- Part 1:Gold Class IV COPD, of moderate to significant emphysema, or evidence of malignancy; medication considered potential for drug drug interaction; creatinine clearance <30ml/min; more than 1 exacerbation requiring antibiotics or oral steroids and/or hospitalization within 3 months of screening; women of child bearing potential • Part 2: Gold spirometry grade IV COPD; medication considered a potential for drug drug interaction; serum creatinine ≥1.9 mg/dL; more than 1 exacerbation requiring antibiotics or oral steroids within 2 months and/or hospitalization within 3 months of screening; any malignancy; evidence of severe emphysema as determined by HRCT; use of oral steroids, theophylline, phosphodiesterase-4 inhibitors or oral antibiotic use (eg.macrolides)