579P - Real-world study of dacomitinib as first-line treatment for patients with EGFR-mutant non-small cell lung cancer

Background

Dacomitinib demonstrated superior survival benefit compared to gefitinib as a first-line treatment in EGFR-mutant non-small cell lung cancer (NSCLC) patients through the phase 3 trial, ARCHER 1050 study. However, there is a lack of real-world data regarding the efficacy of dacomitinib and further sequential treatments after failure of dacomitinib.

Methods

This study included patients with advanced EGFR-mutant NSCLC who received first-line dacomitinib between January 2021 and December 2022 at Samsung Medical Center and St. Vincent Hospital. This study evaluated objective response rate (ORR), progression-free survival (PFS), safety of dacomitinib, and subsequential treatment after failing dacomitinib.

Results

In total, this study included 153 patients, with a median age of 63.7 years. Exon 19 deletion was observed in 50.3%, while the L858R mutation in exon 21 was observed in 46.4% of patients. The ORR was 84.3%. Median follow-up duration was 16.9 months, and the median PFS was 16.7 months (95% CI, 14.4, 25.2). According to type of EGFR mutation, the median PFS was 18.1 months (95% CI, 14.5, not reached) in patients with exon 19 deletion, and 15.9 months (95% CI, 12.5, not reached) in patients with L858R mutation in exon 21. Grade 3 or higher adverse events were observed in 7.2% of patients, with skin rash occurring in 4.6% and diarrhea in 2.0%. Dose reduction of dacomitinib occurred in 85.6% of patients, with a final dose of 30mg in 49.0% and 15mg in 36.6%. Among the 60 patients who experienced disease progression, 32 patients underwent tissue re-biopsy, while among the remaining, 24 patients underwent liquid biopsy. Overall, T790M mutation was detected in 40% of patients who progressed to dacomitinib.

Conclusions

This study highlights the efficacy of dacomitinib as a promising first-line treatment for patients with EGFR-mutant NSCLC in a real-world setting. The detection rate of T790M mutation after dacomitinib treatment failure was similar to that of other 2^nd generation EGFR-TKI.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The author.

Funding

Pfizer.

Disclosure

J.E. Shin: Financial Interests, Institutional, Funding: Pfizer.