(System Info - 260789 RIVERS KATIE 01/17/2014 08:45:23 RIVERSK)
From: Rivers, Katie
Sent: Thursday, December 19, 2013 3:00 PM
To: 'Greenfeder, Scott'
Cc: Valenti, Elizabeth
Subject: Information request for BLA125478/0
Dear Scott,
We have the following information request and clarification for your BLA, STN125478/0:
1.We have reviewed your December 6, 2013, amendment to BLA 125478/0. We note that to develop the –b(4)------------------------ specification limits you used –b(4)---------------------, of which b(4) batches were expired at the time samples were tested for b(4). Only -b(4)--- batches (-b(4)----) were still within the proposed expiration period. We note that run to run and tablet to tablet variances between the expired batches (-b(4)------) and batches –b(4)------ (Figure 1 of December 6, 2013 submission) are not significantly different from each other. However, please define the b(4) specification limits (-b(4)-------------) using data obtained from batches –b(4)----(numbers —b(4)-----------------------------------------------) manufactured in November 2011 and June 2012.
2.Due to our pending move to the FDA White Oak campus, the ---b(4)------------- for measuring potency of Short Ragweed Pollen Allergen Extract will not be validated prior to the projected release of your product. Therefore, we will be using the RID assay for testing the potency of MK-3641.

Please let me know if you have any questions. 
Thank you,
Katie
Katie H. Rivers, M.S.
Regulatory Project Manager, CMC1
FDA/CBER/OVRR/DVRPA
1401 Rockville Pike, HFM-481
Rockville, MD 20852 
Phone 301-796-2640
Fax 301-827-3532
