The High Stakes of Viral Vector Manufacturing

The margin for error in late-stage gene therapy is nearly non-existent. While only 24 viral vector–based gene therapies have been approved to date, hundreds more are moving through clinical pipelines, bringing significant promise alongside intense manufacturing risks.

For developers, the transition from early-stage processes to commercial scale is where programs most frequently fail. As Suparna Sanyal, Commercial Development Director at Lonza, notes, a single mistake in the late phase can trigger costly rework that may revert progress all the way back to toxicology studies. This vulnerability stems from complex biology, manufacturing variability, and high-dose–related fatalities, all of which have increased regulatory scrutiny.

The Biologics License Application (BLA) process serves as the primary bottleneck for commercialization. Regulators require proof that a therapy is safe, efficacious, and consistently manufacturable. Success depends on addressing three specific technical gaps:

• Process Scaling: Developers often attempt to advance early-stage processes into late phases without the stability required for commercial manufacturing. These processes can introduce safety risks or variability that regulators will not accept.
• Analytical Rigor: BLA submissions now demand sophisticated potency assays, stability packages, and advanced characterization.
• Supply Traceability: Gaps in analytics and supply chain oversight can lead to regulatory holds or outright rejection.

The implications for the biotech sector are clear: a failed batch or a supply interruption does more than delay a product; it jeopardizes patient access and erodes investor confidence. For companies moving toward a commercial launch, the choice of a CDMO with specific expertise in infrastructure and process scaling is a strategic necessity rather than an operational preference.

The question for developers is whether their current manufacturing processes are built for scale, or if they are merely functional enough for early clinical trials.