1. Allergenic Extracts – Precipitates Jennifer Bridgewater, M.P.H. CBER, DBPAP

2. Product Line Overview §Standardized Products (n = 19) l Short Ragweed (SRW) - glycerinated and aqueous formulations l Cat, grasses, mites = glycerinated only Exceptions = some cat pelt extracts, intradermal tests with < 50% glycerin (100-1000 AU/BAU/ml) l Venoms = freeze dried, HSA based diluent §Unstandardized (n = 600 - 800) l Glycerinated and/or aqueous

3. Historical Perspective §Precipitates recognized for many years §Early efforts (1970’s) by industry to characterize precipitates l Physical descriptions l Solubility properties §Early efforts by industry to remove precipitates l Manufacturing changes (e.g., bulk “settling” steps) l Formulation changes (e.g., extraction fluids)

4. How Did Precipitate Issue Arise? §Appearance of precipitates noted during Team Biologics inspections of several firms (99-present) §Areas in which precipitates were observed by inspectors: l bulk containers l final containers l retain samples l customer complaint and product return files

5. Physical Characteristics of Precipitates §Examples of terms used by industry to describe precipitate appearance l crystalline l flaky l cloudy l powdery l tarry l fibrous l clumpy

6. Physical Characteristics of Precipitates §Examples of terms used by industry to describe precipitate appearance l color of precipitate l ability to resuspend precipitate into solution l amount of sediment/precipitate at bottom of vial l percentage of extract containing precipitate

7. Current Industry Efforts to Characterize Precipitates § microscopic examination of precipitates l Assess physical appearance §Sterility testing l Rule out microbial contamination §IEF or SDS-PAGE examination of precipitated extracts l In some cases profiles are similar l In some cases bands are missing or lose definition

8. Current Industry Efforts to Characterize Precipitates §Potency testing of precipitated SRW extracts l Compare potency of precipitated final container extract to initial (release) potency value §Protein Nitrogen Units (PNU), pH, phenol testing of precipitated extracts l Compare PNU, PH, and phenol values of precipitated final container extract to initial (release) value

9. Precipitate Data (Unstandardized) ExtractpH release pH retest Diff.PNU release PNU retest Percent Diff. Penicillium7.267.06-.020139000136000- 2.0% 3 Weed Mix 7.087.65+0.576700075000+ 12.0% Red Maple6.86.5-0.313400099000- 26.0% Scrub Oak7.837.68-0.155300067000+ 26.0%

10. Precipitate Potency Data - SRW Lot (1:10 w/v) Antigen E Pre Antigen E Post Difference A281.7252.2-29.5 B243.3231.8-11.5 C317.2204.1-113.1 D294.8334.0+39.2 Data in table taken from pooled data (2 sets of n = 19) 5% average drop in AgE value in pooled data; difference not statistically different

11. Current Knowledge §Aqueous extracts precipitate more than their glycerinated counterparts §Aqueous SRW commonly precipitates §Precipitates are a primary cause of physician complaints (visual appearance) and product returns to industry §Precipitates do not appear to be caused by microbial contamination §Extraction ratio/concentration of extract and phenol may contribute to precipitation

12. Knowledge Gaps §Physicochemical composition of precipitates §Long term effect on potency of the extracts l all but one precipitated extracts are unstandardized, therefore knowledge limited §How precipitated extracts are treated in clinical practice l Are precipitates recognized? l Are precipitated extracts administered as is, decanted and administered, or returned?

13. Knowledge Gaps §Administration of precipitated extracts l Is there a higher risk for adverse events (AE) if a precipitate is injected? l AE reporting for allergenic extracts (MedWatch) is voluntary and passive l Limited number of AE reports submitted to FDA l AE reports = signal system l Information submitted via MedWatch often incomplete

14. Current Research Areas §Physicochemical composition of precipitates §Potency and stability studies of precipitated standardized extracts (limited to aqueous SRW) §Evaluation of pH, phenol content, and PNU of precipitated unstandardized extracts over shelf life

15. Current Regulatory Position §No shipment of final containers exhibiting precipitates §Development of in-house quality control programs (identify and describe precipitates) §Validation of any re-processing procedures performed on precipitated extracts §Modification of labeling to address precipitates §Submit Biological Product Deviation Reports on precipitated lots to CBER

16. Summary §Precipitates occur in allergenic extracts §Aqueous extracts precipitate more than glycerinated extracts §Almost all precipitated extracts unstandardized §Knowledge gaps on precipitated extracts exist §Collaborating with industry to fill knowledge gaps §Prudent regulatory approach

17. Committee Discussion Point §Please discuss future areas of investigation which may provide information in ascertaining the effect of precipitates on the administration of allergenic extracts