Erlotinib versus gefitinib for brain metastases in Asian patients with exon 19 EGFR-mutant lung adenocarcinoma: a retrospective, multicenter study

Antioxidant activity of erlotinib and gefitinib: theoretical and experimental insights

Erlotinib and gefitinib are quinazoline derivatives with antineoplastic properties. Usually, intake of antineoplastic agents results in much a greater degree of oxidative stress, i.e. the production of free radicals, than induced by cancer itself. Hence, anticancerous drugs must also exhibit antioxidant activity but this has not been studied thus far. In this study, the antioxidant activity of erlotinib and gefitinib was examined by experimental and computational studies. It was found that erlotinib and gefitinib exhibit good 2,2-dipheny l-1-picrylhydrazyl (DPPH) radical and hydroxyl radical scavenging (HRS) activities. In DPPH assay, the IC₅₀ for erlotinib and gefitinib were 0.584 and 0.696 mM, respectively, while IC₅₀ for HRS assay were 0.843 and 1.03 mM for erlotinib and gefitinib, respectively. Structural characteristics such as frontier molecular orbitals (FMOs), molecular electrostatic potential maps (MESPs), and global descriptive parameters were calculated at DFT/B3LYP/6-311++G (d,p) on the optimized geometries of erlotinib and gefitinib. UV-visible spectroscopy revealed the possible electronic transitions between the FMOs and their associated excitation energies of both drugs and found that erlotinib has π to π* transitions while gefitinib has π to π* and σ to π* transitions. To elucidate the antioxidant activity of erlotinib and gefitinib, three mechanisms namely hydrogen atom transfer (HAT), single electron transfer proton transfer (SETPT), and sequential proton-loss electron-transfer (SPLET) were employed and articulated the results in arithmetic parameters like bond dissociation energy (BDE), proton affinity (PA), ionization potential (IP), electron transfer enthalpy (ETE), and proton dissociation enthalpy (PDE). Further, molecular docking studies have been carried out to have a better understanding of binding sites and modes of interaction with a well-known antioxidant target protein monoamine oxidase-B (MAO-B) employing docking scores and types of interactions. All the calculated parameters point out that though gefitinib and erlotinib were interchangeable, erlotinib requires a lesser amount of energy for proton transfer and electron transfer, moreover it scavenges radicals easily.

Treatment for Brain Metastases: ASCO-SNO-ASTRO Guideline

PURPOSE

To provide guidance to clinicians regarding therapy for patients with brain metastases from solid tumors.

METHODS

ASCO convened an Expert Panel and conducted a systematic review of the literature.

RESULTS

Thirty-two randomized trials published in 2008 or later met eligibility criteria and form the primary evidentiary base.

RECOMMENDATIONS

Surgery is a reasonable option for patients with brain metastases. Patients with large tumors with mass effect are more likely to benefit than those with multiple brain metastases and/or uncontrolled systemic disease. Patients with symptomatic brain metastases should receive local therapy regardless of the systemic therapy used. For patients with asymptomatic brain metastases, local therapy should not be deferred unless deferral is specifically recommended in this guideline. The decision to defer local therapy should be based on a multidisciplinary discussion of the potential benefits and harms that the patient may experience. Several regimens were recommended for non-small-cell lung cancer, breast cancer, and melanoma. For patients with asymptomatic brain metastases and no systemic therapy options, stereotactic radiosurgery (SRS) alone should be offered to patients with one to four unresected brain metastases, excluding small-cell lung carcinoma. SRS alone to the surgical cavity should be offered to patients with one to two resected brain metastases. SRS, whole brain radiation therapy, or their combination are reasonable options for other patients. Memantine and hippocampal avoidance should be offered to patients who receive whole brain radiation therapy and have no hippocampal lesions and 4 months or more expected survival. Patients with asymptomatic brain metastases with either Karnofsky Performance Status ≤ 50 or Karnofsky Performance Status < 70 with no systemic therapy options do not derive benefit from radiation therapy.Additional information is available at www.asco.org/neurooncology-guidelines.

The different central nervous system efficacy among gefitinib, erlotinib and afatinib in patients with epidermal growth factor receptor mutation-positive non-small cell lung cancer

Background

Brain metastasis is common in non-small cell lung cancer (NSCLC) and has an even higher incidence in epidermal growth factor receptor (EGFR)-mutant cancers. Although EGFR tyrosine kinase inhibitors (TKIs) are effective against brain metastases, it is unknown which first- or second-generation EGFR TKI is most effective.

Methods

Patients treated with first-line gefitinib, erlotinib, or afatinib for advanced EGFR-mutant NSCLC were included. The efficacy against brain metastasis was evaluated by comparing the response rates of measurable and non-irradiated brain metastases, central nervous system progression-free survival (CNS-PFS), and the cumulative incidence of CNS failure.

Results

Among the 559 patients who received EGFR-TKIs (gefitinib, n=299; erlotinib, n=93; afatinib, n=167), 198 had initial brain metastasis before starting EGFR-TKIs. The CNS response rates of gefitinib, erlotinib, and afatinib were 64.7%, 68.2%, and 72.9%, respectively (P=0.78). In the overall study population, irrespective of initial CNS metastasis, the median CNS-PFS was 17.3 months for gefitinib, 12.4 months for erlotinib, and 23.3 months for afatinib (P<0.001). In multivariate analysis for CNS-PFS, the hazard ratio (HR) of afatinib was 0.63 (95% CI, 0.47–0.83) compared with gefitinib or erlotinib. In the competing risk analysis for cumulative incidence of CNS failure, afatinib showed a lower cumulative incidence of CNS failure compared with gefitinib or erlotinib after adjusting for both EGFR mutation type and preexisting CNS metastases (HR 0.51, 95% CI, 0.34–0.75, P=0.0007).

Conclusions

Through there are some limitation as a retrospective study, afatinib showed similar CNS response rates, superior CNS-PFS and cumulative incidence of CNS failure, compared with gefitinib or erlotinib