Gene therapy product developers are seeking more clarity from the US Food and Drug Administration on when viral vectors from the same class will be considered sufficiently different for purposes of awarding orphan drug designation or exclusivity.

In addition, stakeholders want the FDA to better define, and provide examples of, the types of minor differences and additional features that would impact the agency’s “sameness” determination under the orphan drug regulations, and they seek assurance that the agency will share its lessons learned as it gains more experience in making such determinations for gene therapy products.

In a much-anticipated draft guidance issued… Read more »