As of March 2023, 3,900 gene therapy trials were noted as ongoing, completed, or approved across 46 different countries. An analysis of the second quarter of 2024 by the American Society of Gene and Cell Therapy estimates that 2,068 gene therapies and 901 cell therapies are currently in development from pre-clinical to pre-registration stages. As of the first quarter of 2024, there were 32 gene and 68 cell therapies approved worldwide, as well as advances in genetic testing which are enabling improved treatment matching for patients with specific rare diseases.In late 2023, the FDA approved Casgevy, the first CRISPR-based therapy, for sickle cell disease. That milestone has been accompanied by rising IND activity and a wave of new guidance documents from regulatory agencies as genome editing and other individualized approaches move into more routine development. Numbers of gene and cell therapy trials are expanding rapidly. Here, we examine the regulatory mechanisms and market dynamics shaping how gene and cell therapies reach development and, ultimately, patients.
Regulatory frameworks that account for the specific development, manufacturing, and long-term safety monitoring requirements of gene and cell therapies are increasingly central to how these programs move forward.
Navigating regulatory guidelines is also consistently cited as one of the top obstacles for cell and gene therapy developers. In practice, the challenge is often less about whether pathways exist and more about understanding which pathways, designations, and guidance documents apply to a given program across jurisdictions.
Accelerated approval pathways represent one structural mechanism through which regulators are reducing time-to-market for rare disease therapies where unmet need is high and surrogate endpoint data may precede full clinical evidence. The FDA's Accelerated Approval Program is a prominent example of this. As of January 2023, the program had approved more than 300 accelerated approval applications, including four gene therapies.
Key global programs include:
In parallel, the FDA has also published draft frameworks intended to lower barriers for individualized therapies targeting specific genetic conditions, including the Plausible Mechanism Framework and draft guidance on innovative clinical trial designs for cell and gene therapy products studied in small populations.
Accelerated pathways also increase the importance of postapproval evidence planning. The FDA’s draft guidance on postapproval methods for capturing safety and efficacy data for cell and gene therapy products underscores that long-term monitoring infrastructure needs to be built into program design from the outset, rather than treated as a post-launch afterthought.
Orphan drug designation (ODD) is also supporting efforts to enable innovation while delivering therapies to patients more quickly. ODD is a special status which can be granted to specific drug development efforts that focus on delivering therapies for rare diseases. Studies aiming to develop gene or cell therapies for rare disease can apply for ODD status.
In the US, ODD status provides several key benefits:
ODD addresses a core commercial barrier in rare disease development: insufficient market size to justify development investment. By reducing regulatory fees and offering market exclusivity, it changes the economic calculus for sponsors considering genetically stratified or ultra-rare indications. Additionally, the associated tax incentives and fee reductions are an acknowledgement of the high costs involved in developing rare disease treatments, helping to make the cost of launching trials in these areas less prohibitive.
There is also a growing trend towards aligning regulatory standards on a global scale, with multiple governments recognizing the need to align key benchmarks in order to scale and develop rare disease treatments by reducing redundant regulatory submissions across participating jurisdictions.
Harmonisation efforts aim to reduce the regulatory redundancy that currently requires sponsors to navigate separately structured submissions across multiple jurisdictions—a significant operational burden in multi-country gene and cell therapy programmes.
For example, The International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH), a collaborative international network focused on implementing global best practices, has formed a specialist cell therapy group which focuses on discussing innovations and unique regulatory challenges within the cell and gene therapy landscape.
More recently, regulators have begun to standardize technical expectations for genome editing. The FDA has issued draft guidance on safety assessment of genome editing using next-generation sequencing, and international efforts have also produced an internationally recognized lexicon of gene editing terms. Both developments reduce the interpretive burden for sponsors running multi-country programs by clarifying what to measure and how to describe it across agencies.
A careful balancing act is required to encourage and accelerate innovation in gene and cell therapies while at the same time ensuring due processes are in place to protect patient safety and understand the side effects and long term impacts of pioneering treatments.
Regulatory strategy also needs to account for the execution constraints that sit downstream of approval pathways. Manufacturing bottlenecks, communication gaps, and specialist staff shortages can create delays that are not solved by expedited designations alone.
At the same time, many programs face persistent challenges identifying and enrolling genetically eligible patients, particularly when diagnosis is fragmented and eligibility criteria are variant-specific. Favorable pathways matter, but sponsors also need the systems to find patients, coordinate testing, and maintain long-term relationships that support follow-up and postapproval evidence generation.
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