Antiviral treatment for early RSV symptoms
Assessment of Respiratory SYNcytial Virus antivirALs: A Phase 2 Multi-centre Adaptive Randomised Platform Trial For the Assessment of Antiviral Pharmacodynamics in aCute Symptomatic RSV Infection (ARSYNAL-FC)
This trial will test whether antiviral drugs—ribavirin, molnupiravir, or favipiravir—can lower viral levels and help adults 18–64 with early RSV recover faster than receiving no antiviral treatment.
Quick facts
| Phase | Phase 2 |
|---|---|
| Study type | Interventional |
| Enrollment | 1000 (estimated) |
| Ages | 18 Years to 64 Years |
| Sex | All |
| Sponsor | University of Oxford Academic / other |
| Locations | 2 sites (Vientiane and 1 other locations) |
| Trial ID | NCT06488300 on ClinicalTrials.gov |
What this trial studies
This is a randomized, open-label, controlled, group-sequential adaptive platform trial in low-risk adults with early symptomatic RSV. Participants are randomized to one of the antiviral arms (ribavirin, molnupiravir, favipiravir) or to a no-antiviral control, with the control allocation fixed at a minimum of 20%. The primary pharmacodynamic outcome is the rate of viral clearance measured after treatment, and individual participation lasts 28 days. The platform allows comparison of licensed and repurposed antivirals with potential RSV activity using uniform randomization among available interventions.
Who should consider this trial
Good fit: Adults aged 18 to under 65 with early symptomatic RSV (symptoms within 4 days) and a recent positive RSV test with high viral load (PCR Ct <30) who can consent and attend follow-up visits are ideal candidates.
Not a fit: People with chronic illnesses, those taking medications that interact with study drugs, immunocompromised patients, those aged 65 or older, or people presenting later than 4 days or with low viral loads are unlikely to benefit from this outpatient antiviral approach.
Why it matters
Potential benefit: If successful, the treatments could reduce viral load and shorten illness duration for adults with early RSV and guide outpatient antiviral use.
How similar studies have performed: Ribavirin has prior pediatric use for RSV and molnupiravir and favipiravir show antiviral activity in lab studies, but oral antivirals for adult RSV treatment remain largely unproven in clinical trials.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: * Patient understands the procedures and requirements and is willing and able to give informed consent for full participation in the study * Adults, male or female, aged ≥18 to \<65 years at time of consent * Early symptomatic RSV; at least one reported symptom of RSV (including fever, history of fever, myalgias, headache, cough, fatigue, nasal congestion, rhinorrhoea and sore throat) within 4 days (96 hours) * RSV positive by rapid antigen test OR a positive RT-PCR test for RSV viruses within the last 24hrs with a Ct value of \<30 * Able to walk unaided and unimpeded in activities of daily living (ADLs) * Agrees and is able to adhere to all study procedures, including availability and contact information for follow-up visits Exclusion Criteria: The patient may not enter the study if ANY of the following apply: * Taking any concomitant medications or drugs which could interact with the study medications or have antiviral activity * Presence of any chronic illness/condition requiring long term treatment or other significant comorbidity * BMI ≥35 Kg/m2 * Clinically relevant laboratory abnormalities discovered at screening * Haemoglobin \<10g/dL (\<12g/dL for all arms if Ribavirin is in the randomisation) * Platelet count \<100,000/uL * ALT \> 2x ULN * Total bilirubin \>1.5 x ULN * eGFR \<70mls/min/1.73m2 * For females: pregnancy, actively trying to become pregnant or lactating (women on OCP are eligible to join) * Contraindication to taking, or known hypersensitivity reaction to any of the proposed therapeutics * Currently participating in another interventional RSV, influenza or COVID-19 therapeutic trial * Clinical evidence of pneumonia- e.g., shortness of breath, hypoxaemia, crepitations (imaging not required) * Known to be currently co-infected with influenza or SARS-CoV-2 (i.e. confirmed with positive ATK or RT-PCR) * Received any RSV vaccine within the last year
Where this trial is running
Vientiane and 1 other locations
- Laos-Oxford-Mahosot Hospital-Wellcome Trust Research Unit — Vientiane, Laos (Recruiting)
- Faculty of Tropical Medicine, Mahidol University — Bangkok, Thailand (Recruiting)
Study contacts
- Study coordinator: William Schilling, MD
- Email: william@tropmedres.ac
- Phone: +662 203 6333
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.