Vertex (VRTX) Stock Falls After FDA Pauses Diabetes Study in Surprise Move

The study of a key new treatment for type 1 diabetes was put on hold by the U.S. regulators.

The FDA stopped the early-stage study of the product because there was not enough evidence to support an increase in the amount of the product. The drugmaker said it was surprised by the decision because the findings in the first two patients were promising.

Wall Street has been watching the development of VX-880. The product is a cell therapy that has the potential to reach blockbuster sales, which can be as high as $1 billion per year. Early results from the treatment have been trumpeted by the company as it works to shift its focus away from its core cystic fibrosis medicines.

The shares fell at 9:30 a.m. The time is in New York. The stock has gained 25% this year compared with a drop in the S&P 500.

When patients stop making enoughinsulin to control their blood sugar levels, it can lead to a variety of serious problems in the body. The majority of patients with diabetes have the type 2 form of the disease, which occurs when people respond insufficiently toinsulin made by the pancreas.

One patient in the study has received the full target dose of the drug, and early data shows improved control of blood sugar through 29 days. The company said that the patient had a serious adverse event of neutropenia, a low count of white blood cells, but it wasn't related to the drug.