VIENNA — Tenofovir Alafenamide (TAF; Biktarvy) continued to be highly effective for Chronic Hepatitis B virus (HBV) infection for up to 8 years, according to an analysis of long-term data.

Over this time period, viral suppression, defined as an HBV DNA level

For those who were HBeAg-positive, suppression ranged from 91% to 96%.

“These results provide continued support for TAF as the preferred treatment for chronic hepatitis B infection,” Buti said during her presentation at the European Association for the Study of the Liver annual meeting.

In previous phase III trials, TAF showed noninferior efficacy and higher alanine aminotransferase (ALT) normalization compared with TDF at weeks 48 and 96 in viremic and virally suppressed HBeAg-negative and -positive patients.

In the current analysis, HBeAg loss with treatment continued to increase throughout the course of the trial, Buti reported, with rates of HBeAg loss of 44% to 46%. Seroconversion also steadily increased, with rates of 27% to 33% by the end of 8 years.

Of 78 patients who had cirrhosis according to FibroTest scores, two-thirds were apparently free of cirrhosis at 8 years. Of the 29 patients who underwent sequencing analysis, none showed HBV resistance to TAF.

“High rates of liver enzyme normalization were achieved early and were maintained with TAF, while ALT normalization increased in TDF-treated patients switched to TAF in the open-label period,” Buti said.

She conceded that the cost of TAF might hinder its use. “The cost of TAF is higher than TDF. TDF is a generic drug and it’s available in the majority of countries,” she noted, adding that TAF will soon be generic as well.

Aleksander Krag, MD, PhD, of the University of Southern Denmark in Odense, told MedPage Today that the decision on which form of tenofovir to take is an individual choice.

“I always take the patient’s perspective on this,” he said. “And, you know, patients are different. Patients with HBV infection have been concerned about side effects of the medicine they are taking to control this disease.”

“The better safety profile with TAF is a really good signal, and something that will matter a lot to some of these patients,” Krag added. “There will also be patients that say, ‘OK, but I don’t want it.'”

Buti and colleagues used data from two phase III studies that compared TAF and TDF. The trials included 425 HBeAg-negative patients and 873 HBeAg-positive patients.

Among the HBeAg-negative patients, mean age was 45-48, 61% were men, 72% were Asian, and 25% were white. Among HBeAg-positive patients, mean age was 38, 64-65% were men, 80-83% were Asian, and 17-18% were white.

After completing up to 3 years of double-blind treatment, all patients were eligible to receive open-label TAF through week 384.