July 17, 2008

Chelsea Reports Progress in Phase II Arthritis Trial

Chelsea Therapeutics has completed nearly 75% of the planned enrollment in its Phase II trial of CH-1504 in rheumatoid arthritis initiated in January 2008.

To date, Chelsea has enrolled 147 of the planned 200 patients for this 12-week, four-arm, parallel group trial comparing 0.25mg, 0.5mg and 1mg once daily oral doses of CH-1504 to a 20mg once weekly oral dose of methotrexate (MTX). Of the 147 patients currently enrolled in the trial, 41 have completed treatment.

The primary efficacy endpoint of this study is to determine the percent of patients with ACR 20 response at the end of 12 weeks. An ACR 20 response is a standard efficacy measure that requires at least a 20% improvement in a number of different measures of disease activity.

As the improved safety and tolerability of CH-1504 is expected to be a significant advantage over MTX, the trial will also compare a cluster of gastrointestinal system related adverse events, such as nausea, vomiting, and diarrhea, frequently seen with MTX use as well as closely monitor the results of standard liver function tests across dose groups.

Based on current rate of recruitment, enrollment and treatment completion, Chelsea anticipates that the trial will be fully enrolled and that half of the patients (100) will have completed drug treatment by the end of September, 2008 enabling the data safety monitoring board to conduct its planned review early in the fourth quarter of 2008.