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.
Researchers from Duke and UNC team up to find an answer, with funding from the two institutions’ NIH Clinical and Translational Science Awards (CTSA).
For hundreds of millions of people around the world with chronic hepatitis B infection, anti-viral treatments do a good job of keeping the virus under wraps. Anti-viral treatments are essential in slowing damage to the liver, reducing the chance of liver cancer, and helping people live longer. But in the vast majority of cases, there is no end to the infection. If a patient stops medication for any reason, the hepatitis B virus (HBV) re-emerges. The cause of its resilience is circular bits of DNA, called covalently closed circular DNA, or cccDNA, that lurk in the liver cells of infected patients.
“Treatment blocks new viral replication,” said Lishan Su, a professor of microbiology and immunology at the University of North Carolina, Chapel Hill. “It doesn’t touch this cDNA.” When treatment stops, new virus is produced from these cccDNA templates, he continued. As a result, “you need almost lifetime (or very long-term) treatment.”