VIENNA — The Medical University of Vienna presented results from the TTVguideIT clinical trial at the annual congress of the European Society of Nephrology. The study demonstrated that Torque-Teno-virus (TTV)-guided dosing of tacrolimus is non-inferior to standard treatment in kidney transplant recipients.

The TTVguideIT clinical trial evaluated TTV-guided dosing of immunosuppressants. The study was part of the EU-funded Horizon 2020 project TTVguideTX, which received over six million euros in funding over five and a half years and involved twenty partners from ten European countries.

TTV is present in many individuals, does not cause disease, and serves as an indicator of immune system activity. Low TTV levels may indicate an overactive immune system, while high levels may indicate an underactive immune system. "Our aim was to adjust immunosuppression not only according to fixed drug levels, but to align it more closely with the patients' actual immunological status." Gregor Bond said, project coordinator from the Division of Nephrology and Dialysis at the Department of Medicine III at Medical University of Vienna.

The Phase II randomized, controlled trial enrolled 260 adult kidney transplant recipients with low immunological and infectious disease risk. The study took place at 13 academic centers in Austria, Germany, France, the Czech Republic, the Netherlands, and Spain. Patients were randomized four months after transplantation to receive either TTV-guided tacrolimus dosing or standard treatment.

The primary study endpoint measured the occurrence of infections, graft rejection, graft loss, or death. The composite primary endpoint occurred in 35 percent of patients in the TTV-guided group and 38 percent of patients in the control group. Patients in the TTV-guided group maintained lower tacrolimus levels and received lower daily dosages. The trial did not demonstrate a statistical difference in infections.

Bond stated that TTV measurement is approved for clinical use, is cost-effective, easy to measure, and readily standardized. "This approach therefore has the potential to be widely used in further clinical trials and, later, possibly in routine clinical practice," Gregor Bond said. A follow-up multicentre study is currently underway in France, investigating the TTV-guided approach from the second year post-transplant onwards.