New data presented in Seville suggest that some patients with preexisting anti‑AAV antibodies may still be eligible to receive gene therapies, challenging a common exclusion criterion and potentially widening treatment access. The report highlights assay work and patient‑level analyses indicating variable neutralization thresholds that may permit dosing in selected cases. Concurrently, presentations at ESGCT flagged persistent concerns about durability and liver toxicity in hemophilia gene‑therapy programs, underscoring tradeoffs companies face between expanding eligibility and ensuring long‑term safety. For context: anti‑AAV antibodies can neutralize AAV‑based vectors, preventing successful gene delivery; variability in antibody titers and assay design complicate universal exclusion rules.