The principal purpose of the phase I clinical trial is to establish the safety of the VRX496 therapy in patients failing two or more HAART regimens. Each of the five patients in the clinical trial has been dosed with a single infusion of VRX496, and none has experienced any serious adverse events related to the treatment.
In addition to this demonstration of safety, each of the three patients who has completed a one-year post-dosing assessment unexpectedly showed a clinically significant decrease in viral load, which is a measure of HIV’s presence in the body.
The fourth and fifth patients have completed their six- and three-month assessments, respectively, and their viral loads remain stable. The one-year post-dosing assessments of these two patients will be completed in July and September 2005.
In addition to these viral load findings, the CD4 T cells, typically destroyed by HIV, remain stable in the first patient and increased by 20% and 35% in the second and third patients, respectively. The fourth and fifth patients’ CD4 T cell counts also remain stable.
“We believe the VirxSys’ VRX496 therapy has the potential to become the next generation of HIV treatment,” said Dr Riku Rautsola, CEO-designate of VirxSys. “The patients in our clinical trial have multiple-drug resistant HIV, but nevertheless are responding well to this gene therapy.”
In addition to the favorable impact on patient viral load and CD4 T cell counts, data from the clinical trial suggest that the VRX496 is restoring a healthy immune system in these HIV patients. Three of the five patients in the trial developed an improved immune response to HIV and also to diphtheria toxin.
Based on these promising results from the phase I clinical trial, VirxSys plans to meet with the FDA in early March 2005 to present phase I results and discuss plans for a controlled, multicenter, multi-dose trial.
Based on a favorable outcome from this meeting, VirxSys would commence a phase II study in the Q2 2005. A separate phase I/II clinical trial examining the potential role of VRX496 in extending HIV patients’ drug holidays will be started simultaneously at the University of Pennsylvania.