KRAS Inhibitors

KRAS is a RAS-family signalling protein that acts as a binary on/off switch in the cell-division pathway. A single point mutation can jam it "on", sending a permanent proliferate signal — the defining pathology of cancer. RAS mutations (KRAS, NRAS, HRAS) occur in roughly 20% of all cancers, ~3.4m cases a year worldwide, and drive most pancreatic cancers plus subsets of colorectal and lung cancer. Discovered in 1982, RAS proteins were considered "undruggable" for four decades because their smooth surfaces offered few pockets for small molecules.

The 2026 turning point: daraxonrasib

• Drug: daraxonrasib (Revolution Medicines), an oral RAS inhibitor, 300 mg once daily.
• Trial (RASolute 302): ~500 patients with metastatic pancreatic cancer previously treated with chemotherapy, randomised 1:1 against chemotherapy; median overall survival 13.2 vs 6.7 months, hazard ratio ~0.40; grade ≥3 treatment-related adverse events 43.6% vs 57.5%. Presented as the ASCO 2026 plenary to a standing ovation.
• Approval: the FDA fast-tracked it; approval came on 26 August 2026 per It Now Seems Possible to Vaccinate Against Cancer (Economist). The Economist expects it to become first-line therapy.
• Limits: not a cure — resistance to targeted drugs is routine. The gain is months of life, used alongside other treatments.

Why pancreatic cancer first

Pancreatic cancer is usually symptomless, diagnosed after spread, and fatal within a year for most patients. It resists immunotherapy because the KRAS-driven microenvironment is hostile to immune cells — which is also why KRAS inhibition carries a second, unproven hope: remodelling that environment so checkpoint inhibitors (and perhaps Cancer Vaccines) can work.

Where it may reach next (candidate list, not results)

• KRAS-mutant colorectal and lung cancers (see Lung Cancer Screening and Prevention); to a lesser degree endometrial, small-bowel and stomach cancers.
• Other RAS-driven cancers such as multiple myeloma, in theory.
• Paediatric neuroblastoma, where a different mutation disables a gene that normally brakes RAS.
• Refined successors and competitor molecules are expected.

Open questions

• Durability of response and the resistance mechanisms that emerge.
• Whether the immunotherapy-sensitisation theory survives a trial.
• Peer-reviewed publication of RASolute 302 was not confirmed when this page was written; numbers above come from the Economist and trade coverage of the ASCO plenary.

Related

• A New Drug Targets One of Cancers Master Switches (Economist) — the source article (2026-06-20).
• Cancer Vaccines — the other 2026 oncology milestone; the Economist bookends the two.