Inclusion Criteria

• ≥ 7 years of age
• Females of childbearing potential must be willing to use birth control (IUD; oral, transdermal or parenteral contraceptives; abstinence)
• Diagnosis of CF based upon the following criteria:

two clinical features consistent with CF; and either

• A genotype with two identifiable mutations consistent with CF, or

• Sweat chloride > 60 mEq/L by quantitative pilocarpine iontophoresis.

  • Clinically stable with no evidence of acute upper or lower respiratory tract infection.
  • PI determined by fecal elastase < 100 µg/g measured at the Screening Visit unless previously documented.
  • Able to take pancreatic enzyme supplementation in the form of capsules.
  • Able to perform the testing and procedures required for this study, as judged by the Investigator.
  • Willing and able to provide informed consent or assent

Exclusion Criteria:

• < 7 years of age
• Pregnancy, breastfeeding or of childbearing potential and not willing to use birth control (IUD; oral, transdermal or parenteral contraceptives; abstinence) during the study.
• Participation in an investigational study of a drug, biologic, or device not currently approved for marketing within 30 days prior to the Screening Visit except for the Phase III Efficacy Study (Protocol 0000726).
• History of fibrosing colonopathy.
• History of liver transplant, lung transplant or significant surgical resection of the bowel.

Note: Significant resection of the bowel is defined as any resection of the terminal ileum, or ileo-cecal valve. Patients who have had qualitative, long-term changes in nutritional status after any other bowel resection (e.g., increased, or new, need for supplementation compared to pre-op in order to maintain the same nutritional status) should also be excluded.

• Any chronic diarrheal illness unrelated to PI (e.g., sprue or inflammatory bowel disease).
• ALT or AST level > 5 x ULN, or total bilirubin level > 1.5x ULN at the Screening Visit or at Baseline (except for patients with Gilbert Syndrome).
• Signs and/or symptoms of liver cirrhosis or portal hypertension (e.g., splenomegaly, ascites, esophageal varices), or documented liver disease unrelated to CF. (Eligible patients with ALT or AST level > 3x to 5x ULN at the Screening Visit or at Baseline will be tested for viral hepatitis. Other diagnostic testing may be performed at the discretion of the Investigator.)
• Unable to discontinue enteral tube feedings during the study
• Any condition that the Investigator believes would interfere with the intent of this study or would make participation not in the best interest of the patient.
• Baseline CFA ≥ 93% from the Phase III efficacy study (Protocol 0000726).
• Patient is unlikely to complete the study, as determined by the Investigator.