Baloxavir Marboxil: a revolution in the treatment of pediatric influenza

Influenza strains A and B are the leading cause of respiratory tract-restricted acute viral illness, with an infective rate of over 3–5 million, and adding up to 650,000 mortalities globally in all age brackets¹. A wide spectrum of symptoms like cough (usually dry), subjective fever, headache, myalgias, joint ache, fatigue, sore throat, and runny nose are the characteristic presentations that are observed². Each year, it is estimated that hospitalizations of around 16% among children of 5–17 years, and 5% among children below 5 years are contributed to this seasonal illness³. Furthermore, studies in Japan revealed children below 5 years of age are more prone to severe influenza and related complications in comparison to adults³.

The current therapeutic approaches in children include M2 blockers and neuraminidase inhibitors alongside the annual administration of inactivated influenza vaccine in individuals from 6 months of age and older^3,4. Another vaccination modality is a live attenuated influenza vaccine but is suggested only in children above 24 months of age due to increased risk of postvaccination wheezing². However, a few downsides associated with these available options include difficult routes of administration, emerging resistance to different strains, and noncompliance with the repeated dose regimen³. Furthermore, neuraminidase inhibitors were found to be at variance in effectiveness across influenza types in young children (1–5 y)³. One such example is Oseltamivir, which is less potent against the influenza type B virus than the influenza type A virus⁴.

Baloxavir Marboxil, made available under the brand name Xofluenza, is an antiviral drug targeting Influenza strains A and type B, by selectively inhibiting the Cap-Dependent Endonuclease (CEN) activity of this particular virus⁵. The year 2018 marked the very first approval of this drug for the treatment of uncomplicated influenza in adolescents and adults through a single dose given orally¹. Recently, in August 2022, it has been approved by FDA for the treatment of pediatric influenza (age 5–12) as well. In a double-blind, randomized, active-controlled trial (MiniSTONE-2), children infected with influenza were randomized to be given a single dose of oral Baloxavir or oral Oseltamivir twice a day for 5 days and were followed for the next 24 days. There was a rapid decline in viral titers of all the patients given Baloxavir within 24 hours of administration as compared to Oseltamivir. The adverse outcomes noticeable for both the groups were majorly gastrointestinal symptoms, that is, vomiting and diarrhea, with no evidence of severe complications, hospitalization, or deaths. The results showed that the drug is well tolerated by the pediatric population and can be safely administered with fewer treatment-related side effects¹. Japanese studies have also assessed and proved the safety of this drug in pediatric age groups with no reported adverse events other than gastrointestinal disturbances and rapid alleviation of illness⁴.

In developing countries like Pakistan, the influenza virus still poses a major threat to the pediatric population. With emerging resistance to previously available therapeutic options, Baloxavir Marboxil can be promising as a novel alternative to the current standard of care for such children. Moreover, there is a dire need for further larger-scale comprehensive studies to be conducted, particularly in Asian countries where little is known regarding the efficacy and safety of this newly approved drug.

Ethical approval

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Sources of funding

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Author contributions

O.A.S., S.F., and W.N.: wrote the manuscript. O.A.S. and S.F.: review editing, formatting, and referencing.

Conflict of interest disclosures

The authors declare that they have no financial conflict of interest with regard to the content of this report.

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Guarantor

Omer Ahmed Shaikh.