(P27-038-25) Infant Formula With a Synbiotic Blend of Human Milk Oligosaccharides, Bovine Milk Oligosaccharides, and B. infantis Supports Age-Appropriate Growth and is Well Tolerated

Objectives: Infant formulas supplemented with human milk oligosaccharides (HMOs), bovine milk oligosaccharides (MOS), and B. infantis may promote health benefits in formula-fed infants. This randomized, double-blind, controlled trial (NCT06073652) evaluated growth, gastrointestinal (GI) tolerance, and blood and fecal markers of immune development and gut health in healthy infants fed a new synbiotic-supplemented starter formula.

Methods: Infants aged ≥14 days (d) to ≤35d and exclusively formula-fed (n=240) were randomized to receive control (CF; cow’s milk-based alpha-lactalbumin-enriched formula) or experimental formula (EF; same formula with 2.64 g/L added HMOs (2’-FL, 3-FL, DFL, 3’-SL, 6’-SL, LNnT, LNT), 4.56 g/L MOS, and 1x10⁶ CFU/g B. infantis (EF). The primary outcome was weight gain velocity from baseline to 4 months (mo) in EF vs. CF (noninferiority margin –3g/d). Secondary endpoints included other growth measures, GI tolerance evaluated using a diary to assess stool frequency and consistency (5-point scale; 1=watery, 5=hard) and the validated Infant Gastrointestinal Symptom Questionnaire (IGSQ; range 13-65; lower scores indicate fewer GI symptoms). Blood and fecal biomarker/microbiome results will be reported separately.

Results: Weight gain velocity was non-inferior in EF vs. CF-fed infants. In the per-protocol set, the estimated mean difference in weight gain between EF (n=107; mean±SD 28.4±6.5 g/d) and CF-fed infants (n=110; 27.4±6.4 g/d) was 1.01 g/d (95%CI: -0.67, 2.68; p-value for noninferiority < 0.001). There were no significant differences in weight-for-age, length-for-age, weight-for-length, or head circumference-for-age z-scores between groups at any time point. Mean IGSQ scores were low (≤18.0) in both groups at all time points, indicating good GI tolerance, while stools were generally softer (1.8 vs. 2.0 at 1.5, 2 and 4mo, p≤0.0013) and slightly more frequent (~2 vs. ~1.5 stools/d after 2 mo, p≤0.0457) in EF vs. CF-fed infants. AE incidence was similar in both groups (51.4% and 53.5% in EF and CF, respectively). Only 8 SAEs were reported (4 events in 4 infants per group).

Conclusions: A new infant formula supplemented with a synbiotic blend of HMOs, MOS, and B. infantis supports healthy, age-appropriate growth and is well tolerated. Softer stools were observed after only ~19 days of feeding.

Funding Sources: Société des Produits Nestlé SA