Clinical Scorecard: Impact of Combining Baloxavir Marboxil with Neuraminidase Inhibitors Compared to Neuraminidase Inhibitors Alone in Hospitalized High-risk Patients with Severe Influenza: Insights from a Post Hoc Analysis of the Flagstone Study

At a Glance

Key Highlights

• Combination of baloxavir and NAIs significantly reduced 28-day mortality compared to NAIs alone (2.17% vs 11.76%, P = .02) in high-risk severe influenza patients.
• In influenza A H3N2 infected patients, combination therapy shortened time to clinical improvement compared to monotherapy (median 97.53 vs 172.42 hours, P = .013).
• Combination therapy led to faster cessation of viral shedding and greater reduction in viral titers by day 2 without increasing serious adverse events.

Guideline-Based Recommendations

Diagnosis

• Confirm severe influenza via rapid diagnostic tests or RT-PCR within 96 hours of symptom onset.
• Identify high-risk patients by presence of immunosuppression, diabetes, or chronic lung disease.

Management

• Consider baloxavir plus neuraminidase inhibitor combination therapy for hospitalized high-risk patients with severe influenza.
• Administer treatment early during hospitalization to optimize viral clearance and clinical outcomes.

Monitoring & Follow-up

• Monitor time to clinical improvement and viral shedding status.
• Assess for adverse events and serious adverse events during treatment.

Risks

• Combination therapy did not increase serious adverse events compared to monotherapy.
• High-risk patients have elevated baseline mortality and morbidity requiring close clinical monitoring.

Patient & Prescribing Data

Hospitalized patients with severe influenza who are immunocompromised, diabetic, or have chronic lung disease

Dual antiviral therapy with baloxavir plus NAIs improves mortality and viral clearance outcomes without added safety risks compared to NAIs alone.

Clinical Best Practices

• Early identification of high-risk severe influenza patients is critical to guide antiviral therapy decisions.
• Use combination antiviral therapy in patients infected with influenza A H3N2 subtype for improved clinical recovery.
• Maintain vigilant monitoring for clinical improvement and viral shedding to assess treatment efficacy.
• Balance benefits of combination therapy against patient-specific factors and potential drug interactions.

References

• Flagstone Trial ClinicalTrials.gov Registration