Aim: Immunotherapy (IO), the established cornerstone of first-line treatment for KRAS-mutant NSCLC, has suboptimal outcomes. Here, we study pembrolizumab+olomorasib, a second-generation inhibitor of GDP-bound KRAS G12C, in NSCLC patients treated on LOXO-RAS-20001, a phase 1/2 study of olomorasib in KRAS G12C-mutant solid tumors (NCT04956640).
Methods: Patients with advanced KRAS G12C-mutant NSCLC (tissue/plasma) in any treatment line were eligible. Antitumor activity was studied in all patients who had ≥1, or had discontinued before the first, post-baseline response assessment.
Results: As of 30Oct2023, 50 eligible patients received 50-150mg BID PO olomorasib + 200mg Q3W pembrolizumab. During escalation, 2/6 patients treated at 150mg BID developed grade ³3 LFTs, precluding further evaluation of this dose. In 44 patients (50/100mg BID), TRAEs ≥15% (related to olomorasib and/or pembrolizumab) were diarrhea (30%), ALT increased (20%), AST increased (18%); grade 3 TRAEs ≥10% were diarrhea (16%); pneumonitis was seen in 3 patients (grades 2/3/4). Due to TRAEs: 14% of pts had olomorasib dose reduction; dose hold in 27% (olomorasib) and 18% (pembrolizumab); 9% discontinued olomorasib or pembrolizumab; 9% discontinued both. 27 patients remain on treatment, and 17 discontinued treatment (10 due to PD, 4 due to AE). Among 30 efficacy evaluable KRAS G12Ci-naïve patients (60% IO/60% chemotherapy pre-treated) (median follow-up: 6 months [95% CI, 4-7]), ORR was 63% (15 PR/4 unconfirmed PR pending/ongoing; 95% CI, 44-80); DCR was 93% (28/30; 95% CI, 78-99); median PFS was not estimable (95% CI, 5-NE); ORR was 75% (9/12) in PD-L1 ≥50%, 56% (10/18) in PD-L1 <50%/unknown (3 patients PD-L1 unavailable). In 9 first-line patients, ORR was 78% (6 PR/1 unconfirmed PR pending/ongoing; 95% CI, 40-97); DCR was 100%.
Conclusion: Olomorasib (50/100mg BID) + pembrolizumab demonstrated favorable safety and antitumor activity in KRAS G12C-mutant advanced NSCLC. A global, registrational study investigating this combination in first-line NSCLC is currently enrolling (SUNRAY-01/NCT06119581).