Gilead Sciences’ Vemlidy (tenofovir alafenamide) has been approved by the U.S. Food and Drug Administration (FDA) for the treatment of patients with chronic hepatitis B virus (HBV) infection with compensated liver disease.
Findings have shown that the Vemlidy treatment is safer than Gilead’s earlier therapy Viread (tenofovir disoproxil fumarate). Both drugs give rise to the same compound once inside the body, but molecular differences allow Vemlidy to be given at a dose only one-tenth of Viread, substantially lowering the risk of side effects.
The approval of Vemlidy (25 mg, once-daily) rests on data from two Phase 3 studies, including a total of 1,298 patients. The two studies enrolled patients who had been treated with other drugs at an earlier time, and those who had never been treated.
One of the studies (NCT01940341) focused on 873 patients with disease that is positive for hepatitis B e antigen (HBeAg), while the other (NCT01940471) included 425 HBeAg-negative patients. Both studies compared Vemlidy to Viread during 48 weeks of treatment, and both studies achieved their primary endpoint — non-inferiority of Vemlidy compared to Viread, based on HBV DNA levels detected in patients after the treatment period.
An analysis of the collected data from both trials also showed that patients receiving Vemlidy experienced improvements in certain bone and kidney parameters, compared to those taking Viread. Patients receiving Vemlidy also had numerically higher rates of normalization of blood serum alanine aminotransferase (ALT) levels, a marker of liver damage.
“Chronic hepatitis B is a life-threatening illness that affects up to 2.2 million people in the U.S.,” said Calvin Pan, MD, Clinical Professor of Medicine, NYU Langone Medical Center, and investigator in the Vemlidy clinical trials, in a press release. “Clinical trials demonstrated Vemlidy is efficacious with improved renal and bone safety parameters compared to Viread, representing an important development for people living with this chronic disease,” he said.
Both Vemlidy and Viread were generally well-tolerated, with only 1% and 1.2% of patients in the two groups, respectively, quitting treatment because of side effects. Most common side effects were headache, abdominal pain, fatigue, cough, nausea and back pain.
Vemlidy, however, still comes with a boxed warning because drugs of this class are known to cause lactic acidosis, and enlarged and fatty liver. It also can cause acute exacerbations of hepatitis B once the treatment is stopped. Therefore, patients treated with the drug need to be closely monitored even after finishing the treatment.
“Since the mid-1990s, Gilead has been working to improve and simplify care for people living with chronic hepatitis B,” said John Milligan, PhD, president and chief executive officer of Gilead Sciences. “Vemlidy is the first medication approved to treat this disease in nearly a decade, and we are excited to offer a new, effective option to help advance long-term care for patients.”