Japan has approved pediatric use of Xocova (ensitrelvir) for children aged 6–11 years weighing at least 20 kg, supported by Phase 3 data showing favorable safety and pharmacokinetic profiles.
Written By: Disha Jadhao, BPharm
Reviewed By: Pharmacally Editorial Team
Shionogi has secured supplemental approval in Japan for the pediatric use of Xocova (ensitrelvir fumaric acid) in children aged 6 to under 12 years who weigh at least 20 kg, expanding access to the oral antiviral treatment for COVID-19. Japanese regulators also approved a new 25 mg tablet formulation, enabling weight-based dosing in younger patients.
The decision broadens Xocova’s approved use beyond adults and adolescents aged 12 years and older, making it available to a wider pediatric population. The antiviral is approved in Japan for both the treatment and post-exposure prophylaxis of SARS-CoV-2 infection.
Expanding Oral Antiviral Options for Children
COVID-19 continues to cause substantial healthcare burden despite widespread vaccination and prior infection. Treatment options for younger children remain more limited than those available for adults, particularly oral therapies that can be administered outside hospital settings.
Ensitrelvir is an oral SARS-CoV-2 main protease inhibitor discovered through a collaboration between Shionogi and Hokkaido University. The drug blocks the viral main protease, an enzyme essential for viral replication, thereby suppressing the production of new virus particles.
Because Xocova can be prescribed regardless of risk factors for severe disease progression, the expanded indication offers clinicians an additional outpatient treatment option for pediatric patients with COVID-19.
Phase 3 Pediatric Trial Supported Approval
The supplemental approval is based on a Phase 3 study (jRCT2031230140) conducted in Japan involving 117 children aged 6 to under 12 years with confirmed SARS-CoV-2 infection and body weight of at least 20 kg.
Participants received once-daily oral Xocova for five days using weight-based dosing regimens. The study primarily evaluated safety and pharmacokinetics.
Investigators reported no new safety signals, and the treatment was generally well tolerated. Pharmacokinetic analyses showed that plasma concentrations achieved in pediatric patients closely matched exposures predicted for adults receiving therapeutic doses.
Population pharmacokinetic modeling further confirmed that the pediatric dosing strategy produced drug levels consistent with those associated with clinical benefit in adult patients. These findings supported the appropriateness of the approved dosing regimen across the studied weight categories.
New Weight-Based Dosing Regimen
Under the updated label, children aged 6 to under 12 years will receive weight-adjusted doses:
- 40 kg or more: 375 mg on Day 1, followed by 125 mg daily on Days 2–5.
- 30 kg to under 40 kg: 250 mg on Day 1, followed by 125 mg daily on Days 2–5.
- 20 kg to under 30 kg: 150 mg on Day 1, followed by 75 mg daily on Days 2–5.
The newly approved 25 mg tablet supports dosing in lower-weight pediatric patients.
Building on a Growing Global Regulatory Footprint
The pediatric expansion follows a series of regulatory milestones for ensitrelvir. Xocova first received emergency approval in Japan in November 2022 and obtained full approval for COVID-19 treatment in March 2024. In March 2026, Japan also approved the drug for post-exposure prophylaxis following positive results from the Phase 3 SCORPIO-PEP trial (NCT05897541).
Outside Japan, the U.S. FDA approved ensitrelvir in May 2026 for post-exposure prophylaxis of COVID-19. Regulatory reviews remain ongoing in Europe and Taiwan, while the therapy is already available in Singapore through a special access pathway.
The latest approval strengthens Xocova’s position as one of the few oral COVID-19 antivirals with expanding use across both adult and pediatric populations, while supporting Shionogi’s broader strategy to extend access to antiviral therapies worldwide.
What This Means for Patients
The approval expands access to Xocova for children aged 6 to under 12 years who weigh at least 20 kg, providing an additional oral treatment option for COVID-19. With weight-based dosing and a newly approved 25 mg tablet formulation, younger patients can receive therapy tailored to their size. The approval is supported by Phase 3 data showing no new safety concerns and drug exposure levels comparable to those seen in adults receiving therapeutic doses.
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About the Writer
Disha Sanjay Jadhao (LinkedIn) is a pharmacy graduate and healthcare writer with a strong interest in clinical documentation and simplifying healthcare information for better reader understanding. She is enthusiastic, adaptable, and eager to take on new challenges while contributing to clear, accurate, and engaging medical and pharmaceutical content.