Bcl-2 is a critical regulator of apoptosis that is overexpressed in the majority of small cell lung cancers (SCLC). Nativoclax (ABT-263) is a potent and selective inhibitor of Bcl-2 and Bcl-xL. The primary objectives of this phase IIa study included safety at the recommended phase II dose and preliminary, exploratory efficacy assessment in patients with recurrent and progressive SCLC after at least one prior therapy.
Thirty-nine patients received navitoclax 325 mg daily, following an initial lead-in of 150 mg daily for 7 days. Study endpoints included safety and toxicity assessment, response rate, progression-free and overall survival (PFS and OS), as well as exploratory pharmacodynamic correlates.
The most common toxicity associated with navitoclax was thrombocytopenia, which reached grade III–IV in 41% of patients. Partial response was observed in one (2.6%) patient and stable disease in 9 (23%) patients. Median PFS was 1.5 months and median OS was 3.2 months. A strong association between plasma pro–gastrin-releasing peptide (pro-GRP) level and tumor Bcl-2 copy number (R = 0.93) was confirmed. Exploratory analyses revealed baseline levels of cytokeratin 19 fragment antigen 21-1, neuron-specific enolase, pro-GRP, and circulating tumor cell number as correlates of clinical benefit.
Bcl-2 targeting by navitoclax shows limited single-agent activity against advanced and recurrent SCLC. Correlative analyses suggest several putative biomarkers of clinical benefit. Preclinical models support that navitoclax may enhance sensitivity of SCLC and other solid tumors to standard cytotoxics. Future studies will focus on combination therapies.
‘Driver mutations’ are essential for carcinogenesis as well as tumor progression as they confer a selective growth advantage to cancer cells. Identification of driver mutations in growth related protein kinases, especially tyrosine kinases have led to clinical development of an array of tyrosine kinase inhibitors in various malignancies, including lung cancer. Inhibition of epidermal growth factor receptor and anaplastic lymphoma kinase tyrosine kinases have proven to be of meaningful clinical benefit, while inhibition of several other tyrosine kinases have been of limited clinical benefit, thus far. An improved understanding of tyrosine kinase biology has also led to faster drug development, identification of resistance mechanisms and ways to overcome resistance. In this review, we discuss the clinical data supporting the use and practical aspects of management of patients on epidermal growth factor receptor and anaplastic lymphoma kinase tyrosine kinase inhibitors.
Non-small cell lung cancer; tyrosine kinase inhibitor; epidermal growth factor receptor; ALK-translocation; Vascular endothelial growth factor
Molecular pathology of thymomas is poorly understood. Genomic aberrations are frequently identified in tumors but no extensive sequencing has been reported in thymomas. Here we present the first comprehensive view of a B3 thymoma at whole genome and transcriptome levels. A 55-year-old Caucasian female underwent complete resection of a stage IVA B3 thymoma. RNA and DNA were extracted from a snap frozen tumor sample with a fraction of cancer cells over 80%. We performed array comparative genomic hybridization using Agilent platform, transcriptome sequencing using HiSeq 2000 (Illumina) and whole genome sequencing using Complete Genomics Inc platform. Whole genome sequencing determined, in tumor and normal, the sequence of both alleles in more than 95% of the reference genome (NCBI Build 37). Copy number (CN) aberrations were comparable with those previously described for B3 thymomas, with CN gain of chromosome 1q, 5, 7 and X and CN loss of 3p, 6, 11q42.2-qter and q13. One translocation t(11;X) was identified by whole genome sequencing and confirmed by PCR and Sanger sequencing. Ten single nucleotide variations (SNVs) and 2 insertion/deletions (INDELs) were identified; these mutations resulted in non-synonymous amino acid changes or affected splicing sites. The lack of common cancer-associated mutations in this patient suggests that thymomas may evolve through mechanisms distinctive from other tumor types, and supports the rationale for additional high-throughput sequencing screens to better understand the somatic genetic architecture of thymoma.
Thymic carcinomas represent the most aggressive histotype of thymic epithelial tumors (TETs). The 2004 World Health Organization (WHO) classification has assigned a subgroup of thymic carcinomas as t(15:19) carcinomas based on the presence of t(15;19), a translocation found in poorly differentiated and highly aggressive NUT midline carcinomas (NMC). These tumors are characterized by rearrangement of the NUT (nuclear protein in testis) gene on chromosome 15q14, which in most cases fuses to the bromomdomain containing 4 (BRD4) gene on chromosome 19p13.1 through reciprocal t(15;19) translocation, resulting in constitutive BRD4-NUT fusion protein expression. To our knowledge, NUT translocation has been reported only in four thymic carcinomas. Due to the rarity of TETs, the prevalence of NUT rearrangement in TETs has however never been systematically explored.
Formalin-fixed paraffin-embedded samples of histologically-confirmed TETs were evaluated for NUT expression and rearrangement by immunohistochemistry and fluorescence in-situ hybridization respectively.
A series of 148 TETs (37 carcinomas and 111 thymomas) were examined for NUT expression and rearrangement. Only one thymic carcinoma (2.7% of thymic carcinomas or 0.68% of TETs) was found positive for NUT expression and rearrangement.
Rearrangement of NUT is infrequent in TETs. We propose that caution should be taken to distinguish t(15;19) thymic carcinoma from other mediastinal carcinomas, as NMCs are often associated with dreadful prognosis or overt lethality.
t(15;19) translocation; BRD4-NUT; thymoma; thymic carcinoma
PURPOSE OF REVIEW
Testing for epidermal growth factor receptor (EGFR) mutations has become standard practice in treating patients with advanced nonsmall cell lung cancer (NSCLC). EGFR tyrosine kinase inhibitors (TKIs) are being offered as first line therapy in patients with EGFR activating mutations. These drugs offer an increased progression free survival and response rate compared to standard chemotherapy in this setting, however resistance invariably occurs. This review discusses the development of resistance to EGFR TKIs and the progress that is being made to better understand how to overcome this resistance.
Results from recently published papers dealing with resistance to EGFR TKIs are allowing for a better understanding of this mechanism. No one treatment allows for overcoming this resistance. Understanding this resistance will likely become an individualized patient/tumor approach. Selecting which drug or drugs that may be suitable can only be determined based on the molecular mechanism of resistance.
Progress is being made in our understanding of the multiple pathways of resistance. Using a tumors molecular signature at the time of progression can determine the best treatment option.
Epidermal Growth Factor Receptor; Tyrosine Kinase Inhibitors; Resistance; Lung Cancer
Pancreatic cancer is the 4th-leading cause of cancer-related death, and studies on the clinical relevance of its genomic imbalances are warranted.
Recurrent copy number alterations of cytobands and genes were analyzed by array comparative genomic hybridization (aCGH) in 44 resected pancreatic cancer specimens. Prognostic markers identified by aCGH were validated by PCR gene copy number assay in an independent validation cohort of 61 resected pancreatic cancers. The functions of gene identified were evaluated by proliferation, cell cycle and migration assays in pancreatic cancer cells.
We demonstrated recurrent copy number gains and losses in the first cohort. Loss of 18q22.3 was significantly associated with short-term overall survival in the first cohort (p=0.019). This cytoband includes the Carboxypeptidase of glutamate-like (CPGL) gene. CPGL gene deletion was associated with shorter overall survival in the validation cohort (p=0.003). CPGL deletion and mutations of TP53 or Kras appear to be independent events. A Cox model analysis of the two cohorts combined showed that loss of 18q22.3/deletion of the CPGL gene was an independent poor prognostic factor for overall survival (hazard ratio=2.72, p=0.0007). Reconstitution of CPGL or its splicing-variant CPGL-B into CPGL-negative pancreatic cancer cells attenuated cell growth, migration, and induced G1-accumulation.
Loss of 18q22.3/deletion of the CPGL gene is a poor prognostic marker in resected pancreatic cancer, and functional studies suggest the CPGL gene as growth suppressor gene in pancreatic cancer.
Pancreatic cancer; Comparative genomics; CPGL protein; human; Prognosis; Growth suppressor
Epigenetic aberrations offer dynamic and reversible targets for cancer therapy; increasingly, alteration via overexpression, mutation, or rearrangement is found in genes that control the epigenome. Such alterations suggest a fundamental role in carcinogenesis. Here, we consider three epigenetic mechanisms: DNA methylation, histone tail modification and non-coding, microRNA regulation. Evidence for each of these in lung cancer origin or progression has been gathered, along with evidence that epigenetic alterations might be useful in early detection. DNA hypermethylation of tumor suppressor promoters has been observed, along with global hypomethylation and hypoacetylation, suggesting an important role for tumor suppressor gene silencing. These features have been linked as prognostic markers with poor outcome in lung cancer. Several lines of evidence have also suggested a role for miRNA in carcinogenesis and in outcome. Cigarette smoke downregulates miR-487b, which targets both RAS and MYC; RAS is also a target of miR-let-7, again downregulated in lung cancer. Together the evidence implicates epigenetic aberration in lung cancer and suggests that targeting these aberrations should be carefully explored. To date, DNA methyltransferase and histone deacetylase inhibitors have had minimal clinical activity. Explanations include the possibility that the agents are not sufficiently potent to invoke epigenetic reversion to a more normal state; that insufficient time elapses in most clinical trials to observe true epigenetic reversion; and that doses often used may provoke off-target effects such as DNA damage that prevent epigenetic reversion. Combinations of epigenetic therapies may address those problems. When epigenetic agents are used in combination with chemotherapy or targeted therapy it is hoped that downstream biological effects will provoke synergistic cytotoxicity. This review evaluates the challenges of exploiting the epigenome in the treatment of lung cancer.
epigenetics; non-small cell lung cancer; small-cell lung cancer; DNA methylation; histone modification; microRNA
A key challenge in the treatment of thymoma and thymic carcinoma (TC) is in improving our understanding of the molecular biology of these relatively rare tumors. In recent years, significant efforts have been made to dissect the molecular pathways involved in their carcinogenesis. Here we discuss the results of large-scale genomic analyses conducted to date and review the most active chemotherapies and targeted treatments.
We reviewed the literature for chemotherapeutic trials in the last 20 years and trials involving targeted therapies between 1999 and 2010. The search was supplemented by a review of abstracts presented at the annual meetings of the American Society of Clinical Oncology (from 1999 to 2010), at the first International Conference on Thymic Malignancies in 2009, and at a follow-up meeting of the newly formed International Thymic Malignancies Interest Group in 2010.
Surgery remains the treatment of choice for operable tumors, whereas chemotherapy is standard in locally advanced and metastatic disease. Thus far, targeted therapies have been developed empirically. Histone deacetylase inhibitors have shown some activity in thymoma whereas sunitinib may be active in TC. There are no data to support the use of HER2- or EGFR-targeted therapies in thymic malignancies.
Drug development for the treatment of thymic malignancies is difficult because of the rarity of these tumors. Ethnic differences are becoming apparent, with aggressive subtypes being observed in Asians and African Americans. Incremental improvements in our understanding of tumor biology suggest that molecular profiling–directed therapies may be the preferred route of investigation in the future.
To determine the maximum tolerated dose (MTD), toxicities, and pharmacokinetic-pharmacodynamic profile of the heat shock protein 90 (Hsp90) inhibitor PF-04929113 (SNX-5422) in patients with advanced solid tumors and lymphomas.
This was a single institution, phase I, dose-escalation study of PF-04929113 dosed twice-weekly. Endpoints included determination of dose-limiting toxicities (DLT), MTD, the safety profile of PF-04929113, pharmacodynamic assessment of PF-04929113 on Hsp70 induction, pharmacokinetic (PK) analysis of PF 04928473 (SNX-2112) and its prodrug PF-04929113 and assessment of response.
Thirty three patients with advanced malignancies were treated. Dose escalation was continued up to 177 mg/m2 administered orally twice a week. One DLT (non-septic arthritis) was noted. No grade 4 adverse events (AEs) were seen; grade 3 AEs included diarrhea (9%), non-septic arthritis (3%), AST elevation (3%) and thrombocytopenia (3%). No objective responses were seen in 32 evaluable patients. Fifteen patients (47%) had stable disease; 17 patients (53%) had progressive disease. PK data revealed rapid absorption, hepatic and extra-hepatic clearance, extensive tissue binding and almost linear pharmacokinetics of the active drug PF 04928473. PD studies confirmed inhibition of Hsp90 and a linear correlation between PK parameters and Hsp70 induction.
PF-04929113 administered orally twice weekly is well tolerated and inhibits its intended target Hsp90. No objective responses were seen but long lasting stabilizations were obtained. Although no clinically significant drug-related ocular toxicity was seen in this study the development of PF-04929113 has been discontinued due to ocular toxicity seen in animal models and in a separate phase I study.
Developing effective immunotherapy for lung cancer is a daunting but hugely attractive challenge. Until recently, non-small cell lung cancer was thought of as a non-immunogenic tumor, but there is now evidence highlighting the integral role played by both inflammatory and immunological responses in lung carcinogenesis. Despite recent encouraging preclinical and phase I/II data, there is a paucity of phase III trials showing a clear clinical benefit for vaccines in lung cancer. There are many difficulties to overcome prior to the development of a successful therapy. Perhaps a measurable immune response may not translate into a clinically meaningful or radiological response. Patient selection may also be a problem for ongoing clinical studies. The majority of trials for lung cancer vaccines are focused on patients with advanced-stage disease, while the ideal candidates may be patients with a lower tumor burden stage I or II disease. Selecting the exact antigens to target is also difficult. It will likely require multiple epitopes of a diverse set of genes restricted to multiple haplotypes to generate a truly effective vaccine that is able to overcome the various immunologic escape mechanisms that tumors employ. This review discusses active immunotherapy employing protein/peptide vaccines, whole cell vaccines, and dendritic cell vaccines and examines the current data on some novel immunomodulating agents.
vaccines; cancer; T lymphocytes; dendritic cells; immunomodulation
The first-generation epidermal growth factor receptor tyrosine kinase inhibitors erlotinib and gefitinib have been incorporated into treatment paradigms for patients with advanced non-small cell lung cancer. These agents are particularly effective in a subset of patients whose tumors harbor activating epidermal growth factor receptor mutations. However, most patients do not respond to these tyrosine kinase inhibitors, and those who do will eventually acquire resistance that typically results from a secondary epidermal growth factor receptor mutation (eg, T790M), mesenchymal-epithelial transition factor amplification, or activation of other signaling pathways. For patients whose tumors have wild-type epidermal growth factor receptor, there are several known mechanisms of initial resistance (eg, Kirsten rat sarcoma viral oncogene homolog mutations) but these do not account for all cases, suggesting that unknown mechanisms also contribute. To potentially overcome the issue of resistance, next-generation tyrosine kinase inhibitors are being developed, which irreversibly block multiple epidermal growth factor receptor family members (eg, afatinib [BIBW 2992], PF-00299804) and/or vascular endothelial growth factor receptor pathways (eg, BMS-690514, XL647). In addition, drugs that block parallel signaling pathways or signaling molecules downstream of the epidermal growth factor receptor, such as the insulin-like growth factor-1 receptor and the mammalian target of rapamycin, are undergoing clinical evaluation. As drug resistance appears to be pleomorphic, combinations of drugs or drugs with multiple targets may be more effective in circumventing resistance.
Epidermal growth factor receptor; tyrosine kinase inhibitor; non-small cell lung cancer; afatinib; BIBW 2992; PF-00299804; resistance
An American Society of Clinical Oncology (ASCO) focused update updates a single recommendation (or subset of recommendations) in advance of a regularly scheduled guideline update. This document updates one recommendation of the ASCO Guideline Update on Chemotherapy for Stage IV Non–Small-Cell Lung Cancer (NSCLC) regarding switch maintenance chemotherapy.
Recent results from phase III clinical trials have demonstrated that in patients with stage IV NSCLC who have received four cycles of first-line chemotherapy and whose disease has not progressed, an immediate switch to alternative, single-agent chemotherapy can extend progression-free survival and, in some cases, overall survival. Because of limitations in the data, delayed treatment with a second-line agent after disease progression is also acceptable.
Seven randomized controlled trials of carboxyaminoimidazole, docetaxel, erlotinib, gefitinib, gemcitabine, and pemetrexed have evaluated outcomes in patients who received an immediate, non–cross resistant alternative therapy (switch maintenance) after first-line therapy.
In patients with stage IV NSCLC, first-line cytotoxic chemotherapy should be stopped at disease progression or after four cycles in patients whose disease is stable but not responding to treatment. Two-drug cytotoxic combinations should be administered for no more than six cycles. For those with stable disease or response after four cycles, immediate treatment with an alternative, single-agent chemotherapy such as pemetrexed in patients with nonsquamous histology, docetaxel in unselected patients, or erlotinib in unselected patients may be considered. Limitations of this data are such that a break from cytotoxic chemotherapy after a fixed course is also acceptable, with initiation of second-line chemotherapy at disease progression.
Small cell lung cancer (SCLC) is an aggressive lung cancer subtype in need of better therapies. Histone deacetylase inhibitors (HDIs) promote increased lysine acetylation in nucleosomal histones and are thought to relax chromatin, thereby allowing increased access of transcription factors and DNA damaging agents alike to DNA. We studied whether two HDIs, belinostat and romidepsin, could be effectively combined with cisplatin or etoposide (VP-16) for SCLC cells. Analysis of cell survival and synergy was performed using CalcuSyn mathematical modeling to calculate a combination index. Immunostaining of γH2AX was performed to evaluate persistence of DNA damage following simultaneous or sequential exposure. Based on CalcuSyn modeling, HDIs synergized with DNA damaging agents only when added simultaneously. An additive-to-antagonistic effect was seen with HDI pretreatment for 24 h or with addition after cisplatin or etoposide. Furthermore, pretreatment with HDIs resulted in normalization of cell cycle and reduced PARP degradation as compared with simultaneous treatment. The increase in γH2AX phosphorylation confirmed that simultaneous but not sequential treatment enhanced double-stranded DNA breaks. These results suggest that DNA relaxation is not required for synergy of HDIs with DNA damaging agents, and that scheduling of drug administration will be critical for rational development of clinical protocols.
combination index; drug interaction; γH2AX phosphorylation; dsDNA break; synergy; PARP degradation
In lung cancer, early attempts to modulate the immune system via vaccine based therapeutics have to date, been unsuccessful. An improved understanding of tumor immunology has facilitated the production of more sophisticated lung cancer vaccines. It is anticipated, that it will likely require multiple epitopes of a diverse set of genes restricted to multiple haplotypes to generate a truly effective vaccine that is able to overcome the various immunologic escape mechanisms that tumors employ. Other issues to overcome include optimal patient selection, which adjuvant agent to use and how to adequately monitor for an immunological response. This review discusses the most promising vaccination strategies for non small cell lung cancer including the allogeneic tumor cell vaccine belagenpumatucel-L, which is a mixture of 4 allogeneic non small cell lung cancer cell lines genetically modified to secrete an antisense oligonucleotide to TGF-β2 and three other target protein-specific vaccines designed to induce responses against melanoma-associated antigen A3 (MAGE-A3), mucin 1 (MUC1) and epidermal growth factor (EGF).
lung cancer; vaccines
Measurement of tumor response by standard response criteria is challenging in thymic malignancies especially when the pleura is involved, as it often is in stage IV disease. In this study we aimed to determine the effectiveness of volumetric response evaluation criteria in solid tumors (volumetrics) for evaluating response in patients with thymic malignancies treated on a phase II study of belinostat.
We evaluated 25 thymic cancer patients' tumor responses using computed tomography (CT) based response evaluation criteria in solid tumors (RECIST), World Health Organization (WHO), modified RECIST, and volumetrics. As a control we assessed 37 NSCLC patients with RECIST and volumetrics.
Agreement analyses in 23 thymic cancer patients at the time of RECIST-determined progressive disease (PD) compared volumetrics to RECIST, modified RECIST, and WHO criteria. Use of volumetrics was associated with 22% discordance compared to RECIST, 15% vs. modified RECIST, and 22% vs. WHO criteria. Volumetrics revealed PD 72 days earlier than RECIST (p=0.016). In another cohort of 35 NSCLC patients there was 9% discordance between volumetrics and RECIST at the time of PD. Volumetrics demonstrated PD 32 days earlier than RECIST in NSCLC (p=0.0078).
Our study suggests that volumetrics might improve detection of progressive disease. Prospective evaluation of this technique in a larger series of patients with thymic malignancies will be required.
Thymomas are rare tumors of the mediastinum; a limited number of small studies have evaluated the outcomes in these patients. We identified 668 patients with thymoma from the Swedish Cancer Registry, and 2,719 population-based matched controls. We obtained information on autoimmunity from the nationwide inpatient/outpatient hospital discharge Registry. We constructed Kaplan-Meier curves for survival analysis, conditional regression and Cox proportional hazards models to evaluate the association between thymoma and autoimmune diseases, and standardized incidence ratios (SIRs) to evaluate the risk for second cancers following thymoma. Compared with controls, patients with benign or malignant thymoma had a poorer (p <0.001) 5-year (79%, 53% vs. 91%), 10-year (65%, 39% vs. 78%), and 20-year (43%, 18% vs. 55%) overall survival. For thymoma patients, younger age at diagnosis and being diagnosed in recent years were associated with a better survival. Compared with controls, thymoma patients were more likely to have an autoimmune disease at some point during their lives (32.7% vs. 2.4%, respectively, p<0.001), most frequently myasthenia gravis (24.5%), systemic lupus erythematosus (2.4%), and red cell aplasia (1.2%). Thymoma patients had 2-fold excess risk for second cancers compared with the general population, most notably: non-melanoma skin cancer (SIR=10.6, 95% confidence intervals (CI)=6.0–17.3), non-Hodgkin lymphoma (SIR=6.8, 95% CI=3.00–13.0), and cervical (SIR=6.9, 95% CI=1.4–20.1), endocrine (SIR=4.7, 95% CI=1.3–12.0), and prostate cancer (SIR=3.0, 95% CI=1.7–4.8). Despite the improved survival for thymoma patients over time, they have worse survival than controls. Thymoma patients are in need for follow-up to detect and manage autoimmune diseases and cancer.
thymoma; autoimmunity; second cancer
Thymic epithelial tumors are rare malignancies, and there is no standard treatment for patients with advanced disease in whom chemotherapy has failed. Antitumor activity of histone deacetylase (HDAC) inhibitors in this disease has been documented, including one patient with thymoma treated with the pan-HDAC inhibitor belinostat.
Patients and Methods
Patients with advanced thymic epithelial malignancies in whom at least one line of platinum-containing chemotherapy had failed were eligible for this study. Other eligibility criteria included adequate organ function and good performance status. Belinostat was administered intravenously at 1 g/m2 on days 1 to 5 of a 21-day cycle until disease progression or development of intolerance. The primary objective was response rate in patients with thymoma.
Of the 41 patients enrolled, 25 had thymoma, and 16 had thymic carcinoma; patients had a median of two previous systemic regimens (range, one to 10 regimens). Treatment was well tolerated, with nausea, vomiting, and fatigue being the most frequent adverse effects. Two patients achieved partial response (both had thymoma; response rate, 8%; 95% CI, 2.2% to 25%), 25 had stable disease, and 13 had progressive disease; there were no responses among patients with thymic carcinoma. Median times to progression and survival were 5.8 and 19.1 months, respectively. Survival of patients with thymoma was significantly longer than that of patients with thymic carcinoma (median not reached v 12.4 months; P = .001). Protein acetylation, regulatory T-cell numbers, and circulating angiogenic factors did not predict outcome.
Belinostat has modest antitumor activity in this group of heavily pretreated thymic malignancies. However, the duration of response and disease stabilization is intriguing, and additional testing of belinostat in this disease is warranted.
TrkB has been involved in poor cancer outcome. TrkB mutations have been reported in non-small cell lung cancer. In this study, we aimed at characterizing the role of 3 potentially sensitizing TrkB mutations previously reported in lung cancer.
We characterized three activation loop mutants of TrkB (M713I, R715G and R734C) in terms of pathway activation/phosphorylation, migration, anchorage independent growth and sensitivity to a Trk inhibitor, using NIH3T3 cells and Baf3 cells. We also sequenced the tyrosine kinase domain of TrkB in a large number of lung cancer samples of East-Asian origin and cell lines.
None of the mutants were constitutively active in NIH3T3 transformation and migration assays. M713I and R734C mutants showed low levels of autophosphorylation in comparison with wild-type TrkB. Although R715G showed similar level of autophosphorylation to wild-type TrkB upon brain-derived neurotrophic factor stimulation, the mutant was not as competent as wild-type TrkB in supporting IL-3 independent growth of Baf3 cells. In addition, the Trk inhibitor AZD6918 inhibited wild-type TrkB induced cell migration and cell growth, whereas the mutants were relatively resistant to the Trk inhibitor compared to wild-type TrkB. We could not confirm the presence of non-synonymous mutation in 78 lung cancer samples and 29 cell lines.
Wild-type but not mutant TrkB enhances cell migration and transformation. Our study suggests that TrkB mutations should not be used for selection of patients with lung cancer treated with Trk inhibitors. High expression of wild-type TrkB might be beneficial for studies of Trk inhibitors.
ASCO produced the 2011 Focused Update based on phase III randomized clinical trials published on maintenance chemotherapy, addressing one question from the 2009 Guideline Update on chemotherapy for stage IV NSCLC: what is the optimal duration of first-line chemotherapy for stage IV NSCLC?
Sorafenib, a multikinase inhibitor targeting Raf and VEGFR has shown activity in unselected patients with NSCLC. At present there are no validated biomarkers indicative of sorafenib activity.
Patients received sorafenib 400mg bid daily to determine activity and tolerability and to measure its biological effects. KRAS mutation status (N=34), angiogenesis markers (VEGF, bFGF, FLT-1, PLGF-1) and imaging with DCE-MRI to determine early changes in tumor vascular characteristics were evaluated. Three parameters Ktrans, Kep and ve, were measured by DCE-MRI at baseline and day 14 of cycle 1. Cytokine analysis was performed on days 0, 14, 28 and 54.
37 pts with previously treated stage IV NSCLC were enrolled in this single center phase II trial. In 34 evaluable patients, 2 had partial responses, and 20 had stable disease for 3-17 months, a disease control rate of 65%. The median progression-free survival (PFS) was 3.4 months and median overall survival (OS) was 11.6 months. Toxicity was consistent with the known side effects of sorafenib. KRAS (32%) and EGFR mutations (22%), showed no correlation with response, PFS or OS. Kep, was significant in predicting an improvement in OS (p=0.035) and PFS (p=0.029). Cytokine analysis demonstrated an improved OS for bFGF day 0 <6 vs >6 pg/ml (p=0.042) whereas a PFS benefit was seen with bFGF at day 28 <6 vs >6 (p=0.028).
KRAS and EGFR mutational status showed no correlation with response, PFS or OS. Radiological and cytokine changes may act as biomarkers indicative of early angiogenesis inhibition.
The impact of epidermal growth factor receptor (EGFR) and KRAS genotypes on outcomes with erlotinib or gefitinib therapy continues to be debated. This study combines patient data from five trials in predominantly Western populations to assess the impact of EGFR and KRAS mutations on first-line therapy with an EGFR–tyrosine kinase inhibitor (TKI) and compare clinical versus molecular predictors of sensitivity.
Chemotherapy-naïve patients with advanced non–small cell lung cancer and known EGFR mutation status treated with erlotinib or gefitinib monotherapy as part of a clinical trial were eligible for inclusion. Patients received daily erlotinib (150 mg) or gefitinib (250 mg) until disease progression or unacceptable toxicity. Data were collected in a password-protected web database. Clinical outcomes were analyzed to look for differences based on EGFR and KRAS genotypes, as well as clinical characteristics.
Patients (223) from five clinical trials were included. Sensitizing EGFR mutations were associated with a 67% response rate, time to progression (TTP) of 11.8 months, and overall survival of 23.9 months. Exon 19 deletions were associated with longer median TTP and overall survival compared with L858R mutations. Wild-type EGFR was associated with poorer outcomes (response rate, 3%; TTP, 3.2 months) irrespective of KRAS status. No difference in outcome was seen between patients harboring KRAS transition versus transversion mutations. EGFR genotype was more effective than clinical characteristics at selecting appropriate patients for consideration of first-line therapy with an EGFR-TKI.
EGFR mutation status is associated with sensitivity to treatment with an EGFR-TKI in patients with advanced non–small cell lung cancer. Patients harboring sensitizing EGFR mutations should be considered for first-line erlotinib or gefitinib.
A simple, rapid and sensitive liquid chromatography/tandem mass spectrometric (LC/MS/MS) analytical method was developed for quantification of Hsp90 inhibitor PF-04928473 in human plasma, following administration of its prodrug, PF-04929113. Sample processing involved protein precipitation by addition of 0.4 mL of methanol containing internal standard (PF-04972487) to 50 μL volume of plasma sample. Chromatographic separation of PF-04928473 and PF-04972487 was achieved on a Phenomenex® Luna C18(2) (2.0×50 mm, 5 μm) column using a gradient elution method with mobile phase solvents: methanol containing 0.1% formic acid and 0.1% formic acid at a flow rate of 0.25 mL/min. Detection was performed in electrospray positive ionization mode, monitoring the ion transitions from m/z 465.1→350.1 (PF-04928473) and m/z 447.0→329.1 (PF-04972487). The retention times for PF-04928473 and PF-04972487 were 1.86 and 2.85 minutes, respectively. Calibration curves were generated in the range of 2–2000 ng/mL. The accuracy and precision ranged from 94.1–99.0% and 86.7–97.6%, respectively, which were calculated using quality control samples of three different concentrations analyzed in quintuplicate on four different days.
PF-04928473; PF-04929113; Hsp90 inhibitors; SNX-2112; SNX-5422
This study determined whether expression levels of a panel of biologically relevant microRNAs can be used as prognostic or predictive biomarkers in patients who participated in the International Adjuvant Lung Cancer Trial (IALT), the largest randomized study conducted to date of adjuvant chemotherapy in patients with radically resected non-small cell lung carcinoma (NSCLC). Expression of miR-21, miR-29b, miR-34a/b/c, miR-155 and let-7a was determined by quantitative real-time PCR in paraffin embedded formalin fixed tumor specimens from 639 IALT patients. Prognostic and predictive value of microRNA expression for survival were studied using a Cox model, which included every factor used in the stratified randomization, clinicopathological prognostic factors and other factors statistically related to microRNA expression. Investigation of the expression pattern of microRNAs in situ was performed. We also analyzed association of TP53 mutation status and miR-34a/b/c expression, EGFR and KRAS mutation status and miR-21 and Let-7a expression, respectively. Finally, association of p16 and miR-29b expression was assessed. Overall, no significant association was found between any of the tested microRNAs and survival, with the exception of miR-21 where a deleterious prognostic effect of lowered expression was suggested. Otherwise, no single or combinatorial microRNA expression profile predicted response to adjuvant cisplatin-based chemotherapy. Together, our results indicate that the miRNA expression patterns examined were neither predictive nor prognostic in a large patient cohort of radically resected NSCLC randomized to receive adjuvant cisplatin-based chemotherapy versus follow-up only.
non–small cell lung cancer; adjuvant chemotherapy; randomized trial; biomarker; drug resistance; microRNA
Thymic malignancies are rare tumors. The IGF-1/IGF-1R system is involved in the development of the thymus. IGF-1R expression in thymic epithelial malignancies is unknown.
We investigated the expression of insulin-like growth factor 1 receptor (IGF-1R) and phospho-AKT Ser-473 (p-AKT) by immunohistochemistry and the clinicopathological correlations in a retrospective single institution surgical series of 132 thymic epithelial malignancies.
Earlier stages, less aggressive histological types, and complete resections were significant positive prognostic factors for disease-related survival and progression-free survival, and female gender was a better prognostic factor for disease-related survival. IGF-1R and p-AKT proteins were expressed in 20% and 36% of thymic tumors, respectively. They were both more commonly expressed in relapsed than in primary tumors, in more aggressive subtypes and more advanced stages. There was a trend for better survival and progression-free survival in IGF-1R or p-AKT expression negative cases in the whole series; considering the 91 primary tumors only, IGF1R expression was associated with worse progression-free survival (p<0.001).
This retrospective analysis demonstrates stage, histology, gender and resection type as major prognostic factors. The expression of IGF-1R and p-AKT in thymic tumors suggests IGF-1R as a potential target for treatment.
thymoma; IGF-1R; expression; immunohistochemistry; prognosis
The use of targeted therapies for the treatment of thymic malignancies is documented in the literature. However only a few drugs have undergone evaluation in phase II trials. Most of the evidence of the benefit of biologic therapies for thymic malignancies is in the form of case reports and small case series. No major activity has been observed with any agent so far, likely to the lack of selection of patients for targeted therapies and the small numbers studied. A better understanding of the biology of these tumors will be essential in furthering the field.
Thymoma; Thymic Carcinoma; Targeted therapy; Gefitinib; Imatinib; Belinostat; Sorafenib; Cixutumumab; Octreotide