Flexible Regulatory Approaches for Cell/Gene Therapy CMC Info

FDA says it is formalizing and more broadly communicating a flexible regulatory approach to chemistry, manufacturing and controls for cell and gene therapies, a move the agency says is intended to speed development of innovative treatments while maintaining product quality standards. An FDA notice says details are being shared on how it applies regulatory flexibility to CMC requirements for cell and gene therapies as sponsors prepare biologics license applications, adding that the approach has already helped expedite development and is expected to continue guiding FDA review strategies.

FDA commissioner Marty Makary says the policy reflects the unique scientific and manufacturing challenges of cell and gene therapies. “These are common-sense reforms that will address the unique characteristics of cell and gene therapies and foster more innovation,” Makary says in the notice.

According to the agency, CBER has approved nearly 50 cell and gene therapies over the past decade, amid rapid growth in development programs targeting serious and life-threatening diseases with few treatment options. CBER director Vinay Prasad says the surge in submissions has required the agency to apply greater regulatory flexibility, particularly in manufacturing requirements. He says the Center’s experience has shown that such flexibility can support innovation without compromising regulatory rigor.

Cell and gene therapies are often complex, individualized products manufactured in small batches and under tight timelines, factors that can make traditional manufacturing expectations difficult to apply, the agency notes, adding that CBER has used its experience to identify flexibilities already permitted under existing regulations to better accommodate these therapies while still ensuring safety, purity and potency.

Historically, the agency has applied such flexibilities on a case-by-case basis, but that approach has not always been clear to developers. Vijay Kumar, acting director of CBER’s Office of Therapeutic Products, says the agency is now proactively communicating these approaches to ensure all sponsors understand what may be scientifically acceptable.Flexibilities FDA is announcing include:

Development flexibilities:

• Delayed full GMP compliance: Manufacturers are not required to fully comply with commercial GMP requirements under 21 CFR Part 211 before producing material for Phase 2 or Phase 3 trials, consistent with existing regulations for investigational products.
• Lifecycle-based validation: FDA will review process and analytical method validation using a lifecycle approach, recognizing that validation strategies evolve as development progresses.
• Permissive investigational specifications: Final drug substance and drug product specifications are not expected until late in development, allowing more flexible release criteria for investigational use when scientifically justified.
• Manufacturing changes during development: As programs advance toward licensure, the FDA will permit minor manufacturing changes supported by appropriate comparability data, without requiring excessive or burdensome analyses.

Commercial specification flexibilities

• Recognition of small populations: For therapies targeting ultra-rare diseases, FDA acknowledges that limited patient numbers constrain the number of manufacturing lots available to support traditional release specifications.
• Flexible release criteria at approval: CBER will consider justified flexibility in establishing product release specifications for cell and gene therapy BLAs, tailored to the specific product and process.
• Post-approval adjustment: Sponsors may revise and refine release acceptance criteria after approval, based on accumulated manufacturing experience demonstrating consistent product quality.

Process validation flexibilities

• Concurrent release: In certain cases, process performance qualification (PPQ) lots may be released and distributed before all PPQ protocol steps are fully completed.
• No fixed lot requirement: There is no requirement to provide three PPQ lots for validation.
• Science-based lot justification: FDA review will focus on whether the proposed number of PPQ lots is scientifically justified based on overall process understanding, rather than adherence to a fixed numerical expectation.