Flare Therapeutics, a two-year old Cambridge, MA-based drug discovery startup, raised $123 million in Series B funding to target transcription factors, proteins that control gene expression and play a key part in cancer and other disease development.

Series B funding, which follows an $82 million Series A in 2021, was oversubscribed. Pfizer Ventures and GordonMD Global Investments LP co-led the financing. Other existing investors participated, including Boxer Capital, Eventide Asset Management and its incubator Third Rock Ventures. Flare also gained new supporters, including Big Pharma giants Novartis and Eli Lilly.

Funding will go toward powering its clinical trial for FX-909, a small molecule inhibitor targeting the peroxisome proliferator-activated receptor gamma (PPARG), which is expected to take place later this year, according to the company.

“While targeting transcription factors has the potential for incredible impact, their complex structure makes them notoriously difficult to drug, requiring a new approach and new thinking,” said Rob Sims, co-founder and chief scientific officer at Flare.

The fundraise is a relatively stark figure in a difficult startup financing environment but further buoys the upbeat signals coming out of other biotech companies in recent weeks, including the $200 million CARGO Therapeutics and $100 million Rapport Therapeutics rounds.