Cockroach allergen standardization

1. Cockroach allergen standardization

2. Cockroaches

3. Cockroach allergen standardization • Clinical studies • Developing the appropriate surrogate • Correlation • Depletion studies • Fab and scFv combinatorial libraries to cockroach allergens

4. Why is cockroach allergy important? • Ubiquitous • Difficult to control • Associated with asthma • Standardization of cockroach allergen extracts supported by the Allergenic Products Advisory Committee on February 10, 2000

5. Why is cockroach allergen standardization important? • To the patient • More accurate diagnosis • Safer and more effective immunotherapy • To the physician/scientist • Better science (if you can’t measure it, you can’t study it…) • Pathophysiology • Epidemiology • Environmental control • To the FDA • Safer, more effective product

6. Initial studies: Laboratory • Develop/adapt methods for allergen determination • Compare allergen content of different lots

8. Conclusions • Commercially available cockroach allergen extracts: • vary widely in protein content, Bla g 2 content, SDS-PAGE banding pattern, and overall allergenicity. • appear to be less potent and contain less Bla g 1 than the candidate reference extracts • Established that cockroach allergen vaccines need to be standardized

9. Next stage: Clinical • skin testing, histamine release, IT data • establish biological unitage and ideal dosing ranges

10. Goals • Obtain valid clinical data on the biological potency of three commercial German cockroach allergen extracts • Develop surrogate potency testing

11. Goals • Obtain valid clinical data on the biological potency of three commercial German cockroach allergen extracts • Develop surrogate potency testing

12. ID50EAL testing (Intradermal Dilution for 50 mm Sum of Erythema Determines Bioequivalent Allergy Units)

13. NIAID Inner City Asthma Consortium “…established in FY 2002 to explore and evaluate promising new strategies for the treatment of asthma among minority children residing in the inner city. This consortium of basic scientists and clinical investigators will conduct clinical studies to elucidate the immunopathogenesis and natural history of asthma in this population.” From the FY 2003 Budget Justification Narrative, NIAID, http://www.niaid.nih.gov/director/congress/2002/cj/narrative.htm

14. William W. Busse, MD, Chair Gordon R. Bloomberg, MD Peyton A. Eggleston, MD Peter Gergen, MD, MPH James Gern, MD Rebecca S. Gruchalla, MD, PhD Meyer Kattan, MD Carolyn M. Kercsmar, MD Andrew H. Liu, MD Floyd J. Malveaux, MD, PhD Herman Mitchell, PhD Wayne Morgan, MD, CM George T. O’Connor, MD, MS Jacqueline A. Pongracic, MD Hugh A. Sampson, MD Sampson Sarpong, MD Ernestine Smartt, RN Robert C. Strunk, MD Stanley J. Szefler, MD NIAID Inner City Asthma Consortium steering committee

16. Recruitment • Inclusion criteria • 18 to 65 years of age • history of allergic disease, such as allergic rhinitis, related to exposure to the allergen of interest • puncture sum of erythema diameter responses (ΣE) to the allergen concentrate of ≥30 mm.

17. Recruitment • Exclusion criteria • Asthma with use of systemic steroids in the past 12 months • Peak flow < 75% predicted at the time of testing • Skin coloring or condition that would preclude the measurement of erythema responses • Dermographism (> 4 mm ΣE following saline skin test) • Immunotherapy – past or present - with the test allergen • Current use of antihistamines, tricyclic antidepressants, MAO inhibitors, and beta-blockers

18. Allergen extracts chosen • German cockroach • Approved for skin testing • 50% glycerol • 3 different manufacturers

19. RP1: pooled monospecific rabbit sera against Bla g 1, 2, 4 and 5 RP2: rabbit anti-German cockroach RP3: human serum pool S1CR

20. Timetable • Steering committee approval - done • Study centers identified - done • Order extracts - done • IRB approvals - done • IND approval - done • Distribute materials - done • Proficiency testing - in process • Proceed with study

21. Goals • Obtain valid clinical data on the biological potency of three commercial German cockroach allergen extracts • Develop surrogate potency testing

22. Surrogate tests to be evaluated • Competition ELISA (using study sera) • Specific allergen testing • Direct ELISA • Rabbit hyperimmune sera • Clonal chicken and rabbit scFv and Fab • Two-site ELISA • Antibody microarray profiles • Sensitized mast cell lines (H. Sampson)

23. Figure legends: • Antibody/detector system • Antigen/analyte

24. Competition ELISA with pooled allergic human sera • Examples: mites, grasses • Advantages • quantitative • reflects spectrum of allergen recognition • does not require identification of relevant allergens • Disadvantages • use of pooled sera • effects of fluctuations in individual allergens difficult to measure

25. ELISA with monospecific antiserum • Advantages • quantitative • monospecific • Disadvantages • need to identify relevant allergen(s)

26. Two-site ELISA with monoclonal antibodies • Advantages • specificity • Disadvantages • specificity • need to identify relevant allergen(s) • cross-reactivity

27. Antibody microarray • Advantages • quantitative • reflects spectrum of allergen recognition • does not require identification of relevant allergens • Disadvantage • New technology; initial development will be labor intensive and expensive

28. Conclusions • Standardized German and American cockroach allergen vaccines will • facilitate definitive studies on the role of cockroach allergens in inner city asthma, and on the best methods for eradication and treatment • make for safer and more effective products