Targeted Genetics Corporation of Seattle, Washington, a biotechnology company focused on the development and manufacturing of gene delivery technologies, presented additional positive data from its initial phase I clinical trial of tgAAC94 for the treatment of inflammatory arthritis at the 13th Annual Congress of the European Society of Gene Therapy, held in Prague, Czech Republic, October 29–November 1.

The trial was designed to evaluate the safety of a single dose of tgAAC94, an intra-articular recombinant AAV vector that encodes a soluble form of the tumor necrosis factor-alpha (TNF-α) receptor (TNFR:Fc), injected locally into the arthritic joint of patients suffering from inflammatory arthritis who are not currently receiving concomitant TNF-α antagonist therapies. 

Fifteen patients were randomly assigned to receive either one of two escalating dose levels of tgAAC94 (n = 11) or a placebo (n = 4).  The reported study results now include data from patients followed for 12 weeks (as opposed to only 4 to 8 weeks after injection). 

Although the study was not powered to demonstrate efficacy, in the 11 patients treated with a single dose of tgAAC94, continued measurable improvements in swelling and tenderness were observed, with a reduction in mean scores appearing to be greater at the higher dose, suggesting a dose response. No drug-related serious adverse events have been reported to date.

In October 2005, Targeted Genetics Corporation initiated a 40-patient, double-blind, placebo-controlled (with an open-label component) follow-on phase I clinical trial of tgAAC94 to evaluate the drug at two dose levels in patients with rheumatoid arthritis, psoriatic arthritis, or ankylosing spondylitis who may be receiving concomitant treatments of TNF-α blockade therapy.       

—A. Techman