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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)

Gastrointestinal Disorders

Intra-abdominal Hemorrhage

General Disorders and Administration Site Disorders

Application Site Pruritus Feeling Hot Non-cardiac Chest Pain


Hepatic Enzyme Abnormal

Musculoskeletal and Connective Tissue Disorders


Renal and Urinary Disorders


Vascular Disorders



For ATryn (recombinant lyophilized powder) , 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 (recombinant lyophilized powder) in patients treated with ATryn (recombinant lyophilized powder) 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 Ovation Pharmaceuticals, Inc. and submitting them to Ovation 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 Ovation Pharmaceuticals, Inc. at 1-800-455-1141. Ovation 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.