Research progress on the nucleoside/nucleotide-loaded nanomedicines / 浙江大学学报·医学版

Nucleoside drugs play an essential role in treating major diseases such as tumor and viral infections, and have been widely applied in clinics. However, the effectiveness and application of nucleoside drugs are significantly limited by their intrinsic properties such as low bioavailability, lack of targeting ability, and inability to enter the cells. Nanocarriers can improve the physiological properties of nucleoside drugs by improving drug delivery efficiency and availability, maintaining drug efficacy and system stability, adjusting the binding ability of the carrier and drug molecules, as well as modifying specific molecules to achieve active targeting. Starting from the design strategy of nucleoside drug nanodelivery systems, the design and therapeutic effect of these nanomedicines are described in this review, and the future development directions of nucleoside/nucleotide-loaded nanomedicines are also discussed.

Efficacy of Tenofovir-based Rescue Therapy for Patients with Drug-resistant Chronic Hepatitis B / 대한소화기학회지

BACKGROUND/AIMS: Tenofovir disoproxil fumarate (TDF) plays a pivotal role in the management of drug-resistant chronic hepatitis B. However, it remains unclear whether TDF-nucleoside analogue combination therapy provides better outcomes than TDF monotherapy. This study aimed to compare the efficacy of TDF monotherapy with that of TDF-nucleoside analogue combination therapy in patients with drug-resistant chronic hepatitis B. METHODS: This retrospective cohort study included 76 patients receiving TDF-based rescue therapy for more than 12 months. Suboptimal response was defined as serum HBV-DNA level of >60 IU/mL during prior rescue therapy. Multi-drug resistance was defined as the presence of two or more drug resistance-related mutations confirmed by mutation detection assay. The relationship between baseline characteristics and virologic response (HBV DNA <20 IU/mL) at 12 months were evaluated using logistic regression analysis. RESULTS: Fifty-five patients (72.4%) were suboptimal responders to prior rescue therapy, and 26 (34.2%) had multi-drug resistance. Forty-two patients (55.3%) received combination therapy with nucleoside analogues. Virologic response at 12 months was not significantly different between the TDF monotherapy group and TDF-nucleoside analogue combination therapy group (p=0.098). The serum HBV DNA level was reduced to -4.49+/-1.67 log10 IU/mL in the TDF monotherapy group and to -3.97+/-1.69 log10 IU/mL in the TDF-nucleoside analogue combination therapy group at 12 months (p=0.18). In multivariate analysis, female sex (p=0.032), low baseline HBV-DNA level (p=0.013), and TDF monotherapy (p=0.046) were predictive factors for virologic response at 12 months. CONCLUSIONS: TDF monotherapy showed similar efficacy to that of TDF-nucleoside analogue combination therapy in patients with drug-resistant chronic hepatitis B.

Options for the management of antiviral resistance during hepatitis B therapy: reflections on battles over a decade

Although much advancement has been achieved in the treatment of chronic hepatitis B, antiviral resistance is still a challenging issue. Previous generation antiviral agents have already developed resistance in a number of patients, and it is still being used especially in resource limited countries. Once antiviral resistance occurs, it predisposes to subsequent resistance, resulting in multidrug resistance. Therefore, prevention of initial antiviral resistance is the most important strategy, and appropriate choice and modification of therapy would be the cornerstone in avoiding treatment failures. Until now, management of antiviral resistance has been evolving from sequential therapy to combination therapy. In the era of tenofovir, the paradigm shifts again, and we have to decide when to switch and when to combine on the basis of newly emerging clinical data. We expect future eradication of chronic hepatitis B virus infection by proper prevention and optimal management of antiviral resistance.