Vertex's Viacyte Backs Out of CRISPR Diabetes Deal

Vertex Pharma_iStock, hapabapa

Pictured: Entrance to Vertex's office in Boston, Massachusetts/iStock, hapabapa

Vertex Pharmaceuticals’ subsidiary ViaCyte Inc. is not pushing through with its diabetes deal with CRISPR Therapeutics, the Swiss biotech announced Monday.

The partners—which had recently won the FDA’s approval for Casgevy (exagamglogene autotemcel), the first CRISPR-based gene therapy for sickle cell disease—were supposed to advance a gene-edited stem cell therapy for diabetes. Vertex’s opt-out of the deal will take effect in early February 2024.

As per the original agreement, which was signed in September 2018 between ViaCyte and CRISPR, the biotechs would combine ViaCyte’s stem cell expertise with CRISPR’s gene editing technologies to develop a potential beta-cell replacement product that could help patients produce their own insulin without inducing an immune reaction.

In February 2022, the partners dosed the first patient in their Phase I trial of this allogeneic gene-edited cell replacement therapy, dubbed VCTX210.

Vertex bought ViaCyte a few months later, in July 2022, for $320 million in cash. At the time, CEO and president Reshma Kewalramani said that the acquisition would “accelerate our goal of transforming, if not curing T1D.” VCTX210, along with ViaCyte’s platform, was meant to complement Vertex’s own diabetes portfolio, headlined by VX-880, likewise a stem-cell derived insulin-producing islet cell therapy.

Now, because Vertex is backing out of the partnership, all ongoing collaboration assets will be completely owned by CRISPR, though ViaCyte will still be eligible for royalties on net future sales.  

Outside of the ViaCyte collaboration, Vertex is still partnered with CRISPR for a non-exclusive license to the latter’s CRISPR/Cas9 platform to develop a potentially curative cell treatment for type 1 diabetes. This agreement was signed in March 2023 and saw Vertex pay $100 million upfront, as well as pledge up to $230 million in research and development milestones, plus royalties.

ViaCyte opting out of the CRISPR partnership comes one day after Vertex Pharmaceuticals announced that it had paused the Phase I/II study of VX-880 following two patient deaths. The company had found that the mortalities were unrelated to the study drug and said that the suspension was “protocol-specified.” Global regulatory authorities and an independent data monitoring committee will review the data from that study.

Aside from VX-880, Vertex is also advancing VX-264 for type 1 diabetes, for which it is currently in Phase I/II assessments. The candidate uses stem cell–derived islet cells encapsulated in a protective device, which in turn will be implanted into a patient and help produce insulin. According to Vertex’s website, the device protects VX-264 from the immune system, thereby eliminating the need for immunosuppressive therapy.

Tristan Manalac is an independent science writer based in Metro Manila, Philippines. He can be reached at or

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