NCT07459166

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
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 16 (estimated)
• Sponsor: Clear Scientific, Inc. · Industry
• Sex: All
• Age: 18 Years – 55 Years
• Healthy volunteers: Accepted

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).

Conditions

• Fentanyl Overdose
• Fentanyl Poisoning

Interventions

Type	Name	Description
DRUG	Naloxone Hydrochloride	Naloxone for intravenous administration
DRUG	Fentanyl	Fentanyl for intravenous administration
DRUG	Sterile Saline	Sterile Saline for intravenous administration
DRUG	CS-1103	CS-1103 for intravenous administration

Timeline

• Start date: 2026-04-01
• Primary completion: 2026-07-01
• Completion: 2026-10-01
• First posted: 2026-03-09
• Last updated: 2026-03-27

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated drug study