Safety Assessment of a Nucleoside Analogue FNC (2'-deoxy-2'- β-fluoro-4'-azidocytidine ) in Balb/c Mice: Acute Toxicity Study

A small molecule compound targeting hemagglutinin inhibits influenza A virus and exhibits broad-spectrum antiviral activity

Influenza A virus (IAV) is a widespread pathogen that poses a significant threat to human health, causing pandemics with high mortality and pathogenicity. Given the emergence of increasingly drug-resistant strains of IAV, currently available antiviral drugs have been reported to be inadequate to meet clinical demands. Therefore, continuous exploration of safe, effective and broad-spectrum antiviral medications is urgently required. Here, we found that the small molecule compound J1 exhibited low toxicity both in vitro and in vivo. Moreover, J1 exhibits broad-spectrum antiviral activity against enveloped viruses, including IAV, respiratory syncytial virus (RSV), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), human coronavirus OC43 (HCoV-OC43), herpes simplex virus type 1 (HSV-1) and HSV-2. In this study, we explored the inhibitory effects and mechanism of action of J1 on IAV in vivo and in vitro. The results showed that J1 inhibited infection by IAV strains, including H1N1, H7N9, H5N1 and H3N2, as well as by oseltamivir-resistant strains. Mechanistic studies have shown that J1 blocks IAV infection mainly through specific interactions with the influenza virus hemagglutinin HA2 subunit, thereby blocking membrane fusion. BALB/c mice were used to establish a model of acute lung injury (ALI) induced by IAV. Treatment with J1 increased survival rates and reduced viral titers, lung index and lung inflammatory damage in virus-infected mice. In conclusion, J1 possesses significant anti-IAV effects in vitro and in vivo, providing insights into the development of broad-spectrum antivirals against future pandemics.

Efficacy and Safety of Azvudine in Patients With COVID-19 in China: A Meta-Analysis of Observational Studies

BACKGROUND

Azvudine (FNC) is a novel small molecule antiviral drug for treating COVID-19 that is available only on the Chinese market. Despite being recommended for treating COVID-19 by the Chinese guidelines, its efficacy and safety are still unclear. This study aimed to evaluate the protective effect of FNC on COVID-19 outcomes and its safety.

METHODS

We followed the PRISMA 2020 guidelines and searched the PubMed, Embase, Web of Science, Scopus, and China National Knowledge Infrastructure (CNKI) databases to evaluate studies on the effectiveness of FNC in treating COVID-19 in China, focusing on mortality and overall outcomes. Additionally, its impact on the length of hospital stay (LOHS), time to first nucleic acid negative conversion (T-FNANC), and adverse events was evaluated. The inclusion criterion was that the studies were published from July 2021 to April 10, 2024. This study uses the ROBINS-I tool to assess bias risk and employs the GRADE approach to evaluate the certainty of the evidence.

RESULTS

The meta-analysis included 24 retrospective studies involving a total of 11 830 patients. Low-certainty evidence revealed no significant difference in mortality (OR = 0.91, 95% CI: 0.76-1.08) or LOHS (WMD = -0.24, 95% CI: -0.83 to 0.35) between FNC and Paxlovid in COVID-19 patients. Low-certainty evidence shows that the T-FNANC was longer (WMD = 1.95, 95% CI: 0.36-3.53). Compared with the Paxlovid group, low-certainty evidence shows the FNC group exhibited a worse composite outcome (OR = 0.77, 95% CI: 0.63-0.95) and fewer adverse events (OR = 0.63, 95% CI: 0.46-0.85). Compared with supportive treatment, low certainty shows FNC significantly reduced the mortality rate in COVID-19 patients (OR = 0.61, 95% CI: 0.51-0.74) and decreased the composite outcome (OR = 0.67, 95% CI: 0.50-0.91), and very low certainty evidence shows significantly decreased the T-FNANC (WMD = -4.62, 95% CI: -8.08 to -1.15). However, in very low certainty, there was no significant difference in LOHS (WMD = -0.70, 95% CI: -3.32 to 1.91) or adverse events (OR = 1.97, 95% CI: 0.48-8.17).

CONCLUSIONS

FNC appears to be a safe and potentially effective treatment for COVID-19 in China, but further research with larger, high-quality studies is necessary to confirm these findings. Due to the certainty of the evidence and the specific context of the studies conducted in China, caution should be exercised when considering whether the results are applicable worldwide.

TRIAL REGISTRATION

PROSPERO number: CRD42024520565.

FNC (4'-azido-2'-deoxy-2'-fluoro(arbino)cytidine) as an Effective Therapeutic Agent for NHL: ROS Generation, Cell Cycle Arrest, and Mitochondrial-Mediated Apoptosis

Cytotoxic nucleoside analogs (NAs) hold great promise in cancer therapeutics by mimicking endogenous nucleosides and interfering with crucial cellular processes. Here, we investigate the potential of the novel cytidine analog, 4'-azido-2'-deoxy-2'-fluoro(arbino)cytidine (FNC), as a therapeutic agent for Non-Hodgkin lymphoma (NHL) using Dalton's lymphoma (DL) as a T-cell lymphoma model. FNC demonstrated dose- and time-dependent inhibition of DL cell growth and proliferation. IC-50 values of FNC were measured at 1 µM, 0.5 µM, and 0.1 µM after 24, 48, and 72 h, respectively. Further elucidation of FNC's mechanism of action uncovers its role in inducing apoptosis in DL cells. Notable DNA fragmentation and nuclear condensation point to activated apoptotic pathways. FNC-induced apoptosis was concomitant with changes in cellular membranes, characterized by membrane rupture and altered morphology. The robust anticancer effects of FNC are linked to its capacity to induce reactive oxygen species (ROS) production, prompting oxidative stress-mediated apoptosis. Additionally, FNC disrupted mitochondrial membrane potential (MMP), leading to mitochondrial dysfunction, further promoting apoptosis. Dysregulation of apoptotic genes, with upregulation of Bax and downregulation of Bcl-2 and Bcl-xl, implicates the mitochondrial-mediated apoptosis pathway. Furthermore, FNC-induced G2/M phase cell cycle arrest was mediated through modulation of the cell cycle inhibitor p21. Overall, this study highlights the potential of FNC as a promising therapeutic agent for NHL.