BACKGROUND Most patients with non-small-cell lung cancer have no response to the tyrosine kinase inhibitor gefitinib, which targets the epidermal growth factor receptor (EGFR). However, about 10 percent of patients have a rapid and often dramatic clinical response. The molecular mechanisms underlying sensitivity to gefitinib are unknown. METHODS We searched for mutations in the EGFR gene in primary tumors from patients with non-small-cell lung cancer who had a response to gefitinib, those who did not have a response, and those who had not been exposed to gefitinib. The functional consequences of identified mutations were evaluated after the mutant proteins were expressed in cultured cells. RESULTS Somatic mutations were identified in the tyrosine kinase domain of the EGFR gene in eight of nine patients with gefitinib-responsive lung cancer, as compared with none of the seven patients with no response (P<0.001). Mutations were either small, in-frame deletions or amino acid substitutions clustered around the ATP-binding pocket of the tyrosine kinase domain. Similar mutations were detected in tumors from 2 of 25 patients with primary non-small-cell lung cancer who had not been exposed to gefitinib (8 percent). All mutations were heterozygous, and identical mutations were observed in multiple patients, suggesting an additive specific gain of function. In vitro, EGFR mutants demonstrated enhanced tyrosine kinase activity in response to epidermal growth factor and increased sensitivity to inhibition by gefitinib. CONCLUSIONS A subgroup of patients with non-small-cell lung cancer have specific mutations in the EGFR gene, which correlate with clinical responsiveness to the tyrosine kinase inhibitor gefitinib. These mutations lead to increased growth factor signaling and confer susceptibility to the inhibitor. Screening for such mutations in lung cancers may identify patients who will have a response to gefitinib.

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Activating mutations in the epidermal growth factor receptor underlying responsiveness of non-small-cell lung cancer to gefitinib

Receptor tyrosine kinase genes were sequenced in nonsmall cell lung cancer (NSCLC) and matched normal tissue. Somatic mutations of the epidermal growth factor receptor gene EGFR were found in 15 of 58 unselected tumors from Japan and 1 of 61 from the United States. Treatment with the EGFR kinase inhibitor gefitinib (Iressa) causes tumor regression in some patients with NSCLC, more frequently in Japan. EGFR mutations were found in additional lung cancer samples from U.S. patients who responded to gefitinib therapy and in a lung adenocarcinoma cell line that was hypersensitive to growth inhibition by gefitinib, but not in gefitinibinsensitive tumors or cell lines. These results suggest that EGFR mutations may predict sensitivity to gefitinib. Protein kinase activation by somatic mutation or

https://science.sciencemag.org/content/sci/early/2004/04/29/science.1099314.full.pdf

EGFR mutations in lung cancer: correlation with clinical response to gefitinib therapy.

Patients with stage IIIB or IV non–small-cell lung cancer, with performance status from 0 to 3, were eligible if they had received one or two prior chemotherapy regimens. The patients were stratified according to center, performance status, response to prior chemotherapy, number of prior regimens, and prior platinum-based therapy and were randomly assigned in a 2:1 ratio to receive oral erlotinib, at a dose of 150 mg daily, or placebo. results The median age of the 731 patients who underwent randomization was 61.4 years; 49 percent had received two prior chemotherapy regimens, and 93 percent had received platinum-based chemotherapy. The response rate was 8.9 percent in the erlotinib group and less than 1 percent in the placebo group (P<0.001); the median duration of the response was 7.9 months and 3.7 months, respectively. Progression-free survival was 2.2 months and 1.8 months, respectively (hazard ratio, 0.61, adjusted for stratification categories; P<0.001). Overall survival was 6.7 months and 4.7 months, respectively (hazard ratio, 0.70; P<0.001), in favor of erlotinib. Five percent of patients discontinued erlotinib because of toxic effects. conclusions Erlotinib can prolong survival in patients with non–small-cell lung cancer after firstline or second-line chemotherapy.

/pdf/erlotinib-in-previously-treated-non-small-cell-lung-cancer-33prgcvyt1.pdf

Erlotinib in previously treated non-small-cell lung cancer.

In the planned interim analysis of data for the first 200 patients, progression-free survival was significantly longer in the gefitinib group than in the standard-chemotherapy group (hazard ratio for death or disease progression with gefitinib, 0.36; P<0.001), resulting in early termination of the study. The gefitinib group had a significantly longer median progression-free survival (10.8 months, vs. 5.4 months in the chemotherapy group; hazard ratio, 0.30; 95% confidence interval, 0.22 to 0.41; P<0.001), as well as a higher response rate (73.7% vs. 30.7%, P<0.001). The median overall survival was 30.5 months in the gefitinib group and 23.6 months in the chemotherapy group (P = 0.31). The most common adverse events in the gefitinib group were rash (71.1%) and elevated amino transferase levels (55.3%), and in the chemotherapy group, neutropenia (77.0%), anemia (64.6%), appetite loss (56.6%), and sensory neuropathy (54.9%). One patient receiving gefitinib died from interstitial lung disease. CONCLUSIONS First-line gefitinib for patients with advanced non–small-cell lung cancer who were selected on the basis of EGFR mutations improved progression-free survival, with acceptable toxicity, as compared with standard chemotherapy. (UMIN-CTR number, C000000376.)

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Gefitinib or Chemotherapy for Non–Small-Cell Lung Cancer with Mutated EGFR

background The epidermal growth factor receptor (EGFR), which participates in signaling pathways that are deregulated in cancer cells, commonly appears on colorectal-cancer cells. Cetuximab is a monoclonal antibody that specifically blocks the EGFR. We compared the efficacy of cetuximab in combination with irinotecan with that of cetuximab alone in metastatic colorectal cancer that was refractory to treatment with irinotecan. methods We randomly assigned 329 patients whose disease had progressed during or within three months after treatment with an irinotecan-based regimen to receive either cetuximab and irinotecan (at the same dose and schedule as in a prestudy regimen [218 patients]) or cetuximab monotherapy (111 patients). In cases of disease progression, the addition of irinotecan to cetuximab monotherapy was permitted. The patients were evaluated radiologically for tumor response and were also evaluated for the time to tumor progression, survival, and side effects of treatment. results The rate of response in the combination-therapy group was significantly higher than that in the monotherapy group (22.9 percent [95 percent confidence interval, 17.5 to 29.1 percent] vs. 10.8 percent [95 percent confidence interval, 5.7 to 18.1 percent], P=0.007). The median time to progression was significantly greater in the combination-therapy group (4.1 vs. 1.5 months, P<0.001 by the log-rank test). The median survival time was 8.6 months in the combination-therapy group and 6.9 months in the monotherapy group (P=0.48). Toxic effects were more frequent in the combinationtherapy group, but their severity and incidence were similar to those that would be expected with irinotecan alone. conclusions Cetuximab has clinically significant activity when given alone or in combination with irinotecan in patients with irinotecan-refractory colorectal cancer.

https://www.nejm.org/doi/pdf/10.1056/NEJMoa033025

Cetuximab monotherapy and cetuximab plus irinotecan in irinotecan-refractory metastatic colorectal cancer.

ContextMore persons in the United States die from non–small cell lung
cancer (NSCLC) than from breast, colorectal, and prostate cancer combined.
In preclinical testing, oral gefitinib inhibited the growth of NSCLC tumors
that express the epidermal growth factor receptor (EGFR), a mediator of cell
signaling, and phase 1 trials have demonstrated that a fraction of patients
with NSCLC progressing after chemotherapy experience both a decrease in lung
cancer symptoms and radiographic tumor shrinkages with gefitinib.ObjectiveTo assess differences in symptomatic and radiographic response among
patients with NSCLC receiving 250-mg and 500-mg daily doses of gefitinib.Design, Setting, and PatientsDouble-blind, randomized phase 2 trial conducted from November 2000
to April 2001 in 30 US academic and community oncology centers. Patients (N
= 221) had either stage IIIB or IV NSCLC for which they had received at least
2 chemotherapy regimens.InterventionDaily oral gefitinib, either 500 mg (administered as two 250-mg gefitinib
tablets) or 250 mg (administered as one 250-mg gefitinib tablet and 1 matching
placebo).Main Outcome MeasuresImprovement of NSCLC symptoms (2-point or greater increase in score
on the summed lung cancer subscale of the Functional Assessment of Cancer
Therapy-Lung [FACT-L] instrument) and tumor regression (>50% decrease in lesion
size on imaging studies).ResultsOf 221 patients enrolled, 216 received gefitinib as randomized. Symptoms
of NSCLC improved in 43% (95% confidence interval [CI], 33%-53%) of patients
receiving 250 mg of gefitinib and in 35% (95% CI, 26%-45%) of patients receiving
500 mg. These benefits were observed within 3 weeks in 75% of patients. Partial
radiographic responses occurred in 12% (95% CI, 6%-20%) of individuals receiving
250 mg of gefitinib and in 9% (95% CI, 4%-16%) of those receiving 500 mg.
Symptoms improved in 96% of patients with partial radiographic responses.
The overall survival at 1 year was 25%. There were no significant differences
between the 250-mg and 500-mg doses in rates of symptom improvement (P = .26), radiographic tumor regression (P = .51), and projected 1-year survival (P =
.54). The 500-mg dose was associated more frequently with transient acne-like
rash (P = .04) and diarrhea (P = .006).ConclusionsGefitinib, a well-tolerated oral EGFR-tyrosine kinase inhibitor, improved
disease-related symptoms and induced radiographic tumor regressions in patients
with NSCLC persisting after chemotherapy.

https://jamanetwork.com/journals/jama/articlepdf/197532/JOC31026.pdf

Efficacy of Gefitinib, an Inhibitor of the Epidermal Growth Factor Receptor Tyrosine Kinase, in Symptomatic Patients with Non-Small Cell Lung Cancer: A Randomized Trial

Results Of 221 patients enrolled, 216 received gefitinib as randomized. Symptoms of NSCLC improved in 43% (95% confidence interval [CI], 33%-53%) of patients receiving 250 mg of gefitinib and in 35% (95% CI, 26%-45%) of patients receiving 500 mg. These benefits were observed within 3 weeks in 75% of patients. Partial radiographic responses occurred in 12% (95% CI, 6%-20%) of individuals receiving 250 mg of gefitinib and in 9% (95% CI, 4%-16%) of those receiving 500 mg. Symptoms improved in 96% of patients with partial radiographic responses. The overall survival at 1 year was 25%. There were no significant differences between the 250-mg and 500-mg doses in rates of symptom improvement (P=.26), radiographic tumor regression (P=.51), and projected 1-year survival (P=.54). The 500-mg dose was associated more frequently with transient acne-like rash (P=.04) and diarrhea (P=.006). Conclusions Gefitinib, a well-tolerated oral EGFR-tyrosine kinase inhibitor, improved disease-related symptoms and induced radiographic tumor regressions in patients with NSCLC persisting after chemotherapy.

Harris Spiridonidis

Papers

Efficacy of Gefitinib, an Inhibitor of the Epidermal Growth Factor Receptor Tyrosine Kinase, in Symptomatic Patients with Non-Small Cell Lung Cancer: A Randomized Trial

Efficacy of Gefitinib, an Inhibitor of the Epidermal Growth Factor Receptor Tyrosine Kinase, in Symptomatic Patients With Non-Small Cell Lung Cancer