Clinical trial halted after patient became ill

Targeted Genetics put its leading clinical trial on hold yesterday after one of the enrolled patients became seriously ill.

The Seattle biotechnology company said Tuesday that the decision to halt the testing of its inflammatory arthritis drug followed recent discussions with the U.S. Food and Drug Administration. The program will be suspended while additional data is gathered, the company said in a statement.

"We're no longer administering the drug to any patients," said Targeted Genetics spokeswoman Stacie Byars, who added that the company also is monitoring those who have received the therapy.

At this juncture there's not enough evidence to draw any conclusions as to whether the adverse effects were tied to the experimental drug, Byars said.

The company did not provide more specific information about the ill patient's symptoms.

The early-stage study was designed to measure the safety and effectiveness of different doses of the drug.

A major slowdown in the drug's development could be a significant setback for Targeted Genetics, which currently doesn't market any therapies.

But it's still too early to say whether "this is just a hiccup or a permanent hold on the program," said Paul Latta, a Seattle-based analyst with McAdams Wright Ragen.

"The drug could very well still be a viable candidate; we just don't know," Latta said.

About 127 patients have received an initial dose of the active drug or a placebo since the trial began in October 2005, and some 74 patients had a second dose of the active treatment, the company said.

The drug, known as tgAAC94, is designed to be used along with other therapies.

Targeted Genetics is also working on therapies for human immunodeficiency virus, congestive heart failure and Huntington's disease.

Targeted Genetics shares closed at $2.63, down 13 cents or 4.71 percent.

Ángel González: 206-515-5644 or agonzalez@seattletimes.com