For patients who have metastatic squamous non-small cell lung cancer (NSCLC) whose tumors were positive for EGFR copy number, as determined by the FISH analysis, survival tended to be better with the addition of necitumumab to their conventional chemotherapy.
Fred R. Hirsch, MD, PhD
For patients who have metastatic squamous non-small cell lung cancer (NSCLC) whose tumors were positive forEGFRcopy number, as determined by the FISH analysis, survival tended to be better with the addition of the EGFR antibody, necitumumab, to their conventional chemotherapy. However, there is a necessity for more information, in order to see if the potential benefit holds up, according to findings from a biomarker analysis of the phase III SQUIRE trial.
Study author Fred R. Hirsch, MD, PhD, professor of Medicine and Pathology at the University of Colorado, presented the results on behalf of his team at a press conference on September 9, during the 2015 World Conference on Lung Cancer (WCLC) in Denver.
While squamous lung cancer represents 25% to 30% of all lung cancers, therapeutic options have been lacking for decades, says Hirsch.
The additional analyses Hirsch reported at WCLC were based on tumor samples from the SQUIRE trial, published earlier this year inLancet Oncology.1In that trial, 1093 patients with stage IV NSCLC and an ECOG performance status of 0-2 were evenly randomized to first-line treatment with gemcitabine (1250 mg/m2on days 1 and 8) plus cisplatin (75 mg/m2on day 1), with or without necitumumab (absolute IV dose 800 mg). The treatment cycle was 21 days for a maximum of 6 cycles.
At a follow-up of approximately 2 years, median overall survival (OS) in the necitumumab arm was significantly longer (11.5 months), compared with 9.9 months for patients receiving the gemcitabine-cisplatin regimen only (HR, 0.84; 95% CI, 0.74-0.96;P= .012). The 1-year OS rate was 47.7% versus 42.8%, and the 2-year OS rate was 19.9% compared with 16.5%, for the necitumumab and chemotherapy arms, respectively.
These findings provided the basis for the July 2015 decision of the FDA Oncologic Drugs Advisory Committee to support the approval of necitumumab as a first-line treatment in combination with gemcitabine and cisplatin for patients with advanced squamous NSCLC.
Hirsch and his colleagues conducted a further analysis of 982 patients with evaluable immunohistochemistry (IHC) assay results. Nearly all of these patients (95.2%) had tumor samples expressing EGFR protein; only 4.8% had tumors without detectable EGFR protein. The investigators’ analysis revealed no consistent trend for the relationship between either OS or progression-free survival (PFS) with EGFR protein based on IHC values when comparing the two treatment arms.
EGFR analyses, based on the FISH assays, were more intriguing. Archived tumor samples with valid FISH results were available for 51% of SQUIRE patients, and of these, 37.3% (n = 208) had increasedEGFRcopy number. Although median OS trended more favorably for patients with EGFR FISHpositive tumors in the necitumumab arm (12.6 months vs 9.2 months with gemcitabine-cisplatin only), the result was not significant (HR, 0.70; 95% CI, 0.52-0.96).
OS for patients whose FISH assays were negative forEGFRcopy number was also better with necitumumab (11.1 vs 10.7 months), but not significantly so (HR, 1.02). PFS was longer, though again, not significantly, among patients with EGFRFISHpositive tumors who were treated with necitumumab (6.1 vs 5.1 months [HR, 0.71; 95% CI, 0.52-0.97]).
Hirsch said that although the findings did not achieve statistical significance, they are important:
“Is it clinically meaningful? I would say, yes.”
“Copy number detected by this particular assayfluorescent in situ hybridization—seems to predict a better outcome and could in the future be used for effective selection of EGFR antibodies,” he said, adding that the findings demonstrate sufficient potential trends to be investigated in future trials.
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