1224P Systematic review and meta-analysis of immunotherapy effectiveness for pretreated patients with non-small cell lung cancer harboring EGFR exon 20 insertions

Mobocertinib in Patients with EGFR Exon 20 Insertion-Positive Non-Small Cell Lung Cancer (MOON): An International Real-World Safety and Efficacy Analysis

EGFR exon 20 (EGFR Ex20) insertion mutations in non-small cell lung cancer (NSCLC) are insensitive to traditional EGFR tyrosine kinase inhibitors (TKIs). Mobocertinib is the only approved TKI specifically designed to target EGFR Ex20. We performed an international, real-world safety and efficacy analysis on patients with EGFR Ex20-positive NSCLC enrolled in a mobocertinib early access program. We explored the mechanisms of resistance by analyzing postprogression biopsies, as well as cross-resistance to amivantamab. Data from 86 patients with a median age of 67 years and a median of two prior lines of treatment were analyzed. Treatment-related adverse events (TRAEs) occurred in 95% of patients. Grade ≥3 TRAEs were reported in 38% of patients and included diarrhea (22%) and rash (8%). In 17% of patients, therapy was permanently discontinued, and two patients died due to TRAEs. Women were seven times more likely to discontinue treatment than men. In the overall cohort, the objective response rate to mobocertinib was 34% (95% CI, 24-45). The response rate in treatment-naïve patients was 27% (95% CI, 8-58). The median progression-free and overall survival was 5 months (95% CI, 3.5-6.5) and 12 months (95% CI, 6.8-17.2), respectively. The intracranial response rate was limited (13%), and one-third of disease progression cases involved the brain. Mobocertinib also showed antitumor activity following EGFR Ex20-specific therapy and vice versa. Potential mechanisms of resistance to mobocertinib included amplifications in MET, PIK3CA, and NRAS. Mobocertinib demonstrated meaningful efficacy in a real-world setting but was associated with considerable gastrointestinal and cutaneous toxicity.

Real-World Response and Outcomes in Patients With NSCLC With EGFR Exon 20 Insertion Mutations

Introduction

This study describes treatment patterns and outcomes in patients with NSCLC with EGFR exon 20 insertions (EGFRex20ins) in the United States.

Methods

The Flatiron Health electronic health record database was used to select three cohorts among patients diagnosed with NSCLC with EGFRex20ins (January 1, 2011-February 29, 2020): (1) first-line (1L) or patients receiving 1L therapy after documented EGFRex20ins; (2) second or later-line (≥2L) or patients receiving ≥2L therapy after documented EGFRex20ins; and (3) ≥2L postplatinum trial-aligned, or ≥2L patients previously treated with platinum chemotherapy whose baseline characteristics aligned with key eligibility criteria (initiating new treatment after documented EGFRex20ins and ≥1 previous treatment excluding mobocertinib or amivantamab) of the mobocertinib trial NCT02716116. Real-world end points were confirmed overall response rate, overall survival, and progression-free survival.

Results

Of 237 patients with EGFRex20ins-mutated NSCLC, 129 and 114 patients were included in the 1L and ≥2L cohorts, respectively. In 1L patients, platinum chemotherapy plus nonplatinum chemotherapy (31.0%) and EGFR tyrosine kinase inhibitors (28.7%) were the most common regimens. In ≥2L patients, immuno-oncology monotherapy (28.1%) and EGFR tyrosine kinase inhibitors (17.5%) were the most common index treatments. For any 1L, ≥2L, and ≥2L postplatinum trial-aligned patients, the confirmed overall response rate was 18.6%, 9.6%, and 14.0%, respectively; the median overall survival was 17.0, 13.6, and 11.5 months; the median progression-free survival was 5.2, 3.7, and 3.3 months, respectively.

Conclusions

The outcomes for patients with NSCLC with EGFRex20ins were poor. This real-world study provides a benchmark on treatment outcomes in this patient population and highlights the unmet need for improved therapeutic options.

Indirect comparison of mobocertinib and real-world therapies for pre-treated non-small cell lung cancer with EGFR exon 20 insertion mutations

OBJECTIVES

Mobocertinib, a novel oral epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, is available for the treatment of non-small cell lung cancer (NSCLC) with EGFR exon 20 insertion (ex20ins) mutations after platinum chemotherapy. We performed an indirect comparison of clinical trial data and real-world data (RWD) to determine the relative efficacy of mobocertinib vs. other treatments for these patients.

MATERIALS AND METHODS

Data on the efficacy of mobocertinib from a phase I/II trial (NCT02716116) were compared to RWD from a retrospective study in 12 German centers using inverse probability of treatment weighting to adjust for age, sex, Eastern Cooperative Oncology Group score, smoking status, presence of brain metastasis, time from advanced diagnosis, and histology. Tumor response assessment was based on RECIST v1.1.

RESULTS

The analysis included 114 patients in the mobocertinib group and 43 in the RWD group. The confirmed overall response rate (cORR) according to investigator assessment was 0% for standard treatments and 35.1% (95% confidence interval [CI], 26.4-44.6) for mobocertinib (p < 0.0001). Compared to standard regimens in the weighted population, mobocertinib prolonged overall survival (OS, median [95% CI] = 9.8 [4.3-13.7] vs. 20.2 [14.9-25.3] months; hazard ratio [HR] = 0.42 [0.25-0.69], p = 0.0035), progression-free survival (PFS, median [95% CI] = 2.6 [1.5-5.7] vs. 7.3 [5.6-8.8] months; HR = 0.28 [0.18-0.44], p < 0.0001), and time to treatment discontinuation (median [95% CI] = 2.1 [1.2-3.1] vs. 7.4 [6.4-8.5] months; HR = 0.34 [0.18-0.65], p = 0.0004).

CONCLUSION

Mobocertinib was associated with an improved cORR and prolonged PFS and OS compared to standard treatments for patients with EGFR ex20ins-positive NSCLC previously treated with platinum-based chemotherapy.