Optimizing treatment adherence and supporting ongoing desensitization following peanut oral immunotherapy in children: a randomized controlled trial of daily versus weekly peanut ingestion

Chief Investigator: Dr Billy Tao

Funding Amount: $74,843

Recipient: Flinders University

Overview:

Peanut allergy represents a significant health and psychological burden to children and their families. Ongoing ingestion of peanuts is necessary for the maintenance of protection after desensitization. While published data show poor adherence to regular peanut ingestion, these studies fail to provide insight on either the reason, or solution, to this important problem. We have pioneered a safe and effective sequential boiled-to-roasted peanut community-based desensitization method. Desensitized children will be followed in a world first prospective project evaluating whether weekly ingestion of peanuts is as effective as daily ingestion in maintaining desensitization, and exploring other factors influencing treatment adherence.


Research Outcomes:

Researchers: Dr Billy Tao, Dr Sarah Cohen-Woods, Dr Luke Grzeskowiak, Dr Scott Morris, Dr Tim Chataway

Research Completed: 2021

Research Findings:

We investigated optimal maintenance strategy and participants’ mental health 12-months after successful peanut oral immunotherapy. Subjects were randomized to eating peanuts either weekly or daily.

12 subjects participated in the RCT arm before COVID-19 disrupted enrolment. Another 26 subjects participated in an on-line psychosocial questionnaire study. Either daily or weekly ingestion represents viable ongoing maintenance strategy but adverse event and mental health data suggested that small-dose daily maintenance was preferable to once-weekly ingestion.

Key Outcomes:

Background and patient participation:

Peanut allergy affects 3% of Australian children, and peanut oral immunotherapy (POIT) is currently the most effective desensitization method in research. In a previous Channel 7 Children’s Research Foundation-funded study called HYPES, we demonstrated that a primarily home-based POIT method (requiring only 3 office visits), starting with hypoallergenic boiled peanuts, was both safe and effective. This study investigated the optimal maintenance strategy and participants’ mental health status 12 months after desensitization.

Forty-five of original 56 (80%) fully desensitized HYPES participants were contacted after successful funding and Ethics approvals. 43/45 (96%) reported ongoing maintenance at time of contact. 8/45 subjects had experienced either at least one AEs, or one accidental ingestion, post-HYPES. All reactions were mild, requiring either no treatment or just oral antihistamine, and never adrenaline. Subjects were then invited to participate in a randomized controlled trial (RCT), either eating 2 peanuts daily or 14 peanuts once a week.

12 subjects had agreed to participate in the RCT, but further enrolment was disrupted by COVID-19 outbreak and subsequent state-wide lockdown. Many potential participants eventually decided to opt out of formal randomization and instead just answer the psychological questionnaires on line, forming an observation arm of the study.

So, at the end of the enrolment period, 38/45 (84%) had consented to participate in the study but, among them, only 12 (27%) were in the RCT arm and the remaining 26 (73%) in the Observation arm.

RCT arm outcome:

A.        Overall results: All 12 participants completed the 12-month maintenance period, and passed an exit OFC (eating 12 roasted peanuts). Initial randomization distribution was 6:6, but at the end one case of weekly ingestion was forced to change to daily ingestion due to unacceptable AE occurrence, resulting in a final distribution of 7 participants ingesting 2-peanuts daily and five 14-peanuts weekly. No statistically significant difference was found in sequential skin prick test results between the two groups.

B.        AE results: In the daily group, no subject had experienced any AE during the whole study. In the weekly group, 2/6 subjects had experienced AEs, both more than once. The first subject recorded four AEs during a 3-month transition period from daily to weekly ingestion, but zero AE once the transition was completed. The second subject experienced 15 AEs in total, one during transition and 14 after the transition period. Due to this frequent occurrence of AE, his parents wanted to change to daily ingestion and the request was granted. There had been no further AE and the participant successfully passed a 12-peanut OFC on time.

C.        Mental health: We found that participants in the weekly group had higher stress scores compared with daily group, and the difference was statistically significant. This suggested that consuming a larger dose of peanuts once a week could be psychologically more distressing than small, regular daily consumption of peanuts.

Although participants in the weekly group also had greater mean scores on Emotional Impact and Allergy Avoidance compared to daily group, the result could not reach statistical significance due to small sample size.

We are currently designing non-parametric methods to investigate data from the Observation arm.

Conclusion:

Either daily or weekly ingestion represents viable ongoing maintenance strategy in terms of OFC results, but AE and mental health data suggested that small-dose daily maintenance was preferable to once-per-week ingestion.

Research Papers: A manuscript is in preparation for eventual publication in a peer‐reviewed journal.

Related Publications:

Future Outcomes:

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