Bitterroot Bio

Bitterroot Bio is a Palo Alto, California clinical-stage biotechnology company pioneering the field of cardio-immunology - the science of how the immune system drives heart disease. Founded by veterans of Forty Seven (the CD47 company Gilead bought for ~$5 billion), Bitterroot is turning the immune-checkpoint playbook from cancer toward atherosclerosis. Its lead candidate, BRB-002, is an immunomodulating protein that blocks the CD47 'don't eat me' signal on arterial plaque, prompting macrophages to clear inflammation and stabilize plaque - a mechanism that works differently from cholesterol-lowering drugs. The company launched out of stealth in June 2023 with a $145 million Series A, which it called the largest-ever round for a preclinical cardiovascular biotech.