This is a two-part Phase 1 placebo-controlled, double-blind, randomized single and multiple ascending dose study. In Part A, CAT-2003 is administered as a single dose; at two doses (1000 and 2000 mg), subjects will return for a second dose of CAT-2003 or placebo after a high fat meal. In Part B, CAT-2003 is administered for 14 consecutive days.

Major Inclusion Criteria:

• Provision of written informed consent prior to any study-specific procedure;

• Good health as determined by medical history, physical examination, vital signs, ECG, and clinical laboratory measurements;

• Satisfies one of the following:

  1. Females not of childbearing potential: non-pregnant and non-lactating; surgically sterile or postmenopausal for 2 years or at least 1 year with a follicle stimulating hormone assessment (FSH) greater than or equal to 40 IU/L; OR
  2. Males: surgically sterile, abstinent, or subject or partner is utilizing an acceptable contraceptive method during and 3 months after the last study dose;

Major Exclusion Criteria:

• Clinically significant disease that requires a physician's care and/or would interfere with study evaluations
• Clinically significant electrocardiogram (ECG) abnormalities or laboratory results as assessed by the investigator, such as QTcF >450;
• Use of any investigational drug or participation in any investigational study within 30 days prior to screening or 5 half-lives of the study agent, whichever is longer;