Orphan Exclusivity For Gene Therapies Hinges On Two Big Factors
US FDA draft guidance says that ‘minor differences’ in transgenes and/or vectors won’t be enough for orphan exclusivity, but agency will consider ‘additional features of the final product’ in making the determination.
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Gene Therapies: US FDA Clarity Needed On ‘Sameness’ Determinations For Products From Same Vector Class
Agency also should better define, and provide examples of, the types of minor differences and additional features that would affect orphan drug designation and exclusivity determinations, industry sponsors say in comments on January draft guidance.
For two gene therapies with the same transgenes and/or vectors but different promoters, the US FDA’s ‘sameness’ determination under the orphan drug regulations will consider whether that difference has any impact on product activity, the agency's Wilson Bryan says.
US FDA declined stakeholder requests to remove recommendation for placebo controls from a final guidance but added qualifying language on their use ‘when feasible.’ While the agency excised language on biomarker validation from the final guidance, it reaffirmed the need for early establishment of critical quality attributes and critical process parameters.