Yoshitake Murayama

Reliability of the peptide nucleic acid‐locked nucleic acid polymerase chain reaction clamp‐based test for epidermal growth factor receptor mutations integrated into the clinical practice for non‐small cell lung cancers

Gefitinib is an inhibitor of the tyrosine kinase activity of epidermal growth factor receptor (EGFR). Accumulating evidence suggests that gefitinib may provide a survival benefit to EGFR mutation‐positive non‐small lung cancer patients. We have established a clinical test that can detect EGFR mutations from cytological specimens or paraffin‐embedded tissue specimens that are contaminated by normal cells. This test is based on the peptide nucleic acid, locked nucleic acid polymerase chain reaction clamp method that can detect G719S, G719C, L858R, L861Q and seven different exon 19 deletions in the presence of 100–1000‐fold wild‐type alleles. Consequently, using a small aliquot of samples isolated to establish a cancer diagnosis, the EGFR mutation status is determined soon after the diagnosis of cancer is made. We investigated the EGFR mutation status in 86 patients using a variety of cytological specimens (59 bronchoscopy specimens, 16 pleural effusion, 9 sputum, and 2 pericardial effusion) and in 46 patients who had a disease relapse and paraffin‐embedded tissues were available. Forty‐five patients (34%) were positive for mutation (29 exon 19 deletions, 16 L858R and 1 L861Q). The sensitivity and the specificity of this test was 97% and 100%, respectively. EGFR mutation status thereby obtained was used to determine each patients therapeutic regimen. This test is easily integrated into the normal clinical practice for lung cancer, while allowing the medical staff to select therapeutic regimen depending on the EGFR mutation status. (Cancer Sci 2007; 98: 246–252)

Peptide nucleic acid-locked nucleic acid polymerase chain reaction clamp-based detection test for gefitinib-refractory T790M epidermal growth factor receptor mutation

Mutations in the epidermal growth factor receptor (EGFR) are observed in a fraction of non‐small‐cell lung cancers (NSCLS). EGFR mutation‐positive NSCLS responds to gefitinib. Secondary T790M mutation confers gefitinib resistance to NSCLS. A detection test for the T790M mutation was designed based on the peptide nucleic acid–locked nucleic acid polymerase chain reaction clamp method. The specificity and sensitivity of the test were both greater than 0.99. The test revealed that only a small population of the PC‐13 cells carried the T790M mutation. The test also revealed that the T790M mutation was found in none of 151 NSCLC specimens obtained before gefitinib treatment, whereas it was found in four of four specimens obtained from NSCLS that had become refractory to gefitinib. In one patient in whom the L858R‐positive EGFR allele was amplified to multiple copies, an L858R‐T790M double‐mutant allele emerged during the gefitinib therapy. This allele was expressed highly. The T790M mutation detection test based on the peptide nucleic acid–locked nucleic acid polymerase chain reaction clamp method is sensitive and specific, and is applicable to clinical practice. It detects T790M‐positive cells in the course of gefitinib treatment, and thus will help to devise therapies effective for T790M‐positive NSCLS. (Cancer Sci 2008; 99: 595–600)

Combination therapy with carboplatin and paclitaxel for small cell lung cancer

BACKGROUND Although small cell lung cancer (SCLC) is an aggressive cancer, few useful treatment options exist after relapse. Information concerning the efficacy and safety of carboplatin plus paclitaxel in patients with SCLC is limited. METHODS From April 2007 to October 2016, 318 patients with SCLC received chemotherapy at our institution. The medical records of patients treated with carboplatin and paclitaxel after first-line chemotherapy with platinum plus etoposide or irinotecan were retrospectively analyzed. The objectives were to investigate the frequency at which a carboplatin and paclitaxel regimen was administered to patients with SCLC in clinical practice, and to determine the response rate, progression-free survival (PFS), and tolerability of such agents. RESULTS A total of 24 (7.5%) patients (male, n = 21; female, n = 3; median age, 67 years; performance status, 0-1/≥2, 15/8 patients; limited/extensive disease, 6/15 patients; sensitive/refractory relapse, 3/21 patients) were treated with carboplatin plus paclitaxel. This regimen was chosen due to interstitial lung disease (ILD) (n = 17), radiation pneumonitis (n = 3), combination with palliative radiation therapy (n = 2), and the presence of other cancers (n = 2). The response rate was 33.3%, and the disease control rate was 62.5%. The median PFS and overall survival were 4.1 and 8.7 months, respectively. Grade 3/4 hematologic toxicities observed included neutropenia (54.2%), anemia (4.2%), and thrombocytopenia (8.3%). With the exception of grade 3 neuropathies (n = 2), non-hematologic toxicities were mild. No patients experienced an acute exacerbation of ILD. CONCLUSION A combination of carboplatin plus paclitaxel as second-line chemotherapy is effective and feasible in patients with SCLC, especially in those with ILD.