The Penguin Study: A Randomised, Double-Blinded, Equivalence Trial on the Safety and Suitability of an Infant Formula with Partially Hydrolysed 100% Whey Protein.

Background/Objectives: This study aimed to demonstrate the safety and suitability of an infant formula manufactured from partially hydrolysed whey protein (PHF) compared to standard formula manufactured from intact cow's milk proteins (IPF; whey-casein ratio, 60:40) in healthy term infants. Methods: This multicentre, randomised, double-blinded, placebo-controlled trial included infants of mothers who intended to exclusively formula feed. Infants ≤ 28 days of age received PHF or IPF for at least 90 and up to 180 days. A group of exclusively breastfed infants was included for reference. The safety evaluation consisted of an equivalence analysis of weight gain within +/-3 g/d after 90 days, further growth parameters, and adverse events. Results: Of the 249 infants randomised, 143 (76 IPF; 67 PHF), as well as 45 breastfed infants, completed the study per protocol. The mean difference in daily weight gain between the formula groups was within the equivalence margins (-2.4 g/d (95% CI 0.3-4.5)) with estimated means (SEM) of 34.9 (0.78) g/d (IPF) and 32.5 (0.76) g/d (PHF). No significant differences in weight gain, length, and head circumference or in the number, severity, or type of adverse events were observed. Comparable growth patterns were observed in the breastfed group. Conclusions: The PHF is safe and supports adequate infant growth with a daily weight gain non-inferior to a standard IPF.