Name | Baloxavir marboxil |
CAS number | 1985606-14-1 (marboxil) |
Description | Baloxavir marboxil, an antiviral prodrug, demonstrates potent in vitro and in vivo bioactivity by inhibiting the influenza virus's cap-dependent endonuclease, a key enzyme for replication. In vitro, its active form, baloxavir acid, has a 50% inhibitory concentration (IC50) of 1.4–3.1 nM for influenza A and 4.5–8.9 nM for influenza B viruses. Its 50% effective concentration (EC50) in cell cultures is as low as 0.73 nM for A/H1N1 strains and 0.83 nM for A/H3N2 strains. In animal models, a single oral dose completely prevented mortality in mice with lethal influenza A and B infections. When treatment was delayed up to 96 hours post-infection, baloxavir still significantly reduced lung viral titers by over a 100-fold within 24 hours and prevented death, showing superior efficacy compared to oseltamivir in these models. |
Related CAS | 1985605-59-1 (Baloxavir) 1985606-14-1 (marboxil) |
Synonym | Baloxavir marboxil; S 033188; S-033188; S033188; Xofluza; |
Appearance | Solid powder |
Quality Standard | USP, EP, BP, CP |
Shipping Condition | Shipped under ambient temperature as non-hazardous chemical. This product is stable enough for a few weeks during ordinary shipping and time spent in Customs. |
Storage Condition | Dry, dark and at 0 - 4 ℃ for short term (days to weeks) or -20 ℃ for long term (months to years). |
Shelf Life | >2 years if stored properly |
Sample package | Aluminium foil bag |
Commercial package | Aluminium Tin, Fiber drum |
Origin | China |
Baloxavir marboxil More Info
Baloxavir marboxil is an orally administered antiviral medication specifically indicated for the treatment of uncomplicated influenza A and B infections in adults and pediatric patients (aged 5 years and older) who have been symptomatic for no more than 48 hours. It also serves as a prophylactic agent to prevent influenza A and B in individuals aged 12 years and older after close contact with an infected person.
Mechanism of Action
Unlike traditional influenza drugs (e.g., oseltamivir) that target the viral neuraminidase enzyme, baloxavir marboxil acts through a novel mechanism: it inhibits the influenza virus cap-dependent endonuclease, an enzyme essential for the virus to synthesize its own mRNA and replicate within host cells. This unique mode of action provides efficacy against both influenza A and B viruses, including strains that may be resistant to neuraminidase inhibitors.
Pharmacokinetics
After oral administration, baloxavir marboxil is rapidly absorbed and hydrolyzed in the body to its active metabolite, baloxavir acid. The peak plasma concentration of the active metabolite is reached within 4 hours. It is widely distributed in body tissues, with moderate protein binding (approximately 80%). The drug is primarily eliminated via the liver and kidneys, with a terminal half-life of about 89 hours in adults, allowing for a single-dose treatment regimen— a key advantage over multi-dose antiviral alternatives.
Dosage and Administration
Treatment of influenza: For adults and adolescents aged 12 years and older, the recommended dose is a single oral tablet of 40 mg or 80 mg, based on body weight (40 mg for those ≤80 kg, 80 mg for those >80 kg). Pediatric patients aged 5–11 years receive a weight-based oral suspension as a single dose.
Prophylaxis of influenza: A single 40 mg tablet is recommended for adults and adolescents aged 12 years and older after close contact with an infected individual.
The drug can be taken with or without food, but co-administration with dairy products or calcium-fortified beverages should be avoided, as divalent cations may reduce its absorption.
Safety and Adverse Effects
Baloxavir marboxil is generally well-tolerated. The most common adverse reactions reported in clinical trials include diarrhea, nausea, headache, and abdominal pain, which are mild to moderate in severity and resolve spontaneously. Serious adverse events are rare, but hypersensitivity reactions (e.g., rash, angioedema) have been documented in isolated cases.
Notably, the emergence of baloxavir-resistant influenza strains has been observed in some patients, particularly those with prolonged viral shedding. Therefore, the drug should be used in accordance with influenza surveillance data and clinical guidelines to minimize resistance risks.
Clinical Efficacy
Clinical trials have demonstrated that baloxavir marboxil reduces the duration of influenza symptoms (e.g., fever, cough, sore throat) by approximately 24 hours compared to placebo, and its efficacy is non-inferior to oseltamivir. For post-exposure prophylaxis, a single dose has been shown to significantly lower the risk of developing influenza in exposed individuals, with a protective efficacy of around 86%.
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