A Study to Confirm Efficacy of a Single Dose of Baloxavir Marboxil in the Post-exposure Prophylaxis (PEP) of Influenza Virus Infection in Chinese Participants (Pearlstone)

September 15, 2026 updated by: Hoffmann-La Roche

A Phase III, Randomized, Double-blinded, Placebo-controlled Study to Confirm Efficacy of a Single Dose of Baloxavir Marboxil in the Post-exposure Prophylaxis of Influenza Virus Infection in Chinese Participants

The main purpose of the study is to evaluate the efficacy of a single dose of baloxavir marboxil compared with placebo in the PEP of influenza virus infection with respect to symptomatic, laboratory-confirmed influenza in participants who are household contacts (HHCs) of participants with influenza (index participants).

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

325

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

  • Name: Fastest response: use the inquiry form https://www.gene.com/contact-us/submit-medical-inquiry

Study Contact Backup

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

Index Participants (Participants With Influenza Virus Infection):

  • First participant in a household with influenza virus infection in the current influenza season
  • Fewer than 6 HHCs
  • Agreement by all household members to participate in the study and comply with the study protocol for the duration of the study
  • Diagnosed as having influenza with positive rapid influenza diagnostic test (RIDT) or polymerase chain reaction (PCR) result
  • Onset of symptoms within 48 hours or less at time of signing Informed Consent Form (ICF)/Assent Form
  • PCR (-) or antigen test (-) for severe acute respiratory virus-coronavirus 2 (SARS-CoV-2) using point-of-care or local laboratory test

HHCs of Index Participants:

  • Lived with the index participant for 48 hours or more prior to informed consent/assent
  • Meet all the following criteria and are judged not to have influenza virus infection by the investigator: body temperature (tympanic) <37.5 degrees Celsius (°C); no influenza-like symptoms (cough, sore throat, headache, nasal discharge/nasal congestion, feverishness or chills, muscle or joint pain, or fatigue) at screening; negative RIDT or PCR result for influenza
  • For participants 12 years of age or older, ability to evaluate influenza symptoms by using a participant influenza symptoms diary; For participants under 12 years of age, capability of parents/caregivers to evaluate influenza symptoms by using a participant influenza symptoms diary
  • PCR (-) or antigen test (-) for SARS-CoV-2 using point-of-care or local laboratory test

Exclusion Criteria:

HHCs of Index Participants:

  • Diagnosed with influenza during the current influenza season
  • Unable to live with the index patient from screening until Day 10
  • Live with a household member who has any influenza-like symptom(s) other than the index participant on the day of screening
  • Live with household members other than the index participant who was diagnosed with or strongly suspected to have influenza during the current influenza season
  • Have any underlying diseases requiring systemic (oral or injection), or nasal treatment of antipyretics/analgesics, corticosteroids, or immunosuppressive agents
  • Immunocompromised
  • Use of any medications with anti-influenza effect within 30 days prior to screening
  • Known allergy and/or history of significant intolerance against baloxavir marboxil
  • Exposure to an investigational drug within 30 days or 5 half-lives of the drug prior to screening, whichever is longer

Note: Other protocol-defined inclusion/exclusion criteria may apply

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Baloxavir Marboxil
HHCs will receive baloxavir marboxil according to their body weight as outlined in the protocol.
Drug: Baloxavir marboxil
Baloxavir marboxil will be administered to the HHCs as per the schedule specified in the protocol.
Other Names:
  • Xofluza; RO7191686
Placebo Comparator: Placebo
HHCs will receive baloxavir marboxil matching placebo according to their body weight as outlined in the protocol.
Drug: Placebo
Baloxavir marboxil matching placebo will be administered to the HHCs as per the schedule specified in the protocol.
No Intervention: No Intervention
Index participants will not receive any study treatment but will continue to receive SOC treatment for influenza, as per the local guidelines.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Percentage of Participants who are Infected With Influenza Virus (Reverse Transcription - Polymerase Chain Reaction [RT-PCR] Positive), and Present With Fever and at Least one Respiratory Symptom
Time Frame: From Day 1 up to Day 10
From Day 1 up to Day 10

Secondary Outcome Measures

Outcome Measure
Time Frame
Percentage of Participants who are Infected With Influenza Virus (RT-PCR Positive), and Present With Fever or at Least one Influenza Symptom (Respiratory or Systemic)
Time Frame: From Day 1 up to Day 10
From Day 1 up to Day 10
Percentage of Participants who are Infected With Influenza Virus (RT-PCR Positive) Regardless of Body Temperature or Influenza Symptoms
Time Frame: From Day 1 up to Day 10
From Day 1 up to Day 10
Number of Participants With Adverse Events (AEs) and Serious Adverse Events (SAEs)
Time Frame: Up to Day 21
Up to Day 21

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Hoffmann-La Roche

Investigators

  • Study Director: Clinical Trials, Hoffmann-La Roche

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

September 22, 2026

Primary Completion (Estimated)

April 30, 2027

Study Completion (Estimated)

April 30, 2027

Study Registration Dates

First Submitted

September 15, 2026

First Submitted That Met QC Criteria

September 15, 2026

First Posted (Actual)

September 18, 2026

Study Record Updates

Last Update Posted (Actual)

September 18, 2026

Last Update Submitted That Met QC Criteria

September 15, 2026

Last Verified

September 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • YV46459

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

For eligible studies, qualified researchers may request access to individual patient level clinical data. See Roche's commitment to transparency of clinical study information here: https://go.roche.com/data_sharing.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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