A wave of FDA rejections reveals how CMC issues are becoming a leading barrier to approval in advanced therapy development.<\/p>\n
In July 2025, three high-profile gene and cell therapy programs were delayed or rejected by the US Food and Drug Administration (FDA).\u00a0<\/p>\n
Capricor\u2019s<\/a> CAP-1002, an allogeneic cell therapy for Duchenne muscular dystrophy, received a Complete Response Letter (CRL) due to incomplete clinical, CMC, and non-clinical data. Ultragenyx\u2019s<\/a> DTX401, an AAV-based gene therapy for glycogen storage disease type Ia, was issued a CRL citing manufacturing data gaps and facility readiness concerns. Rocket Pharmaceuticals’<\/a> Kresladi, an ex vivo lentiviral gene therapy for leukocyte adhesion deficiency-I, was also delayed due to outstanding CMC questions.<\/p>\n Despite targeting different diseases and using distinct platforms, all three programs were stalled not by safety or efficacy concerns, but by shortcomings in manufacturing readiness. The message from regulators is clear: without a robust CMC strategy and validated processes, clinical innovation alone is no longer enough.<\/p>\n These rejections are not isolated events. Recent data show that 74% of CRLs issued by the FDA<\/a> between 2020 and 2024 were driven by quality or manufacturing deficiencies. That includes gaps in process control, insufficient stability data, unvalidated analytical methods, or unresolved issues from Good Manufacturing Practices (GMP) inspections.\u00a0<\/p>\n And it\u2019s not just late-stage programs under scrutiny. According to Amy Gamber<\/a>, Founder of BioMeridian Consulting<\/a>, the FDA is also turning back early-stage submissions. \u201cAbout 40% of investigational new drugs (INDs) are being stopped or not accepted due to CMC issues,\u201d she noted. \u201cThese are often early-stage companies that have already poured months of effort and capital into getting ready. Then suddenly, they\u2019re told their CMC package isn\u2019t adequate. That means more delays, more costs, and more stress.\u201d<\/p>\n Rising regulatory expectations\u00a0<\/p>\n This shift reflects a broader evolution in regulatory expectations. As Tony Hitchcock<\/a>, a bioprocessing consultant with over 30 years\u2019 experience in advanced biologics, explained, gene therapy has progressed beyond proof-of-concept and into more mainstream development. \u201cRegulators now have a deeper understanding of the factors that influence safety and therapeutic functionality. In parallel, there have been significant advances in manufacturing processes and analytical tools for characterizing both production and final products. As a result, it\u2019s no surprise that regulators now expect more comprehensive and higher-quality data in CMC submissions, particularly around process performance and product characterization. Expectations are also rising for process consistency, especially with regard to batch-to-batch variability, purity and potency.\u201d<\/p>\n \u201cIt\u2019s no surprise that regulators now expect more comprehensive and higher-quality data in CMC submissions, particularly around process performance and product characterization.\u201d \u2013 Tony Hitchcock.<\/p>\n These rising expectations place even greater pressure on early-stage development decisions. Nowhere is the phrase “the process is the product” more accurate than in gene and cell therapy. Early decisions about vector type, cell source, expansion method, or gene-editing approach have far-reaching consequences. These foundational choices shape not just the product\u2019s performance, but its manufacturability, regulatory risk, and scalability.\u00a0<\/p>\n \u201cEarly-stage design choices must be made through the lens of eventual commercial feasibility,\u201d noted Arnaud Deladeriere<\/a>, President and Principal Consultant at Cell & Gene Consulting<\/a>. \u201cThat means selecting vector backbones and packaging systems compatible with scalable, well-characterized platforms; minimizing complex genetic elements that introduce variability or require bespoke analytics; and choosing host cell lines with documented performance in GMP settings. Too often, sponsors prioritize speed to IND and overlook critical factors like yield, stability, scalability, and regulatory history. By building cross-functional alignment early \u2014 across research, process development, regulatory, and quality \u2014 teams can avoid painting themselves into a corner later.\u201d<\/p>\n Rethinking development strategy<\/p>\n Historically, many biotechs have prioritized early clinical milestones over manufacturing maturity, deferring CMC planning until proof of concept was established. This approach, driven by cost constraints and investor focus on clinical outcomes, frequently pushed process development, facility planning, and regulatory alignment to later stages. But, as regulatory expectations around manufacturing increase, developers are now beginning to reconsider this approach: investing earlier in manufacturing infrastructure, building internal teams with deep technical expertise, or forging strategic Contract Development and Manufacturing Organization (CDMO) partnerships.\u00a0<\/p>\n \u201cThe key is to view CDMO selection as a true partnership. Decisions should be based on capability, technical competence, and \u2014 critically \u2014 cultural alignment between organizations,\u201d noted Tony Hitchcock. \u201cFor some early stage biotechs, working with a smaller, highly specialized CDMO may be more effective than partnering with a large multinational, especially if the goal is to divest assets during clinical development.\u201d\u00a0<\/p>\n Relying on cost as the primary decision driver often leads to problems. Companies that try to reduce expenses by developing processes internally and then handing them off to a CDMO without proper alignment can encounter delays, rework, and unexpected costs. \u201cFortunately, several CDMOs now offer well-established production platforms for cell and gene therapies, and while upfront costs may be higher, the value of their experience and infrastructure can be substantial,\u201d said Tony.\u00a0<\/p>\n This kind of deep, early alignment is critical as therapies advance toward late-stage development. Regulatory agencies now expect sponsors to demonstrate that manufacturing changes, such as tech transfers, scale-up activities, or switching facilities, will not compromise product quality, safety, or efficacy. Without comprehensive comparability data, validated control strategies, and clear documentation, even minor process deviations can result in a CRL. For companies relying on external manufacturing partners, the strength of the CDMO relationship often determines how smoothly these transitions are managed and whether a product ultimately reaches approval.<\/p>\n New tools alongside new expectations\u00a0<\/p>\n While the regulatory bar is rising, the landscape isn\u2019t all caution and constraint. Advances in manufacturing platforms, analytics, and process standardization are helping developers to navigate CMC complexity with greater confidence.<\/p>\n \u201cThese include suspension-based HEK293 (Human embryonic kidney 293)\u00a0systems with standardized plasmid workflows, which are better suited for large-scale manufacturing. Modular, closed-system bioreactors and automated fill-finish technologies are also reducing contamination risks and improving reproducibility,\u201d Arnaud said. \u201cOn the analytics side, digital platforms that integrate real-time process data with quality readouts are enabling more proactive control strategies. Finally, there\u2019s a growing push toward standardized viral vector platforms \u2014 with common backbones, release methods, and analytics \u2014 which regulators are increasingly receptive to. These platforms reduce uncertainty, enable better comparability, and shorten development timelines.\u201d<\/p>\n At the same time, these technological advances are raising regulatory expectations. \u201cWeak CMC can compromise both your trial approval and your ability to secure marketing authorization,\u201d noted Amy Gamber. \u201cWe\u2019re seeing greater clarity, but also more specificity, in recent EMA and FDA guidelines. Potency assays are now expected in first-in-human trials. There\u2019s also increased scrutiny on non-viral delivery tools, validation, comparability, and safety testing. A few years ago, we were navigating these areas with limited guidance. Today, regulators are far more prescriptive about what they want to see.\u201d<\/p>\n Smart sponsors are taking note. The regulatory bar isn\u2019t just higher \u2014 it\u2019s moving. Those who anticipate where it\u2019s heading and build with that in mind will be better positioned to advance through development and bring products to patients faster.<\/p>\n","protected":false},"excerpt":{"rendered":"A wave of FDA rejections reveals how CMC issues are becoming a leading barrier to approval in advanced…\n","protected":false},"author":2,"featured_media":57342,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[50],"tags":[200,79],"class_list":["post-57341","post","type-post","status-publish","format-standard","has-post-thumbnail","category-genetics","tag-genetics","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/57341","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=57341"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/57341\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/57342"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=57341"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=57341"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=57341"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}