US Food and Drug Administration (FDA) Commissioner Scott Gottlieb and Center for Biologics Evaluation and Research (CBER) Director Peter Marks on Tuesday detailed plans for the agency to keep pace with an expected influx of applications for cell and gene therapies over the coming years.
"The FDA is witnessing a surge of cell and gene therapy products entering early development, evidenced by a large upswing in the number of investigational new drug (IND) applications," Gottlieb and Marks say.
By 2020, Gottlieb and Marks say they expect to be receiving upwards of 200 INDs for cell and gene therapies each year, adding to the 800 active INDs for such products already filed with the agency. By 2025, they predict the agency will be approving between 10 and 20 cell and gene therapy products annually.
The two FDA leaders draw a comparison between the current landscape for cell and gene therapies to the proliferation of antibody drugs in the late 1990s once platforms for creating antibodies that wouldn't be rejected by a patient's immune system were widely available.
"In this case, it was the advent of safe and effective vectors for the delivery of gene therapy products, such as the adoption of adeno-associated virus (AAV) vectors," Gottlieb and Marks say.
To promote the continued development of new cell and gene therapies, Gottlieb and Marks say that FDA will take a number of steps, including adding as many as 50 additional reviewers to its staff, leveraging expedited pathways, issuing new guidance and taking enforcement action
against clinics that fail to comply with FDA regulations.
According to Gottlieb and Marks, accelerated approval is particularly relevant for gene therapies as the agency can mandate postmarket studies to measure the durability of the treatment and long-term safety issues that would be difficult to address in the premarket setting.
As for new guidance, Gottlieb and Marks say the agency will develop a series of clinical guidance documents for different areas of product development, such as gene therapies for inherited blood disorders and neurodegenerative diseases.
In some cases, Gottlieb and Marks say that a more traditional approach to drug development may be warranted for certain gene therapies, such as those intended to address the symptoms of a neurodegenerative disease or target an "expression of a protein or enzyme believed to play a role in the advance of the disease."
In another planned guidance, Gottlieb and Marks say the agency will tackle the manufacturing complexities of cell-based gene therapies, such as chimeric antigen receptor (CAR) T-cell therapies, in a future guidance.
"The guidance that we intend to issue will promote a better understanding of the critical quality attributes and other factors related to product manufacturing," they write, adding that one of their goals will be to minimize the need for bridging studies for minor manufacturing changes for cell therapies.
The two also say that FDA will issue a guidance later this year outlining how researchers can "pool their clinical data after following a common manufacturing protocol, and thereby develop a more robust data set for purposes of gaining a [Biologics License Application] BLA."