- Patient has a calculated or measured creatinine clearance of <20 mL/minute within 14 days before registration. (Creatinine Clearance is indicated through the Serum Creatinine. If the Serum Creatinine is abnormal, the physician may then due a 24 hour urine to further clarify Creatinine Clearance. A 24 hour urine test is not required per study.)