CAMBRIDGE, Mass. — Clear Scientific announced positive results from a Phase 2 clinical trial of CS-1103, an experimental treatment designed to bind and inactivate fentanyl while accelerating its removal from the body.
The company said the trial met all its endpoints, demonstrating that CS-1103 accelerated fentanyl elimination and showed a favorable safety profile. Clear Scientific plans to begin Phase 3 testing in the first half of 2027.
CS-1103 is an injectable small-molecule sequestrant designed to bind fentanyl and accelerate its excretion through urine. Unlike naloxone, which blocks the effects of opioids, the experimental treatment is intended to physically remove fentanyl from the body.
The randomized, double-blind Phase 2 trial enrolled 16 healthy adults at a single clinical site. All participants received fentanyl followed by naloxone and were then administered either CS-1103 or a placebo.
According to the company, CS-1103 increased fentanyl excretion through urine by 25 times compared with the control group, significantly reducing the amount of fentanyl remaining in the body. The treatment did not interfere with naloxone.
All 16 participants completed the study, and a single intravenous dose of CS-1103 was well tolerated, with no serious adverse events reported.
“Fentanyl in the body makes rescue and transition to treatment significantly more challenging,” said Shekar Shetty, Chief Executive Officer of Clear Scientific.
Shetty said the treatment could potentially prevent the recurrence of opioid effects after an initial overdose reversal, reduce withdrawal complications and allow patients to transition more safely to addiction treatments such as buprenorphine and methadone.
The company said the findings were consistent with earlier nonclinical studies demonstrating that CS-1103 rapidly reverses respiratory depression caused by synthetic opioids.
However, the Phase 2 study focused on fentanyl clearance and safety in healthy adults. Its effectiveness in treating patients experiencing fentanyl overdoses has not yet been established.
Clear Scientific is initially developing its sequestrant technology to target fentanyl, methamphetamine and cocaine. The company is also exploring applications in central nervous system disorders and metabolic diseases.
