Standard Operating Procedure for Productivity Testing in Small-Scale Biosimilar Cultures

Department	Biosimilars
SOP No.	SOP/BS/022/2025
Supersedes	SOP/BS/022/2022
Page No.	Page 1 of 13
Issue Date	04/05/2025
Effective Date	06/05/2025
Review Date	04/05/2026

1. Purpose

To describe the procedure for assessing productivity of biosimilar-expressing cell clones using small-scale cultures to support early clone ranking and upstream development.

2. Scope

This SOP applies to the Cell Line Development and Upstream Process Development teams evaluating recombinant protein production in shake flasks or deep well plates (DWP).

3. Responsibilities

• Upstream Scientist: Plans and executes productivity runs and documents results.
• CLD Technician: Performs culture maintenance and sampling.
• QA Representative: Verifies result entries and cross-checks against production logs.

4. Accountability

The Head of Upstream Development is accountable for ensuring the reliability of productivity data generated in small-scale models for biosimilar clone progression.

5. Procedure

5.1 Culture Setup

1. Revive selected clones from WCB or cryovials and expand in T-flasks.
2. Inoculate shake flasks (e.g., 250 mL with 50 mL working volume) or DWP (2 mL per well) at 0.3–0.5 × 10⁶ cells/mL.
3. Use production medium or serum-free platform media.
4. Incubate at 36–37°C, 5% CO₂, shaking at 120–180 rpm.

5.2 Sampling Schedule

1. Collect 1–2 mL samples on Day 0, 3, 5, and 7 (or as per protocol).
2. Measure viable cell density and viability using Trypan Blue or automated cell counter.
3. Centrifuge and collect supernatants for protein analysis.

5.3 Protein Quantification

1. Quantify expressed protein using:
   • ELISA for biosimilar mAb or recombinant protein
   • Protein A HPLC for monoclonal antibodies
2. Prepare standard curves using reference standards.
3. Calculate yield in mg/L and document in Productivity Log (Annexure-1).

5.4 Data Analysis

1. Determine specific productivity (qP) = Protein (pg/cell/day).
2. Rank clones by final titer and qP value.
3. Compare against productivity benchmarks from historical data or innovator values.

6. Abbreviations

• DWP: Deep Well Plate
• qP: Specific Productivity
• ELISA: Enzyme-Linked Immunosorbent Assay
• HPLC: High Performance Liquid Chromatography

7. Documents

1. Productivity Testing Log (Annexure-1)
2. Cell Growth and Viability Log (Annexure-2)

8. References

• ICH Q6B – Specifications: Test Procedures and Acceptance Criteria
• WHO Guidelines for Cell-Based Biosimilar Characterization
• CDSCO Biosimilar Guidelines (India)

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Productivity Testing Log

Date	Clone ID	Day	Protein Titer (mg/L)	qP (pg/cell/day)	Operator
03/05/2025	CL-BS-022	7	860	32.1	Sunita Reddy

Annexure-2: Cell Growth and Viability Log

Date	Clone ID	Day	Viable Cell Density (×10⁶/mL)	Viability (%)	Operator
03/05/2025	CL-BS-022	5	3.6	95	Rajesh Kumar

Revision History:

Revision Date	Revision No.	Revision Details	Reason for Revision	Approved By
04/05/2025	2.0	Added deep well plate option and qP calculation method	Process update and analytical enhancement