The purpose of this study is to evaluate the safety and tolerability of Creon micro in children younger than four years with pancreatic exocrine insufficiency.

A prospective open-label, multi-center study evaluating safety and tolerability of Creon Micro in pediatric subjects from at least one month to less than four years of age with Pancreatic Exocrine Insufficiency (PEI) due to Cystic Fibrosis (CF). Referring to the European Medicines Agency (EMEA) pediatric age criteria for the purpose of the study, subjects are categorized as infants and toddlers (< 2 years) and children, (2 years to < 4 years). In total, 40 subjects will be enrolled (20 subjects in each age subgroup). Subjects receive their prescribed pancreatic enzyme supplementation at the individual dose until start of treatment with Creon Micro, if the subjects were on pancreatic enzyme supplementation before start of the study. Subjects will be treated with Creon Micro during the study. The treatment duration is 3 months.

Inclusion Criteria:

• Children younger than four years with confirmed cystic fibrosis diagnosis and a body weight of at least 2 kilograms

Exclusion Criteria:

• Ileus or acute abdomen
• history of fibrosing colonopathy
• history of distal ileal obstruction without surgery
• solid organ transplant or surgery affecting the large bowel, other than appendectomy