US FDA predicts gene therapy surge and moves to clarify expectations

Gene therapy developers targeting the US market have a clearer idea of what it will take to win approval thanks to new guidance documents issued by the FDA.

The US regulator set out its expectations for developers in six documents published last week. There are final guidance documents on gene therapies for hemophilia, retinal disorders and rare diseases.

In addition, there are final guidance documents on chemistry, manufacturing and controls (CMC), observational studies and on the assessment of gene therapies that use retroviral vectors.

Image: iStock/Piotrekswat

There is also draft guidance explaining how the FDA will interpret “sameness” when deciding whether to award orphan drug status.

The agency said that when assessing two gene therapies targeting the same disease it will consider both the gene itself and the viral vector.

Gene therapy approvals

To date only four gene therapies that introduce new genetic material into a patient’s cell have been approved by the FDA.

However, many more gene therapies are on the way according to the agency which said it anticipates more approvals in the coming years based on the 900 investigational new drug (IND) it has received.

FDA Commissioner Stephen Hahn said, “The growth of innovative research and product development in the field of gene therapy is exciting to us as physicians, scientists and regulators.

“These therapies, once only conceptual, are rapidly becoming a therapeutic reality for an increasing number of patients with a wide range of diseases, including rare genetic disorders and autoimmune diseases.”

Evolving science and regulations

This was echoed by Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, who stressed the importance of effective gene therapy regulations.

“As the regulators of these novel therapies, we know that the framework we construct for product development and review will set the stage for continued advancement of this cutting-edge field and further enable innovators to safely develop effective therapies for many diseases with unmet medical needs.”

Marks cited the rapid pace of scientific development as a challenge for the agency, explaining that assessing the safety, efficacy and long-term impact of gene therapies is highly complex.