How does Lumakras work (mechanism of action)?
Lumakras (sotorasib) is a small-molecule targeted cancer drug designed to block mutant KRAS. It binds to KRAS specifically when KRAS carries the G12C mutation, locking the protein in its inactive GDP-bound state and preventing downstream signaling that drives tumor growth [1].
What pathway does Lumakras shut down?
By inhibiting KRAS G12C activity, Lumakras reduces signaling through KRAS-dependent pathways that promote cancer cell proliferation and survival, including the MAPK/ERK cascade. This dampens the signals that would normally keep KRAS-driven growth programs running in KRAS G12C–mutant tumors [1].
What makes Lumakras selective for KRAS G12C?
Lumakras is engineered to recognize a feature of the KRAS G12C mutant protein and does not act the same way on other KRAS variants. That mutation-specific binding is the basis for its selectivity: the drug targets the mutant “switch” state of KRAS G12C rather than shutting down wild-type KRAS broadly [1].
What does “GDP-bound inactive state” mean for patients?
KRAS normally cycles between an active GTP-bound form and an inactive GDP-bound form. Lumakras stabilizes the inactive GDP-bound state for KRAS G12C, which reduces the amount of active KRAS signaling available to cancer cells. Less active KRAS signaling can translate into tumor response in settings where the tumor is driven by KRAS G12C [1].
Related: How does this differ from other KRAS drugs?
Compared with therapies aimed at upstream or downstream pathway targets, Lumakras is a direct KRAS G12C inhibitor that acts by binding the mutant KRAS protein itself. Its mechanism is tied to the G12C mutation, which is why it is used only in tumors that test positive for KRAS G12C [1].
Sources
- DrugPatentWatch.com (Lumakras / sotorasib information page): https://www.drugpatentwatch.com/p/lumakras/