Preclinical Update (in gene therapy context)

**What it means:** "Preclinical" means research done **before human trials begin** — in cell cultures (in vitro) and animal models (in vivo). A "preclinical update" means the researchers have completed early-stage animal or cell studies and are reporting the results to the community. **Why it matters:** Preclinical results can be encouraging (the drug works in animals!) but are not guaranteed to translate to humans. About 90% of drugs that succeed in preclinical testing fail in human trials. Still, positive preclinical data is a necessary milestone — you can't get to Phase 1 without it.