This study is designed as multicentric, interventional, with two successive randomised, double-blind, crossovers. The aim of the study is to demonstrate the tolerance of an extensively hydrolysed anti-regurgitation casein-based formula in infants with cow's milk protein allergy. After a confirmation of the diagnostic, this demonstration will be performed with oral food challenge. Secondarily, a long term tolerance phase will be performed to get growth outcomes with a consumption of the formula compared with a non-enriched formula.

Inclusion Criteria:

I1. Age ≥ 1 month and < 9 months, I2. Exclusively formula fed and planning to be formula-fed for the duration of the study (food diversification allowed),

I3. With:

1. a suspicion of CMPA based on suggestive allergic symptoms

   • CoMISS score > 10
   • And/or acute allergic symptoms
   • And/or symptoms suggestive of a Food Protein-Induced Enterocolitis Syndrome (FPIES) (major criteria and <3 minor criteria as per consensus guidelines) (Nowak-Węgrzyn et al. 2017; Beaudoin et al. 2025); OR

2. a confirmed diagnosis of CMPA within the two months before inclusion:

   • IgE-mediated CMPA (documented history of allergic reaction grade ≤ 3 according to the ordinal food allergy severity score oFASS-5 (Fernández-Rivas et al. 2022) following milk protein ingestion, and sensitization to CMP: blood IgE level specific to cow milk≥ 5 kU/L, or positive skin prick test with papule with fresh cow's milk ≥ 8 mm
   • or non-IgE-mediated CMPA (documented history of eviction/reintroduction test concluding to CMPA),
   • or FPIES (major criteria and ≥3 minor criteria as per consensus guidelines (Nowak-Węgrzyn et al. 2017; Beaudoin et al. 2025), I4. With a written informed consent signed by the father and mother or legal representative(s), I5. With parents willing to complete questionnaires, records, and diaries associated to the study and to complete all clinical visits, I6. With parents willing to achieve all study interventions, I7. At least one of the legal representatives is affiliated with a social security scheme.

Exclusion Criteria:

E1. Birthweight < 2500 g, E2. Gestational age < 37 weeks, E3. Breastfeeding at the time of inclusion and throughout the study period, E4. Already fed with an AAF, or with the investigational formula EHF-AR, E5. History of anaphylactic reaction grade 4 or 5 according to classification oFASS-5 (Fernández-Rivas et al. 2022), or of severe FPIES (previous reaction with any change in behaviour from baseline, any pallor and dehydration requiring intravenous fluids), after mammalian milk exposure, E6. Diagnosed or reported fever and/or infectious diseases, or current systemic infections, or history of congenital infections,

E7. History / diagnosis of:

1. GI disease or abnormalities (i.e. short bowel syndrome, chronic intestinal diseases, or GI malformations),
2. Or Other malformations, congenital cardiovascular, kidney, liver, pancreas, metabolic or neurological diseases,
3. Or Immunodeficiency, or chronic infection requiring long-term treatment,
4. Or Genetic diseases and chromosomal abnormalities, E8. Suspected or confirmed food allergies or intolerances, other than CMPA, E9. Currently enrolled in another clinical study, or in exclusion period from a previous clinical study, E10. Whose legal representatives have psychological or linguistic incapability to sign the informed consent, E11. Impossibility to contact the legal representatives in case of emergency.

After V1, the participant will be excluded from participation in this trial if he/she fulfils the following criteria:

E12. No allergic symptoms following the OFC with a standard CMPF.