Laboratory of Immunobiochemistry site visit

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Laboratory of Immunobiochemistry site visit

• Jay E. Slater, MD
• FDA/CBER/OVRR/DBPAP
• June 29, 2006

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Laboratory of Immunobiochemistry (LIB)

• LIB supports the regulatory mission of CBER and
  FDA in assuring the safety and efficacy of
  allergenic products in the US by
• original research
• directed research projects
• expert advice
• lot release data
• BLA and IND review

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The last dedicated site visit for LIB was in
January 2002

• LIB was functioning at one of the best levels in
  recent memory
• With the limited resources available, LIB
  needed to be well focused to achieve worthwhile
  results
• LIB encouraged to direct future efforts and
  resources toward continued standardization of
  allergenic extracts

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Scientific goals

• Allergen structure/function
• Product quality/safety/efficacy
• Characterization of allergen extracts
• Product quality/safety/efficacy
• Modulation of T cell function
• Review of novel agents/formulations

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Staffing

• Principal Investigators
• Jay E. Slater, MD, Lab Chief
• Ronald Rabin, MD - Senior Staff Fellow
• Research Fellows
• Bo Chi, MD, PhD
• Nicolette deVore, PhD
• (Shoba Amarnath, PhD)
• (Srikant Bykadi, MS)
• (Ming Zhang, MD)
• Research Technicians
• Mona Febus
• Cherry Valerio
• Katia Dobrovolskaia
•  

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LIB research program

• PI Ronald Rabin, MD
• Modification of multidrug resistant protein
  (MRP-1) activity as a potential mechanism of
  immunomodulation
• Characterization of responses to respiratory
  syncytial virus (RSV) by T-cells
• PI Jay E. Slater, MD
• Endotoxins in allergen extracts
• Biological potency of German cockroach allergen
  extracts
• Antibody microarray methods to determine allergen
  potency and composition

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German cockroach allergen standardization
Katia Dobrovolskaia ICAC Mona Febus DAIT/NIAID Ch
erry Valerio JA Woodfolk, PhD University of
Virginia
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The problem

• Cockroach allergy has been associated with asthma
  in the inner city
• Rosenstreich et al. N Engl J Med 1997
  3361356-63.
• Eggleston et al. J Allergy Clin Immunol 1998
  102563-70.
• Cockroach allergen extracts are non-standardized
• Standardized extracts are needed to
• Increase the safety and efficacy of extracts used
  for allergen immunotherapy
• Perform valid scientific studies of this
  important public health problem

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Aims

• Establish biological potency for German cockroach
  allergenic extracts
• Establish surrogate in vitro method for
  estimating biological potency

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IND 11319 German Cockroach Allergen
Standardization Evaluation (CASE)

• Sponsor DAIT/NIAID
• Four sites
• Baltimore
• Washington DC
• Chicago
• Denver

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IND 11319 German Cockroach Allergen
Standardization Evaluation (CASE)

• Purpose
• Determination of the biological potency of three
  (3) commercially available German cockroach
  allergen extracts and test of their
  bioequivalence.
• Patient Population
• Adults with a history of allergic disease or
  asthma and a demonstrated sensitivity to German
  cockroach allergen tested.

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Conclusions/next steps

• Biological potencies of three German cockroach
  extracts have been determined
• These potencies appear to be low, but successful
  IT dosing should be achievable
• No single allergen assay will provide an adequate
  measure of overall potency
• allergens other than those tested may be
  significant
• surrogate potency test will have to take this
  uncertainty into account

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Antibody microarrays for allergen
standardization(see Briefing Document, pp.56-62)

• Nicolette deVore, PhD

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How do we measure potency?

• Total protein (hymenoptera)
• Overall allergen (grasses, mites)
• Pooled human antibody
• Specific allergen (cat, ragweed)
• Sheep antibody

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The dilemma of these potency measures

• In order to measure specific allergens, we need
  to know which allergens are relevant
• If we measure overall allergenicity, we are
  unable to detect the absence of specific (and
  potentially important) allergens

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Antibody microarray plan
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Aims

• To develop a recombinant antibody microarray
  method for identifying individual allergens in
  complex mixtures
• potency
• profile
• Test this method using known simpler extracts
  (cat and short ragweed)
• Apply this technique to complex extracts, such as
  German cockroach allergen extracts

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Summary

• In our studies so far, we have
• applied phagemid library screening techniques to
  raising specific scFv antibodies to allergens
• developed appropriate antibody-screening methods
  to assess scFv function in the antibody
  microarray platform
• validated the use of the antibody microarray to
  measure the potency of allergens

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Microarray development plan

• Develop a quantifiable fingerprint of complex
  allergen mixtures using clonal allergen-specific
  scFvs and polyvalent sera
• Advance to more complex allergen extracts
• Yellow jacket venom
• German cockroach
• American cockroach