775:
Peanut Oral Immunotherapy Threshold Dose for Reactivity: What is the Upper Limit?
Monday, March 5, 2018
South Hall A2 (Convention Center)
Carla M. Davis, MD FAAAAI, Aikaterini Anagnostou, MD MSc PhD, Sridevi Devaraj, PhD, Daisy Tran, RN, Avina Nguyen, B.S., Kathy Pitts, RN, Charles Minard, PhD, Danielle Guffey, MS, Jordan S Orange, MD PhD FAAAAI, Sara Anvari, MD, MSc
RATIONALE: Previous peanut oral immunotherapy (POIT) trials have examined the efficacy of treatment through assessment of the proportion of subjects successfully completing a double blind placebo controlled food challenge (DBPCFC) with up to a cumulative dose of 5000 mg of peanut protein after 3900 mg maintenance dosing. The upper threshold for clinical reactivity after POIT has not been determined.

METHODS: A single center pilot clinical trial of POIT with peanut allergic subjects was performed with a build-up phase to a daily maintenance dose of 3900 mg of peanut protein or highest tolerated dose, over ~48 weeks. Skin prick testing (SPT) was performed at baseline and at maintenance. The upper threshold dose of clinical reactivity was measured with DBPCFC to a cumulative dose of 26,225 mg. A general linear mixed model was used to compare mean challenge reaction doses at baseline versus 1 year.

RESULTS: Of 15 treated subjects, 10 (67%) subjects advanced to maintenance dosing with 9 on 3900 mg daily. Of nine subjects, 8 (89%) reacted to >10,725 mg and 4 (44%) to >15,225 mg (6,725-26,225 mg). The mean cumulative reaction dose at baseline was 149 mg compared with 14,038 mg at maintenance. The mean cumulative reaction dose increased by 13,889 mg (P=0.0001). Median peanut SPT wheal size decreased from 18 to 4 mm (p=0.002).

CONCLUSIONS: POIT with 3900 mg regular maintenance dosing induced clinical desensitization to doses as high as 2-6 times the daily dose amount. The upper threshold dose of clinical reactivity following POIT can be significantly higher than maintenance dosing.