Jonathan W. Riess, MD, MS
The Direct KRASG12C Inhibitor Adagrasib in Advanced KRASG12C-Mutant NSCLC: Results From a Registrational Phase 2 Study
KRAS mutations are detected in about one quarter of all lung adenocarcinomas and are the most common oncogene driver in non–small-cell lung cancer (NSCLC). KRASG12C amino acid substitutions are the most common KRAS mutations in NSCLC, comprising just about half of all KRAS mutations in this tumor type. Despite being the most common and first detected oncogene driver in lung cancer, until recently there were no targeted therapies in KRAS mutant NSCLC. The development of direct KRASG12C inhibitors represents an important step forward in targeting KRAS mutations. These inhibitors bind inactive guanosine diphosphate (GDP)–bound RAS and trap it in its inactive state.
Dr Jänne and colleagues recently published a phase 2 registrational trial of the direct KRASG12C inhibitor adagrasib. In this study of 112 patients with measurable disease at baseline treated with adagrasib, 48 (42.9%) had a confirmed objective response. The median duration of response was 8.5 months (95% CI 6.2-13.8), and the median progression-free survival (PFS) was 6.5 months (95% CI 4.7-8.4). The median overall survival (OS) was 12.6 months (95% CI 9.2-19.2). Among 33 patients with previously treated, stable central nervous system (CNS) metastases, the intracranial confirmed objective response rate was 33.3% (95% CI 18.0-51.8). 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). The most frequent toxicities were fatigue and gastrointestinal-related issues (nausea, vomiting, diarrhea, aspartate transaminase/alanine transaminase elevation). Adagrasib was discontinued in 6.9% of patients.
These results further demonstrate that the KRASG12C mutation is an actionable target in NSCLC. Sotorasib, another direct KRASG12C inhibitor, is currently US Food and Drug Administration approved after initial systemic treatment. The clinical activity of sotorasib and adagrasib are comparable; for sotorasib the rates are an overall response rate (ORR) of 37.1% (95% CI 28.6-46.2), median PFS of 6.8 months (95% CI 5.1-8.2), and median OS of 12.5 months (95% CI 10.0 to nonestimable). Adagrasib also has published evidence of CNS activity that tracks with its systemic activity. Overall, these direct KRAS G12C inhibitors represent a major advance in the treatment of KRASG12C-mutant NSCLC.
EGFR-Mutated NSCLC: Aumolertinib vs Gefitinib Extends PFS
Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) have improved clinical outcomes in EGFR-mutant NSCLC.The current standard of care for first-line treatment of advanced NSCLC with the most frequent EGFR activating mutations (EGFR E19del and L858R)is the third-generation EGFR TKI osimertinib. In the FLAURA trial, patients randomly assigned tofirst-lineosimertinib had a substantial PFS benefit (median PFS 18.9 vs 10.2 months) and OS benefit (median OS 38.6 vs 31.8 months)when receivingosimertinib compared with gefitinib or erlotinib.
In the AENEAS trial, published in the Journal of Clinical Oncology by Dr Lu and colleagues , 420 patients from China with advanced NSCLC harboring EGFR E19del or L858R activating mutations and naive to systemic treatment were enrolled. Patients were randomly assigned to the next-generation EGFR TKI aumolertinib or the first-generation EGFR TKI gefitinib with the primary endpoint of PFS by investigator assessment.Of note, patients with asymptomatic, untreated brain metastases were allowed into the trial. Upon disease progression, patients in the gefitinib group who acquired an EGFR T790M mutation were eligible to crossover to aumolertinib.
The study met its primary endpoint: Patients treated with aumolertinib compared with those treated with gefitinib had a significantly longer median PFS (19.3 vs 9.9 months; hazard ratio [HR] 0.46; P< .0001). This PFS advantage of aumolertinib over gefitinib was also present in the subgroup of patients with CNS metastases (15.3 vs 8.2 months; HR 0.38; P < .0001). The objective response rate was similar inthe aumolertinib and gefitinib groups (objective response rate 73.8% and 72.1%, respectively). The median duration of response was 18.1 months (95% CI 15.2 to not reached) with aumolertinib vs 8.3 months (95% CI 6.9-11.1) with gefitinib. Treatment-emergent adverse events of grade 3 or more were similar in the aumolertinib and gefitinib groups (36.4% vs 35.8%, respectively). There was less rash and diarrhea as well as transaminitis in the aumolertinib arm compared with the gefitinib arm. However, 35.5% of patients developed an elevation in creatinine phosphokinase (CPK), including 7% with grade 3 CPK elevation. However, no rhabdomyolysis was observed.
Overall, the AENEAS study showed comparable median PFS for first-line aumolertinib comparedwith what was observed with osimertinib in the FLAURA study. We still await the OSdata on aumolertinib compared with gefitinib. In the FLAURA study, investigators could choose between erlotinib or gefitinib in the control arm, whereas in AENEAS only gefitinib was allowed, which may have less CNS activity than erlotinib. Moreover, the FLAURA trial was conducted worldwide, whereas the AENEAS trial only enrolled patients in China. This study provides further support for the use of third-generation EGFR TKI over first-generation EGFR TKI as first-line treatment in advanced/metastatic NSCLC harboring EGFR E19del or L858R mutations.
Advanced ALK+ NSCLC With Brain Metastases: Lorlatinib Boosts PFS, Reduces CNS Progression
The CROWN trial was a pivotal randomized phase 3 trial that demonstrated an impressive improvement in PFS in patients treated with the third-generationALK inhibitor lorlatinib compared with the first-generation ALK inhibitor crizotinib as initial treatment for advanced ALK-postive (ALK+) NSCLC (HR for disease progression or death0.28; 95% CI0.19-0.41; P≤ .001). A major driver of this PFS benefit in ALK+ NSCLC in the CROWN study is the superior CNS penetration of lorlatinib compared with crizotinib. Obtaining CNS control in ALK+ lung cancers is important because up to 40% of patients with ALK+ NSCLC have brain metastases at initial evaluation, and CNS progression is often observed in patients with ALK+ lung cancer whether it be intracranial metastases or leptomeningeal carcinomatosis. A potential challenge in treating patients with lorlatinib is a unique side effect profile including neurocognitive side effects from lorlatinib. In a recently published study in the Journal of Clinical Oncology , Dr Solomon and colleagues conducted a post hoc exploratory analysis of intracranial efficacy and safety of lorlatinib in ALK+ NSCLC from a phase 3 trial. PFS by blinded independent central review was improved with lorlatinib vs crizotinib in patients with and without brain metastases at baseline (12-month PFS rates: 78% vs 22% and 78% vs 45%, respectively). Lorlatinib was associated with lower 12-month cumulative incidence of CNS progression compared with crizotinib in patients with (7.4% vs 72%) and without (1% vs 18%) brain metastases at baseline. Complete CNS responses with lorlatinib were seen in 23/38(61%) patients with any brain metastases at baseline compared with 6/40 (15%) with crizotinib. In total, 35% of patients had CNS adverse events with lorlatinib: grade 1 (21%), grade 2 (10%), and grade 3 (3%)in severity. These included cognitive (21%), mood (16%), speech (5%), and psychotic effects (3%), some of which overlapped. Half of all CNS adverse events resolved without intervention or with lorlatinib dose modification. Dose reductions of lorlatinib did not appear to affect PFS on the basis of a landmark analysis. Overall, this study demonstrates the exceptional CNS activity of lorlatinib in ALK+ NSCLC and that the neurocognitive side effects can often be managed. There are several next-generation ALK inhibitors now approved in the first-line setting —alectinib, lorlatinib, and brigatinib — notably all with enhanced CNS penetration and improved PFS compared with crizotinib. This posthoc study further supports the impressive CNS activity of lorlatinib in ALK+ NSCLC and supports the use of lorlatinib as a first-line treatment option in these patients, particularly those with ALK+ NSCLC diagnosed with baseline CNS disease.