From THE DEPARTMENT OF CLINICAL SCIENCE AND EDUCATION, SÖDERSJUKHUSET Karolinska Institutet, Stockholm, Sweden DIAGNOSTICS AND TREATMENT OF NUT AND PEANUT ALLERGY Josef Brandström Stockholm 2018 All previously published papers were reproduced with permission from the publisher. Published by Karolinska Institutet. Cover image by Martin Ask Printed by Eprint AB 2018 © Josef Brandström, 2018 ISBN 978-91-7831-007-4 Diagnostics and treatment of nut and peanut allergy THESIS FOR DOCTORAL DEGREE (Ph.D.) By Josef Brandström Principal supervisor: Opponent: Docent Caroline Nilsson Med.dr. Anna Kaarina Kukkonen Karolinska Institutet Helsinki University Institutionen för klinisk forskning och utbildning, Skin and Allergy Hospital Södersjukhuset Co-supervisor(s): Examination board: Docent Anna Nopp Docent Guro Gafvelin Karolinska Institutet Karolinska Institutet Institutionen för klinisk forskning och utbildning, Institutionen för Medicin, Solna Södersjukhuset Enheten för immunologi och allergi Docent Gunnar Lilja Professor Göran Wennergren Karolinska Institutet Göteborgs Universitet Institutionen för klinisk forskning och utbildning, Institutionen för kliniska vetenskaper Södersjukhuset Avdelningen för pediatrik Med.dr. Mirja Vetander Docent Anders Åhlin Karolinska Institutet Karolinska Institutet Institutionen för miljömedicin Institutionen för klinisk forskning och utbildning, Södersjukhuset ABSTRACT Background: The prevalence of allergy to foods has increased over the last decades and among children in Europe as many as 8 % have an allergy to one or more types of food. However, many children have received an incorrect diagnosis of food allergy due to shortcomings of available diagnostic tests, especially in the case of suspected allergy to nuts or peanuts. Newer diagnostic tools, like component-resolved diagnostics (CRD) and basophil activation test (BAT), e.g., basophil allergen threshold sensitivity (CD-sens), have shown an improved diagnostic accuracy compared with older tests. The most severe acute manifestation of allergy, the anaphylactic allergic reaction, is most commonly caused by an allergy to peanut or nuts, and there have been no treatments available that might change the course of the disease. While disease-modifying allergen immunotherapy has for decades been offered as routine practice for the treatment of pollen or house dust mite allergy, severely food-allergic patients have had to settle for strict elimination diets and use of emergency medication in case of accidental intake. During the past decade, oral immunotherapy (OIT) has emerged as a potential disease-modifying treatment for food allergies, but OIT needs to be refined before it can become widely implemented. Major limitations of OIT have been frequent allergic reactions and that patients with a more severe allergy have a less favorable treatment outcome. The anti-IgE antibody omalizumab has been shown to increase the tolerated amount of food allergen among food-allergic patients (as long as the treatment continues) and facilitate initiation of immunotherapy in patients with severe allergies. Objectives: Hazelnut study: To evaluate the new diagnostic tests CRD and CD-sens in children with a suspected hazelnut allergy. FASTX study (Food Allergen Suppression Therapy with Xolair®): To evaluate safety and efficacy of oral immunotherapy with adjuvant omalizumab in severely peanut- allergic patients. Methods: In the study of diagnostic tests for hazelnut allergy, we used CRD to measure IgE antibody (ab) levels to the hazelnut components Cor a 1, Cor a 8, Cor a 9 and Cor a 14 in 40 children with a doctor’s diagnosis of suspected hazelnut allergy. We also assessed basophil allergen threshold sensitivity (CD-sens) to hazelnut and CRD to hazelnut components and compared the concordance of these tests to double-blind placebo-controlled food challenge (DBPCFC). In the FASTX study, open- label omalizumab was given to 23 severely peanut-allergic adolescents, with the aim of increasing the amount of peanut they could safely ingest so that OIT could be safely initiated. Omalizumab doses were titrated until CD-sens analyses indicated a very low reactivity to peanut allergen stimulation. Thereafter, an open peanut challenge was performed, assessing the tolerated peanut dose while on omalizumab, and peanut OIT was started the following day. After reaching the maintenance dose of 10 g of peanuts, the protective omalizumab treatment was phased out with guidance from CD-sens and the clinical picture. Results: DBPCFC revealed that only 8/40 of the patients with a suspected hazelnut allergy were allergic to hazelnuts. The diagnostic accuracy of the new diagnostic tests, CD-sens and IgE-ab to Cor a 9 and Cor 14, were far superior to the previously available tests (IgE-ab to hazelnut, Cor a 1 and Cor a 8). IgE-abs to Cor a 9 and Cor a 14 were present in all hazelnut-allergic patients; for Cor a 9 the median IgE-ab level was 4.5 kU /l (range 0.7–97.5) among hazelnut-allergic children, compared with A 0.1 kU /l (range < 0.10–36.2) (P < 0.01) in the hazelnut-tolerant group. The levels of IgE-ab to Cor a A 14 were 5.6 kU /l (0.9–78.7) for the hazelnut-allergic group and 0.04 kU /l (< 0.10–13.9) in the A A hazelnut-tolerant group (P < 0.001). Median CD-sens among allergic patients was 8.9 compared with 0.05 in tolerant patients (P = 0.05). The diagnostic accuracy of CD-sens to hazelnut was maintained in subgroup-analyses where patients without IgE-ab to Cor a 9 or Cor a 14 > 0.35 kU /l were excluded from analyses. A After omalizumab treatment, all 23 patients passed a peanut challenge of > 3 g of peanuts (median 10 g) and were started on OIT the following day. Among the 14 patients who went through a peanut challenge prior to enrollment, the tolerated dose increased at least 50-fold (median). However, 15/23 patients needed an increased omalizumab dose in order to accomplish a suppression of CD-sens. All 23 patients successfully reached the 10 g maintenance dose. After a median of 23 months of OIT, 11/23 (48 %) of the study subjects had been able to discontinue omalizumab while continuing and tolerating OIT and thereafter passing an open peanut challenge. Systemic reactions (n = 43) occurred with a frequency of 0.3 % of OIT doses and adrenaline was administered after 0.1 % of the doses. We found that successfully treated patients had significantly lower baseline CD-sens and lower IgE-ab to peanut and peanut components Ara h 1, Ara h 2 and Ara h 3 compared with patients unable to discontinue the protective omalizumab treatment. OIT induced an increase of IgG4-ab to peanut, Ara h 2 and Ara h 6 that was significantly higher in successfully treated patients. A substantial proportion, 6/23 (26 %) of the patients dropped out of the study, mainly due to fear of allergic reactions and an abomination for the taste of peanuts. Conclusions: CD-sens to hazelnut and component-resolved diagnostics can improve the accuracy when diagnosing hazelnut allergy in pediatric patients. CD-sens may further improve the diagnostic accuracy in cases when the diagnostic work-up using CRD has been inconclusive. The anti-IgE-ab omalizumab can efficiently increase the tolerated peanut dose, which in turn allows for a safer practice of peanut oral immunotherapy in severely allergic patients. Peanut oral immunotherapy induces an increased tolerance to peanuts; the increased tolerance is at least partially explained by the production of protective allergen-specific antibodies of IgG4-subtype. Despite the increased tolerance, allergic reactions continuously occur during pOIT. We need to find ways to minimize this major limitation before OIT can be widely implemented; development of hypoallergenic OIT preparations, use of immune stimulatory adjuvants and improved patient selection might help in accomplishing a safer and more effective treatment. LIST OF SCIENTIFIC PAPERS I. Brandstrom J, Nopp A, Johansson SG, Lilja G, Sundqvist AC, Borres MP, Nilsson C, Basophil allergen threshold sensitivity and component-resolved diagnostics improve hazelnut allergy diagnosis. Clinical and Experimental Allergy: Journal of the British Society for Allergy and Clinical Immunology 2015;45: 1412-8. II. Brandstrom J, Vetander M, Lilja G, Johansson SG, Sundqvist AC, Kalm F, Nilsson C, Nopp A, Individually dosed omalizumab: an effective treatment for severe peanut allergy. Clinical and Experimental Allergy: Journal of the British Society for Allergy and Clinical Immunology 2016. III. Brandström J, Vetander M, Sundqvist A-C, Lilja G, Johansson S.G.O., Melén E, Sverremark Ekström E, Nopp A, Nilsson C. Individually dosed omalizumab enables peanut oral immunotherapy in severely peanut allergic adolescents. Submitted CONTENTS 1 Introduction ..................................................................................................................... 1 2 Background...................................................................................................................... 3 2.1 Food allergy ........................................................................................................... 3 2.1.1 Definition ................................................................................................... 3 2.1.2 Classification of food allergy .................................................................... 3 2.1.3 Epidemiology ............................................................................................ 3 2.1.4 Pathophysiology ........................................................................................ 4 2.1.5 The IgE-mediated allergic reaction .......................................................... 4 2.1.6 Allergens and cross-reactivity .................................................................. 5 2.2 Nut and peanut allergy diagnostics ....................................................................... 5 2.2.1 Skin prick test ............................................................................................ 6 2.2.2 Allergen-specific IgE-abs ......................................................................... 6 2.2.3 Component-resolved diagnostics (CRD) ................................................. 6 2.2.4 Oral food challenge (OFC) ....................................................................... 7 2.3 Basophil activation test ......................................................................................... 7 2.3.1 CD-sens ..................................................................................................... 8 2.3.2 Allergen-binding activity (ABA) .............................................................. 8 2.3.3 Clinical implications for CD-sens ............................................................ 9 2.3.4 Summary of nut and peanut allergy diagnostics ...................................... 9 2.4 Treatment of food allergy .................................................................................... 10 2.4.1 Allergen immunotherapy ........................................................................ 10 2.4.2 Sub-cutaneous immunotherapy .............................................................. 10 2.4.3 Oral immunotherapy ............................................................................... 10 2.4.4 Sub-lingual immunotherapy ................................................................... 11 2.4.5 Epicutaneous immunotherapy ................................................................ 12 2.4.6 Omalizumab ............................................................................................ 12 2.4.7 Omalizumab and food allergy ................................................................ 12 2.4.8 OIT with adjuvant omalizumab .............................................................. 13 2.5 Immunologic effects in allergen immunotherapy .............................................. 13 2.5.1 Effects on antibodies ............................................................................... 14 2.5.2 Effects on B and T cells .......................................................................... 15 3 Aims ............................................................................................................................... 17 4 Methods ......................................................................................................................... 19 4.1 Study populations ................................................................................................ 19 4.1.1 The Hazelnut study (Paper 1) ................................................................. 19 4.1.2 The FASTX study (Papers 2 and 3) ....................................................... 19 4.2 Study designs ....................................................................................................... 19 4.2.1 Hazelnut study ......................................................................................... 19 4.2.2 FASTX study .......................................................................................... 20 4.3 Procedures ........................................................................................................... 21 4.3.1 Food challenges ....................................................................................... 21 4.3.2 CD-sens ................................................................................................... 22 4.3.3 IgE and IgG/G4 analysis ......................................................................... 22 4.3.4 Skin prick test and conjunctival provocation (FASTX study) ............... 23 4.4 Data collection and statistics ............................................................................... 23 4.4.1 Data collection ......................................................................................... 23 4.4.2 Statistical analysis ................................................................................... 24 4.5 Ethics and registration ......................................................................................... 24 5 Results ............................................................................................................................ 25 5.1 Food challenges (papers 1-3) .............................................................................. 25 5.2 Diagnostic markers for hazelnut allergy (Paper 1) ............................................. 26 5.2.1 IgE-abs to hazelnut and hazelnut components ....................................... 26 5.2.2 CD-sens ................................................................................................... 27 5.3 FASTX (papers 2 and 3) ..................................................................................... 28 5.3.1 Dosage of omalizumab ........................................................................... 28 5.3.2 Who needs an increased omalizumab dose? .......................................... 29 5.4 Peanut oral immunotherapy (pOIT) .................................................................... 29 5.4.1 Adverse events ........................................................................................ 30 5.4.2 Drop-outs ................................................................................................. 31 5.5 Immunology ......................................................................................................... 32 5.5.1 Predictors of outcome ............................................................................. 32 5.5.2 Immunological changes .......................................................................... 32 5.6 Unpublished data ................................................................................................. 33 5.6.1 Subgroup analysis of CD-sens in hazelnut diagnostics study ................ 33 5.6.2 CD-sens in relation to adverse events ..................................................... 33 5.6.3 Long-term pOIT without omalizumab ................................................... 33 6 Discussion ...................................................................................................................... 35 6.1 Hazelnut allergy diagnostics study ..................................................................... 35 6.1.1 CD-sens to hazelnut ................................................................................ 35 6.1.2 Strengths and limitations ......................................................................... 36 6.1.3 Clinical implications ............................................................................... 36 6.2 Peanut oral immunotherapy combined with omalizumab .................................. 36 6.2.1 OIT vs. traditional AI (for allergies to pollen, pet, house dust mite etc.) .......................................................................................................... 37 6.2.2 Oral immunotherapy; does it work? Is it worth it? ................................ 38 6.3 OIT in a near future ............................................................................................. 39 6.3.1 Important questions in OIT ..................................................................... 39 6.3.2 Improving OIT ........................................................................................ 39 7 Ethical considerations ................................................................................................... 41 8 Conclusions ................................................................................................................... 43 9 Sammanfattning på svenska .......................................................................................... 44 10 Acknowledgements ....................................................................................................... 47 11 References ..................................................................................................................... 49