KRas G12C inhibitor 4

KRASG12C Inhibition with Sotorasib in Advanced Solid Tumors

Background: No therapies for targeting KRAS mutations in cancer have been approved. The KRAS p.G12C mutation occurs in 13% of non-small-cell lung cancers (NSCLCs) and in 1 to 3% of colorectal cancers and other cancers. Sotorasib is a small molecule that selectively and irreversibly targets KRASG12C. Methods: We conducted a phase 1 trial of sotorasib in patients with advanced solid tumors harboring the KRAS p.G12C mutation. Patients received sotorasib orally once daily. The primary end point was safety. Key secondary end points were pharmacokinetics and objective response, as assessed according to Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1. Results: A total of 129 patients (59 with NSCLC, 42 with colorectal cancer, and 28 with other tumors) were included in dose escalation and expansion cohorts. Patients had received a median of 3 (range, 0 to 11) previous lines of anticancer therapies for metastatic disease. No dose-limiting toxic effects or treatment-related deaths were observed. A total of 73 patients (56.6%) had treatment-related adverse events; 15 patients (11.6%) had grade 3 or 4 events. In the subgroup with NSCLC, 32.2% (19 patients) had a confirmed objective response (complete or partial response) and 88.1% (52 patients) had disease control (objective response or stable disease); the median progression-free survival was 6.3 months (range, 0.0+ to 14.9 [with + indicating that the value includes patient data that were censored at data cutoff]). In the subgroup with colorectal cancer, 7.1% (3 patients) had a confirmed response, and 73.8% (31 patients) had disease control; the median progression-free survival was 4.0 months (range, 0.0+ to 11.1+). Responses were also observed in patients with pancreatic, endometrial, and appendiceal cancers and melanoma. Conclusions: Sotorasib showed encouraging anticancer activity in patients with heavily pretreated advanced solid tumors harboring the KRAS p.G12C mutation. Grade 3 or 4 treatment-related toxic effects occurred in 11.6% of the patients. (Funded by Amgen and others; CodeBreaK100 ClinicalTrials.gov number, NCT03600883.).

Sotorasib for Lung Cancers with KRAS p.G12C Mutation

Background: Sotorasib showed anticancer activity in patients with KRAS p.G12C-mutated advanced solid tumors in a phase 1 study, and particularly promising anticancer activity was observed in a subgroup of patients with non-small-cell lung cancer (NSCLC).
Methods: In a single-group, phase 2 trial, we investigated the activity of sotorasib, administered orally at a dose of 960 mg once daily, in patients with KRAS p.G12C-mutated advanced NSCLC previously treated with standard therapies. The primary end point was objective response (complete or partial response) according to independent central review. Key secondary end points included duration of response, disease control (defined as complete response, partial response, or stable disease), progression-free survival, overall survival, and safety. Exploratory biomarkers were evaluated for their association with response to sotorasib therapy.
Results: Among the 126 enrolled patients, the majority (81.0%) had previously received both platinum-based chemotherapy and inhibitors of programmed death 1 (PD-1) or programmed death ligand 1 (PD-L1). According to central review, 124 patients had measurable disease at baseline and were evaluated for response. An objective response was observed in 46 patients (37.1%; 95% confidence interval [CI], 28.6 to 46.2), including in 4 (3.2%) who had a complete response and in 42 (33.9%) who had a partial response. The median duration of response was 11.1 months (95% CI, 6.9 to could not be evaluated). Disease control occurred in 100 patients (80.6%; 95% CI, 72.6 to 87.2). The median progression-free survival was 6.8 months (95% CI, 5.1 to 8.2), and the median overall survival was 12.5 months (95% CI, 10.0 to could not be evaluated). Treatment-related adverse events occurred in 88 of 126 patients (69.8%), including grade 3 events in 25 patients (19.8%) and a grade 4 event in 1 (0.8%). Responses were observed in subgroups defined according to PD-L1 expression, tumor mutational burden, and co-occurring mutations in STK11, KEAP1, or TP53.
Conclusions: In this phase 2 trial, sotorasib therapy led to a durable clinical benefit without new safety signals in patients with previously treated KRAS p.G12C-mutated NSCLC. (Funded by Amgen and the National Institutes of Health; CodeBreaK100 ClinicalTrials.gov number, NCT03600883.).

Adagrasib in Non-Small-Cell Lung Cancer Harboring a KRASG12C Mutation

Background: Adagrasib, a KRAS^G12C inhibitor, irreversibly and selectively binds KRAS^G12C, locking it in its inactive state. Adagrasib showed clinical activity and had an acceptable adverse-event profile in the phase 1-1b part of the KRYSTAL-1 phase 1-2 study.
Methods: In a registrational phase 2 cohort, we evaluated adagrasib (600 mg orally twice daily) in patients with KRAS^G12C -mutated non-small-cell lung cancer (NSCLC) previously treated with platinum-based chemotherapy and anti-programmed death 1 or programmed death ligand 1 therapy. The primary end point was objective response assessed by blinded independent central review. Secondary end points included the duration of response, progression-free survival, overall survival, and safety.
Results: As of October 15, 2021, a total of 116 patients with KRAS^G12C -mutated NSCLC had been treated (median follow-up, 12.9 months); 98.3% had previously received both chemotherapy and immunotherapy. Of 112 patients with measurable disease at baseline, 48 (42.9%) had a confirmed objective response. The median duration of response was 8.5 months (95% confidence interval [CI], 6.2 to 13.8), and the median progression-free survival was 6.5 months (95% CI, 4.7 to 8.4). As of January 15, 2022 (median follow-up, 15.6 months), the median overall survival was 12.6 months (95% CI, 9.2 to 19.2). Among 33 patients with previously treated, stable central nervous system metastases, the intracranial confirmed objective response rate was 33.3% (95% CI, 18.0 to 51.8). Treatment-related adverse events occurred in 97.4% of the patients - grade 1 or 2 in 52.6% and grade 3 or higher in 44.8% (including two grade 5 events) - and resulted in drug discontinuation in 6.9% of patients.
Conclusions: In patients with previously treated KRAS^G12C -mutated NSCLC, adagrasib showed clinical efficacy without new safety signals. (Funded by Mirati Therapeutics; ClinicalTrials.gov number, NCT03785249.).

Identification of MRTX1133, a Noncovalent, Potent, and Selective KRASG12D Inhibitor

KRAS^G12D, the most common oncogenic KRAS mutation, is a promising target for the treatment of solid tumors. However, when compared to KRAS^G12C, selective inhibition of KRAS^G12D presents a significant challenge due to the requirement of inhibitors to bind KRAS^G12D with high enough affinity to obviate the need for covalent interactions with the mutant KRAS protein. Here, we report the discovery and characterization of the first noncovalent, potent, and selective KRAS^G12D inhibitor, MRTX1133, which was discovered through an extensive structure-based activity improvement and shown to be efficacious in a KRAS^G12D mutant xenograft mouse tumor model.

Targeting Krasg12c -mutant cancer with a mutation-specific inhibitor

The RAS genes, which include H, N, and KRAS, comprise the most frequently mutated family of oncogenes in cancer. Mutations in KRAS - such as the G12C mutation - are found in most pancreatic, half of colorectal and a third of lung cancer cases and is thus responsible for a substantial proportion of cancer deaths. Consequently, KRAS has been the subject of exhaustive drug-targeting efforts over the past 3-4 decades. These efforts have included targeting the KRAS protein itself but also its posttranslational modifications, membrane localization, protein-protein interactions and downstream signalling pathways. Most of these strategies have failed and no KRAS-specific drugs have yet been approved. However, for one specific mutation, KRAS^G12C , there is light on the horizon. MRTX849 was recently identified as a potent, selective and covalent KRAS^G12C inhibitor that possesses favourable drug-like properties. MRTX849 selectively modifies the mutant cysteine residue in GDP-bound KRAS^G12C and inhibits GTP-loading and downstream KRAS-dependent signalling. The drug inhibits the in vivo growth of multiple KRAS^G12C -mutant cell line xenografts, causes tumour regression in patient-derived xenograft models and shows striking responses in combination with other agents. It has also produced objective responses in patients with mutant-specific lung and colorectal cancer. In this review, we discuss the history of RAS drug-targeting efforts, the discovery of MRTX849, and how this drug provides an exciting and long-awaited opportunity to selectively target mutant KRAS in patients.