The FDA released additional CBER draft guidance detailing how cell and gene therapy developers can leverage prior knowledge. The agency outlined the types of information companies may reuse across clinical, nonclinical, and manufacturing-related activities. The guidance is positioned as an extension of broader FDA flexibility efforts intended to reduce redundant work and accelerate development timelines when scientifically justified. For developers, it clarifies how prior evidence can support parts of study design and manufacturing work, potentially improving planning efficiency and reducing avoidable experimentation. Companies and CDMOs are expected to scrutinize what qualifies as “prior knowledge” and how it can be documented in submissions to support regulatory decision-making.