TXL for hepatitis B safe, effective in phase 2a study

SHANGHAI — Study results showed tenofovir exalidex to be safe and effective for treating healthy patients with hepatitis B, according to a presenter at the Asian Pacific Association for the Study of Liver annual meeting.

Tawesak Tanwandee, MD, associate professor of medicine in the division of gastroenterology at Siriraj Hospital, Bangkok, Thailand, presented data from the ongoing phase 2a study of tenofovir exalidex (ContraVir), or TXL. TXL is a novel lipid acyclic nucleoside phosphonate that delivers high intracellular concentrations of the active antiviral agent tenofovir, marketed as Viread (tenofovir disoproxil fumarate, Gilead Sciences), according to the manufacturer.

According to Tanwandee, high levels of tenofovir in the blood have been associated with kidney and bone toxicities, whereas the low levels of tenofovir seen in the current studies of TXL may mitigate these adverse effects.

The study included two cohorts: the CTRV-CMX-102 study of 50 healthy volunteers, with 10 patients receiving placebo, and the CTRV-CMX-201 study of 49 patients with HBV, with eight patients receiving Viread. There were no serious adverse events or discontinuation for adverse events in either study group.

The healthy volunteer group taking TXL saw approximately 30% decrease in AUC with high fat meal and no accumulation between day 1 and day 14 of the study. The results for the HBV group showed approximately dose-proportional pharmacokinetics with increasing doses from 5 mg up to 100 mg and no accumulation between day 1 and day 14. There were lower levels of free tenofovir in the patients taking TXL compared with the eight patients receiving Viread.

The pharmacokinetic results were consistent with once a day dosing and TXL can be taken with or without food.

“Successful HBV treatment will be treatment with combinations of drugs, like for HIV and HCV,” Tanwandee told Healio.com/Hepatology. “The next steps for TXL will be testing it in combination with other drugs that are active against HBV. These study results are promising steps toward patients having a wide choice of effective HBV treatments in the future. TXL has the potential to be a key component of future, successful combination treatments for HBV infection.” – by Talitha Bennett

Reference: Tanwandee T, et al. Abstract OP221. Presented at: The Asian Pacific Association for the Study of the Liver Annual Meeting 2017; Feb. 15-19, 2017; Shanghai.

Disclosure: Tanwandee reports no relevant financial disclosures.