1. (Part 1) has Moderate to Severe Renal Impairment (equivalent to NKF KDOQI Stage 3 or 4, not receiving dialysis) as determined by estimated Glomerular Filtration Rate (eGFR) calculated by the abbreviated MDRD equation, and not expected to go on dialysis until ≥ 8 weeks after first administration of investigational product. Stage 5, non-dialysis patients with eGFR of 10 15 mL/min per 1.73 m2 will also be eligible for Part 1 on a case-by-case basis.