Vertex Presents Positive Data for Zimislecel in Type 1 Diabetes at the American Diabetes Association 85th Scientific Sessions

Vertex Pharmaceuticals Incorporated (Nasdaq: VRTX) today announced simultaneous presentation and publication of updated data from the Phase 1/2 portion of the Phase 1/2/3 FORWARD-101 clinical trial of zimislecel (VX-880), an investigational stem cell-derived, fully differentiated islet cell therapy, in people with type 1 diabetes (T1D) with impaired hypoglycemic awareness and severe hypoglycemic events (SHEs). The data were featured in an oral presentation at the American Diabetes Association (ADA) annual conference in Chicago as part of the symposium, “Innovation and Progress in Stem Cell-Derived Islet-Cell Replacement Therapy,” from 6:15-6:30 p.m. CT (abstract 2025-A-1921) and published online by the New England Journal of Medicine.

The data are from 12 patients who received the full dose of zimislecel as a single infusion and were followed for at least one year, as of October 2024. Results from the study to date continue to demonstrate the transformative potential of zimislecel with consistent and durable patient benefit with longer follow-up. All 12 participants:

• Demonstrated engraftment with glucose-responsive endogenous C-peptide production, which was durable through one year of follow-up.
• Achieved the ADA targets of HbA1c <7% and time in range of >70%.
• Were free of SHEs from day 90 onwards.
• Had a reduction in exogenous insulin use (mean reduction in daily insulin dose: 92%).
  • 10/12 (83%) no longer required exogenous insulin at Month 12.
• Achieved the Phase 1/2 primary endpoint of elimination of SHEs with HbA1c <7%.

Zimislecel continues to be generally well tolerated. Most adverse events (AEs) were mild or moderate, and there were no serious AEs related to zimislecel treatment. As previously reported, two patient deaths occurred, both unrelated to treatment with zimislecel. The safety profile is generally consistent with the immunosuppressive regimen used in the study, the infusion procedure, and complications from long-standing diabetes.

“These data on the first fully differentiated, stem cell-derived, off-the-shelf islet cell therapy continue to be unprecedented. The magnitude, consistency and durability of the results from all 12 patients with more than one year of follow-up reinforce the transformative potential of zimislecel for people living with T1D complicated by severe hypoglycemia,” said Carmen Bozic, M.D., Executive Vice President, Global Medicines Development and Medical Affairs, and Chief Medical Officer at Vertex. “We are excited to complete enrollment and dosing in the Phase 1/2/3 Program and look forward to potential regulatory submissions next year.”