Seaport Therapeutics Inc. has closed an oversubscribed $225 million series B financing round to support its work developing novel neuropsychiatric medicines.

The founding CEO of Alnylam Pharmaceuticals Inc. is now leading the charge with newly launched City Therapeutics Inc., which just completed a $135 million series A financing. City’s executive chair, John Maraganore, will be in familiar territory as the new company plans to develop RNAi-based medicines using next-generation siRNA engineering. He expects dozens of these therapies to reach the market in a relatively short period of time, not just from City Therapeutics but from other companies. It’s a period in the development timeline that he finds reminiscent of the rise and development of monoclonal antibodies.

Booster Therapeutics is ready to open up a new arm of the proteasome after raising $15 million in seed funding to advance small molecules it says can degrade multiple types of harmful proteins. Rather than tagging single disease proteins with a ubiquitin marker for degrading via 26S proteasomes, these compounds directly activate 20S proteasomes that naturally recognize disordered proteins without the need for ubiquitin tagging.

Purespring Therapeutics Ltd. has raised £80 million (US$104.6 million) in a series B, putting it on course to be the first to take a gene therapy for a kidney disease into the clinic. The money enables the company to move the lead program, PS-002, for the treatment of IgA nephropathy to clinical proof of concept and advance programs in other complement-mediated kidney diseases, and in an undisclosed glomerular kidney disease.

Integrated Biosciences Inc. has closed a $17.2 million seed financing to support its work combining synthetic biology and artificial intelligence (AI)-driven small-molecule drug discovery to produce next-generation therapeutics targeting age-related diseases.