GB-0669 Phase 1 Trial Reports Long Half-Life, Mild Adverse Reactions

Key Takeaways

• GB-0669 was well tolerated, with no dose-limiting toxicities and only mild adverse reactions.
• Exposure was dose-proportional up to 2400 mg, and the half-life was 54 days.
• Serum live virus neutralization increased at 600 mg and 1200 mg with separation from placebo.

GB-0669 showed a 54-day half-life in a first-in-human phase 1 trial in healthy adults randomized to active treatment or placebo. No dose-limiting toxicities were observed, and all adverse reactions were grade 1 or 2. Exposure was dose-proportional through 2400 mg, while serum live virus neutralization increased at 600 mg and 1200 mg with separation from placebo. The authors concluded that 1200 mg should be explored in phase 2 for immunocompromised individuals with COVID-19.

The study enrolled healthy adults aged 18 to 55 years in a randomized, placebo-controlled phase 1 design. The trial included 51 participants, with 36 assigned to GB-0669 and 15 to placebo. Single intravenous dosing was evaluated in five ascending cohorts of 100, 300, 600, 1200, and 2400 mg. Participants were monitored for 43 weeks.

Safety findings were limited to mild events across the dose range. Researchers observed no dose-limiting toxicities, and every adverse reaction was grade 1 or 2.

Dose-dependent increases in serum live virus neutralization were seen at 600 mg and 1200 mg, with separation from placebo at those doses. The estimated neutralizing index supported therapeutic efficacy for two weeks after administration.