Can a pill stop COVID-19 before it starts?
NCT ID NCT05897541
First seen Sep 16, 2026 · Last updated Sep 17, 2026 · Updated 1 time
Summary
Researchers are testing whether an antiviral tablet called S-217622 can prevent symptomatic COVID-19 in people who live with someone who has symptoms. The trial enrolls household contacts of a person with symptomatic COVID-19 and gives them either the antiviral or a placebo for a short period. The main goal is to see how many people in each group test positive for SARS-CoV-2 and develop COVID-19 symptoms.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- S-217622, an experimental antiviral tablet
- What this could lead to
- If it works, people exposed to COVID-19 at home could take a short course of tablets to avoid getting sick, similar to how Tamiflu is used for flu.
- What could go wrong
- The antiviral may not prevent enough infections to be useful, or it may only work against certain variants. Like any drug, it can cause side effects, and a phase 3 trial is needed to know if benefits outweigh risks.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 3
Large-scale testing in a bigger group. Usually the last step before a treatment can be approved.
- Participants
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3,701 people
The number who actually took part.
- Started
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Jun 2023
- Finished
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Sep 2024
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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Children (under 18), adults (18 to 64) and older adults (65 and over)
- Sex
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Anyone
- Healthy volunteers
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Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: Index Participants Only 1 index participant from each household will be enrolled in the study. Participants are eligible to be included as an index participant if all of the following criteria apply: 1. Pediatric participants or adult participants (of any age) 2. The index participant must: 1. Have at least 1 COVID-19 symptom within 24 hours before the index participant providing informed consent. COVID-19 symptom(s) must be deemed by the investigator as related to the current SARS-CoV-2 infection (not related to preexisting comorbidities) or deemed as preexisting and worsened due to SARS-CoV-2 infection. 2. Must have positive SARS-CoV-2 test (a nucleic acid amplification test or antigen test) from any respiratory tract specimen from a sample collected prior to randomization of the participant 3. Must have a potential study participant who can participate in the study after onset of COVID-19 symptoms in an index participant Study Participants Multiple study participants from the same household are allowed to be enrolled in the study. The study intervention randomization will be performed based at the study participant's level. Participants will be eligible to be included in the study only if all of the following criteria apply: 1. ≥ 12 years of age at the time of signing the informed consent 2. Has a negative screening for SARS-CoV-2 infection, as determined by SARS-CoV-2 test (a nucleic acid amplification test or antigen test) from any respiratory tract specimen (for example, oropharyngeal, nasopharyngeal or nasal swab, or saliva). 3. Has lived in household with index participant and will continue to live in same household and share common areas such as dining rooms and bathrooms until the end of the study 4. Must not be considered by the investigator or subinvestigator to have SARS-CoV-2 infection and: 1. No measured fever at Screening (defined as body temperature ≥ 38.0°Celsius \[C\] per tympanic or rectal thermometer or ≥ 37.5°C per axillary, oral, or forehead/temporal thermometer) 2. No COVID-19 symptoms at Screening (if a participant has COVID-19-like symptoms caused by comorbidities, only 1 symptom will be allowed) 5. Capable and willing to complete a participant diary 6. a. Male participants: Participants with partners that are woman of childbearing potential (WOCBP) must agree to use effective contraception. Participants with pregnant partners must agree to use effective contraception. b. Female participants: A female participant is eligible to participate if she is not pregnant or breastfeeding, and the following conditions applies: * Is not a WOCBP or * All of the following apply: * Is a WOCBP and using a contraceptive method that is effective as described in the protocol. * A WOCBP must have a negative urine pregnancy test within 24 hours before the first dose of study intervention period. * If a urine pregnancy test cannot be confirmed as negative (for example, an ambiguous result), a serum pregnancy test must be negative. * Additional requirements for pregnancy testing during and after study intervention as described in the protocol. * The investigator/subinvestigator will review medical history, menstrual history, and recent sexual activity to decrease the risk of inclusion of a woman with an early undetected pregnancy. 7. Participant must be randomized ≤ 72 hours from onset of COVID-19 symptoms in the index participant. Exclusion Criteria: Study Participants: Participants will be excluded from the study if any of the following criteria apply: 1. Tested positive for SARS-CoV-2 in the past 6 months. 2. Have an underlying disease requiring systemic corticosteroids (excluding topical), antipyretics/analgesics, or immunosuppressive agents. 3. Known current renal impairment defined as creatinine clearance \< 30 milliliters/minute by Cockcroft Gault or requiring dialysis. 4. Participants with severe liver dysfunction, such as known history of cirrhosis or liver decompensation (including ascites, variceal bleeding, or hepatic encephalopathy). 5. Received approved, authorized, or investigational convalescent plasma, or other anti- SARS-CoV-2 biologic products within 3 months of the Screening Visit 6. Received approved, authorized, or investigational anti-SARS-CoV-2 monoclonal antibodies (mAbs) in the last 6 months. 7. Received any SARS-CoV-2 vaccine within 6 months prior to the Screening Visit or is expected to receive a SARS-CoV-2 vaccine or other approved, authorized, or investigational postexposure prophylaxis treatments until the end of the study. 8. Participants who have used any of the following drugs within 14 days prior to enrollment: 1. Strong cytochrome P450 (CYP) 3A inducer 2. Products containing St. John's wort 9. Exposed to an investigational drug within 30 days or 5 half-lives of the drug prior to the Screening Visit. 10. Positive urine pregnancy test at Screening Visit or are lactating. 11. Known allergy/sensitivity or any hypersensitivity to components of S-217622 or placebo for S-217622. 12. Any condition or circumstance that, in the opinion of the investigator or subinvestigator, would compromise the safety of the participant or the quality of the study data. Note: Other protocol-defined Inclusion/Exclusion criteria may apply.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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ACRC Trials - Carrollton - Hunt - PPDS
Carrollton, Texas, 75010, United States
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Absolute Clinical Research, LLC
Phoenix, Arizona, 85051-5775, United States
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Accel Research Site - Achieve - Birmingham - ERN - PPDS
Birmingham, Alabama, 35216, United States
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Accel Research Sites - Nona Pediatric Center - ERN - PPDS
Orlando, Florida, 32829-8070, United States
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Advances In Health Inc
Pearland, Texas, 77584-8075, United States
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Alina Clinical Trials, LLC
Dallas, Texas, 75225-6301, United States
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Alliance for Multispecialty Research LLC - Roy
Roy, Utah, 84067-9108, United States
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Alliance for Multispecialty Research, LLC - Kaysville - PPDS
Kaysville, Utah, 84037-4300, United States
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Alma Research
Miami, Florida, 33165, United States
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American Research Centers of Florida
Pembroke Pines, Florida, 33027-1717, United States
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Apex Research Group
Fair Oaks, California, 95628-2501, United States
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Ark Clinical Research - Long Beach - ClinEdge - PPDS
Long Beach, California, 90815-2521, United States
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Ascada Research LLC
Fullerton, California, 92835-4127, United States
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Balanced Life Health Care Solutions - SKYCRNG - PPDS
Lawrenceville, Georgia, 30046-8703, United States
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Bayside Clinical Research-West Tampa
Tampa, Florida, 33607, United States
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BioClinical Research Alliance
Miami, Florida, 33155-6542, United States
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C & R Research Services USA
Houston, Texas, 77022, United States
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CCM Clinical Research Group
Miami, Florida, 33133-4231, United States
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CTMD Research, Inc. Palm Springs - Hunt - PPDS
Palm Springs, Florida, 33406-7671, United States
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Care United Research, LLC - Elligo - PPDS
Forney, Texas, 75126-4174, United States
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Care and Cure Clinic
Houston, Texas, 77090-1243, United States
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Central Alabama Research
Birmingham, Alabama, 35209-8401, United States
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Central Florida Internists - Conway
Orlando, Florida, 32812-7331, United States
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Centro Médico San Nicolás Grupo Oroño
San Nicolás de los Arroyos, Buenos Aires, B2900, Argentina
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Child Healthcare Associates - East Syracuse
East Syracuse, New York, 13057-9305, United States
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Clinical Associates in Research Therapeutics of America
San Antonio, Texas, 78212-4829, United States
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Clinical Trials Management Services, LLC
Thousand Oaks, California, 91360, United States
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Clinical Trials of South Carolina - ClinEdge - PPDS
Moncks Corner, South Carolina, 29461-5017, United States
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Clínica Mayo de U.M.C.B. S.R.L
San Miguel de Tucumán, Tucumán Province, T4000IHE, Argentina
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Clínica Privada Independencia
Munro, Buenos Aires, 1605, Argentina
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Coastal Pediatric Associates
Charleston, South Carolina, 29414-5834, United States
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Combined Research Orlando Phase I-IV LLC
Orlando, Florida, 32807-3555, United States
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Continental Clinical Research, LLC
Miami, Florida, 33144-4273, United States
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Cullman Clinical Trials
Cullman, Alabama, 35055-1902, United States
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Cyn3rgy Research - ClinEdge - PPDS
Gresham, Oregon, 97030-8319, United States
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DCT-McAllen Primary Care Research, LLC dba Discove
McAllen, Texas, 78503-1397, United States
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Denenchofu Family Clinic
Ōta-ku, Tokyo Province, 145-0071, Japan
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Eagle Clinical Research
Chicago, Illinois, 60621-3116, United States
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Entrust Clinical Research
Miami, Florida, 33176-1530, United States
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Epic Medical Research LLC - DeSoto
DeSoto, Texas, 75115-2043, United States
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Florida Research Center, Inc.
Miami, Florida, 33144-2069, United States
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Flourish Research - Leesburg - PPDS
Leesburg, Florida, 34748-5077, United States
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Flourish Research - Miami - PPDS
Miami, Florida, 33186-9066, United States
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Frontier Clinical Research - Scottdale
Scottdale, Pennsylvania, 15683-2460, United States
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Fujimaki Ear, Nose and Throat Clinic (Ent Clinic)
Ichikawa-Shi, Chiba, 272-0143, Japan
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Fujimino Emergency Hospital
Miyoshi-machi, Iruma-gun, Saitama, 354-0044, Japan
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Fukuda Medical Clinic
Toda-shi, Saitama, 335-0015, Japan
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GCP Global Clinical Professionals, LLC
Miami, Florida, 33169-5732, United States
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Global Health Clinical Trials
Miami, Florida, 33165-2968, United States
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Global Healthcare Clinic
Chiyoda-Ku, Tokyo, 102-0083, Japan
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Global Medical Research - M3 WR
Dallas, Texas, 75224-2367, United States
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Hamamatsu Medical Center
Hamamatsu, Shizuoka, 432-8580, Japan
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Hanoi University of Medicine - Clinical Trial Unit
Quận Đống Đa, Ha Noi, Thu Do, 100000, Vietnam
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Healthstar Research
Hot Springs, Arkansas, 71913-8184, United States
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Henry Ford Hospital
Detroit, Michigan, 48202-2608, United States
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Hitachi,Ltd.,Tsuchiura Medical & Health Care Center
Tsuchiura, Ibaraki, 300-0012, Japan
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Hope Clinical Trials
Coral Gables, Florida, 33134-1642, United States
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Hosokawa Surgical Clinic
Nagoya-Shi Nakamura-Ku, Aiti, 453-0812, Japan
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Hospital Interzonal General de Agudos Vicente Lopez Y Planes
General Rodriguez, Buenos Aires, 1748, Argentina
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Hospital Rawson
Córdoba, 5000, Argentina
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I.V.A.M. Clinical & Investigational Center
Doral, Florida, 33126, United States
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INECO Neurociencias Oroño
Rosario, Santa Fe Province, S2000DTP, Argentina
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Iizuka Hospital
Iizuka-Shi, Hukuoka, 820-8505, Japan
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Ikebukuro Higashiguchi Mame Clinic
Toshima-ku, 170-0013, Japan
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Instituto Médico Río Cuarto
Río Cuarto, Córdoba Province, 5800, Argentina
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Instituto Médico de la Fundación Estudios Clínicos
Rosario, Santa Fe Province, S2013DTC, Argentina
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Instituto de Investigaciones Clínicas Zárate
Zárate, Buenos Aires, B2800DGH, Argentina
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Invictus Clinical Research Group, LLC
Coconut Creek, Florida, 33073-3458, United States
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Irie Naika Syounika Iin
Fukuoka, Fukuoka, 812-0053, Japan
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Ivetmar Medical Group, LLC
Miami, Florida, 33155-6542, United States
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Japanese Red Cross Fukuoka Hospital
Fukuoka, Hukuoka Province, 815-0082, Japan
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KODAIRA Hospital
Toda-Shi, Saitama, 335-0035, Japan
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KU Wichita Center for Clinical Research
Wichita, Kansas, 67214-3124, United States
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Kaiseikai Kita Shin Yokohama Internal Medicine Clinic
Yokohama, Kanagawa, 223-0059, Japan
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Kamezawa Clinic
Kasugai-Shi, Aiti, 486-0817, Japan
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Kamoike Otolaryngology Clinic
Kagoshima, Kagoshima-ken, 890-0063, Japan
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Kanagawa Himawari Clinic
Kawasaki-Shi, Kanagawa, 216-0006, Japan
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Kasukabe Medical Center
Kasukabe, Saitama, 344-8588, Japan
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Kendall South Medical Center
Miami, Florida, 33185-4082, United States
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Kijima Kids Clinic
Higashiokitama-gun, Yamagata, 999-0121, Japan
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Kikuchi Internal clinic
Maebashi, Gunma, 370-3573, Japan
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LCC Medical Research - Miami - ClinEdge - PPDS
Miami, Florida, 33126-1921, United States
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Lapis Clinical Research-Denver
Denver, North Carolina, 28037-8254, United States
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Lee's Clinic
Osaka, Osaka, 531-0073, Japan
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Lynn Institute of The Rockies - ERN - PPDS
Colorado Springs, Colorado, 80918-1662, United States
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MIH Clinic Yoyogi
Shibuya-Ku, Tokyo, 151-0051, Japan
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Main Street Physicians Care - Waterway
Little River, South Carolina, 29566, United States
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Maruyama Tame Pediatrics
Sapporo, Hokkaidô, 064-0821, Japan
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MedQuest Translational Sciences
Miami Lakes, Florida, 33016, United States
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Medical Corporation Kojyokai Hirose Clinic
Tokorozawa-Shi, Saitama, 359-1111, Japan
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Medical Corporation Nakano Children's Clinic
Yokohama, Kanagawa, 222-0012, Japan
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Megumi Clinic
Kasuyagun Shimemachi, Fukuoka, 811-2201, Japan
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Meridian International Research
Miami Lakes, Florida, 33014-6433, United States
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Miami Clinical Research - ClinEdge - PPDS
Miami, Florida, 33155, United States
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Montana Medical Research
Missoula, Montana, 59808, United States
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Moriyama Otolaryngology
Kagoshima, Kagoshima-ken, 890-0034, Japan
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Morizono medical clinic
Kitakyushu-shi, Hukuoka, 807-0072, Japan
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Motosumiyoshi-ekimae Cocoromi Clinic
Kawasaki-Shi, Kanagawa, 211-0025, Japan
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Murasakibaru Tahara Hospital
Kagoshima, Kagoshima-ken, 890-0082, Japan
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Musashino Hospital
Kodaira-Shi, Tokyo, 187-0031, Japan
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NHO Okinawa Hospital
Ginowan-Shi, Okinawa, 901-2214, Japan
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NMMM PHARMEDICA Health Research Institute
Lombardy East, Johannesburg, Gauteng, 2090, South Africa
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Nagaoka Chuo General Hospital
Nagaoka-Shi, Niigata, 940-8653, Japan
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Nagata Hospital
Yanagawa-Shi, Hukuoka, 832-0059, Japan
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Nakayama Pediatric Clinic
Nagasaki, 852-8133, Japan
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Neighborhood Healthcare
Escondido, California, 92025-4604, United States
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New Horizon Medical Group, LLC
Houston, Texas, 77065, United States
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Newtown Clinical Research Centre
City of Johannesburg, Gauteng, 2001, South Africa
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Nishikasai ekimae Family Clinic
Edogawa-ku, Tokyo, 134-0088, Japan
-
Nishioka Hospital
Sapporo-Shi Toyohira-Ku, Hokkaidô, 062-0034, Japan
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Nishiyamato Keiwa Hospital
Naka, Ibaraki, 311-0133, Japan
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Nozaki Clinical
Musashino-Shi, Tokyo, 180-0022, Japan
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Oceane7 Medical & Research Center, Inc.
Miami, Florida, 33144-2155, United States
-
Okayama University Hospital
Okayama, 700-8558, Japan
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Olivo Medical and Wellness Center
Chicago, Illinois, 60618-8101, United States
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One of a Kind Clinical Research Center LLC
Scottsdale, Arizona, 85258-4590, United States
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Ormond Beach Clinical Research
Ormond Beach, Florida, 32174-8196, United States
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Osaka City Juso Hospital
Osaka, 532-0034, Japan
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Preferred Research Partners - ClinEdge - PPDS
Little Rock, Arkansas, 72211-3868, United States
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Premier Clinical Research Institute - Miami - ClinEdge - PPDS
Miami, Florida, 33122-1335, United States
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PriMed Clinical Research - ClinEdge - PPDS
Dayton, Ohio, 45429-3658, United States
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Progressive Medical Research - ClinEdge - PPDS
Port Orange, Florida, 32127, United States
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Progressive Medicine of the Triad, LLC
Winston-Salem, North Carolina, 27103-1552, United States
-
Quality Research of South Florida
Hialeah, Florida, 33016-1811, United States
-
Rancho Cucamonga Clinical Research
Rancho Cucamonga, California, 91730-3062, United States
-
Renew Health Clinical Research, LLC
Tampa, Florida, 33607-2529, United States
-
Research Institute of South Florida Inc
Miami, Florida, 33173-4648, United States
-
Rinku General Medical Center
Izumisano, Osaka, 598-0048, Japan
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Rochester Clinical Research - ATLAS - Rochester - PPDS
Rochester, New York, 14609-3173, United States
-
SPICA Clinical Research
Columbia, South Carolina, 29223-6301, United States
-
Saint Hope Foundation Inc
Bellaire, Texas, 77401-4500, United States
-
Sanatorio Allende S.A
Córdoba, X5000JHQ, Argentina
-
Sanatorio Medico de Diagnostico Y Tratamiento
Santa Fe, S3000FUJ, Argentina
-
Shimamura Memorial Hospital
Nerima-Ku, Tokyo, 177-0051, Japan
-
Shiwa Chuo Syounika
Shiwa-gun, 028-3318, Japan
-
Shizuka Medical Clinic
Takasaki-shi, 370-0071, Japan
-
Shoda Hospital
Annaka-Shi, Gunma, 379-0116, Japan
-
Smart Cures Clinical Research
Rolling Hills Estates, California, 90274-7604, United States
-
Southwest Family Medicine Associates
Dallas, Texas, 75235-1715, United States
-
Soyukai Medical Corporation Yamaguchi clinic
Ōta-ku, 145-0063, Japan
-
Suita Municipal Hospital
Suita, Ôsaka, 564-8567, Japan
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Suncoast Research Group LLC - Flourish - PPDS
Miami, Florida, 33135-1687, United States
-
Suto Hospital
Annaka-shi, Gunma, 379-0016, Japan
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Takahashi Medical Clinic
Kokubunji-Shi, Tokyo, 185-0014, Japan
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Takahashi Pediatric Clinic
Kobe-Shi Nada-Ku, Hyôgo, 657-0846, Japan
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Takinogawa Hospital
Kita-ku, Tokyo, 114-0023, Japan
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Tampa Bay Health Care
Tampa, Florida, 33615, United States
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Tashiro Endocrinolgy Clinic
Fukuoka, Fukuoka, 814-0153, Japan
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Teine Otolaryngology Clinic
Sapporo, Hokkaidô, 006-0815, Japan
-
Terada Clinic Respiratory Medicine and General Practice
Himeji-shi, Hyôgo, 670-0849, Japan
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Toda Internal Medicine & Neurology
Akashi-Shi, Hyôgo, 674-0081, Japan
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Tokyo Center Clinic
Chuo-ku, Tokyo, 103-0028, Japan
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Tokyo Shinagawa Hospital Social Medical Corporation Association Tokyokyojuno-kai
Shinagawa-ku, Tokyo, 140-0011, Japan
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Tomita Internal medicine clinic
Fukuoka, Fukuoka, 810-0033, Japan
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Torrance Clinical Research Institute
Lomita, California, 90717-2101, United States
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Toyama Rosai Hospital
Uozu-Shi, Toyama, 937-0042, Japan
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Tranquil Clinical Research
Webster, Texas, 77598-3900, United States
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Trident Clinical
Sol Plaatjie, Northern Cape, 8301, South Africa
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Tristar Clinical Investigations, P.C.
Philadelphia, Pennsylvania, 19114-1030, United States
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TrueBlue Clinical Research
Brandon, Florida, 33511-4850, United States
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Tsuchiura Beryl Clinic
Tsuchiura-Shi, Ibaraki, 300-0062, Japan
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Universal Medical and Research Center, LLC
Coral Gables, Florida, 33134-1602, United States
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Universal Medical and Research Center, LLC Homestead
Homestead, Florida, 33030-6057, United States
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University of Medicine Center, Ho Chi Minh City
Ho Chi Minh City, 700000, Vietnam
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University of Miami - 1150 NW 14th St
Miami, Florida, 33136-1104, United States
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University of Tsukuba Hospital
Tsukuba, Ibaraki, 305-8576, Japan
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University of the Ryukyus Hospital - 207 Uehara
Okinawa-Shi, Okinawa, 903-0215, Japan
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Uno Internal Medicine Respiratory Clinic
Isesaki-Shi, Gunma, 372-0831, Japan
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VIP Trials
San Antonio, Texas, 78230, United States
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Valencia Medical and Research Center
Miami, Florida, 33165-3912, United States
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Valley Institute of Research
Fort Worth, Texas, 76164-9041, United States
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Velocity Clinical Research - Covington - PPDS
Gulfport, Mississippi, 39503-2637, United States
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Vida Clinical Sites
Dearborn Heights, Michigan, 48127-2234, United States
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Voyage Medical - Michigan
Canton, Michigan, 48188-2866, United States
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WellNow Urgent Care & Research - Huber Heights
Dayton, Ohio, 45424-4019, United States
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Yokohama Municipal Citizens Hospital
Yokohama, Kanagawa, 240-0062, Japan
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Yoshida Clinic
Suginami-ku, Tokyo, 167-0043, Japan
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Yotsuya Naika
Shinjuku-Ku, Tokyo, 160-0017, Japan
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