- The Food and Drug Administration has stopped Vertex from continuing a clinical trial testing a promising cell therapy for Type 1 diabetes, judging the company has "insufficient information" to study a higher dose of the treatment as planned.
- The clinical hold, which Vertex announced in a statement Monday, comes after startlingly positive results from the first patient given the therapy, known as VX-880. Nine months after the treatment, that patient no longer needed to take synthetic insulin, while blood and laboratory testing indicated his body was producing its own.
- Vertex treated the first and second patients in its trial with a half dose and, following the recommendation of independent trial monitors, treated a third with a full dose in the second phase of the study, which is meant to enroll four other participants. That progression seems to be what the FDA is questioning with its hold, which Vertex said it would work to address.
From Vertex's perspective, the results it's obtained from the first two patients in its study represent "proof of concept" for a treatment that's designed to replace the insulin-producing cells destroyed by Type 1 diabetes with ones made from stem cells.
Initial results from the first patient, released last October, helped to validate the company's approach, which was developed over decades by the laboratory of Doug Melton, a Harvard University professor who recently joined Vertex as a distinguished fellow. (Melton founded a biotech company called Semma Therapeutics, which Vertex bought in 2019 for nearly $1 billion.)
That patient no longer needs to inject himself with synthetic insulin, and further follow-up data indicates his body is now able to control blood sugar levels. According to Vertex, a second patient has been able to reduce insulin use by about a third and shows signs that treatment is restoring insulin production as well.
A third patient, who was given a full dose of VX-880, is only 29 days out from treatment and will be more comprehensively examined after three months.
No serious adverse reactions have been reported, while the most commonly reported side effects were judged unrelated to treatment.
However, the FDA, at least according to Vertex, doesn't agree the company has enough information to proceed with "dose escalation," an industry term for evaluating progressively higher doses of a treatment.
"We are surprised by the clinical hold placed on the study," said Carmen Bozic, Vertex's chief medical officer, in a statement.
The company said it will work with the agency to understand and address its concerns "so that the trial can resume at U.S. sites as soon as possible." Nine of the 10 study sites are located in the U.S., while the 10th is in Montreal, according to a federal database of clinical trials.
Overall, Vertex intends to enroll 17 patients in the early-stage trial, which is divided into three phases.
VX-880 consists of pancreatic islet cells that are derived from stem cells and differentiated into their mature form. It's administered by an infusion into a vein that conveys blood to the liver. Patients treated with VX-880 must take immunosuppressants so their immune system doesn't destroy the islet cells.
Vertex is also working on another version of VX-880 "encapsulated" in an immunoprotective device that's surgically implanted. The company aims to ask the FDA later this year for clearance to begin human testing.
The hold is an unexpected roadblock, however, and it's unclear what impact the delay might have on Vertex's plans. According to Michael Yee, an analyst at Jefferies, recent clinical holds for cell therapies have been lifted quickly, generally within four to five months.
"We're hopeful for a speedy resolution and [management] also indicated they are being very transparent [with the] FDA," Yee wrote in a May 2 note to clients.
Vertex shares fell 5% in early trading Monday.