The A Mab heavy and light chain genes were cloned into a single vector under a strong CMV promoter. After transfection, 5,000 clones were screened using FACS (for specific productivity) and ClonePix (for secretion rate). Clone A-Mab-7B12 was selected based on:
Molecule: Humanized IgG1 mAb targeting a cancer antigen. Indication: Solid tumors. Target Dose: 500 mg per patient, every 3 weeks. Annual Demand: 50 kg (clinical → early commercial). Critical Quality Attributes (CQAs):
The purified Mab-X is now in a low-pH, high-salt buffer unsuitable for injection. The case study addresses two final challenges: A Mab A Case Study In Bioprocess Development
A Mab’s high concentration (20 g/L intermediate) posed a challenge. Standard 20 nm filters fouled rapidly. The solution: Planova 20N with pre-filtration using 0.1 µm and operation at constant pressure (2 bar). Flux dropped only 30% over 4 hours, acceptable for GMP.
After 14 days of culture, the 10,000 L bioreactor yields ~52 kg of Mab-X, but it is diluted in a soup of HCPs, DNA, media components, and product variants. The downstream case study follows three core steps: The A Mab heavy and light chain genes
To ensure safety, the eluate undergoes low-pH viral inactivation (pH 3.6 for 90 minutes). For Mab-X, which is moderately acid-labile, the team adds 100 mM sodium acetate as a stabilizing excipient during this step. Post-inactivation, pH is raised to 5.5 using 2M Tris base. Analytical data confirm >4 log reduction of model viruses (xMuLV) without compromising product quality.
Low pH hold (pH 3.6 for 60 minutes) was used. But with A Mab’s sensitivity, they optimized to pH 3.7 for exactly 30 minutes – no longer, no shorter. Validation showed >4 log reduction of model virus (xMuLV). Indication: Solid tumors
From this case study on Mab-X, the bioprocess development community can extract four universal lessons:
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