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Response to Comment on Bioassays - December 17, 2009 - Prevnar 13

From: Sirota, Lev

Sent: Wednesday, December 23, 2009 11:50 PM

To: Smith, Michael (CBER)

Cc: Vaillancourt, Julienne; Sweeney, Colleen; Horne, Amelia(Dale); Lin, Tsai-Lien

Subject: DCC Login ID 479430 loaded by GIA; STN 125324 Prevnar 13 Clinical – Response to Comment From December 17, 2009 on Bioassays




I reviewed the applicant's response and have no further concerns.

The reviewer's comment and applicant's answer is attached below.



Dr. Lev Sirota completed his statistical review of the bioassays and there is one comment

(see below) regarding any potential future validation assays.

In the Pneumococcal Enzyme-linked Immunosorbent Assays (PnELISAs) sub-section of

section “Analytical and Bioanalytical Methods” you used a criterion for linearity of

--(b)(4)--. This criterion appears to be too liberal. All presented linear regression data in this

part of study demonstrate a coefficient of correlation of 0.99 and above. CBER

recommends that you make criterion more stringent for future validations of the method.

Please comment.

1.1 Response

We concur and will make the correlation criterion more stringent for future validations.


Lev A. Sirota, Ph.D.

Division of Biostatistics OBE/CBER/FDA

Tel: 301-827-6075 Fax: 301-827-5218


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