M E M O R A N D U M
Department of Health and Human Services
Public Health Service
Food and Drug Administration
Center for Biologics Evaluation and Research 
To:   File (STN 125512/0)
Thomas Maruna, Regulatory Project Manager, OBRR/IOD/RPM Staff
From:   Ze Peng, PhD, OBRR/DHRR/LH
Through:   Mark Weinstein, PhD, Assoc. Dep. Dir. for Science, OBRR/IOD
                  Basil Golding, MD, Division Director, OBRR/DHRR
Subject:   Final review of Adventitious Agents Safety Information in Baxter’s original BLA for Antihemophilic Factor VIII (Recombinant), Porcine Sequence
Cc:   Natalya Ananyeva, PhD, Committee Chair, OBRR/DHRR/LH
Executive Summary
This memorandum summarizes the review of Adventitious Agents Safety Information in an original Biologics License Application (BLA) under STN 125512/0 submitted by Baxter for Antihemophilic Factor VIII (Recombinant), Porcine Sequence. The proposed proprietary name of this product is OBIZUR. As described below, the measures taken by Baxter to control adventitious agents in the manufacture of OBIZUR drug product are acceptable; therefore, I recommend approval of the BLA under STN 125512/0.
Evaluation of safety regarding adventitious agents 
For the non-viral adventitious agents including bacteria, fungi, and mycoplasma, the potential of contamination of these agents is well controlled by: (1) using appropriate environmental control monitoring in the manufacturing process; (2) using single-use equipment items wherever possible to minimize the risk of contamination from one batch to another, e.g., product-contact disposable equipment including culture flasks, pipettes, and bioprocess containers that are purchased pre-sterilized; (3) cleaning both single-use and multi-use equipment types per corresponding procedures, e.g., the chromatography -------------------------------------------(b)(4)-------------------------------------------------------- (4) employing in-process controls, e.g., testing for endotoxins, bioburden, and mycoplasma in -----(b)(4)---------; and (5) employing filtration steps including -(b)(4)-- sterile filtration. The potential of OBIZUR to be contaminated with non-viral adventitious agents is further reduced by testing the final product for sterility, endotoxins, and ----(b)(4)----------------. Baxter manufactures OBIZUR according to GMP regulations.
(b)(4) raw materials of biological origin are used in the manufacture of OBIZUR. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------(b)(4)--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Polysorbate 80 and sucrose used in the manufacture of OBIZUR are derived from plant sources. Thus, the potential risk of adventitious viruses or transmissible spongiform encephalopathy agents is minimized.
The potential of contamination by infectious viruses in cell culture is well controlled for up to --------------------------------(b)(4)------------------------------------------------- in the manufacture of OBIZUR, which is produced in a (b)(4) baby hamster kidney (BHK-M) cell line. Baxter performed viral tests on the Master Cell Bank (MCB) for OBIZUR that are consistent with the International Conference on Harmonisation (ICH) Q5A(R1) guideline. -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------(b)(4)-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Baxter routinely tests cell cultures used in the manufacturing process for adventitious viruses to ensure that viruses are below their detectable levels.
Additionally, the potential risk of viral contamination of OBIZUR is further mitigated through two dedicated viral clearance steps: Solvent/Detergent (S/D) treatment --------------------------------------------------(b)(4)----------------------------------------------------------; and 15 nm nanofiltration (two -(b)(4)- 15N filters connected in series). The ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------(b)(4)--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- The wide range of physico-chemical properties of these model viruses demonstrates the ability of the manufacturing process to reduce potential viral contamination from OBIZUR. Down-scale studies on the relevant steps resulted in the following overall log reduction factors, in parenthesis, for these viruses: ----------------(b)(4)------------------------------------------------------------------. We find these results support the proposal that viral clearance is effective in the manufacture of OBIZUR.
Background
The active ingredient in OBIZUR is a recombinant porcine Factor VIII (rFVIII) with a truncated B domain of 24 amino acid residues, which is produced in a baby hamster kidney (BHK) cell line. The molecular mass of this product is 170 kDa. OBIZUR is formulated as a sterile, non-pyrogenic, lyophilized powder for intravenous injection only. When reconstituted with its diluent, sterile Water for Injection, each container of OBIZUR contains nominally 500 IU of rFVIII.
The manufacturing process of OBIZUR includes two dedicated viral clearance steps: Solvent/Detergent (S/D) treatment --------------(b)(4)----------------------------------------------------------------- and 15 nm nanofiltration (two -(b)(4)- 15N filters connected in series). ----------------------------------------------------(b)(4)-------------------------------------------------------------------------------------------------------------------------------. Furthermore, no raw materials or ingredients of human or animal origin other than -----b(4)----------------------are used in the manufacturing process, which further mitigates the potential of viral contamination. ----------------------------------------(b)(4)---------------------------------------------------------------------------------------------------------.
Summary of Review
Flow chart of the manufacturing process of OBIZUR
The flow chart of the manufacturing process of OBIZUR includes the following steps:
OBIZUR drug substance
1. ------------(b)(4)------------------------------------------------------
2. ------------(b)(4)--------------
3. ------------(b)(4)-------------------------------------------------
4. ------------(b)(4)-----------------------
5. ------------(b)(4)--------------------------------------------------------------------------------------------------------------------------------
6. ------------(b)(4)-----------------------
7. ------------(b)(4)----------------
8. ------------(b)(4)--------------------------------------------
9. ------------(b)(4)-------------------------------------------------
10. -----(b)(4)-------- 
OBIZUR drug product
11. ---------------(b)(4)----------------------------------------
12. Sterile filtration
13. Aseptic filling
14. Lyophilization
15. Over-sealing
16. Visual inspection
17. Labeling and packaging
Product reviewer’s comment: Bolded in the above flow chart are the two dedicated viral inactivation/removal steps. ----------------------(b)(4)---------------------------------------------------------------------------------------------------- steps also contribute to viral --(b)(4)---. The validation reports for these clearance steps were reviewed, and the results demonstrate that these steps are capable of either inactivating or removing viruses, thus lowering the potential of viral contamination.
Evaluation of safety of adventitious agents (Section 3.2.A.2) 
1. Control of non-viral adventitious agents 
For the non-viral adventitious agents including bacteria, fungi, and mycoplasma, the potential of contamination of these agents is well controlled through the use of (1) product-contact disposable equipment used in cell expansion and harvest steps are purchased pre-sterilized; (2) both single-use and multi-use equipment are cleaned according to validated cleaning and sanitization procedures, e.g., the ----------------------------------------------(b)(4)---------------------------------------------------------------------------------------------------------------------, filters, stoppers, and over-seals are all purchased pre-sterilized; (4) in-process controls, e.g., endotoxin testing, bioburden, and freedom from mycoplasma in ----(b)(4)---------; and (5) filtration steps including -(b)(4)- sterile filtration. The potential of OBIZUR to be contaminated with non-viral adventitious agents is further reduced by testing the final product for sterility and endotoxins. Baxter manufactures OBIZUR according to GMP regulations.
2. Testing of all mammalian cell banks for the absence of infectious viruses 
Master cell bank used for the production of OBIZUR is also well controlled regarding the potential of viral contamination. The MCB named ---(b)(4)------ has been tested for viruses according to ICH Q5A(R1). All the tests were found negative for the presence of viruses except for the -------(b)(4)-------------------------------------------------------------. This MCB is also found to be absent of mycoplasma, bacteria, and fungi. Furthermore, cells at the limit of in vitro cell age used for production -------(b)(4)--------------------- were tested, and found negative for mycoplasma, bacteria, fungi, and adventitious viruses other than (b)(4). The data are summarized as follows:
[(b)(4)]
[(b)(4)]
Product reviewer’s comment: The tests performed on the MCB are consistent with ICH Q5A(R1) guidance. All test results for endogenous and adventitious viruses were negative except for ---------------------------------------------------------------------------------------------------------(b)(4)-----------------------------------------------------------. Moreover, there are two dedicated virus inactivation/removal steps in the manufacturing process. These steps are used to reduce the potential of the DP to be contaminated with endogenous or adventitious viruses.
According to the ICH guidance Q5A, the full tests for viral safety are not required to be performed on the WCB if these tests are performed on the MCB: viral safety should be evaluated at least once on the cells at the limit of in vitro cell age used for production. The data shown above provided further assurance that the manufacturing process is not prone to be contaminated by potential adventitious viruses. Therefore, these data are considered to be sufficient to support both MCB and WCB used for the manufacture of OBIZUR.
3. Control of materials used in the manufacturing process 
No animal-derived raw materials other than (b)(4) are used in the manufacturing process. Materials of biological origin used in the manufacturing process include ---------------------------------------------------------------------------------------------------------------------------------------------(b)(4)-------------------------------------------------------------------- sucrose, and polysorbate 80 are derived from plant sources, and are unlikely to pose a viral safety risk to the OBIZUR final product. ----------------------------------------------------(b)(4)-------------------------------------------------------------------------------------------------------. The manufacturer certifies that this raw material is compliant with the requirements of the ----(b)(4)-----------------------. ------------------------------------------------------------------------------------------------------------------------------------------------(b)(4)----------------------------------------------- ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------(b)(4)----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------:
o -----(b)(4)--------------
o -----(b)(4)---------
o -----(b)(4)---
o -----(b)(4)-----------------
o -----(b)(4)-----------
o -----(b)(4)-----------------------------
o -----(b)(4)----------------
-----------------------------------------------------------------------------------------------------------------------------------------------(b)(4)-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------.
4. Testing the capacity of the OBIZUR purification process to clear viruses 
There are two dedicated steps for viral clearance in the manufacturing process of OBIZUR, which are S/D treatment ------------------------(b)(4)-------------------------------------------------- and 15-nm nanofiltration (two --(b)(4)-- 15N filters connected in series). ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------(b)(4)------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- These viruses resemble viruses which may contaminate the OBIZUR drug product, and represent a wide range of physico-chemical properties that tests the ability of the manufacturing process to eliminate viruses.
1) Solvent/Detergent treatment
To evaluate the capacity of S/D treatment to clear viruses, Baxter did a validation study (Study No. PR111308) on the down-scale system. The equivalence of the down-scale system and the full-scale was demonstrated by determination of a broad set of process parameters and by comparing the values obtained with the respective ranges specified for manufacturing. Comparison of the -----------(b)(4)---------------------------- in the relevant intermediates further demonstrated the equivalence of both scales. The data support the qualification of the system scaled down to (b)(4). Thus, the viral clearance data derived from the down-scale system appear to be appropriate to be used for evaluating the viral clearance capacity of S/D treatment at the full-scale.
To demonstrate the robustness of this step for vial clearance, Baxter -----------------(b)(4)------------------- in the down-scale study (Study No. TCR 09-087). The -----(b)(4)------------------ for the S/D treatment is also ----(b)(4)-------------------------- of the acceptance criterion. The details of these parameters are listed as follows:
[(b)(4)]
The samples used for the virus clearance study were obtained from the full-scale, and all samples are tested for toxicity and interference with virus titration assays. The down-scale viral clearance data on S/D treatment are summarized below:
[(b)(4)]
As shown above, ---(b)(4)-- of S/D treatment achieved at least 5 log10 virus reduction factors. No infectivity was detected after --(b)(4)-- of S/D treatment for both ----(b)(4)----------- viruses, even under the worst case scenario, i.e., -------------(b)(4)---------------------------------------------. Additionally, the similar results were generated in Study No. PR111308, in which the concentrations of S/D treatment used are reduced to (b)(4) of the targeted values at the full-scale.
2) Nanofiltration:
The nanofilters used in nanofiltration are manufactured by ---(b)(4)---------- with a pore size of 15 nm, and a ---(b)(4)---- use. The nanofiltration step is executed through two 15 nm nanofilters that are connected in series. The integrity of the nanofilters is measured using a ----(b)(4)------- for ----(b)(4)------------ and a ----(b)(4)----- test for ------(b)(4)------------------. To evaluate the capacity of nanofiltration to clear viruses, Baxter did a qualification study (Study No. 113172-RPT/2.0) on a down-scale system. In this study, the acceptance criteria on the critical parameters such as -------------------------------------------------(b)(4)-------------------------------------------------------------------------- are identical between the down-scale and the full-scale. As shown in the table below, the rFVIII activity step yield and variant profile during the nanofiltration were found to be comparable between the down-scale and the full-scale.
 
[(b)(4)]
These data support the qualification of this system scaled down to (b)(4)--. Thus, the viral clearance data derived from the down-scale system can be used for evaluating the viral clearance capacity of nanofiltration at the full-scale.
To demonstrate the robustness of nanofiltration regarding viral clearance, Baxter selected a relatively high product load under high pressure in the virus clearance study. These conditions were considered to raise the risk of viruses breaking through the membrane. The details are listed as follows:
[(b)(4)]
The samples used in the virus clearance studies were obtained from the full-scale. All samples were tested for --------------------------(b)(4)----------------------------------- independent runs were used for each virus in the study. Viruses selected include ------------------------------------(b)(4)--------------------------------------------------------------------------. As the data show in the following table, nanofiltration can remove both non-enveloped and enveloped viruses by -------------(b)(4)-----------
2 Pages Determined to be Not Releasable: (b)(4)
validation reports on these two assays, and listed under Section 3.2.A.2. Upon review, we consider both assays are completely validated according to the relevant FDA guidance. The viral clearance data generated using these assays are valid in the evaluation of the referenced steps. Therefore, this response is acceptable.
3) Virus reduction factors
The viral clearance data from the above mentioned down-scale studies are summarized as follows:
[(b)(4)]
Product reviewer’s Comment: Virus selection in the down-scale studies is consistent with the FDA recommendation regarding the biological drug products derived from cell lines of human or animal origin. The qualification of the down-scale systems used for viral clearance is acceptable, and the viral clearance data derived from these down-scale systems are sufficient to support the effectiveness of viral clearance in the commercial manufacturing process.
Recommendation
The process assuring the safety from non-viral adventitious agents including bacteria, fungi, and mycoplasma is well controlled through the use of validated cleaning/sanitization procedures, in-process controls, filtration steps including (b)(4)-- sterile filtration, and release tests of sterility, endotoxins, and -----(b)(4)---------------- in the final product. The safety of the product from contamination with adventitious viruses is enhanced through complete viral tests of the MCB and cells at the limit of the in vitro cell age used for production. Furthermore, no raw materials or ingredients of human or animal origin other than (b)(4) are used in the manufacturing process. The potential of viral contamination from (b)(4) is well controlled because ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------(b)(4)----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------. Additionally, viral safety is further enhanced by two dedicated viral clearance steps: ---------------(b)(4)----------------------------------------------, and 15-nm nanofiltration. The steps of ----------------------------------------------------------------------------------------------------(b)(4)------------------------------------------------------------. The measures taken by Baxter to control adventitious agents in the manufacture of OBIZUR are acceptable. Therefore, I recommend approval of the BLA under STN 125512/0.
