•Exclusion criterion was added to exclude pregnant or breastfeeding females •This amendment addressed a comment from an Independent Reviewing Authority (IRA), which requested that the protocol explicitly exclude pregnant females from study participation

•The time from onset of symptoms of an acute HAE attack to initiation of study drug treatment was increased from 4 hours to 8 hours •Information on the reconstitution of CINRYZE was updated to include the use of Mix2Vial transfer system •Throughout the protocol, the trademark symbol “™” was replaced with the registration symbol “®”

•Monitoring for potential thrombotic events (Venous thromboembolism (VTE), both Deep vein thrombosis (DVT) and Pulmonary embolism (PE)) •Added urinalysis with microscopy (if subject able to provide specimen; Groups 1-4) on Day 1 (pre-dose) and Day 2, and Complete blood count (CBC) with White blood cell (count) (WBC) count differential, platelet count (Groups 3 and 4, only) •Revised total blood volume collected to approximately 26 milliliter (mL) (from 22 mL) for Groups 1 and 2 •Specified that 41 mL of blood collected for subjects with minimum PK assessments, and 77 mL (from 51 mL) for subjects with all additional PK assessments in Groups 3 and 4 •Inclusion criteria: removed history of C1 INH gene mutation •Exclusion criteria: -timeframe of within 7 days prior to dosing for any prior HAE attack and specified “for the treatment or prevention of an HAE attack” with regard to receipt of any C1 INH product within 7 days prior to dosing -added suspect alternate explanation for symptoms other than acute HAE attack, and history of narcotic-seeking behavior and/or drug/alcohol abuse •Added information on thrombogenicity from preclinical data with Cetor and CINRYZE, and Thrombotic/thromboembolic events (T/TE) events from previous studies •Stopping and restarting rules were added for T/TE events and anaphylactic reaction •Laryngeal attack definition was expanded as pharyngeal or oral swelling that resulted in airway compromise •Vital signs to be measured immediately post completion of the infusion •Added dietary and electrolyte supplements as prior and concomitant medications •To report all SAEs occurring up to 30 days after the last dose to the Sponsor and IRA and SAEs with an onset greater than 30 days after last dose if considered related to study drug •Serum BUN and creatinine measurements were added to Days 3 and 5 if the subjects had the optional PK visit

•Inclusion Criteria: The requirement for subjects to have a history of swelling of the face, extremities, gastrointestinal tract, genitourinary tract, or larynx was removed. •Ethical Conduct of the Study, was added.