Michelle S. Ginsberg

Activity of SU11248, a Multitargeted Inhibitor of Vascular Endothelial Growth Factor Receptor and Platelet-Derived Growth Factor Receptor, in Patients With Metastatic Renal Cell Carcinoma

PURPOSE Renal cell carcinoma (RCC) is characterized by loss of von Hippel Lindau tumor suppressor gene activity, resulting in high expression of pro-angiogenic growth factors: vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF). SU11248 (sunitinib malate), a small molecule inhibitor with high binding affinity for VEGF and PDGF receptors, was tested for clinical activity in patients with metastatic RCC. PATIENTS AND METHODS Patients with metastatic RCC and progression on first-line cytokine therapy were enrolled onto a multicenter phase II trial. SU11248 monotherapy was administered in repeated 6-week cycles of daily oral therapy for 4 weeks, followed by 2 weeks off. Overall response rate was the primary end point, and time to progression and safety were secondary end points. Results Twenty-five (40%) of 63 patients treated with SU11248 achieved partial responses; 17 additional patients (27%) demonstrated stable disease lasting > or = 3 months. Median time to progression in the 63 patients was 8.7 months. Dosing was generally tolerated with manageable toxicities. CONCLUSION SU11248, a multitargeted receptor tyrosine kinase inhibitor of VEGF and PDGF receptors, demonstrates antitumor activity in metastatic RCC as second-line therapy, a setting where no effective systemic therapy is presently recognized. The genetics of RCC and these promising clinical results support the hypothesis that VEGF and PDGF receptor-mediated signaling is an effective therapeutic target in RCC.

Optimization of dosing for EGFR-mutant non-small cell lung cancer with evolutionary cancer modeling.

Predictive models of EGFR-mutant tumor behavior point to alternative drug dosing strategies to prevent and treat acquired resistance. Harnessing Evolution to Improve Lung Cancer Therapy Like any organism under severe evolutionary pressure, a few select members of a cancer cell population acquire molecular changes that strengthen the clan’s chances of survival. Therapeutic drugs exert a powerful selective force on characteristically compliant cancer cells, as the common recurrence of drug-resistant cancers testifies. To learn how to better fight the potent forces of evolution, Chmielecki et al. examined the behavior of non–small cell lung cancer (NSCLC) before and after the cells acquire resistance to targeted therapy, which inevitably they do. The growth characteristics of these cells were consistent with patient tumor behavior, enabling construction of a mathematical model that predicted alternative therapeutic strategies to delay the development of drug-resistant cancer cells. The authors made paired isogenic cell lines that were sensitive and resistant to afatinib and erlotinib—drugs used to treat NSCLC that are directed against the epidermal growth factor receptor (EGFR) tyrosine kinase, which is activated in a subset of NSCLCs. To the authors’ surprise, the drug-resistant cells grew more slowly than their sensitive counterparts, and resistance was not maintained in the absence of selection. Multiple clinical observations corroborated these findings. For example, patients with resistant tumors showed a slow course of disease progression, and patients with acquired resistance have re-responded to tyrosine kinase inhibitor (TKI) therapy after a drug holiday. The authors then constructed an evolutionary mathematical model of tumor behavior based on the differential growth rates of TKI-sensitive and TKI-resistant cells in heterogeneous tumor cell populations. Understanding the growth dynamics of how tumors behave allowed the authors to calculate what would happen under different treatment regimes. Their models predicted that continuous administration of a low-dose EGFR TKI combined with high-dose pulses of an EGFR TKI should delay the onset of resistance. Subsequent cellular studies bore out this prediction. Modeling also indicated the wisdom of prolonging treatment with the EGFR TKI after the development of resistance to prevent fast overgrowth by the sensitive cells, a result also born out in vitro and in vivo. Ultimate proof will have to come from patients. Clinical trials based on these alternative dosing strategies will be the true test of the utility of evolutionary mathematical modeling in designing cancer treatments. If they prove beneficial, individual models based on the characteristics of diverse cancer cell types could offer clues for designing optimal treatment strategies. Non–small cell lung cancers (NSCLCs) that harbor mutations within the epidermal growth factor receptor (EGFR) gene are sensitive to the tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib. Unfortunately, all patients treated with these drugs will acquire resistance, most commonly as a result of a secondary mutation within EGFR (T790M). Because both drugs were developed to target wild-type EGFR, we hypothesized that current dosing schedules were not optimized for mutant EGFR or to prevent resistance. To investigate this further, we developed isogenic TKI-sensitive and TKI-resistant pairs of cell lines that mimic the behavior of human tumors. We determined that the drug-sensitive and drug-resistant EGFR-mutant cells exhibited differential growth kinetics, with the drug-resistant cells showing slower growth. We incorporated these data into evolutionary mathematical cancer models with constraints derived from clinical data sets. This modeling predicted alternative therapeutic strategies that could prolong the clinical benefit of TKIs against EGFR-mutant NSCLCs by delaying the development of resistance.

Response to Cabozantinib in Patients with RET Fusion-Positive Lung Adenocarcinomas

The discovery of RET fusions in lung cancers has uncovered a new therapeutic target for patients whose tumors harbor these changes. In an unselected population of non-small cell lung carcinomas (NSCLCs), RET fusions are present in 1% to 2% of cases. This incidence increases substantially, however, in never-smokers with lung adenocarcinomas that lack other known driver oncogenes. Although preclinical data provide experimental support for the use of RET inhibitors in the treatment of RET fusion-positive tumors, clinical data on response are lacking. We report preliminary data for the first three patients treated with the RET inhibitor cabozantinib on a prospective phase II trial for patients with RET fusion-positive NSCLCs (NCT01639508). Confirmed partial responses were observed in 2 patients, including one harboring a novel TRIM33-RET fusion. A third patient with a KIF5B-RET fusion has had prolonged stable disease approaching 8 months (31 weeks). All three patients remain progression-free on treatment.

Phase I Trial of Bevacizumab Plus Escalated Doses of Sunitinib in Patients With Metastatic Renal Cell Carcinoma

PURPOSE Both bevacizumab and sunitinib target the vascular endothelial growth factor pathway and demonstrate activity against advanced renal cell carcinoma (RCC). In this phase I study, the maximum-tolerated dose (MTD) and safety of sunitinib in combination with bevacizumab were examined in patients with advanced RCC. PATIENTS AND METHODS Three cohorts of three to six patients were treated with escalated doses of daily oral sunitinib (ie, 25 mg, 37.5 mg, 50 mg) for 4 weeks followed by a 2-week break and with fixed doses of bevacizumab (10 mg/kg) intravenously once every 2 weeks. Dose-limiting toxicities (DLTs) were assessed during the first cycle to determine the MTD, and an expanded cohort was treated to obtain additional safety information. RESULTS Of 26 study participants, 25 received treatment at one of three dose levels. Grade 4 hemorrhage, identified as a DLT, occurred in one patient in each of cohorts 2 and 3. The MTD was determined to be sunitinib 50 mg/bevacizumab 10 mg/kg, but chronic therapy at this dose level frequently resulted in grades 3 to 4 hypertension and hematologic and vascular toxicities. Overall, 48% of patients discontinued treatment because of adverse events. One complete and 12 partial responses were observed, which provided an objective response rate of 52%. CONCLUSION In this phase I trial of patients with metastatic RCC, the combination of sunitinib and bevacizumab caused a high degree of hypertension and vascular and hematologic toxicities at the highest dose level. We do not plan to pursue additional study of this regimen at these doses in patients with RCC.

Response to MET Inhibitors in Patients with Stage IV Lung Adenocarcinomas Harboring MET Mutations Causing Exon 14 Skipping

UNLABELLED Mutations in the MET exon 14 RNA splice acceptor and donor sites, which lead to exon skipping, deletion of the juxtamembrane domain containing the CBL E3-ubiquitin ligase-binding site, and decreased turnover of the resultant aberrant MET protein, were previously reported to be oncogenic in preclinical models. We now report responses to the MET inhibitors crizotinib and cabozantinib in four patients with stage IV lung adenocarcinomas harboring mutations leading to MET exon 14 skipping, highlighting a new therapeutic strategy for the 4% of lung adenocarcinoma patients whose tumors harbor this previously underappreciated genetic alteration. SIGNIFICANCE Oncogenic mutations in the MET exon 14 splice sites that cause exon 14 skipping occur in 4% of lung adenocarcinomas. We report responses to the MET inhibitors crizotinib and cabozantinib in patients with lung adenocarcinomas harboring MET exon 14 splice site mutations, identifying a new potential therapeutic target in this disease.

An initial experience with FDG-PET in the imaging of residual disease after induction therapy for lung cancer

BACKGROUND The 2-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) imaging is an advance over computed tomography alone in the staging of untreated nonsmall cell lung cancer (NSCLC). Aside from one 9-patient study, there are no data comparing FDG-PET imaging with surgical staging of NSCLC after induction therapy. METHODS We reviewed our institutional experience with FDG-PET imaging followed by surgical staging of nonsmall cell lung cancer after induction therapy. A nuclear physician blinded to surgical findings reviewed the FDG-PET scans and assigned a clinical TNM stage. A thoracic surgeon assigned a pathologic TNM stage. Then the clinical TNM stage and the pathologic TNM stage were compared. RESULTS Fifty-six patients (30 males and 26 females; median, age 60) with nonsmall cell lung cancer underwent chemotherapy (40 patients), chemoradiation (11 patients), or radiation alone (5 patients) followed by PET and operations. PET had a positive predictive value of 98% for detecting residual viable disease in the primary tumor. PET over-staged nodal status in 33% of patients, under staged nodal status in 15%, and was correct in 52%. PET correctly classified all patients with M1 disease. CONCLUSIONS Positron emission tomography after induction therapy accurately detects residual viable primary tumor, but not the involvement of mediastinal lymph nodes.

Phase II trial of antiepidermal growth factor receptor antibody C225 in patients with advanced renal cell carcinoma.

Fifty-five patients with metastatic renal cell carcinoma (RCC) were treated on a multicenter, single-arm Phase II trial. Patients received single-agent Cetuximab (C225) administered by intravenous infusion at a loading dose of 400 or 500 mg/m2 followed by weekly maintenance doses at 250 mg/m2. None of the patients treated with C225 achieved either a complete or partial response. The median time to progression was 57 days. The most frequently reported grade 3 or 4 toxicity treatment-related adverse events were acne (17%) and rash or dry skin (4%). The lack of clinical response or suggestion of prolonging time to progression compared to historical data with interferon-alfa supports no further study of single-agent C225 in patients with metastatic RCC.

Automatic detection of small lung nodules on CT utilizing a local density maximum algorithm

Increasingly, computed tomography (CT) offers higher resolution and faster acquisition times. This has resulted in the opportunity to detect small lung nodules, which may represent lung cancers at earlier and potentially more curable stages. However, in the current clinical practice, hundreds of such thin‐sectional CT images are generated for each patient and are evaluated by a radiologist in the traditional sense of looking at each image in the axial mode. This results in the potential to miss small nodules and thus potentially miss a cancer. In this paper, we present a computerized method for automated identification of small lung nodules on multislice CT (MSCT) images. The method consists of three steps: (i) separation of the lungs from the other anatomic structures, (ii) detection of nodule candidates in the extracted lungs, and (iii) reduction of false‐positives among the detected nodule candidates. A three‐dimensional lung mask can be extracted by analyzing density histogram of volumetric chest images followed by a morphological operation. Higher density structures including nodules scattered throughout the lungs can be identified by using a local density maximum algorithm. Information about nodules such as size and compact shape are then incorporated into the algorithm to reduce the detected nodule candidates which are not likely to be nodules. The method was applied to the detection of computer simulated small lung nodules (2 to 7 mm in diameter) and achieved a sensitivity of 84.2% with, on average, five false‐positive results per scan. The preliminary results demonstrate the potential of this technique for assisting the detection of small nodules from chest MSCT images. PACS number(s): 87.57.–s, 87.90.+y

Phase II Trial of Thalidomide for Patients With Advanced Renal Cell Carcinoma

PURPOSE To assess efficacy and toxicity of thalidomide in patients with advanced renal cell carcinoma (RCC). PATIENTS AND METHODS Twenty-six patients with RCC were treated with thalidomide at a starting dose of 200 mg daily. Thalidomide was increased by 200 mg every 2 weeks until a maximum dose of 800 mg or prohibitive toxicity was reached. Fifteen patients had prior nephrectomy, 11 patients had no prior systemic therapy, and 15 had received one prior systemic regimen. RESULTS A maximum dose of 800 mg, 600 mg, 400 mg, and 200 mg was reached in five, 10, eight, and three patients, respectively. Grade 2 and 3 dyspnea occurred in four and three patients, respectively. Grade 2 and 3 neurologic toxicity was observed in five and two patients, respectively. Of the 25 assessable patients, the best response was stable disease in 16 (95% confidence interval [CI], 43% to 82%) patients. The 6-month progression-free survival rate was 32% (95% CI, 14% to 50%). Three patients achieved prolonged stable disease of 16, 16+, and 18+ months, including two patients who were refractory to previous cytokine therapy. Fifty-seven percent were alive at 1 year (95% CI, 37% to 76%). CONCLUSION This trial does not support the routine use of thalidomide to induce partial response for metastatic RCC. Because disease stabilization occurs as a part of the natural history of metastatic RCC, the potential effect of thalidomide on progression-free and overall survival for patients with advanced RCC is being addressed in a randomized phase III trial. New immunomodulatory analogs of thalidomide that have shown potentially greater antitumor effects in preclinical models warrant study in metastatic RCC.

Bronchioloalveolar carcinoma and lung adenocarcinoma: the clinical importance and research relevance of the 2004 World Health Organization pathologic criteria.

Introduction: Advances in the pathology and computed tomography (CT) of lung adenocarcinoma and bronchioloalveolar carcinoma (BAC) have demonstrated important new prognostic features that have led to changes in classification and diagnostic criteria. Methods: The literature and a set of cases were reviewed by a pathology/CT review panel of pathologists and radiologists who met during a November 2004 International Association for the Study of Lung Cancer/American Society of Clinical Oncology consensus workshop in New York. The group addressed the question of whether sufficient data exist to modify the 2004 World Health Organization (WHO) classification of adenocarcinoma and BAC to define a “minimally invasive” adenocarcinoma with BAC. The problems of diffuse and/or multicentric BAC and adenocarcinoma were evaluated. Results: The clinical concept of BAC needs to be reevaluated with careful attention to the new 2004 WHO criteria because of the major clinical implications. Existing data indicate that patients with solitary, small, peripheral BAC have a 100% 5-year survival rate. The favorable prognostic impact of the restrictive criteria for BAC is already being detected in major epidemiologic data sets such as the Surveillance Epidemiology and End-Results registry. Most lung adenocarcinomas, including those with a BAC component, are invasive and consist of a mixture of histologic patterns. Therefore, they are best classified as adenocarcinoma, mixed subtype. This applies not only to adenocarcinomas with a solitary nodule presentation but also to tumors with a diffuse/multinodular pattern. The percentage of BAC versus invasive components in lung adenocarcinomas seems to be prognostically important. However, at the present time, a consensus definition of “minimally invasive” BAC with a favorable prognosis was not recommended by the panel, so the 1999/2004 WHO criteria for BAC remain unchanged. In small biopsy specimens or cytology specimens, recognition of a BAC component is possible. However, it is not possible to exclude an invasive component. The diagnosis of BAC requires thorough histologic sampling of the tumor. Conclusion: Advances in understanding of the pathology and CT features of BAC and adenocarcinoma have led to important changes in diagnostic criteria and classification of BAC and adenocarcinoma. These criteria need to be uniformly applied by pathologists, radiologists, clinicians, and researchers. The 2004 WHO classification of adenocarcinoma is readily applicable to research studies, but attention needs to be placed on the relative proportion of the adenocarcinoma subtypes. Other recently recognized prognostic features such as size of scar, size of invasive component, or pattern of invasion also seem to be important. More work is needed to determine the most important prognostic pathologic features in lung adenocarcinoma.