Two Patient Deaths Force Vertex to Pause Diabetes Trial

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Pictured: Man in suit holding up his hand in a stop sign/iStock, turk_stock_photographer

Vertex Pharmaceuticals on Sunday reported that it had paused a Phase I/II study of its investigational islet cell therapy VX-880 in type 1 diabetes following two patient deaths.

In its announcement, the Boston, MA–based company said that the deaths were “unrelated” to the study treatment and that the study pause was “protocol-specified.” Global regulatory authorities and an independent data monitoring committee will review the “totality of the data” from this study.

VX-880 is an investigational, stem cell–derived insulin-producing islet cell therapy that Vertex says restores the pancreas’ ability to release insulin in response to blood glucose levels. According to Vertex’s website, the candidate is fully differentiated and is designed to be infused in the hepatic portal vein and be used in conjunction with standard immunosuppression.

Vertex is currently running a three-part Phase I/II study of VX-880 in patients with type 1 diabetes who have recurrent hypoglycemic events and an impaired awareness of hypoglycemia. As of the last data cut-off, Vertex had already dosed 14 patients, all of whom showed islet cell engraftment and were able to produce endogenous insulin.

Additionally, VX-880 lowered HbA1c levels in patients to below 7% and eliminated the need for exogenous insulin.

Aside from the two patient deaths, Vertex reported that VX-880 had a safety profile consistent with that of immunosuppressives. The company had previously released data for VX-880 in October 2023 showing that two patients who had been in the study for at least 12 months did not experience serious hypoglycemic events between 90 days and 12 months. At the time, Vertex also said that VX-880 was “generally well tolerated,” with most adverse events being mild or moderate in severity.

In May 2022, the FDA placed a clinical hold on VX-880, citing concerns about dose escalation. According to the regulator, there was not enough information at the time to support increasing the dose of the islet cell therapy in patients. The FDA lifted the regulatory pause in July 2022.

Vertex also provided updates for several of its programs in its Sunday press announcement. Most notable, however, was the absence of highly-anticipated data from the Phase III program of its acute pain candidate VX-548.

The company said in its news release that it had completed three Phase III studies for VX-548 in acute pain, but that its results will be available in “early 2024.”

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

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