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

Conditions

• Fentanyl Overdose
• Fentanyl Poisoning

Eligibility Criteria

Sex

ALL

Age

18 Years - 55 Years

Healthy Volunteers

Accepted

Interventions

• Naloxone Hydrochloride — DRUG
  Naloxone for intravenous administration
• Fentanyl — DRUG
  Fentanyl for intravenous administration
• Sterile Saline — DRUG
  Sterile Saline for intravenous administration
• CS-1103 — DRUG
  CS-1103 for intravenous administration

Study Details

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).

Key Dates

Start date

May 31, 2026

Status verified

May 2026

Primary completion

Jul 31, 2026

Completion

Oct 31, 2026

Study Design

Enrollment

16 participants (estimated)

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

TREATMENT

Arms

• Placebo Comparator: Placebo
  Participants receive naloxone blockade (400 μg, IV), followed by fentanyl (200 μg, IV), followed by placebo (saline).
• Active Comparator: Active
  Participants receive naloxone blockade (400 μg, IV), followed by fentanyl (200 μg, IV), followed by CS-1103 (1,000 mg, IV).

Primary Outcome Measure

Number of participants with CS-1103-related adverse events (AEs) assessed by physical examinations [ Time Frame: 3 days plus follow-up on Day 10 ]

Central Contacts

• Anna Del Rosario, B.S.
  617-621-8500
  [email protected]
• Piercen Oliver, Ph.D.
  617-621-8500
  [email protected]

Locations (1)

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