Atrium Therapeutics formally launched as a spinout from Avidity Biosciences after Novartis completed its $12 billion acquisition of Avidity. The new company, led by former Avidity executives Kathleen Gallagher and Sarah Boyce, assumed Avidity’s public listing and began operations with about $270 million in cash and a public ticker carried over from Avidity. Atrium is taking forward preclinical RNA programs targeting rare cardiac conditions including PRKAG2 syndrome and PLN cardiomyopathy, areas Novartis excluded from its acquisition. The company positioned these programs to address unmet rare cardiomyopathies and intends to progress candidates toward IND‑enabling studies. Investors and partners will watch Atrium’s ability to translate Avidity’s muscle‑targeted RNA delivery technology into cardiac indications and to secure further financing or partnerships as it advances preclinical assets into the clinic.