule out other causes of thrombocytopenia and to confirm ITP, including:

• Complete blood count
• Peripheral blood smear
• Platelet-bound antibodies assay
• Antinuclear antibody test
• Direct antiglobulin test
• HIV test

If these tests are inconclusive, physicians may order additional tests, including bone marrow biopsy or CT scan.

Q.  How is ITP treated?
A.  The goal of treatment is to build up a safe platelet count so that patients with ITP can live normal, active lives. Treatment may include surgery as well as medication. The choice of treatment depends on the patient’s platelet count and any signs and symptoms.

Q.  What are some of the treatment options?
A.  Typical treatment of adult chronic ITP involves four lines of defense. If a treatment is not effective, the next therapy is attempted. Individual physicians may have different approaches to treatment, but the general approach is as follows:

1. First-line treatment — corticosteroids or intravenous immunoglobulin (IVIG)
2. Second-line treatment — anti-D (Rh) immunoglobulin in Rh-positive patients
3. Third-line treatment — alternative treatments or investigational agents
4. Fourth-line treatment — splenectomy (surgical removal of the spleen; the spleen is where the platelets are destroyed in people with ITP)

Q.  How does anti-D immunoglobulin work to treat ITP?
A.  Anti-D immunoglobulin (or anti-D) is used in patients who cannot tolerate or do not respond to initial treatment with corticosteroids or IVIG. Patients receiving anti-D must have Rh-positive blood and must not have had a splenectomy. It is believed that anti-D forms red blood cell (RBC) complexes that block the destruction of the targeted platelets.

Q.  How is Rhophylac^® for ITP administered?
A.  Rhophylac^® in the treatment of ITP must be administered intravenously. It is suggested that the dose be calculated, then pooled into a larger container, such as a large volume syringe or a sterile, empty infusion bag.

Q.  What is the dosing of Rhophylac^® for ITP?
A.  The recommended dosage of Rhophylac^® for ITP is 250 IU (50 mcg) per kg. 

Q.  What is the suggested rate of IV administration for Rhophylac^® in ITP?
A.  Rhophylac^® should be administered at a rate of 2 to 8 mL/minute.

Q.  Is Rhophylac^® a new product?
A.  No. Although not approved for ITP until 2007, Rhophylac^® was introduced in Europe in 1996 and received approval from the US Food & Drug Administration (FDA) in 2004 for the suppression of rhesus (Rh) isoimmunization in pregnancy, obstetric conditions, and in incompatible transfusions in Rh-negative individuals. More than 1.5 million doses have been given worldwide with no confirmed cases of viral transmission.

Q.  Does Rhophylac^®  interfere with other medications or therapies?
A.  Immunoglobulins can temporarily reduce the effectiveness of some vaccines, such as measles, mumps, and rubella (MMR),  and varicella. The immunizing physician can decide whether repeating the vaccine at a later date will be necessary.

Q.  Is Rhophylac^® safe to use in women with ITP who are pregnant or nursing?
A.  The safety of usage in pregnant patients with ITP or in nursing mothers with ITP has not been evaluated.

Q.  What adverse events have been reported with use of Rhophylac^® for ITP? 
A.  Adverse reactions occurring during the treatment of ITP were evaluated in 98 Rho(D)-positive adults with chronic ITP who received a single dose of Rhophylac^® 250 IU (50 mcg) per kg body weight. Adverse reactions that occurred in more than 10% of subjects were chills (35%), fever (25%), increase in bilirubin (21%), and headache (11%). All adverse reactions were mild to moderate in intensity with the exception of a case of severe headache. Signs of hemolysis were also observed.

Q.  What kind of donor screening is done to help ensure viral safety in the production of Rhophylac^®?
A.  Rhophylac^® is produced from blood plasma collected from healthy Rh-negative male and female volunteers in the US who are sensitized (i.e., immunized) with Rh-positive red blood cells. To ensure the highest possible safety standards, each donor is carefully selected and screened to reduce the risk of receiving contaminated donations. Each blood donation undergoes two types of testing:

• Viral marker screening, including hepatitis B surface antigen, human immunodeficiency virus 1 and 2 antibodies, and alanine aminotransferase activity
• Polymerase chain reaction screening, which tests for evidence of enveloped viruses (HIV, hepatitis B virus, and hepatitis C virus) and non-enveloped viruses (hepatitis A virus and parvovirus B19)

For more information on donor screening and plasma collection, see About Rhophylac^® for ITP — Safety and Tolerability .

Q.  What other safety steps are involved in the production of Rhophylac^®?
A.  Rhophylac^® is produced using a unique manufacturing process called ChromaPlus™ , which consists of three complementary steps to inactivate and/or remove enveloped and/or non-enveloped viruses:

• Solvent/detergent (S/D) treatment
• Ion exchange chromatography
• Nanofiltration

Learn more about the ChromaPlus™ Manuacturing system.

Q.  What studies have been performed to demonstrate the efficacy of Rhophylac^® in ITP?
A.  In a study conducted in Europe and the US, 98 Rho(D)-positive adults with chronic ITP and a platelet count of 30,000/microliter or less were treated with Rhophylac^®. Patients received a single IV dose of 250 IU (50 mcg) per kg body weight. Overall, 66% of patients responded with a platelet increase of at least 20,000 to 30,000/microliter. A regression of hemorrhage was seen in 88% of the 50 subjects having bleeding at baseline.  Learn more about the efficacy of Rhophylac^® .

Q.  Have there been reported cases of disseminated intravascular coagulation (DIC) associated with the use of Rhophylac^® for ITP? 
A.  DIC has been associated with the use of anti-D immunoglobulin. Currently, however, there have been no reported cases of DIC associated with Rhophylac^®.

Q.  Can Rhophylac^® be used for ITP in Rh-negative patients? 
A.  No. Anti-D immunoglobulins are only effective in treating ITP in Rh-positive patients who have not had a splenectomy.

Q.  Can Rhophylac^® be used for ITP in pediatric patients?
A.  Rhophylac^® is indicated for use in adult patients with chronic ITP. While no clinical studies have specifically been done with Rhophylac^® on pediatric subjects, studies have demonstrated the safe and effective use of Rho(D) Immune Globulin in children with ITP.

Q.  What is the IgA content of Rhophylac^®?
A.  The IgA content of Rhophylac^® is below the limit of detection of 5 mcg/mL.

Q.  Does Rhophylac^® contain thimerosal (mercury) or latex? 
A.  Rhophylac^® has never been formulated with thimerosal (mercury) or any other preservative, nor does it contain latex.

Q.  Does Rhophylac^® contain any maltose? 
A.  Unlike some brands of anti-D immunoglobulin, Rhophylac^® does not contain maltose.