Vertex and Enlaza Therapeutics Partner to Advance Gene Therapy and Autoimmune Disease Treatments

CAMBRIDGE, M.A., September 2, 2025 – Vertex Pharmaceuticals has entered into a strategic partnership with Enlaza Therapeutics to develop next-generation conditioning drugs for its sickle cell and thalassemia gene therapy, Casgevy, and to explore new treatments for autoimmune diseases. The collaboration, announced today, is centered on Enlaza’s proprietary permanently binding “small format” drug conjugates and T cell engagers.

Under the terms of the deal, Vertex will provide a $45 million payment, including an upfront payment and an equity investment in Enlaza. Enlaza is eligible to receive over $2 billion in future milestone payments over the four-year collaboration.

This partnership aligns with Vertex’s ongoing efforts to develop gentler conditioning regimens for Casgevy. The current treatment requires patients to undergo intense chemotherapy to prepare their bone marrow for the new gene-edited blood stem cells. This can lead to severe and long-term side effects, including infertility, and limits the patient population eligible for the therapy. A safer conditioning regimen could significantly broaden patient access to Casgevy.

Enlaza’s technology is based on creating protein drugs with permanent, covalent bonds. This is a departure from the typical, weaker noncovalent bonds used in protein drugs. Enlaza believes this approach will lead to safer and more effective antibody-based drugs by ensuring the treatment remains localized at the diseased cells, minimizing off-target effects on healthy cells.

While the specific autoimmune diseases to be targeted were not disclosed, this collaboration builds on Vertex’s prior partnerships with ImmunoGen and Orum Therapeutics to address the critical need for safer conditioning treatments. The pursuit of gentler conditioning regimens is a key focus for companies in the gene therapy space, including Beam Therapeutics, all aiming to make these potentially curative therapies more accessible and safer for patients.