LC-Plasma for Preventing URTIs and Reducing Symptoms

A Randomized Controlled Trial Evaluating the Efficacy of Lactococcus Lactis JCM 5805 (LC-Plasma) Lactic Acid Bacteria in Preventing Upper Respiratory Tract Infections and Reducing Symptom Severity and Duration

The goal of this study is to evaluate the efficacy of the LC-Plasma in preventing upper respiratory tract infections (URTIs) in healthy volunteers. Researchers will compare LC-Plasma to placebo to see if LC-Plasma prevents URTIs. Participants will take a tablet containing LC-Plasma or placebo daily for 24 weeks.

Study Overview

• Status: Completed
• Conditions: Healthy Volunteer; URTI
• Intervention / Treatment: Dietary supplement: LC-Plasma; Other: Placebo

• Study Type: Interventional
• Enrollment (Actual): 637
• Phase: Phase 3

Contacts and Locations

Study Locations

• Australia
  • Queensland
    • Brisbane, Queensland, Australia, 4006
      • RDC Clinical

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Adults aged 18-60 years living in Australia
• Individuals with a history of recurrent upper respiratory tract infections
• Able to provide informed consent
• Generally healthy
• Agree to not participate in another clinical trial while enrolled in this trial
• Agree to maintain their usual daily activities without significant changes. This includes not changing their current diet or stopping/starting a new exercise regimen during entire study period
• Agree not to travel internationally for over 1 month in a single trip during the intervention period (baseline to study completion).
• Females of childbearing potential must a prescribed form of birth control

Exclusion Criteria:

• Serious illness e.g., liver disease, kidney disease, heart disease, mood disorders, neurological disorders such as multiple sclerosis.
• Unstable illness e.g., changing medication/treatment.
• BMI <18.5, >30
• Current malignancy (excluding Basal Cell Carcinoma) or chemotherapy or radiotherapy treatment for malignancy within the previous 2 years.
• Individuals with chronic respiratory conditions (e.g., asthma, chronic obstructive pulmonary disease).
• Has current symptoms of an acute sickness.
• Active smokers, nicotine use or drug (prescription or illegal substances) abuse
• Current alcohol use (>14 alcoholic drinks week)
• Allergic to any of the ingredients in the active or placebo formula
• Pregnant or lactating woman
• People medically prescribed medications within the last month that would affect the immune and/or the inflammatory response excluding topical steroid use.
• Participants who are currently participating in any other clinical trial or who have participated in any other clinical trial during the past 1 month
• Participants with cognitive damage
• Participants with seasonal allergic rhinitis
• Regular use of antihistamines
• Individuals deemed unsuitable for participation by the Principal Investigator (PI) of this study.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: LC-Plasma; 1 tablet containing 50mg LC-Plasma is taken daily for 24 weeks.	Dietary supplement: LC-Plasma; 1 tablet containing 50mg LC-Plasma is taken daily for 24 weeks
Placebo Comparator: Placebo; 1 tablet containing 50mg microcrystalline cellulose is taken daily for 24 weeks	Other: Placebo; 1 tablet containing 50mg MCC is taken daily for 24 weeks

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cumulative incidence number of URTIs	Cumulative incidence number of Upper Respiratory Tract Infections (URTIs)	Day 1 to 24 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cumulative number of infected participants	Cumulative number of infected participants	Day 1 to week 24
Cumulative number of days that participant recorded symptom positive to WURSS-24 system	Cumulative number of days that participant recorded symptom positive to WURSS-24 (Wisconsin Upper Respiratory Symptom Survey) scoring system during intervention period.	Day 1 to week 24
Cumulative scores of each parameter in WURSS-24 scoring system, as well as the total sum of all parameters for each participant.	Cumulative scores of each parameter in WURSS-24 scoring system during the intervention period, as well as the total sum of all parameters for each participant.	Day 1 to week 24
Length of URTI symptomatic days per one URTI episode.	Length of Upper Respiratory Tract Infection (URTI) symptomatic days per one URTI episode.	Day 1 to week 24

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Safety: Occurrence of adverse events and Serious Adverse Events	Occurrence of adverse events and Serious Adverse Events	Day 1 to week 24

Collaborators and Investigators

• Sponsor: RDC Clinical Pty Ltd
• Collaborators: Kirin Holdings Company, Limited
• Investigators: Study Director: Yusuke Ushida, Kirin Holdings Company, Limited; Study Director: Osamu Kanauchi, Kirin Holdings Company, Limited

Study record dates

Study Major Dates

• Study Start (Actual): March 28, 2025
• Primary Completion (Actual): January 10, 2026
• Study Completion (Actual): January 10, 2026

Study Registration Dates

• First Submitted: February 10, 2025
• First Submitted That Met QC Criteria: February 10, 2025
• First Posted (Actual): February 14, 2025

Study Record Updates

• Last Update Posted (Actual): March 6, 2026
• Last Update Submitted That Met QC Criteria: March 4, 2026
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Keywords: URTI; Healthy volunteer; LC-Plasma
• Other Study ID Numbers: KURTIS

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No