Aerska Therapeutics, a startup developing 'brain shuttle' technology to deliver larger molecules across the blood‑brain barrier, raised $39 million in a follow‑on financing, the company told STAT. The round arrives just months after an initial raise, an uncommon cadence in biotech financing. Aerska’s approach tethers siRNA packages to antibodies that exploit iron transport to cross into the brain, founders Jack O’Meara and Alnylam alum Stuart Milstein told STAT. The company hopes the platform will enable gene‑silencing therapeutics for neurological diseases that are currently inaccessible to larger biologics. Investors backed the round to accelerate preclinical development and translate blood‑brain barrier targeting into clinical candidates.