Flare Therapeutics Raises $85M Series C Led by Third Rock, Nextech

Flare Therapeutics, a Cambridge-based biotech focused on transcription-factor drugs, closed an $85 million Series C round led by existing investors Third Rock Ventures and Nextech Invest. The round included Pfizer Ventures, Boxer Capital, GordonMD Global Investments, Invus, Casdin Capital, Eli Lilly and Company, Novartis, Agent Capital and Eventide Asset Management.

Alongside the financing, the company named Anna Protopapas as chief executive officer. Protopapas previously led Mersana Therapeutics and held senior roles at Novartis and Biogen. Her appointment signals a push toward clinical execution as Flare moves its lead programs into later-stage testing.

The proceeds will fund Flare's prioritized pipeline, working capital and general corporate purposes. The company is developing small-molecule drugs that target transcription factors, a class of proteins historically considered undruggable. Its lead candidate targets the transcription factor RORγt in autoimmune diseases, with early clinical data expected in the next 12 to 18 months.

Lilly's participation in the round is notable given its own interest in transcription-factor biology and its broader push into immunology. The pharma giant has been expanding its early-stage pipeline through both internal R&D and venture investments.

Flare has now raised roughly $230 million across three rounds since its 2020 founding. The Series C brings in a mix of crossover investors and specialist healthcare funds, a structure that gives the company flexibility to fund Phase 2 work without rushing toward an IPO.