Study Design and Rationale for the PACE-LUNG Trial: A Multicenter, Single-Arm, Phase II Clinical Trial Evaluating the Efficacy of Additional Chemotherapy for Patients with EGFRm NSCLC with the Continued Presence of Plasma ctDNA EGFRm at Week 3 After Start of Osimertinib First-Line Treatment

Abstract

Background: Tyrosine kinase inhibitors (TKI) targeting the epidermal growth factor receptor (EGFR) like the third-generation TKI osimertinib have substantially improved the treatment of patients with advanced non-small cell lung cancer (NSCLC) harboring sensitizing EGFR mutations. However, there is a subset of patients that do not benefit from these therapies in terms of response rate or progression-free-survival (PFS). It has been shown that persistence of EGFR mutations in circulating tumor DNA (ctDNA) at weeks 3 and 6 after start of osimertinib predicts shorter PFS. These patients may benefit from additional chemotherapy. While combination therapies with older TKI have been demonstrated effective in improving outcome, they are associated with a significant increase in toxicity.

Patients and methods: PACE-LUNG is a multicenter, single-arm, investigator initiated, phase II trial conducted with the German national Network Genomic Medicine (nNGM). Patients with stage IIIB or IV NSCLC and exon 19 deletion or p.L858R EGFR mutation not amenable to curative treatment with persisting ctDNA after 3 to 4 weeks of first-line osimertinib monotherapy will receive additional chemotherapy (4 cycles of either cisplatin/pemetrexed or carboplatin/pemetrexed). Afterwards, osimertinib will be continued as standard of care until disease progression or intolerable toxicity. The primary endpoint is PFS. Secondary endpoints include overall survival, response rate, safety, and quality of life. Concomitant translational research will be performed to identify patterns of mutational evolution in ctDNA upon disease progression or ctDNA persistence. Enrollment started in December 2021.

Discussion: The PACE-LUNG trial is designed to evaluate the efficacy and safety of a biomarker-driven strategy for therapy escalation in patients at high risk for early treatment failure. This approach aims not only to improve treatment outcomes, but also to limit the anticipated additional toxicity to high-risk patients.

Trial registration number: 2019-004757-88 (EudraCT).

Keywords: EGFR; EGFRm Clearance; Liquid biopsy; Response-stratified therapy; Treatment escalation.