Tolerability of a new amino acid-based formula for children with IgE-mediated cow’s milk allergy

This prospective trial was conducted from March 2019 to March 2020 on patients aged 1–36 months with sure diagnosis of IgE-mediated CMA consecutively observed at tertiary centre for paediatric allergy.

The study protocol, the subject information sheet, the informed consent form, and the clinical chart were reviewed and approved by the Ethics Committee of the University of Naples Federico II. The study was conducted in accordance with the Helsinki Declaration (Fortaleza revision 2013), the Good Clinical Practice Standards (CPMP/ICH/135/95), and the current Decree-Law 196/2003 regarding personal data and all the requirements set out in the European regulations on this subject. The study was registered in the ClinicalTrials.gov Protocol Registration System with the ID number NCT03909113.

At baseline, after obtaining informed consent from the parents/tutors of each subject, the clinical status of the patients was carefully assessed by a multidisciplinary team composed of paediatricians, paediatric allergists, paediatric nurses, and dietitians to exclude those with concomitant comorbidities. Infectious diseases or other conditions were ruled out by means of a complete physical examination, including vital signs, neurological status, body growth pattern, nutritional status, hydration, skin evaluation, otoscopy, evaluation of oral cavity, respiratory/abdomen/lymph node examination. At enrolment, anamnestic, demographic, anthropometric, and clinical data (including data related to CMA), as well as information on sociodemographic factors, were obtained from the parents of each child, collected in a specific clinical chart, and entered into the study database.

Then, a skin prick test (SPT) with the new AAF was performed. Briefly, the skin prick test was performed with the new AAF reconstituted according to the manufacturer’s instructions. The new AAF was applied to the patient’s volar forearm. Skin prick tests were performed using a 1-mm single peak lancet (ALK, Copenhagen, Denmark) with histamine dihydrochloride (10 mg/ml) and an isotonic saline solution (NaCl 0.9%) as positive and negative controls, respectively. Reactions were recorded on the basis of the largest diameter (in millimetres) of the wheal-and-flare reaction at 15 min. The SPT result was considered “positive” if the wheal was 3 mm or larger, without reaction to the negative control.

Subsequently, the patients underwent the DBPCFC with the new AAF or the placebo formula (namely, the formula previously given to the child as part of the child’s successful elimination diet before study inclusion) introduced in a random order, as previously described [23].

We created a computer-generated randomization list of participant numbers indicating the order in which each study formula was used in the oral food challenge (OFC). Randomization and preparation of the challenges were performed by an independent dietician not directly involved in the study and in the patient’s care. In addition, bottles were covered by a paper sheet so that they were not distinguishable. The investigator, the nursing staff, and the family were therefore not informed of what formula the child was being fed.

Before each OFC day, the investigator ensured that the child did not present any clinical abnormalities and had stopped all medications, including anti-histamines, that could have interfered with the administration of the OFC. Subjects were eating nothing for 1 h with allowance for light meals 2 h prior to each session of OFC.

Briefly, every 20 min, successive doses (0.5, 1, 3, 10, 30, 50 and 100 mL) were administered in a blinded manner under medical supervision. The infants were observed for 2 h after the final dose and then discharged. In the case of a positive OFC, at any testing dose, the patient was treated as deemed necessary by the investigator and remained under observation until symptom resolution.

If patients did not show any symptoms within the first 24 h, to assess long-term tolerance and reveal any false-negative results to the challenges, parents administered one single top dose (about 200 ml) of the tested formula (new AAF or placebo) to the patients every day at home for 7 days (7-day home feeding period), and parents were instructed not to introduce any new foods. In addition, an emergency treatment plan and prescriptions for emergency medications were provided to the parents. If any symptoms occurred during this period, the subjects returned to the outpatient clinic on the same day. During the 7-d home feeding period, parents were invited to record daily the following: the total amount of formula ingested by the subject; the types of foods eaten; the presence and severity of vomiting, diarrhoea, rash, runny nose, wheezing, or any other symptoms (rated as mild, moderate, or excessive); the number of bowel movements and stool colour, consistency and odour; any adverse or serious adverse events; and the formula acceptability by their child, from very unsatisfied to very satisfied. After a 7-day home feeding period of the new AAF or placebo administration, the patients were examined, and the parents were interviewed at the centre. To rule out a false-negative challenge result, parents contacted the centre if any symptoms occurred in the following 7 days after the OFC procedures. The challenge was considered negative if the patient tolerated the entire challenge, including the observation period.

All objective and subjective symptoms were assessed simultaneously by experienced paediatric allergists and were registered using a standardized symptom score [23, 24] (Supplementary Table 1).

The new AAF was provided by the study sponsor and was reconstituted according to the manufacturer’s instructions. The composition of the new AAF is described in Table 1.

All study procedures and assessments were performed as shown in Fig. 1.

The primary study outcome was the evaluation of the hypoallergenicity of the new AAF paediatric patients with IgE-mediated CMA.