Overall response to first-line tyrosine kinase inhibitor and second-line chemotherapy is predictive of survival outcome in epidermal growth factor receptor-mutated adenocarcinoma

Distinct Benefit of Overall Survival between Patients with Non-Small-Cell Lung Cancer Harboring EGFR Exon 19 Deletion and Exon 21 L858R Substitution

BACKGROUND

Exon 19 deletion (Del19) and exon 21 L858R substitution (L858R), which account for 90% of epidermal growth factor receptor (EGFR) mutations as common mutations, are associated with favorable outcomes with EGFR-tyrosine kinase inhibitors (TKIs) compared with other uncommon EGFR mutations in non-small-cell lung cancer (NSCLC). However, whether there are differences in overall survival (OS) between patients with these common EGFR mutations remains controversial.

METHODS

The subjects studied were 74 NSCLC patients with common EGFR mutations treated with gefitinib or erlotinib. Using univariate and multivariate analyses, we retrospectively compared the clinicopahological characteristics of patients harboring Del19 with those harboring L858R.

RESULTS

Compared with patients harboring L858R, EGFR-TKIs provided a significant OS benefit in patients harboring Del19 (p = 0.024), as well as favorable therapeutic responses (p = 0.045) and progression-free survival (PFS) benefits (p = 0.031). In multivariate analyses, Del19 was independently associated with PFS (p = 0.029) and OS (p = 0.009), whereas no parameters other than pleural dissemination at the initial treatment were associated with EGFR mutation types.

CONCLUSION

Del19 and L858R have distinct prognostic implications and may require individual therapeutic strategies.

Drug Resistance to EGFR Inhibitors in Lung Cancer

BACKGROUND

The discovery of mutations in epidermal growth factor receptor (EGFR) has dramatically changed the treatment of patients with non-small-cell lung cancer (NSCLC), the leading cause of cancer deaths worldwide. EGFR-targeted therapies show considerable promise, but drug resistance has become a substantial issue.

METHODS

We reviewed the literature to provide an overview of the drug resistance to EGFR tyrosine kinase inhibitors (TKIs) in NSCLC.

RESULTS

The mechanisms causing primary, acquired and persistent drug resistance to TKIs vary. Researchers and clinicians, who have used study findings to develop more effective therapeutic approaches, have found that the sequential use of single agents presents a formidable challenge, suggesting that multidrug combinations must be considered.

CONCLUSIONS

In the era of precision medicine, oncologists should promptly obtain an accurate diagnosis of drug resistance in each patient to be able to design the most relevant combination therapy to overcome patient-specific drug resistance.

A Phase I Trial of Temsirolimus and Pemetrexed in Patients with Advanced Non-Small Cell Lung Cancer

BACKGROUND

Pemetrexed is an antifolate chemotherapeutic agent approved for use in non-small cell lung cancer (NSCLC). The mammalian target of rapamycin (mTOR) pathway is implicated in lung cancer development and inhibited by temsirolimus.

METHODS

We performed a phase I study evaluating the combination of pemetrexed and temsirolimus in advanced non-squamous NSCLC.

RESULTS

Eight patients were enrolled in this study. The dose-limiting toxicities included grade 4 thrombocytopenia, grade 3 leukopenia and grade 3 neutropenia. The maximum tolerated dose was determined to be pemetrexed 375 mg/m2 intravenously on day 1 and temsirolimus 25 mg intravenously on days 1, 8 and 15. No objective responses were noted and 3 patients had stable disease as the best response.

CONCLUSION

The combination of pemetrexed and temsirolimus is feasible and well tolerated. This combination may be further evaluated in patients with mTOR pathway activation, particularly in those with TSC1 or STK11 mutations.