Expression of a Mutant p53 Results in an Age-Related Demographic Shift in Spontaneous Lung Tumor Formation in Transgenic Mice

BACKGROUND:Mutations in the P53 gene are among the most common genetic abnormalities in human lung cancer. Codon 273 in the sequence-specific DNA binding domain is one of the most frequently mutated sites. METHODOLOGY:To investigate the role of mutant p53 in lung tumorigenesis, a lung specific p53(273H) transgenic mouse model was developed. Rates of lung cancer formation in the transgenic animals and their littermates were evaluated by necropsy studies performed in progressive age cohorts ranging from 4 to 24 months. In order to establish the influence of other common genetic abnormalities in lung tumor formation in the animals, K-Ras gene mutation and p16INK4a (p16) promoter methylation were evaluated in a total of 281 transgenic mice and 189 non-transgenic littermates. PRINCIPAL FINDINGS:At the age extremes of 4-12 and 22-24 months no differences were observed, with very low prevalence of tumors in animals younger than 12 months, and a relatively high prevalence at age 22 months or older. However, the transgenic mice had a significant higher lung tumor rate than their non-transgenic counterparts during the age of 13-21 months, suggesting an age-related shift in lung tumor formation induced by the lung-specific expression of the human mutant p53. Histopathology suggested a more aggressive nature for the transgenic tumors. Older mice (>13 months) had a significantly higher rate of p16 promoter methylation (17% v 82%). In addition, an age related effect was observed for K-Ras codons 12 or 13 mutations, but not for codon 61 mutations. CONCLUSIONS/SIGNIFICANCE:These results would suggest that the mutant p53(273H) contributes to an acceleration in the development of spontaneous lung tumors in these mice. Combination with other genetic and epigenetic alterations occurring after the age of 13 months is intimately linked to its oncogenic potential

Phase II randomized, double-blind, placebo-controlled study of tivantinib in men with asymptomatic or minimally symptomatic metastatic castration-resistant prostate cancer (mCRPC)

Background Tivantinib is a non-ATP competitive inhibitor of c-MET receptor tyrosine kinase that may have additional cytotoxic mechanisms including tubulin inhibition. Prostate cancer demonstrates higher c-MET expression as the disease progresses to more advanced stages and to a castration resistant state. Methods 80 patients (pts) with asymptomatic or minimally symptomatic mCRPC were assigned (2:1) to either tivantinib 360 mg PO BID or placebo (P). The primary endpoint was progression free survival (PFS). Results Of the 80 pts. enrolled, 78 (52 tivantinib, 26 P) received treatment and were evaluable. Median follow up is 8.9 months (range: 2.3 to 19.6 months). Patients treated with tivantinib had significantly better PFS vs. those treated with placebo (medians: 5.5 mo vs 3.7 mo, respectively; HR = 0.55, 95% CI: 0.33 to 0.90; p = 0.02). Grade 3 febrile neutropenia was seen in 1 patient on tivantinib while grade 3 and 4 neutropenia was recorded in 1 patient each on tivantinib and placebo. Grade 3 sinus bradycardia was recorded in two men on the tivantinib arm. Conclusions Tivantinib has mild toxicity and improved PFS in men with asymptomatic or minimally symptomatic mCRPC

Immunotherapy of lung cancer: An update

In Germany lung cancer is the leading cause of cancer-associated death in men. Surgery, chemotherapy and radiation may enhance survival of patients suffering from lung cancer but the enhancement is typically transient and mostly absent with advanced disease; eventually more than 90% of lung cancer patients will die of disease. New approaches to the treatment of lung cancer are urgently needed. Immunotherapy may represent one new approach with low toxicity and high specificity but implementation has been a challenge because of the poor antigenic characterization of these tumors and their ability to escape immune responses. Several different immunotherapeutic treatment strategies have been developed. This review examines the current state of development and recent advances with respect to non-specific immune stimulation, cellular immunotherapy ( specific and non-specific), therapeutic cancer vaccines and gene therapy for lung cancer. The focus is primarily placed on immunotherapeutic cancer treatments that are already in clinical trial or well progressed in preclinical studies. Although there seems to be a promising future for immunotherapy in lung cancer, presently there is not standard immunotherapy available for clinical routine

Variability in organ-specific EGFR mutational spectra in tumour epithelium and stroma may be the biological basis for differential responses to tyrosine kinase inhibitors

Organ-specific differences in epidermal growth factor receptor (EGFR) mutational spectra and frequencies were found in lung cancer and sporadic and BRCA1/2-related breast cancers. Additionally, we found a high frequency of EGFR mutations in the tumour stroma of these invasive breast carcinomas. Those organ-specific mutational spectra and potential targets in the cancer-associated stroma might influence the efficacy of TKI therapy

Irinotecan, cisplatin and mitomycin in inoperable gastro-oesophageal and pancreatic cancers – a new active regimen

Irinotecan, mitomycin and cisplatin all demonstrate activity in gastro-oesophageal cancers. This novel combination was administered to outpatients with previously untreated inoperable gastro-oesophageal or pancreatic cancer, in a 28-day cycle. A total of 26 out of 31 patients with gastro-oesophageal cancer and 12 out of 14 patients with pancreatic cancer have been treated with this combination, and were evaluable for response. The overall response rates for patients with gastro-oesophageal cancer was 42%, with a median survival of 9.5 months. In patients with pancreatic cancer, the overall response rate was 42% with a median survival of 8 months. There was a statistically significant increase in survival between those patients who achieved a stable disease response and those who achieved either a partial response or complete response. The toxicity profiles for both cancers were virtually identical. There were five treatment-related deaths, and a high admission rate (42%). Thus irinotecan, mitomycin and cisplatin is a new combination with activity in inoperable upper gastro-oesophageal cancers, but with a high toxicity profile. Future developments include reducing the dose of irinotecan and number of cycles of therapy to four

Erlotinib in African Americans With Advanced Non–Small Cell Lung Cancer: A Prospective Randomized Study With Genetic and Pharmacokinetic Analyses

Prospective studies focusing on EGFR inhibitors in African Americans with NSCLC have not been previously performed. In this phase II randomized study, 55 African Americans with NSCLC received erlotinib 150mg/day or a body weight adjusted dose with subsequent escalations to the maximum allowable, 200mg/day, to achieve rash. Erlotinib and OSI-420 exposures were lower compared to previous reports, consistent with CYP3A pharmacogenetics implying higher metabolic activity. Tumor genetics revealed only two EGFR mutations, EGFR amplification in 17/47 samples, 8 KRAS mutations and 5 EML4-ALK translocations. Although absence of rash was associated with shorter time to progression (TTP), disease control rate, TTP, and 1-year survival were not different between the two dose groups, indicating the dose-to-rash strategy failed to increase clinical benefit. Observed low incidence of toxicity and low erlotinib exposure suggest standardized and maximum allowable dosing may be suboptimal in African Americans

Phase i trial of axitinib combined with platinum doublets in patients with advanced non-small cell lung cancer and other solid tumours

BACKGROUND: This phase I dose-finding trial evaluated safety, efficacy and pharmacokinetics of axitinib, a potent and selective secondgeneration inhibitor of vascular endothelial growth factor receptors, combined with platinum doublets in patients with advanced non-small cell lung cancer (NSCLC) and other solid tumours. METHODS: In all, 49 patients received axitinib 5mg twice daily (b.i.d.) with paclitaxel/carboplatin or gemcitabine/cisplatin in 3-week cycles. Following determination of the maximum tolerated dose, a squamous cell NSCLC expansion cohort was enroled and received axitinib 5mg b.i.d. with paclitaxel/carboplatin. RESULTS: Two patients experienced dose-limiting toxicities: febrile neutropenia (n¼1) in the paclitaxel/carboplatin cohort and fatigue (n¼1) in the gemcitabine/cisplatin cohort. Common nonhaematologic treatment-related adverse events were hypertension (36.7%), diarrhoea (34.7%) and fatigue (28.6%). No gradeX3 haemoptysis occurred among 12 patients with squamous cell NSCLC. The objective response rate was 37.0% for patients receiving axitinib/paclitaxel/carboplatin (n¼27) and 23.8% for patients receiving axitinib/gemcitabine/cisplatin (n¼21). Pharmacokinetics of axitinib and chemotherapeutic agents were similar when administered alone or in combination. CONCLUSION: Axitinib 5mg b.i.d. may be combined with standard paclitaxel/carboplatin or gemcitabine/cisplatin regimens without evidence of overt drug–drug interactions. Both combinations demonstrated clinical efficacy and were well tolerated.This study was sponsored by Pfizer Inc. Support was provided in part by National Institutes of Health grant P30 CA006927 to the Fox Chase Cancer Center. We thank the patients who participated in this study and the physicians who referred them, as well as the study coordinators and data managers, Shelley Mayfield and Carol Martins at Pfizer Inc. for support of the study conduct, and Gamal ElSawah, Pfizer Medical Affairs, for his review of the manuscript. Medical writing support was provided by Joanna Bloom, of UBC Scientific Solutions (Southport, CT, USA) and Christine Arris at ACUMED (Tytherington, UK) and was funded by Pfizer In