A Study to Evaluate the Single Dose Safety, Tolerability and Pharmacokinetics of IV BCX4430

This single ascending dose study will evaluate the safety, tolerability, and PK of single
doses of galidesivir vs. placebo administered as IV infusions in healthy subjects enrolled in
up to four dose cohorts of 8 subjects each. A single dose of study drug will be administered
per cohort: 6 subjects will receive galidesivir IV, and 2 subjects will receive matching
placebo.

Key Inclusion Criteria:

- written informed consent

- males and non-pregnant, non-lactating females

- BMI 19.0-32.0

- willing to abide by contraceptive requirements

- normal vitals

- willing to abide by study procedures and restrictions

Exclusion Criteria:

- clinically significant medical condition or medical history or psychiatric condition
or history of psychiatric condition

- abnormal cardiac finding, or laboratory/urinalysis abnormality at screening

- known family history of sudden death or long QT syndrome, family or personal history
of QT prolongation, or arrhythmia that required medical intervention

- current participation in any other investigational drug study or participation in an
investigational drug study within 3 months of screening visit

- use of prescription, OTC, or herbal medications during study or use of any specified
medications within 30 days prior to study

- Recent or current history of alcohol or drug abuse

- Regular use of tobacco or nicotine products

- Positive serology for HBV, HCV, or HIV

- history of severe adverse reaction to or known sensitivity to any drug

- pregnant, lactating, or planning to become pregnant within 30 days of the study. Male
subjects with pregnant female partners are excluded