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Modulation of Gut MicroFLORA With Rifaximin to Reduce High Platelet Reactivity in Post-ACS Patients on Ticagrelor

Modulation of Gut Microflora With Rifaximin to Reduce High Platelet Reactivity in Post-Acute Coronary Syndrome Patients on Ticagrelor (FLORA-ACS)

Status
Not yet recruiting
Phases
Phase 4
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07203846
Acronym
FLORA-ACS
Enrollment
50
Registered
2025-10-02
Start date
2026-01-01
Completion date
2027-06-30
Last updated
2025-10-02

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

ACS - Acute Coronary Syndrome, Anti-Bacterial Agents, Blood Platelets, Drug Effects, Drug Resistance, Dysbiosis, Microbiota, Myocardial Infarction (MI), Platelet Aggregation, Platelet Aggregation Inhibitors, Platelet Function Tests, Rifaximin, Ticagrelor

Keywords

high platelet reactivity, HPR, Multiplate aggregometry, multiple electrode aggregometry, MEA, microbiome, gut flora, eubiotic, 16S rRNA sequencing, P2Y12 inhibitor

Brief summary

The FLORA-ACS study aims to evaluate the relationship between dysbiosis and high platelet reactivity during treatment with ticagrelor in patients with a history of acute coronary syndromes and investigate the use of rifaximin to eliminate dysbiosis and thus provide effective antiplatelet treatment.

Detailed description

A research hypothesis has been formulated indicating dysbiosis of the gut microbiota as a possible cause of high platelet reactivity (HPR) during treatment with an antiplatelet agent, ticagrelor, in post-acute coronary syndrome (ACS) patients. The use of rifaximin, an antibiotic exhibiting an eubiotic effect, may correct gut dysbiosis and help determine whether changes in the microbiota influence HPR. The FLORA-ACS study will enroll 50 subjects with a history of ACS treated with ticagrelor (standard maintenance dose of 90 mg orally twice a day) and characterized by HPR. Participants will be enrolled in the study no sooner than 1 month and no later than 12 months following the ACS incident. Platelet activity will be tested using the multiple electrode aggregometry method (Multiplate analyzer) with the HPR defined based on the consensus paper of the Working Group on On-Treatment Platelet Reactivity. Concurrently, fecal samples will be collected for microbiome profiling. The microbiota will be analyzed in terms of fecal bacterial richness and diversity using 16S ribosomal RNA sequencing. Participants will receive a 7-day course of oral rifaximin (400 mg every 12 hours). Both platelet activity and microbiota testing will be conducted at baseline and post-treatment. Additional laboratory testing will include complete blood count and C-reactive protein. An analysis of major adverse cardiovascular events (MACE) occurrence within a 6-month follow-up period is planned.

Interventions

DRUGRifaximin

Participants receiving a 7-day course of oral rifaximin 400 mg every 12 hours

Sponsors

Ministry of Science and Higher Education, Poland
CollaboratorOTHER_GOV
Collegium Medicum w Bydgoszczy
Lead SponsorOTHER

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No

Inclusion criteria

* Between 18 and 80 years of age * History of acute coronary syndrome no sooner than 1 month and no later than 12 months prior to study inclusion * Current treatment with ticagrelor (90 mg orally twice a day) * High platelet reactivity assessed with multiple electrode aggregometry method (AUC of \>46 U) * Provision of informed consent prior to any study procedures

Exclusion criteria

* History of hypersensitivity to rifaximin or other rifamycin-derived agent * Ongoing treatment with rifamycins * Platelet count \< 100×10\^9/L or \> 450×10\^9/L * Treatment with antibiotics, probiotics, or glucocorticoids within 3 months prior to study inclusion * History of gastrointestinal diseases such as inflammatory bowel disease, bowel obstruction, or gastrointestinal tumor * Infection, including gastrointestinal infection, within a month prior to study inclusion * History of Clostridium difficile infection * Current use of specific medications (warfarin, glycoprotein IIb/IIIa inhibitors, immunosuppressants, bile acid sequestrants, antidiarrheal agents) * Impaired liver function classified as Child-Pugh class B or C * Hemodynamic instability * Pregnancy or breastfeeding * Patients considered by the investigator to be uncooperative

Design outcomes

Primary

MeasureTime frameDescription
Change in platelet reactivity in Multiplate0-7 daysRelative reduction in platelet reactivity from baseline to post-intervention by \>10%, assessed with Multiplate analyzer (multiple electrode aggregometry)
Achievement of platelet reactivity below HPR0-7 daysAchieving platelet reactivity below HPR in a patient with a higher baseline value, assessed with Multiplate analyzer (multiple electrode aggregometry)

Secondary

MeasureTime frameDescription
Relative reduction in platelet reactivity in thromboelastography0-7 daysRelative reduction in platelet reactivity from baseline to post-intervention by \>10%, assessed with Platelet Mapping assay (thromboelastography)
Relative reduction in platelet reactivity0-7 daysRelative reduction in platelet reactivity from baseline to post-intervention by \>10%, assessed with VerifyNow P2Y12 assay
Changes in microbiome profile0-7 daysChanges in microbiome profile post-intervention assessed using 16S rRNA sequencing
Achieving platelet reactivity below HPR in thromboelastography0-7 daysAchieving platelet reactivity below HPR in a patient with a higher baseline value, assessed with Platelet Mapping assay (thrombelastography)
Achieving platelet reactivity below HPR in VerifyNow0-7 daysAchieving platelet reactivity below HPR in a patient with a higher baseline value, assessed with VerifyNow P2Y12 assay

Countries

Poland

Contacts

Primary ContactKlaudyna Grzelakowska, MD
klaudyna.grzelakowska@gmail.com+48525854023

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026