Laboratory of Immunobiochemistry

site visit

Jay E. Slater, MDFDA/CBER/OVRR/DBPAP

June 29, 2006

2/19

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

3/19

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”

4/19

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

5/19

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

 

6/19

LIB research programPI: 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

German cockroach allergen standardization

Katia Dobrovolskaia ICAC

Mona Febus DAIT/NIAID

Cherry Valerio JA Woodfolk, PhDUniversity of Virginia

8/19

The problem Cockroach allergy has been associated

with asthma in the inner city Rosenstreich et al. N Engl J Med 1997; 336:1356-63. Eggleston et al. J Allergy Clin Immunol 1998; 102:563-70.

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

9/19

Aims

Establish biological potency for German cockroach allergenic extracts

Establish surrogate in vitro method for estimating biological potency

10/19

IND 11319: German Cockroach Allergen Standardization Evaluation (CASE)

Sponsor: DAIT/NIAID Four sites

Baltimore Washington DC Chicago Denver

11/19

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.

IND 11319: German Cockroach Allergen Standardization Evaluation (CASE)

12/19

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

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

Nicolette deVore, PhD

14/19

How do we measure potency?

Total protein (hymenoptera) Overall allergen (grasses, mites)

Pooled human antibody Specific allergen (cat, ragweed)

Sheep antibody

15/19

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

16/19

Nitrocellulose coated chip

Antibody microarray plan

Apply clonal scFvs

Allergens bind to specific scFvsIncubate w/allergens

17/19

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

18/19

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

19/19

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