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A Phase 2 Safety, Tolerability, PK, and Efficacy Study of CS-1103 Following Fentanyl Challenge With Naloxone Blockade

A Phase 2 Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Efficacy of a Single Dose of Intravenous CS 1103 Following a Single Intravenous Dose of Fentanyl in Healthy Subjects With Naloxone Blockade

Status
Not yet recruiting
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07459166
Enrollment
16
Registered
2026-03-09
Start date
2026-04-01
Completion date
2026-10-01
Last updated
2026-03-27

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

Conditions

Fentanyl Overdose, Fentanyl Poisoning

Brief summary

The purpose of the study is to evaluate the safety, tolerability, pharmacokinetics, and efficacy of CS-1103 (1,000 mg), given by intravenous (IV) infusion in healthy participants in the presence of a clinically relevant dose of fentanyl (200 μg, IV), with naloxone blockade (400 μg, IV).

Interventions

Naloxone for intravenous administration

DRUGFentanyl

Fentanyl for intravenous administration

DRUGSterile Saline

Sterile Saline for intravenous administration

CS-1103 for intravenous administration

Sponsors

Clear Scientific, Inc.
Lead SponsorINDUSTRY
National Institute on Drug Abuse (NIDA)
CollaboratorNIH

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender
ALL
Age
18 Years to 55 Years
Healthy volunteers
Yes

Inclusion criteria

Major Inclusion Criteria: 1. Healthy participants aged 18 to 55 years, inclusive; 2. Have prior experience with opioids, such as from a dental procedure, chronic pain management, or previous inpatient surgical procedure; 3. A body mass index between 18.0 to 30.0 kg/m2, inclusive, and a minimum body weight of 56 kg; 4. Females must not be lactating and must have a negative pregnancy test during screening and admission. Major

Exclusion criteria

1. Estimated glomerular filtration rate \<60 mL/min/1.73 m2; 2. History of cardiovascular disease; 3. History of any clinically important disease or disorder which, in the opinion of the Investigator, may interfere with safe study participation.

Design outcomes

Primary

MeasureTime frameDescription
Number of participants with CS-1103-related adverse events (AEs) assessed by physical examinations3 days plus follow-up on Day 10Physical examinations
Number of participants with CS-1103-related adverse events (AEs) assessed by electrocardiograms (ECGs)3 days plus follow-up on Day 10Digital 12-lead electrocardiograms (ECGs). Any correlation between CS-1103 plasma concentrations and changes in QT intervals will be noted
Number of participants with CS-1103-related adverse events (AEs) assessed by vital signs3 days plus follow-up on Day 10Blood pressure, pulse rate, respiratory rate, oxygen saturation, and body temperature
Number of participants with CS-1103-related adverse events (AEs) assessed by laboratory parameters3 days plus follow-up on Day 10Clinical chemistry, hematology, coagulation, and urinalysis
Time course of CS-1103 blood and urine concentrations48 hoursMeasurement of plasma and urine concentrations of CS-1103
Time course and magnitude of urine excretion of fentanyl48 hoursMeasurement of concentration of fentanyl in urine

Secondary

MeasureTime frameDescription
Effect of CS-1103 and fentanyl on QT interval48 hoursConcentration-QT correlation performed on baseline-corrected QTcF time-matched with PK for fentanyl and CS-1103 in plasma
Effect of CS-1103 on the naloxone plasma and urine PK, if any48 hoursMeasurement of standard urine and plasma PK parameters between placebo and CS-1103 treated participants

Countries

United States

Contacts

CONTACTAnna Del Rosario, B.S.
adelrosario@clearsci.com617-621-8500
CONTACTPiercen Oliver, Ph.D.
poliver@clearsci.com617-621-8500
PRINCIPAL_INVESTIGATORXinhua Li, Ph.D.

Clear Scientific, Inc.

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Mar 28, 2026