Incidence and determinants of achieving HBsAg <1500 IU/mL in treatment-naive CHB patients with tenofovir alafenamide and entecavir
In a retrospective study of treatment-naïve chronic hepatitis B patients, tenofovir alafenamide (TAF) demonstrated a significantly higher incidence of achieving HBsAg <1500 IU/mL compared to entecavir (ETV), with TAF treatment and baseline ALT ≥40 U/L identified as independent predictors of this outcome, particularly benefiting HBeAg-negative patients and those with elevated ALT levels.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
For millions of people around the world, a virus called hepatitis B lives quietly inside their livers. It is a persistent guest that can cause serious damage over time, leading to scarring or cancer. For decades, the standard treatment has been to suppress the virus, keeping it from multiplying so the liver can heal. However, this suppression is rarely a permanent cure. The virus often hides in a dormant state within liver cells, ready to wake up if the medication stops. The ultimate goal for doctors and patients is a "functional cure," where the virus is not just suppressed but effectively cleared from the body, allowing the patient to stop taking medication safely. A critical step toward this goal is lowering a specific protein on the surface of the virus, known as the surface antigen, to a very low level. When this level drops below a certain threshold, it signals that the immune system is finally gaining the upper hand, opening the door for a combination therapy that might finish the job and achieve a true cure.
Researchers in China recently set out to see which of two common medications helps patients reach this critical low level faster. They looked at a group of people who had never taken antiviral drugs before and started them on either entecavir or tenofovir alafenamide. Both drugs are powerful tools that stop the virus from copying itself, but scientists suspected they might work differently on the surface antigen. The study followed these patients over several years, tracking how many of them managed to lower that surface protein to the desired target. The results showed a clear difference between the two groups. Patients taking tenofovir alafenamide were significantly more likely to reach the target level than those taking entecavir. This finding suggests that for certain patients, choosing the right starting medication could be the key to moving closer to a life free of chronic infection.
The study involved 211 patients who began treatment between 2017 and 2025. To ensure a fair comparison, the researchers carefully matched the patients so that the two groups were as similar as possible in age, gender, and initial health status. They then watched how these patients responded over time, with a median follow-up period of nearly two years. The primary question was simple: how many people would see their surface antigen levels drop below 1,500 IU/mL? This specific number is important because it marks the point where patients are considered "optimal candidates" for adding a second type of treatment, an interferon therapy, which has a better chance of clearing the virus completely.
The results were distinct. In the group taking tenofovir alafenamide, about one-third of the patients reached the target level. In contrast, only about one in seven patients taking entecavir reached the same milestone. When the researchers looked at the data over a three-year period, the difference remained clear, with the tenofovir alafenamide group showing a much higher rate of success. Furthermore, most of the patients who reached this low antigen level also had their virus completely undetectable in their blood, a combination that is highly desirable for long-term health. The study confirmed that the type of drug used was a major factor in this outcome, with tenofovir alafenamide proving more effective at driving down these specific levels.
The researchers also investigated which patient characteristics made a difference. They found that patients who started treatment with elevated levels of a liver enzyme called ALT were more likely to reach the target. High ALT levels usually indicate that the liver is currently inflamed and the immune system is actively fighting the virus. The data suggested that when the immune system is already engaged, the tenofovir alafenamide drug works particularly well to push the surface antigen levels down. This effect was especially noticeable in patients who were already in a later stage of the infection, where a different viral marker called HBeAg was no longer present. For these specific groups, the advantage of tenofovir alafenamide over entecavir was even more pronounced.
While the study provides strong evidence for the benefits of tenofovir alafenamide in this specific context, the researchers noted that their work was limited to a single hospital and a relatively small number of patients. They also pointed out that the follow-up time, while substantial, was not long enough to see if these patients eventually achieved a complete cure or stopped taking medication entirely. The study did not include detailed genetic testing of the virus or analysis of liver tissue samples, which could offer further insights. Despite these limitations, the findings offer a practical guide for doctors. They suggest that for patients with active liver inflammation or those in the later stages of infection, starting with tenofovir alafenamide might be the better strategic choice to help them reach the threshold needed for a potential cure. This approach could help more people transition from lifelong management to a state where the virus is truly under control.
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