For decades, KRAS mutations were considered undruggable — a frustrating reality given that KRAS G12D is the dominant driver in pancreatic cancer and present in roughly one in twenty lung cancer patients. A new class of targeted protein degraders may finally be changing that calculus, with implications for some of oncology's hardest-to-treat malignancies.
This phase 1 trial enrolled 203 patients with previously treated advanced solid tumors carrying the KRAS p.G12D variant, evaluating setidegrasib (ASP3082) — an intravenously administered protein degrader — across doses ranging from 10 to 800 mg weekly. At the selected phase 2 dose of 600 mg, 36% of the 45 NSCLC patients achieved a confirmed partial response (95% CI: 22–51%), a striking result for a first-in-human study in a heavily pretreated population. Grade 3 or higher adverse events occurred in 42% of patients at this dose, though treatment discontinuation was rare, affecting only 2 patients. The most common treatment-related effects were transient infusion reactions (80%) and nausea (30%).
What makes setidegrasib mechanistically distinct is its mode of action: rather than inhibiting KRAS enzymatic activity — the approach taken by sotorasib and adagrasib against the related G12C variant — it leverages targeted protein degradation to eliminate the mutant KRAS protein entirely. This strategy sidesteps the competitive binding limitations that often underpin acquired resistance to KRAS inhibitors. The G12C inhibitor class established proof-of-concept that KRAS is druggable, but G12D is far more prevalent in pancreatic ductal adenocarcinoma, a disease where median survival remains under a year. This trial's pancreatic cohort data, not yet fully disclosed in this excerpt, will be critical to watch. Key limitations include the phase 1 design, small per-cohort sample sizes, and absence of randomized comparators. Whether response durability justifies the infusion burden remains an open question for phase 2.