EMA Regulation of Stem Cell Therapies

The European Medicines Agency regulates stem cell products under the Advanced Therapy Medicinal Products regulation, which came into force in 2009 and covers gene therapies, somatic cell therapies, and tissue-engineered products across the EU through a single centralized review by the Committee for Advanced Therapies [1]. This is a more centralized system than the FDA's, since a single EMA authorization applies across all EU member states at once rather than requiring separate national approvals.

Holoclar became the first stem-cell-containing ATMP recommended for approval in the EU. It is an ex vivo expanded autologous human corneal epithelial cell product containing limbal stem cells, used to treat moderate to severe limbal stem cell deficiency caused by chemical or physical burns to the eye [2][3]. The European Commission granted Holoclar conditional marketing authorization on 17 February 2015, based partly on evidence that 72% of 104 patients had a stable corneal surface at one year after implantation [2][4]. On 22 February 2024, the Commission converted that conditional authorization to a full, standard marketing authorization, making Holoclar the longest-standing fully approved stem cell medicine in the EU [4][5].

Alofisel (darvadstrocel) was the only other EMA-approved mesenchymal stem cell product, and its regulatory history illustrates how commercially fragile even a successful ATMP approval can be. Alofisel uses expanded allogeneic adipose-derived stem cells to treat complex perianal fistulas in adults with Crohn's disease whose fistulas had not responded adequately to at least one conventional or biologic therapy. The European Commission approved it on 23 March 2018 [6][7]. On 13 December 2024, the Commission withdrew Alofisel's marketing authorization at the request of its manufacturer, Takeda, which stated it was permanently stopping marketing of the product in the EU for commercial rather than safety reasons [8][9]. As of this withdrawal, Holoclar is the only fully approved stem-cell-based ATMP remaining on the EU market.

Withdrawal is common across the EU's broader ATMP category, not just for stem cell products specifically. A review of ATMPs with EMA marketing authorization found that 22% of all approved ATMPs, seven out of thirty-two products, had been withdrawn, and six of those seven withdrawals were driven by commercial reasons rather than new safety or efficacy concerns [10]. Named examples of withdrawn or discontinued ATMPs include ChondroCelect, a cartilage cell product withdrawn from the market effective 30 November 2016 [11]; Provenge, a prostate cancer cell therapy; Zalmoxis, a genetically modified T-cell therapy; MACI, a matrix-induced autologous chondrocyte implant; and Glybera, the first EU-approved gene therapy, whose authorization was not renewed after it expired in October 2017 [10][12].

The regulatory pipeline continues to add candidates behind these two headline products. Waskyra, a gene-modified hematopoietic stem cell therapy for Wiskott-Aldrich syndrome, received a positive opinion from the Committee for Advanced Therapies in 2025, putting it on track for possible approval [13]. The CAT's own quarterly reporting tracks this pipeline alongside the shrinking list of currently marketed ATMPs [12].

The pattern across both US and EU regulation tells a consistent story: getting a stem cell product through rigorous trials to full approval is difficult and rare, and staying on the market afterward is not guaranteed even for products that clear that bar. Readers should treat 'EMA-approved' or 'ATMP-classified' marketing claims from any clinic with the same scrutiny given to FDA claims, since classification as an ATMP under evaluation is a regulatory category, not proof of approval or efficacy.