ContraVir reports positive Phase IIa trial data of tenofovir exalidex to treat Hepatitis B infection


US-based biopharmaceutical company ContraVir has reported positive data from its ongoing Phase IIa trial of tenofovir exalidex (TXL) to treat Hepatitis B infection.

TXL has been developed as a potent analog based on the successful antiviral drug tenofovir.

It features a liver-targeting structure that decreases circulating levels of tenofovir, thereby lowering systemic exposure and reducing chances of renal side effects.

The Phase IIa, multiple ascending-dose clinical trial is being conducted to evaluate tenofovir exalidex while treating 84 treatment-naïve patients with chronic HBV infection.

The study featured a sequential dose escalation format, according to which ten patients were divided in each cohort to receive daily dosages of 5mg, 10mg, 25mg, 50mg, 100mg, 150mg and 200mg of TXL, with two patients per cohort receiving 300mg of tenofovir disoproxil fumarate (TDF).

Results suggested that TXL has exhibited increased anti-viral activity while administered in its highest dose of 100mg.

"We believe demonstrating this unique profile for TXL may open many doors in terms of developing new combination therapies for HBV that have curative potential."

ContraVir CEO James Sapirstein said: "We are pleased with the antiviral profile that is being exhibited by TXL at this first stage in our clinical evaluation of this drug in HBV patients.

"TXL has shown an excellent safety profile, and we are encouraged that as we go to higher doses above 100mg we may see even greater antiviral activity with a continued excellent safety profile.

"We believe demonstrating this unique profile for TXL may open many doors in terms of developing new combination therapies for HBV that have curative potential."

Prompted by the positive data, the company is now planning to evaluate 150mg dosage of TXL following recent clearance of the product by the independent data safety monitoring board (DSMB).


Image: Ground glass hepatocytes seen in chronic hepatitis B liver biopsy. Photo: courtesy of Nephron.