Native and rearranged ALK copy number and rearranged cell count in non-small cell lung cancer: implications for ALK inhibitor therapy.

BACKGROUND: Patients with anaplastic lymphoma kinase (ALK)-positive non-small cell lung cancer (NSCLC) respond to ALK inhibitors. Clinically, the presence of ≥15% cells with rearrangements identified on break-apart fluorescence in situ hybridization (FISH) classifies tumors as positive. Increases in native and rearranged ALK copy number also occur. METHODS: In total, 1426 NSCLC clinical specimens (174 ALK-positive specimens and 1252 ALK-negative specimens) and 24 ALK-negative NSCLC cell lines were investigated. ALK copy number and genomic status were assessed by FISH. RESULTS: Clinical specimens with 0% to 9%, 10% to 15%, 16% to 30%, 31% to 50%, and >50% ALK-positive cells were identified in 79.3%, 8.5%, 1.4%, 2.7%, and 8.1%, respectively. An increased native ALK copy number (≥3 copies per cell in ≥40% of cells) was detected in 19% of ALK-positive tumors and in 62% of ALK-negative tumors. In ALK-negative tumors, abundant, focal amplification of native ALK was rare (0.8%). Other atypical patterns occurred in approximately 6% of tumors. The mean native ALK copy number ranged from 2.1 to 6.9 copies in cell lines and was not correlated with crizotinib sensitivity (50% inhibitory concentration, 0.34-2.8 µM; r = 0.279; P = .1764). Neither native or rearranged ALK copy number nor the percentage of positive cells correlated with extra-central nervous system progression-free survival in ALK-positive patients who were receiving crizotinib. CONCLUSIONS: Overall, 8.5% of tumors fell below the established positivity threshold by ≤5%. Further investigation of ALK by other diagnostic techniques in such cases may be warranted. Native ALK copy number increases alone were not associated with sensitivity to ALK inhibition in vitro. However, rare, complex patterns of increased native ALK in patients should be studied further; because, otherwise, atypical rearrangements contained within these may be missed.

Clinical benefit from pemetrexed before and after crizotinib exposure and from crizotinib before and after pemetrexed exposure in patients with anaplastic lymphoma kinase-positive non-small-cell lung cancer.

BACKGROUND: Crizotinib produces high response rates and prolonged PFS in ALK+ NSCLC. Retrospective analyses suggest enhanced sensitivity to pemetrexed in crizotinib naive ALK+ NSCLC. Cross-resistance between crizotinib and pemetrexed has not been previously investigated. PATIENTS AND METHODS: Patients with stage IV ALK+ NSCLC treated with PEM-CRIZ, or CRIZ-PEM were identified. Overall PFS and PFS excluding central nervous system events (eCNS) were compared. RESULTS: Objective response rates in evaluable patients were 66% (PEM-CRIZ) and 75% (CRIZ-PEM) for pemetrexed and 84% (CRIZ-PEM) and 66% (PEM-CRIZ) for crizotinib. For PEM-CRIZ (n = 29), median PFS and eCNS PFS were both 6 months with pemetrexed, and 10 and 14.5 months, respectively, with crizotinib. For CRIZ-PEM (n = 9), median PFS and eCNS PFS were 4.5 and 3 months, respectively, with pemetrexed, and 8.5 and 7.5 months, respectively, with crizotinib. There was a statistically significant increase in the risk of an overall PFS event with pemetrexed when administered after crizotinib (P = .0277; hazard ratio [HR], 2.5898; 95% confidence interval [CI], 1.1100-6.0424), but differences in the risk of an eCNS PFS event were not significant (P = 0.4913; HR, 1.3521; 95% CI, 0.5727-3.1920). Neither overall nor eCNS PFS for patients while taking crizotinib was associated with a sequence effect relative to pemetrexed. CONCLUSION: Crizotinib and pemetrexed are active drugs in ALK+ NSCLC. PFS benefit appeared higher with crizotinib than with pemetrexed. PFS benefit from pemetrexed was less after crizotinib compared with before crizotinib, however, this difference was only statistically significant for overall and not eCNS PFS. Pemetrexed exposure did not seem to affect crizotinib outcomes.

Oncogene status predicts patterns of metastatic spread in treatment-naive nonsmall cell lung cancer.

BACKGROUND: The discovery of distinct subsets of nonsmall cell lung cancer (NSCLC) characterized by activation of driver oncogenes has greatly affected personalized therapy. It is hypothesized that the dominant oncogene in NSCLC would be associated with distinct patterns of metastatic spread in NSCLC at the time of diagnosis. METHODS: A total of 209 consecutive patients with stage IV nonsquamous NSCLC with an EGFR (epidermal growth factor receptor) mutation (N = 39), KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog) mutation (N = 49), ALK (anaplastic lymphoma receptor tyrosine kinase) gene rearrangement (N = 41), or wild-type for all 3 (triple negative, N = 80) were included. The percentage of patients with metastatic disease at a given site was compared between each molecular cohort (EGFR, KRAS, or ALK) and the triple negative cohort. RESULTS: ALK gene rearrangement was significantly associated with pericardial disease (odds ratio [OR] = 4.61; 95% confidence interval [CI] = 1.30, 16.37; P = .02) and pleural disease (OR = 4.80; 95% CI = 2.10, 10.97; P < .001). Patients with ALK gene rearrangements (OR = 5.50; 95% CI = 1.76, 17.18; P = .003) and patients with EGFR mutations (OR = 5.17; 95% CI = 1.63, 16.43; P = .006) were predisposed to liver metastasis compared to the triple negative cohort. No molecular cohort had a predisposition to pulmonary nodules, or adrenal, bone, or brain metastasis compared to the triple negative cohort. The mean number of metastatic disease sites in patients within the ALK rearranged cohort was significantly greater than that of the triple negative cohort (mean = 3.6 sites vs 2.5 sites, P < .0001). CONCLUSIONS: The results support the hypothesis that the dominant molecular oncogenes in NSCLC are associated with different biological behaviors manifesting as distinct patterns of metastatic spread at the time of diagnosis.

Correlations between the percentage of tumor cells showing an anaplastic lymphoma kinase (ALK) gene rearrangement, ALK signal copy number, and response to crizotinib therapy in ALK fluorescence in situ hybridization-positive nonsmall cell lung cancer.

BACKGROUND: Fluorescence in situ hybridization (FISH), using break-apart red (3') and green (5') ALK (anaplastic lymphoma kinase) probes, consistently shows rearrangements in <100% of tumor cells in ALK-positive (ALK+) nonsmall cell lung cancer (NSCLC). Increased copy numbers of fused and rearranged signals also occur. Here, correlations are explored between the percentage of ALK+ cells and signal copy number and their association with response to ALK inhibition. METHODS: Ninety ALK+ NSCLC cases were evaluated. The percentage of positive cells, pattern of positivity (split, single red, or both), and copy number of fused, isolated red and green signals were recorded. Thirty patients had received crizotinib. RESULTS: Increased isolated red signal copy number (contributing to both single red and split patterns of positivity) correlated with a higher percentage of ALK+ cells (r = 0.743, P < .0001). Mean fused copy number was negatively associated with isolated red signal copy number (r = -0.409, P < .0001). Neither percentage of positive cells (r = 0.192, P = .3), nor copy number of isolated red signal (r = 0.274, P = .195) correlated with maximal tumor shrinkage with crizotinib. CONCLUSIONS: The strong association between increased copy number of key ALK signals and percentage of positive cells suggests that the <100% rate of cellular positivity in ALK+ tumors is due to technical factors, not biological factors. In ALK+ tumors, neither the percentage of positive cells nor signal copy number appear to be informative variables for predicting benefit from ALK inhibition. The inverse relationship between fused and isolated red copy number suggests ALK+ may be a distinct "near-diploid" subtype of NSCLC that develops before significant chromosomal aneusomy occurs.

A phase I/II study of erlotinib in combination with the anti-insulin-like growth factor-1 receptor monoclonal antibody IMC-A12 (cixutumumab) in patients with advanced non-small cell lung cancer.

INTRODUCTION: This phase I/II study evaluated the safety and antitumor effect of the combination of erlotinib with cixutumumab, a recombinant fully humanized anti-insulin-like growth factor-1 receptor IgG1 monoclonal antibody, in advanced non-small cell lung cancer (NSCLC). METHODS: Patients with advanced NSCLC were treated in an initial safety-lead and drop-down cohorts using erlotinib 150 mg/d with cixutumumab 6 or 5 mg/kg on days 1, 8, 15, and 22 in 28-day cycles (cohorts 1 and 2). Emerging pharmacokinetic data led to an additional cohort (3 + 3 design) with cixutumumab at 15 mg/kg on day 1 in 21-day cycles (cohort 3). RESULTS: Eighteen patients entered the study (6 at 6 mg/kg, 8 at 5 mg/kg, and 4 at 15 mg/kg), with median age of 65 years. Four of six patients at 6 mg/kg experienced dose-limiting toxicities (DLTs), whereas at 5 mg/kg, one of eight patients experienced DLT but three of eight patients still required a dose delay during cycle 1. At 15 mg/kg every 21 days, two of four patients experienced DLTs. In all cohorts, DLTs were either G3 rash or fatigue. Five patients had stable disease as best response and 14 patients had progressive disease. The median progression-free survival was 39 days (range 21-432+ days). Biomarkers analyses showed a trend toward better progression-free survival seen with higher free baseline insulin-like growth factor-1 levels as seen with other insulin-like growth factor-1R inhibitors. CONCLUSIONS: The combinations of cixutumumab at 6 mg/kg every 7 days and 15 mg/kg every 21 days and full-dose erlotinib are not tolerable in unselected patients with NSCLC, as measured by DLT. Cixutumumab at 5 mg/kg every 7 days was tolerable per DLT, but dose delays were common. Efficacy in unselected patients with NSCLC seems to be low.