12-Week Safety and Efficacy Study of BCX4161 as an Oral Prophylaxis Against HAE Attacks

Key Inclusion Criteria:

1. A clinical diagnosis of HAE type I or II

2. Documented HAE attacks within a defined calendar period; in the absence of documented
HAE attacks, subjects will be required to enter a run-in period to document attacks

3. Access to acute attack medications

4. Sexually active women of child-bearing potential and sexually active men must utilize
highly effective contraception

Key Exclusion Criteria:

1. Women who are pregnant or breast-feeding

2. Any clinical condition or medical history that would interfere with the subject's
safety or ability to participate in the study

3. Use of C1INH or tranexamic acid for prophylaxis of HAE attacks

4. Current participation in any other investigational drug study or within the last 30
days

5. History of or current alcohol or drug abuse

6. Infection with hepatitis B, hepatitis C or HIV