Romanelli arrives at a pivotal moment for the company, which is currently advancing its lead gene-editing program, TSRA-196, into clinical trials. Developed in collaboration with Regeneron Pharmaceuticals, the therapy targets alpha-1 antitrypsin deficiency. Beyond this, the firm is working on treatments for sickle cell disease—backed by a $50 million investment from the Gates Foundation—and exploring in vivo CAR-T applications for oncology and autoimmune conditions.

During his three-decade tenure at Merck & Co., Romanelli managed a $25 billion international portfolio and spearheaded the company’s expansion in China. Geoff von Maltzahn, Tessera’s co-founder and chairman, noted that Romanelli’s expertise in scaling global businesses is essential as the company shifts its focus toward commercialization and broad clinical delivery. In addition to his CEO role, Romanelli will join the company’s board of directors and assume a position as a CEO-Partner at Flagship Pioneering, the firm that founded Tessera in 2018.