( LUND Sweden March 13 2007--Active B...)Active Biotech's I-3D Micro-dosing Clinical Trial Concluded,Health

LUND, Sweden, March 13, 2007--Active Biotech AB (Stockholm:ACTI.ST) and Chelsea Therapeutics International Ltd (NASDAQ:CHTP) has performed a first human micro-dosing trial of an I-3D compound.

The aim of the study was to determine the pharmacokinetic characteristics of the compound in humans. The trial was performed in healthy volunteers.

The study demonstrated that the selected I-3D compound (ABR-224050) has pharmacokinetic properties that make it well suitable for once daily oral administration.

Based on the results of the micro-dosing study, it has now been determined that the compound has a half-life of around 60 hours, which is significantly shorter than that of a comparable substance; Arava® (Sanofi Aventis). However, this half-life is in the long range compared to the target for the project.

Prior to initiating further Phase I clinical trials, the Active Biotech and Chelsea Therapeutics Joint Development Committee therefore plans to continue preclinical optimization of ABR-224050 and conduct further comparisons versus other compounds in the I-3D portfolio during 2007.

As a consequence, the current plan to start Phase I trials in 2007 has been modified and further I-3D Phase I trials are now expected to commence 2008.

In May 2006, Active Biotech and Chelsea Therapeutics signed an agreement for the co-development and commercialization of the I-3D portfolio, a group of orally active compounds that inhibit the enzyme dihydroorotate dehydrogenase (DHODH), for the treatment of primarily rheumatoid arthritis, RA. At the time of the agreement, Active Biotech had already isolated more than 15 compounds and conducted extensive preclinical modeling resulting in the identification of two potential lead compounds. Pursuant to the agreement, a Joint Development Committee was established to direct the continued development of I-3D compounds with the initial objective of sel
'"/>