lost a quarter of their value in Monday's after-hours session after the biotech company said it was discontinuing clinical trials on a rheumatoid arthritis treatment.
Vertex and development partner
ended a phase 2-B trial of its pralnacasan oral treatment for rheumatoid arthritis after an animal toxicity study showed liver abnormalities after nine months of high doses.
The company and the FDA agreed that two shorter-term ongoing phase 1 trials will continue as planned, as the toxicity findings didn't imply safety concerns in the significantly shorter Phase I trials.
"This is an unexpected toxicology finding, and the prudent action is to discontinue the ongoing Phase II clinical studies and fully evaluate the toxicology results before moving ahead," Aventis said in a statement. "We are committed to working with Vertex to better understand and hopefully resolve this issue."
No significant adverse events associated with liver toxicity were found in subjects and patients who participated in pralnacasan studies.
The shares were recently crossing on Instinet at $9.41, down $3.24, or 25.6%, from their 4 p.m. EST close.
Vertex also said it lost $86.4 million, or $1.12 a share, in the latest third quarter compared with a loss of $33.5 million, or 44 cents a share, last year. The latest period included a $42.4 million lease-restructuring charge. Total revenue in the latest quarter was $18.4 million, compared with $34.3 million in 2002.