Once just a theory, gene therapies are now a therapeutic reality for some patients. These platforms may have the potential to treat and cure some of our most intractable and vexing diseases. The policy framework we construct for how these products should be developed, reviewed by regulators, and reimbursed, will help set the stage for the continued advancement of this new market. Last year, we announced our comprehensive policy framework for regenerative medicine, including a draft guidance that describes the expedited programs, such as the breakthrough therapy designation, and the regenerative medicine advanced therapy (RMAT) designation, that may be available to sponsors of these therapies. Today, we’re unveiling a complementary framework for the development, review and approval of gene therapies.
Scott Gottlieb, MD
In the past 12 months, we’ve seen three separate gene therapy products approved by the FDA. This reflects the rapid advancements in this field. An inflection point was reached with the development of vectors that could reliably deliver gene cassettes in vivo, into cells and human tissue. In the future, we expect this field to continue to expand, with the potential approval of new treatments for many debilitating diseases. These therapies hold great promise. Our new steps are aimed at fostering developments in this innovative field.
Gene therapies are being studied in many areas, including genetic disorders, autoimmune diseases, heart disease, cancer and HIV/AIDS. We look forward to working with the academic and research communities to make safe and effective products a reality for more patients. But we know that we still have much to learn about how these products work, how to administer them safely, and whether they will continue to work properly in the body without causing adverse side effects over long periods of time. In contrast to traditional drug review, some of the more challenging questions when it comes to gene therapy relate to product manufacturing and quality, or questions about the durability of response, which often can’t be fully answered in any reasonably sized pre-market trial. For some of these products, we may need to accept some level of uncertainty around these questions at the time of approval. For example, in some cases the long-term durability of the effect won’t be fully understood at the time of approval. Effective tools for reliable post-market follow up, such as required post-market clinical trials, are going to be one key to advancing this field and helping to ensure that our approach fosters safe and innovative treatments.
Even when there may be uncertainty about some questions, we need to make certain we assure patient safety and adequately characterize the potential risks and demonstrated benefits of these products. In part because of the added questions that often surround a new technology like gene therapy, these products are initially being aimed at devastating diseases, many of which lack available therapies, including some diseases that are fatal. In such cases of devastating diseases without available therapies, we’ve traditionally been willing to accept more uncertainty to facilitate timely access to promising therapies. In such cases, drug sponsors are generally required to conduct post-marketing clinical trials, known as phase 4 confirmatory trials, to confirm clinical benefit of the drug. This is the direction Congress gave the FDA by creating vehicles like the accelerated approval pathway.
When it comes to novel technologies like gene therapy, the FDA is steadfastly committed to a regulatory path that maintains the agency’s gold standard for assuring safety and efficacy. As we develop this evidence-based framework, we’re going to have to modernize how we approach certain aspects of these products in order to make sure our approach is tailored to the unique challenges created by these new platforms.