Kailera Therapeutics closed a $600 million Series B led by Bain Capital Private Equity to advance KAI‑9531, a weekly injectable metabolic candidate that targets two pathways similar to marketed GLP‑1/Tirzepatide biology. The financing will fund global Phase 3 trials and broader pipeline development for oral and injectable metabolic programs. Investors framed the financing as a bet on blockbusters for obesity and metabolic disease; coverage from MedCity News and fundraising trackers positioned this round among the largest private biotech financings of 2025. Kailera intends to use funds for regulatory planning, trial expansion and manufacturing scale‑up for a candidate entering pivotal testing.