Erlotinib, gefitinib have similar efficacy in NSCLC patients with EGFR mutation

By Sarah Pritchard, medwireNews Reporter

Disease progression-free survival (PFS) is similar for patients with non-small-cell lung cancer (NSCLC) and epidermal growth factor receptor (EGFR) mutations whether they receive erlotinib or gefitinib, show the results of a South Korean study.

Furthermore, PFS did not differ among those who received either of these EGFR tyrosine kinase inhibitors (EGFR–TKIs) as first-line rather than a later line of therapy, report the researchers in the Journal of Thoracic Oncology.

The results highlight that “EGFR TKIs can induce durable and high responses irrespective of the line of therapy”, say Myung-Ju Ahn from Sungkyunkwan University School of Medicine in Seoul, and colleagues.

The team compared outcomes for 121 pairs of NSCLC patients, matched for gender, smoking status, cancer stage and EGFR mutation status (exon 19 deletion vs L858R point mutation), who harboured mutations in either exon 19 or 21. Patients received either 150 mg/day oral erlotinib or 250 mg/day oral gefitinib in 28-day cycles and outcomes included response rate – assessed according to Response Evaluation Criteria in Solid Tumours guidelines — disease control rate, PFS and overall survival.

Patients in the erlotinib group underwent a median of 10.8 treatment cycles and those in the gefitinib group received a median 12.7 cycles, and while no patients in either group achieved a complete response, the overall response rates were similar, at 74.4% and 76.9%, respectively. PFS was longer in the gefitinib than the erlotinib group, at 11.7 compared with 9.6 months, but this difference did not reach statistical significance, remark Ahn et al.

In multivariate analysis, an Eastern Cooperative Oncology Group performance status of at least 2, nonadenocarcinoma (vs adenocarcinoma) and presence of central nervous system and/or intra-abdominal metastasis significantly independently predicted poor PFS, with respective hazard ratios of 2.61, 3.62, 1.50 and 1.71.

In a subgroup analysis of the 63 patients who received EGFR TKI as first-line therapy, median PFS was also nonsignificantly different according to treatment type, at 14.5 months for erlotinib and 11.7 months for gefitinib.

Finally, only a small number of patients needed dose adjustment, indicating that EGFR TKI treatment was “well tolerated”, note the researchers, who observed neither interstitial lung disease-like events nor toxic death in either treatment group.

They conclude by warning that the number and types of chemotherapy regimens administered before or after EGFR–TKI treatment were not accounted for in the cohort and “may have introduced potential bias” affecting PFS.

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