Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to the rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

The short-term safety of ZENPEP was assessed in two clinical trials conducted in 53 patients, ages 1 to 23 years, with exocrine pancreatic insufficiency (EPI) due to CF. In both studies, ZENPEP was administered in doses of approximately 5,000 lipase units per kilogram per day, for lengths of treatment ranging from 19 to 42 days. The population was nearly evenly distributed in gender, and approximately 96% of patients were Caucasian.

Study 1 was a randomized, double-blind, placebo-controlled, 2-treatment, crossover study of 34 patients, ages 7 to 23 years, with EPI due to CF. In this study, patients were randomized to receive ZENPEP at individually titrated doses (not to exceed 2,500 lipase units per kilogram per meal) or matching placebo for 6 to 7 days of treatment, followed by crossover to the alternate treatment for an additional 6 to 7 days. The mean exposure to ZENPEP during this study, including titration period and open label transition, was 30 days.

The incidence of adverse events (regardless of causality) was similar during double blind ZENPEP treatment (56%) and placebo treatment (50%). The most common adverse events reported during the study were gastrointestinal complaints, which were reported more commonly during placebo treatment (41%) than during ZENPEP treatment (32%), and headache, which was reported more commonly during ZENPEP treatment (15%) than during placebo treatment (0). The type and incidence of adverse events were similar in children (7-11 years), adolescents (12-16 years), and adults (greater than 18 years).

Because clinical trials are conducted under controlled conditions, the observed adverse event rates may not reflect the rates observed in clinical practice.

Table 1 enumerates treatment-emergent adverse events that occurred in at least 2 patients (greater than or equal to 6%) treated with either ZENPEP or placebo in Study 1. Adverse events were classified by Medical Dictionary for Regulatory Activities (MedDRA) terminology.

Table 1: Treatment-Emergent Adverse Events Occurring in at least 2 Patients (greater than or equal to 6%) During Treatment Period and Crossover Treatment Period of the Placebo-Controlled, Crossover Clinical Study of ZENPEP (Study 1)

Study 2 was an open-label, uncontrolled study of 19 patients, ages 1 to 6 years, with EPI due to CF. After a 4-14 days screening period on the current PEP, patients in Study 2 received ZENPEP at individually titrated doses ranging between 2,300 and 10,000 lipase units per kg body weight per day, with a mean of approximately 5000 lipase units per kg body weight per day (not to exceed 2,500 lipase units per kilogram per meal) for 14 days. There was no comparator treatment, and adverse events were collected on patient diary entries and at each study visit.

The most commonly reported adverse events were gastrointestinal, including abdominal pain and steatorrhea, and were similar in type and frequency to those reported in the double-blind, placebo-controlled trial (Study 1).