6 ADVERSE REACTIONS The most common adverse drug reactions (frequency ≥ 5% of subjects) observed in clinical trials were infusion site erythema, infusion site pain, fatigue, and back pain. The most common adverse drug reactions (frequency ≥ 5% of subjects) observed in clinical trials were infusion site erythema, infusion site pain, fatigue and back pain (6). To report SUSPECTED ADVERSE REACTIONS, contact BPL Inc., at 1-844-4275-872 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience As 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 trial of another drug and may not reflect the rates observed in clinical practice. During the clinical development of COAGADEX involving two multicenter, open-label, non-randomized clinical studies, 18 individual subjects with hereditary Factor X deficiency received at least one dose of COAGADEX. Sixteen subjects aged 12 to 58 years with moderate to severe hereditary Factor X deficiency (basal FX:C < 5 IU/dL) received doses of COAGADEX for pharmacokinetic evaluation, on-demand treatment and control of bleeding episodes, and/or perioperative management of minor surgical or dental procedures. A total of 468 infusions were administered, including 242 for on-demand treatment and control of bleeding episodes, 6 for perioperative management and 31 for PK assessments. Spontaneous, traumatic and menorrhagic bleeding episodes were treated with an on-demand dose of 25 IU/kg for up to 2 years. Two subjects aged 55 and 59 years with mild hereditary Factor X deficiency (basal FX:C 6 IU/dL and 8 IU/dL) received COAGADEX for perioperative management of four major surgical procedures. There were 40 exposure days to COAGADEX. Six adverse reactions were reported in 2 of the 18 subjects. These were infusion site erythema (2 reports in 1 subject [5.6%]), fatigue (2 reports in 1 subject [5.6%]), back pain (1 report [5.6%]) and infusion site pain (1 report [5.6%]). 6.2 Immunogenicity All subjects underwent Factor X inhibitor testing (inhibitor screen and Nijmegen-Bethesda assay) at baseline, end of study and at 3-monthly intervals in between. For subjects who underwent surgery, inhibitor testing was done pre-surgery and on discharge. All inhibitor tests were negative. Additionally, comparison of pharmacokinetic (PK) parameters at the repeat PK assessment with those at first dose did not suggest development of any inhibitors to Factor X. The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay. Additionally, the observed incidence of antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, it may be misleading to compare the incidence of antibodies to COAGADEX in the studies described above with the incidence of antibodies in other studies or to other products.