Efficacy and Safety of Ganciclovir Capsules in the Treatment of Refractory Moderate-to-severe Allergic Rhinitis

Inclusion Criteria: 1. Aged between 18 and 65 years. 2. Diagnosed with moderate-to-severe perennial allergic rhinitis based on Chinese guideline for diagnosis and treatment of allergic rhinitis (2022, revision) with Allergic Rhinitis Control Test (ARCT) score \<20. 3. Total Nasal Symptom Score (TNSS) ≥6 or at least two of the four subdomains(sneezing, rhinorrhea, nasal itching, and nasal obstruction) ≥2 at the time of both screening and randomization. And the improvement in TNSS was assessed as \< 30% at randomization compared to screening. 4. The participant is allergic to dust mites or other perennial allergens 5. Voluntarily participate in the clinical trial and sign the informed consent. Exclusion Criteria: 1. Participants with hypersensitivity to ganciclovir capsules and its excipients. 2. Have symptoms of viral infection, fever and other systemic symptoms in the past 2 weeks. 3. Pregnant or lactating women and participants who have pregnancy plan during the study period. 4. Participants with severe neutropenia (absolute neutrophil count less than 0.5\*10\^9/L) or severe thrombocytopenia (platelet count less than 2.5\*10\^10/L). 5. Comorbidities such as upper and lower respiratory tract infections, history of acute or chronic sinusitis, dry rhinitis, atrophic rhinitis, severe deviated septum and asthma. 6. Participants with other severe heart, lung, liver and kidney disease. 7. Participants who had received any live or attenuated vaccine within 4 weeks prior to baseline or intended to receive live or attenuated vaccine (or BCG treatment) during the study period or within 4 weeks after the last administration of the investigational drug product. 8. Participants with a history of HIV infection or who test positive for HIV serology. 9. Participants currently infected or chronically infected with hepatitis B virus (HBV) or hepatitis C virus (HCV). 10. Participants with cirrhosis and/or chronic hepatitis. 11. Participants who have been diagnosed with active parasitic infections or are at high risk of developing such infections.。 12. Participants with a known or suspected history of immunosuppression, including a history of invasive opportunistic infections (e.g., histoplasmosis, listeriosis, coccidioidomycosis, pneumosporidiosis, aspergillosis). Or participants with what researchers believe to be unusually frequent, recurring, or prolonged infections. 13. Participants with a known history of malignancy within 5 years prior to screening. 14. Participants with severe co-morbidities that, in the opinion of the investigator, would adversely affect their participation in this study. 15. Participants with combined neurological or psychiatric disorders who are unable or reluctant to cooperate. 16. Participants with disabilities prescribed by law (blind, deaf, mute, mentally challenged, mentally handicapped, etc.). 17. Participants suspected or having a history of alcohol and drug abuse. 18. Other participants who have been involved in other clinical trials within 3 months before the screening. 19. The researchers consider it inappropriate to participate in this clinical trial.