April 1, 2025
Vertex Pharmaceuticals announced1 that its Practical Cure project, VX-264, will not continue advancement in clinical trials after the therapy failed to achieve performance milestones at the 90-Day mark. This news came last Friday during the company’s T1D program update.
Though the end to any Practical Cure trial is disappointing, Vertex clearly reiterates that it maintains its commitment to delivering a T1D cure. Its other T1D projects, and a series of new ones planned, will not be affected. Vertex remains the lead horse in the race for a sustainable beta cell supply solution.
We deeply appreciate and value this transparency and speed of communication. This consistent ability to provide timely and transparent updates—for better or for worse—is essential and unusual. This speed and clarity allow us to take the learning and move forward quickly onto the next test.
VX-264 Background
VX-264 was a phase I/II trial2 that transplanted insulin-producing, stem cell-derived beta cells into a patient with T1D. The cells used in this trial were the same as those used in VX-880, which demonstrated safety and efficacy in previous trials. This trial, VX-264, hoped to protect those cells from the body’s autoimmune attack. Instead of immunosuppression, the cells were protected from the T1D autoimmune attack with an encapsulation device.
The 90-Day follow-up revealed the therapy was safe and well tolerated, but C-peptide production (a hormone that indicates insulin production) was “not observed at levels necessary to deliver benefit,” resulting in the trial’s end. Carmen Bozic, M.D., Executive V.P. of Vertex, thanked those involved with the study and indicated the company will continue its encapsulation development: “Today’s data show that more work needs to be done to advance the ‘cells plus device’ program, and we are committed to doing so.”
Other T1D Updates
VX-880 (a.k.a. ‘Zimislecel’) is a phase III3 clinical trial testing the same proprietary cell line as VX-264, using full-body immunosuppression instead of an encapsulation device. This trial is on track and preparing to file a global regulatory submission for market approval in 2026. If successful, this would be the first FDA-approved stem cell-derived beta cell line. JDCA hopes the cell line itself will be widely available to researchers and will enable much wider and broader testing of solutions to stop the autoimmune attack.
Alternatives to full-body immunosuppression. Vertex continues research to pinpoint alternative approaches to overcoming the autoimmune attack in T1D. The company says that it will explore several different research pathways, including gene-edited islets to evade the immune system, encapsulation devices to protect transplanted cells, and alternative forms of immunosuppression that are safer and more tolerable to the body.
Footnotes
1. Vertex, “Program Updates for Type 1 Diabetes Portfolio,” March 28, 2025.
Vertex Pharmaceuticals’ press release announcing T1D program updates: VX-264 trial end, VX-880 future plans, and intention to pursue alternative methods of cell protection.
2. National Library of Medicine, “A Safety, Tolerability, and Efficacy Study of VX-264 in Participants With Type 1 Diabetes,” Accessed March 28, 2025.
Clinical trial database with detailed information on the VX-264 trial. Vertex Pharmaceuticals has not altered the status of the trial since announcing its closure.
3. JDCA, “Vertex T1D Trial Moves into Phase III,” November 21, 2024.JDCA article detailing Vertex Pharmaceuticals’ VX-880 trial progression into phase III and the implications for solving the cell supply issue if approved for market.
