The EPICAL trial, a phase Ib study combining first line afatinib with anti-EGF vaccination in EGFR-mutant metastatic NSCLC

Abstract

Introduction

Combination of anti-EGFR monoclonal antibodies or immune checkpoint inhibitors with TKIs has shown minimal benefit in EGFR mutant (EGFR-mut) NSCLC patients. Consequently, new combination approaches are needed.

Patients and methods

The EPICAL was a single arm, phase 1b study to evaluate safety, tolerability and anti-tumor activity of first line afatinib combined with anti-EGF vaccination in advanced EGFR-mut patients. EGFR status and mutations in liquid biopsies were determined by reverse transcriptase-polymerase chain reaction; serum biomarkers by ELISA and Western blotting analysis.

Results

The assay enrolled 23 patients, 21 completed the anti-EGF immunization phase. Treatment was well tolerated and no serious adverse events (SAEs) related to the anti-EGF vaccine were reported. Objective response and disease control rates were 78.3% (95%CI = 53.6–92.5) and 95.7% (95%CI = 78.1–99.9), respectively. After a median follow-up of 24.2 months, median progression-free survival (PFS) was 14.8 months (95% CI = 9.5–20.1) and median overall survival (OS) 26.9 months (95% CI = 23.0–30.8). Among the 21 patients completing the immunization phase, PFS was 17.5 months (95% CI = 12.0–23.0) and OS 26.9 months (95% CI = 24.6-NR). At the end of the immunization phase, all 21 patients showed high serum titers of anti-EGF antibodies, while EGF levels had decreased significantly. Finally, treatment with fully immunized patient's sera inhibited the EGFR pathway in tumor cells growing in vitro.

Conclusions

Combination treatment with an anti–EGF vaccine is well tolerated; induces a sustained immunogenic effect and might enhance the clinical efficacy of EGFR TKIs.