H3B-6545 + palbociclib

H3B-6545 + palbociclib is a combination therapy consisting of H3B-6545, a selective estrogen receptor covalent antagonist (SERCA), and palbociclib, a CDK4/6 inhibitor. This combination is being investigated for the treatment of estrogen receptor-positive (ER+), HER2-negative breast cancer. H3B-6545 works by selectively and covalently binding to a cysteine that is unique to estrogen receptor alpha (ERα), inhibiting its activity in both wild-type and mutant forms. Palbociclib inhibits cyclin-dependent kinases 4 and 6, preventing cell cycle progression. The combination aims to provide enhanced efficacy in patients with advanced breast cancer, including those with resistance to standard endocrine therapies.