Standard Operating Procedure for Back-Up Seed Train Planning in Biosimilar Manufacturing

Department	Biosimilars
SOP No.	SOP/BS/137/2025
Supersedes	SOP/BS/137/2022
Page No.	Page 1 of 10
Issue Date	04/05/2025
Effective Date	06/05/2025
Review Date	04/05/2026

1. Purpose

To define the strategy and procedure for planning, preparing, and maintaining back-up seed trains in biosimilar upstream processes to mitigate risk of primary seed train failure and ensure batch continuity.

2. Scope

This SOP applies to all seed expansion operations including vial thaw, shake flask culture, spinner flask, and N-1 bioreactor stages intended for both primary and back-up seed trains in biosimilar manufacturing operations.

3. Responsibilities

• Production (Upstream Team): Plan, prepare, and culture back-up seed trains per protocol.
• QC Microbiology: Test back-up cultures for sterility and mycoplasma.
• QA: Review and approve back-up seed train plans and deviation handling.

4. Accountability

The Head of Upstream Operations is accountable for ensuring a validated back-up seed train strategy is implemented and documented to maintain production timelines and compliance.

5. Procedure

5.1 Risk-Based Justification

1. Back-up seed train must be planned for:
   • High-value batches
   • Regulatory validation runs
   • Single-batch dependency timelines
2. Justification to be recorded in Annexure-1: Seed Train Planning Form and approved by QA.

5.2 Preparation of Back-Up Seed Train

1. Thaw an additional vial from the same Working Cell Bank (WCB) as the primary seed.
2. Parallel seed expansion to be carried out under same environmental and equipment conditions.
3. Label vessels as “BACK-UP” and maintain segregation from primary cultures.

5.3 Culture Monitoring

1. Monitor back-up cultures for:
   • Cell viability and growth profile
   • Contamination signs (turbidity, color change)
   • Microscopic morphology
2. Record results in Annexure-2: Back-Up Culture Log.

5.4 Storage and Termination

1. Back-up seed can be:
   • Used for inoculation if primary fails
   • Terminated post QA clearance once primary is successful
2. Autoclave or chemically disinfect back-up cultures as per biosafety protocols.

5.5 Deviation Handling

1. If primary seed train fails:
   • Log deviation and initiate back-up usage approval
   • Update batch documentation and justification
2. Record events in Annexure-3: Back-Up Usage Report.

6. Abbreviations

• WCB: Working Cell Bank
• QA: Quality Assurance
• SOP: Standard Operating Procedure

7. Documents

1. Seed Train Planning Form – Annexure-1
2. Back-Up Culture Log – Annexure-2
3. Back-Up Usage Report – Annexure-3

8. References

• ICH Q9 – Quality Risk Management
• WHO TRS 978 – GMP for Biologicals
• Internal Master Cell Bank and Seed Expansion SOPs

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Seed Train Planning Form

Batch No.	Primary/Back-Up	WCB Lot	Planned Date	QA Approved
BS-UP-119	Back-Up	WCB-017	05/05/2025	Yes

Annexure-2: Back-Up Culture Log

Date	Vessel ID	Cell Viability	Observations	Remarks
05/05/2025	SF-BKP-01	96%	Normal	Ready

Annexure-3: Back-Up Usage Report

Date	Reason for Use	Deviation ID	Authorized By	Disposition
06/05/2025	Primary growth failure	DEV/USP/057	QA Head	Approved

Revision History:

Revision Date	Revision No.	Revision Details	Reason for Revision	Approved By
04/05/2025	2.0	Added deviation handling and tracking annexures	GMP Strengthening