3-4OAS Two Year Follow-up after Rush Oral Immunotherapy for Peanut-Induced Anaphylaxis

Wednesday, 14 October 2015: 16:15 - 16:30
Room R1 ABC (Floor 3) (Coex Convention Center)

Kenichi Nagakura, MD , Pediatrics, Sagamihara National Hospital, Sagamihara, Japan

Sakura Sato, MD , Clinical Research Center for Allergy and Rheumatology, Sagamihara National Hospital, Sagamihara, Japan

Noriyuki Yanagida, MD , Pediatrics, Sagamihara National Hospital, Sagamihara, Japan

Makoto Nisihino, MD , Pediatrics, Sagamihara National Hospital, Sagamihara, Japan

Tomoyuki Asaumi, MD , Pediatrics, Sagamihara National Hospital, Sagamihara, Japan

Kiyotake Ogura, MD , Pediatrics, Sagamihara National Hospital, Sagamihara, Japan

Motohiro Ebisawa, MD, PhD , Clinical Research Center for Allergy and Rheumatology, Sagamihara National Hospital, Sagamihara, Japan

<Objective>The purpose of this study is to examine the efficacy and safety of rush oral immunotherapy (ROIT) to induce desensitization and tolerance for peanut anaphylaxis.
<Methods>We enrolled 25 peanut anaphylactic patients who underwent ROIT between 2011 and 2013. After ROIT in admission, they gradually increased ingestion of peanut powder up to 3 g/day at home. Thereafter they took maintenance dose daily. Premedication (antihistamine and leukotriene antagonist) was withdrawn, when they were able to consume 3g of peanut without symptoms (desensitization). When no symptoms were seen for 3 months, they underwent an oral food challenge (OFC) after 2 weeks of peanut avoidance to confirm unresponsiveness. If the result of 3g OFC was negative, they further received a 10g OFC 1 year later.
<Results>We analyzed 23 subjects (median age 8.6 y) whose treatment period exceeded 2 y after ROIT. All of them had a history of anaphylaxis to peanut. Nine of them had a history of anaphylactic shock to peanut. Prior to ROIT, median threshold eliciting initial symptoms and anaphylaxis was 125 mg and 875 mg, respectively. Median peanut specific IgE was 37.7 kUa/L and median Ara h 2 specific IgE 36.3 kUa/L. All of the subjects reached desensitization by 8 months after ROIT. Nine (39%) were confirmed to have achieved unresponsiveness within 1 y, 15 (65%) at 2 y and 3 subjects passed the 10 g OFC. Peanut specific IgE decreased gradually to 18.2 kUa/L at 1 y after ROIT and 12.4 kUa/L at 2 y. Ara h 2 specific IgE decreased gradually to 16.1 kUa/L at 1 y and 7.5 kUa/L at 2 y. Adverse reaction rate per ingestion during admission was 43% and that of any home dose was 5%. Three subjects received adrenaline during ROIT in admission and 2 subjects during maintenance at home. After confirmed unresponsiveness, 4 subjects developed mild adverse reactions due to 3 g of peanut intake. <Conclusion>ROIT for peanut anaphylaxis increased the threshold and induced desensitization. Even after achieving unresponsiveness, careful long term observation would be still necessary from our experience.