An ultrastructural investigation of developing vasomotor innervation in rat peripheral vessels

The developing innervation was investigated in three muscular peripheral arteries from male Wistar rats. These were the superficial epigastric and saphenous arteries, branching from the femoral artery in the thigh, and the tail artery. At maturity the tail and saphenous are similar in size and the superficial epigastric is about half the size of the other two. They are approximately the same size at birth and were chosen because of the resemblance of the tunica media among them. The general pattern of the developing innervation was similar in all three, starting with nerve processes containing mainly empty vesicles. As development proceeded, the processes usually were enclosed within Schwann cells, and both the number of clear vesicles and the number of vesicles with dense cores increased. Tubular membranes probably budded off vesicles. The development of the innervation was mainly postnatal, although some processes seen in the fetus may have been growth cones. The tail artery was the latest to develop recognizable nerves, although the number increased dramatically and had surpassed those in the other two vessels by 12 days of age. It had the densest nerve plexus at maturity. Only adrenergic vasomotor innervation was present in these vessels. The nerves retained a precise relationship, adjacent to the outermost layer of smooth muscle cells and external elastic lamina, throughout development. The Schwann cell population increased very slowly and was similar in each vessel at each age. This meant that the tail artery had many more nerve processes per Schwann cell than the other two vessels. These three muscular arteries, then, varied in the rate of development of their adrenergic innervation and in the final density.     

Rechallenge treatment with a platinum-based regimen in patients with sensitive relapsed small-cell lung cancer

Among patients with relapsed small-cell lung cancer (SCLC), those who relapse?>?90 days after first-line chemotherapy are classified sensitive relapse. Rechallenge with a first-line platinum-based regimen has been used in sensitive relapsed SCLC patients, but its importance is not known. We evaluated the outcome of rechallenge with platinum-based chemotherapy for sensitive relapse patients. We reviewed consecutive patients with sensitive relapsed SCLC who received second-line chemotherapy between January 1999 and December 2016. We evaluated the treatment outcomes of platinum-based rechallenge and non-rechallenge regimens for second-line chemotherapy in sensitive relapse patients. Of 245 patients, 81 sensitive relapse patients received second-line chemotherapy. Sixty-seven patients (82.7%) were treated with rechallenging platinum-based regimens (“rechallenge group”) and 14 patients (17.3%) were treated with other regimens (“non-rechallenge group”) as second-line chemotherapy. Median progression-free survival (PFS) was 5.1 months in the rechallenge group and 3.5 months in the non-rechallenge group, and median survival time was 10.8 and 8.2 months, respectively. There were no significant differences in PFS or overall survival (OS) between the two groups. Sub-analyses of patients who received chemotherapy alone as first-line treatment showed that the rechallenge group had longer PFS than that of the non-rechallenge group (median 5.4 vs. 3.6 months, p?=?0.0038), and the rechallenge group had a tendency to have longer OS than non-rechallenge group. These data suggest that rechallenge treatment with a platinum-based regimen could be second-line chemotherapy in patients with sensitive relapsed SCLC, especially those treated with chemotherapy alone as first-line therapy.     

Digital PCR analysis of plasma cell-free DNA for non-invasive detection of drug resistance mechanisms in EGFR mutant NSCLC: Correlation with paired tumor samples

As the development of resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) has become an issue of concern, identification of the mechanisms responsible has become an urgent priority. However, for research purposes, it is not easy to obtain tumor samples from patients with EGFR mutation-positive non-small-cell lung cancer (NSCLC) that has relapsed after treatment with EGFR-TKIs. Here, using digital PCR assay as an alternative and noninvasive method, we examined plasma and tumor samples from patients with relapsed NSCLC to establish the inter-relationships existing among T790M mutation, activating EGFR mutations, HER2 amplification, and MET amplification. Paired samples of tumor and blood were obtained from a total of 18 patients with NSCLC after they had developed resistance to EGFR-TKI treatment, and the mechanisms of resistance were analyzed by digital PCR. Digital PCR analysis of T790M mutation in plasma had a sensitivity of 81.8% and specificity of 85.7%, the overall concordance between plasma and tissue samples being 83.3%. MET gene copy number gain in tumor DNA was observed by digital PCR in three patients, of whom one exhibited positivity for MET amplification by FISH, whereas no patient demonstrated MET and HER2 copy number gain in plasma DNA. Digital PCR analysis of plasma is feasible and accurate for detection of T790M mutation in NSCLC that becomes resistant to treatment with EGFR-TKIs.     

Pembrolizumab plus pemetrexed-platinum for metastatic nonsquamous non–small-cell lung cancer: KEYNOTE-189 Japan Study

Pembrolizumab plus pemetrexed-platinum significantly improved overall survival (OS) and progression-free survival (PFS) with manageable safety compared with placebo plus pemetrexed-platinum in patients with previously untreated metastatic nonsquamous non–small-cell lung cancer (NSCLC) without EGFR/ALK alterations in the global, randomized, double-blind, phase 3 KEYNOTE-189 study. We present results of Japanese patients enrolled in the KEYNOTE-189 global and Japan extension studies. Patients were randomized 2:1 to intravenous pembrolizumab 200 mg or placebo every 3 weeks (Q3W) for up to 35 cycles. All patients received pemetrexed 500 mg/m² plus the investigator’s choice of cisplatin or carboplatin Q3W for four cycles, followed by maintenance pemetrexed 500 mg/m² Q3W (all intravenous). Co–primary endpoints were OS and PFS. Forty Japanese patients enrolled (pembrolizumab, n = 25; placebo, n = 15). At data cutoff (20 May 2019; median time from randomization to data cutoff, 18.5 [range, 14.7‒38.2] months), the median OS was not reached in the pembrolizumab plus pemetrexed-platinum arm; the median OS was 25.9 (95% confidence interval [CI], 11.9‒29.0) months in the placebo plus pemetrexed-platinum arm (hazard ratio [HR] .29; 95% CI, .07‒1.15). The median (95% CI) PFS was 16.5 (8.8‒21.1) compared with 7.1 (4.7‒21.4) months (HR, .62; 95% CI, .27‒1.42), respectively. There were no grade 5 adverse events (AE). Grade 3/4 AE occurred in 72% vs 60% of patients in the pembrolizumab vs placebo arms; 40% vs 20% had immune-mediated AE, and 4% vs 0% had infusion reactions. Efficacy and safety outcomes were similar to those from the global study and support first-line therapy with pembrolizumab plus pemetrexed-platinum in Japanese patients with nonsquamous NSCLC without EGFR/ALK alterations.