High- versus low-lipase acid-resistant enzyme preparations in cystic fibrosis: a crossover randomized clinical trial.

High-strength pancreatic enzyme preparations have recently come into widespread use in some countries for treatment of pancreatic insufficiency in cystic fibrosis. However, the therapeutic equivalence of these preparations to the standard acid-resistant microsphere preparations, under the same lipase dosage, has not been demonstrated by appropriate clinical trials; they are also considered responsible for severe colonic stricture. In a randomized crossover study, 20 adolescent or adult cystic fibrosis patients were treated in hospital with both low-lipase (A) and high-lipase (B) enteric-coated microsphere preparations. The fat excretion coefficient, evaluated over two 72-h fat balance periods (measured fat intake, 1.43 to 3 g/kg/day according to age), was the main response variable, secondary variables being stool wet and dry weight, fecal nitrogen output, and energy loss. With both preparations, patients were given a daily dose of 1,500-2,000 lipase BP U/g fat ingested, distributed across four meals. The low-strength preparation was divided into three doses during each meal, while the high-strength preparation was taken as a single dose in the middle of each meal. The considerable variability of results did not provide conclusive evidence of equivalence or significant differences between the two preparations in terms of steatorrhea and other variables. However, mean differences between the two treatments and their 95% confidence intervals showed less satisfactory results with the high-lipase preparation. A high-strength preparation is thought to release relatively less enzyme activity in the small intestine, forcing patients to increase their dosage and possibly creating a dangerous enzyme hyperconcentration in the large intestine. For this reason, the occasional occurrence of colonic stricture should be borne in mind, as must the possible scope for division of dosage during each meal.