"The U.S. Food and Drug Administration today approved Promacta (eltrombopag) to treat low blood platelet count in pediatric patients – ages one year and older – with a rare blood disorder called chronic immune thrombocytopenic purpura "...
The serious adverse reaction that has been reported in clinical studies is hemorrhage (intra-abdominal, hemarthrosis and post procedural). The most common adverse events reported in clinical trials at a frequency of ≥ 5% are hemorrhage and infusion site reaction.
Clinical Trial Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
Adverse reactions that occurred in clinical trials with hereditary AT deficient patients are shown in Table 3 by System Organ Class.
Table 3: Adverse Reactions in Hereditary AT Deficient Patients (one event per patient, 2% of total population, n=47)
General Disorders and Administration Site Disorders
Application Site Pruritus
Non-cardiac Chest Pain
Hepatic Enzyme Abnormal
Musculoskeletal and Connective Tissue Disorders
Renal and Urinary Disorders
For ATryn, a potential safety issue is the development of an immunological reaction to the recombinant protein or any of the potential contaminating proteins. Assays were developed and used to detect antibodies directed against antithrombin (Recombinant), goat AT, or goat-milk proteins. No confirmed specific immunological reaction was seen in any of the patients tested, nor were there any clinical adverse events that might indicate such a response.
A post-marketing patient registry has been established to collect additional data on the immunogenic potential of ATryn in patients treated with ATryn on more than one occasion. Physicians are encouraged to participate in the registry by collecting pre- and post-treatment serum samples from patients according to instructions provided by rEVO Biologics, Inc. and submitting them to rEVO Biologics, Inc. for analysis for the development of antibodies to antithrombin (Recombinant). Serum samples should be collected within one week before initiation of treatment and on days 1, 7 and 28 days from initiation of treatment. Physicians wanting to participate in this program are encouraged to contact rEVO Biologics, Inc. at 1-800-610-3776. rEVO Biologics, Inc. will provide detailed instructions for the collection, processing and shipping of samples, as well as all tubes and labels that are necessary for the collection and processing of samples.
Read the Atryn (recombinant lyophilized powder) Side Effects Center for a complete guide to possible side effects
The anticoagulant effect of heparin and low molecular weight heparin (LMWH) is enhanced by antithrombin. The half-life of antithrombin may be altered by concomitant treatment with these anticoagulants due to an altered antithrombin turnover. Thus, concurrent administration of antithrombin with heparin, low molecular weight heparin, or other anticoagulants that use antithrombin to exert their anticoagulant effect must be monitored clinically and biologically. To avoid excessive anticoagulation, regular coagulation tests (aPTT, and where appropriate, anti-Factor Xa activity) are to be performed at close intervals, with adjustment in dosage of the anticoagulant as necessary.
Read the Atryn Drug Interactions Center for a complete guide to possible interactions
Last reviewed on RxList: 5/25/2016
Additional Atryn Information
- Atryn Drug Interactions Center: antithrombin iii, hum recom iv
- Atryn Side Effects Center
- Atryn FDA Approved Prescribing Information including Dosage
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
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