XTL Announces the Completion of Hepatitis C Treatment Study

XTL Biopharmaceuticals has completed a Phase I study with XTL-6865. The primary goal of the trial was to evaluate safety and pharmacokinetic properties of XTL-6865 in patients with chronic hepatitis C.

XTL-6865, which targets the E2 envelope protein of the hepatitis C virus, is composed of two fully-human monoclonal antibodies and is administered intravenously. The study enrolled 32 patients into eight cohorts, each consisting of three treated patients and one placebo patient. Of the eight cohorts in the study, the first seven were single-administration cohorts with doses ranging from 5 to 2,400 mg. The eighth cohort received 1,200 mg for five consecutive days.

In this study, XTL-6865 was shown to be safe at high doses. The study also enabled the company to establish the pharmacokinetic properties of XTL-6865 in patients with chronic hepatitis C. For all single doses, the T-max was reached immediately at the end of the XTL-6865 infusion. For the highest single dose, 2,400 mg, the C-max was between 500 and 1,000 micrograms/mL and the t1/2 was approximately five days. For the lower single doses, the t1/2 was two to three days.

The study provided evidence of binding of the antibody to circulating virus and the formation of immune complexes, believed to be important for virus neutralization in the serum. No statistically significant changes in viral RNA were observed. Given the short duration of administration of XTL-6865, and the fact the patients in this study had a high rate of viral replication at baseline, no significant change in viral load was expected.

The results of this Phase I trial potentially pave the way for trials that would evaluate XTL-6865 in patients with hepatitis C undergoing liver transplantation or in chronic hepatitis C patients with low viral load. XTL intends to seek a collaborative partnership for the future development of this compound.