This is an open-label, single-arm clinical study investigating the long-term safety of ALTU-135 treatment in patients with cystic fibrosis (CF)-related exocrine pancreatic insufficiency (PI).

Inclusion Criteria

• Females of childbearing potential must be willing to use birth control

• 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 milliequivalents per liter (mEq/L) by quantitative pilocarpine iontophoresis.

• Clinically stable with no evidence of acute upper or lower respiratory tract infection

• Exocrine pancreatic insufficiency (PI) determined by fecal elastase < 100 micrograms per gram (µg/g) measured at Screening

• 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

Exclusion Criteria:

• Age <7 years
• Pregnancy, breastfeeding or of childbearing potential and not willing to use birth control
• Participation in an investigational study of a drug, biologic, or device not currently approved for marketing within 30 days prior to Screening
• History of fibrosing colonopathy
• History of liver transplant, lung transplant or significant surgical resection of the bowel
• Any chronic diarrheal illness unrelated to PI
• Abnormal liver function (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
• 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 coefficient of fat absorption (CFA) ≥ 93% from the Phase III efficacy study
• Patient is unlikely to complete the study, as determined by the Investigator