Membrane adsorber design for lentiviral vector recovery

The growing demand for lentiviral vectors (LVs) in cell and gene therapies has highlighted significant challenges in large-scale LV production, particularly low product recovery. Anion-exchange chromatography (AIEX) is widely used for LV capture. However, AIEX accounts for most of the product loss in downstream processing, due to excessive interaction strengths in current commercially available membranes causing irreversible LV binding. To address this, a new AIEX membrane structure that reduces LV interaction strength by lowering ligand density, using direct ligand grafting, and incorporating tighter pore size distributions is tested. Four prototypes were created with Q and D anion-exchange chemistries at 1.05 (R1) and 1.32 (R2) μm pore sizes. Prototypes minimized product loss from irreversible binding, with high total particle recoveries irrespective of time spent in the adsorbed state ( $\sim$ 90% at t = 3 min, $\sim$ 80% at t = 100 min). Narrower elution ranges were shown, with LV eluted <450 mM NaCl. The best-performing prototype, DR2, exhibited a ∼3-fold higher functional product recovery than standard Q-membranes for LV encoding GFP (50%) and CAR (73%) transgenes. At large-scale, downstream processes using DR2 membranes showed a 3.5-fold improvement in functional product recovery at drug substance (43%) compared to a standard Q-membrane process (12%). These results demonstrate that adsorbents designed for lentiviral vectors significantly enhance downstream recoveries.