Prognostic and therapeutic impact of the KRAS G12C mutation in colorectal cancer.

KRAS G12C mutations are critical in the pathogenesis of multiple cancer types, including non-small cell lung (NSCLC), pancreatic ductal adenocarcinoma (PDAC), and colorectal (CRC) cancers. As such, they have increasingly become a target of novel therapies in the management of these malignancies. However, the therapeutic success of KRAS G12C inhibitors to date has been far more limited in CRC and PDAC than NSCLC. In this review, we briefly summarize the biochemistry of KRAS targeting and treatment resistance, highlight differences in the epidemiology of various G12C-mutated cancers, and provide an overview of the published data on KRAS G12C inhibitors for various indications. We conclude with a summary of ongoing clinical trials in G12C-mutant CRC and a discussion of future directions in the management of this disease. KRAS G12C mutation, targeted therapies, colorectal cancer, non-small cell lung cancer, pancreatic cancer, drug development.

Clinical and Genomic Features of Response and Toxicity to Sotorasib in a Real-World Cohort of Patients With Advanced KRAS G12C-Mutant Non-Small Cell Lung Cancer.

PURPOSE: With the recent approval of the KRAS G12C inhibitor sotorasib for patients with advanced KRAS G12C-mutant non-small cell lung cancer (NSCLC), there is a new need to identify factors associated with activity and toxicity among patients treated in routine practice. MATERIALS AND METHODS: We conducted a multicenter retrospective study of patients treated with sotorasib outside of clinical trials to identify factors associated with real-world progression free survival (rwPFS), overall survival (OS), and toxicity. RESULTS: Among 105 patients with advanced KRAS G12C-mutant NSCLC treated with sotorasib, treatment led to a 5.3-month median rwPFS, 12.6-month median OS, and 28% real-world response rate. KEAP1 comutations were associated with shorter rwPFS and OS (rwPFS hazard ratio [HR], 3.19; P = .004; OS HR, 4.10; P = .003); no significant differences in rwPFS or OS were observed across TP53 (rwPFS HR, 1.10; P = .731; OS HR, 1.19; P = .631) or STK11 (rwPFS HR, 1.66; P = .098; OS HR, 1.73; P = .168) comutation status. Notably, almost all patients who developed grade 3 or higher treatment-related adverse events (G3+ TRAEs) had previously been treated with anti-PD-(L)1 therapy. Among these patients, anti-PD-(L)1 therapy exposure within 12 weeks of sotorasib was strongly associated with G3+ TRAEs (P < .001) and TRAE-related sotorasib discontinuation (P = .014). Twenty-eight percent of patients with recent anti-PD-(L)1 therapy exposure experienced G3+ TRAEs, most commonly hepatotoxicity. CONCLUSION: Among patients treated with sotorasib in routine practice, KEAP1 comutations were associated with resistance and recent anti-PD-(L)1 therapy exposure was associated with toxicity. These observations may help guide use of sotorasib in the clinic and may help inform the next generation of KRAS G12C-targeted clinical trials.

Immune Checkpoint Inhibitors in Non-Small Cell Lung Cancer.

Historically, lung cancer was long considered a poorly immunogenic malignancy. In recent years, however, immune checkpoint inhibitors have emerged as promising therapeutic agents in non-small cell lung cancer (NSCLC). To date, the best characterized and most therapeutically relevant immune checkpoints have been cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and the programmed cell death protein-1 (PD-1) pathway. In early studies, PD-1/programmed cell death ligand-1 (PD-L1) inhibitors demonstrated promising antitumor activity and durable clinical responses in a subset of patients. Based on these encouraging results, multiple different PD-1/PD-L1 inhibitors have entered clinical development, and two agents (nivolumab and pembrolizumab) have gained regulatory approval in the United States for the treatment of NSCLC. In several large, randomized studies, PD-1/PD-L1 inhibitors have produced significant improvements in overall survival compared with single-agent docetaxel delivered in the second-line setting, effectively establishing a new standard of care in NSCLC. In the present report, we provide an overview of the rationale for checkpoint inhibitors in lung cancer, recent clinical trial data, and the need for predictive biomarkers. THE ONCOLOGIST: 2017;22:81-88 IMPLICATIONS FOR PRACTICE: Strategies targeting negative regulators (i.e., checkpoints) of the immune system have demonstrated significant antitumor activity across a range of solid tumors. In non-small cell lung cancer (NSCLC), programmed cell death protein-1 (PD-1) pathway inhibitors have entered routine clinical use because of the results from recent randomized studies demonstrating superiority against single-agent chemotherapy in previously treated patients. The present report provides an overview of immune checkpoint inhibitors in lung cancer for the practicing clinician, focusing on the rationale for immunotherapy, recent clinical trial data, and future directions.

Metastatic melanoma and immunotherapy.

Harnessing the immune system to attack cancer cells has represented a holy grail for greater than 100years. While prospects of tumor-selective durable immune based therapies have provided small clinical signals for many decades, recent years have demonstrated a virtual explosion in progress. Melanoma has led the field of cancers in which immunotherapy has produced major clinical inroads. The most significant and impactful immunotherapies for melanoma utilize immune checkpoint inhibition to stimulate T cell mediated tumor killing. The major targets of checkpoint blockade have thus far been CTLA4 and PD1, two key receptors for central and peripheral immune tolerance. This review discusses current understanding of how these checkpoint blockade therapeutics have led to major clinical responses in patients with advanced melanoma. It is likely that we are poised to see significantly greater anti-cancer immunotherapy efficacy, both in improving response rates and durability for melanoma, and for other less immunogenic malignancies.

Epidermal RelA specifically restricts contact allergen-induced inflammation and apoptosis in skin.

Strong inhibition of NF-κB signaling in the epidermis results in spontaneous skin inflammation in mice and men. As there is evidence for linkage between polymorphisms within the NF-κB signaling pathway and human inflammatory skin phenotypes, we asked whether partial functional inhibition of NF-κB signaling in epidermal keratinocytes can modulate clinically relevant skin inflammation. We therefore mutated rela specifically in the epidermis of mice (RelA(E-MUT) mice). These mice show no inflammatory phenotype. Induction of contact allergy, but not croton oil-induced irritant dermatitis, resulted in stronger ear swelling and increased epidermal thickness in RelA(E-MUT) mice. Both contact allergen and croton oil treatment led to increased expression of calgranulins A and B (S100A8/A9) in RelA(E-MUT) mice. Epidermal hyperproliferation in RelA(E-MUT) mice was non-cell autonomous as cultured primary epidermal keratinocytes from RelA(E-MUT) mice showed reduced proliferation compared with controls. These results demonstrate that epidermal RelA specifically regulates delayed-type hypersensitivity-induced skin inflammation. In addition, we describe here an essential but nonspecific function of RelA in the protection of epidermal keratinocytes from apoptosis. Our study identifies functions of NF-κB signaling in the epidermis and corroborates a specific role of epidermal keratinocytes in the regulation of skin inflammation.