Abstract: BACKGROUND: Following the discovery that mutant KRAS is associated with resistance to anti-epidermal growth factor receptor (EGFR) antibodies, the tumours of patients with metastatic colorectal cancer are now profiled for seven KRAS mutations before receiving cetuximab or panitumumab. However, most patients with KRAS wild-type tumours still do not respond. We studied the effect of other downstream mutations on the efficacy of cetuximab in, to our knowledge, the largest cohort to date of patients with chemotherapy-refractory metastatic colorectal cancer treated with cetuximab plus chemotherapy in the pre-KRAS selection era. METHODS: 1022 tumour DNA samples (73 from fresh-frozen and 949 from formalin-fixed, paraffin-embedded tissue) from patients treated with cetuximab between 2001 and 2008 were gathered from 11 centres in seven European countries. 773 primary tumour samples had sufficient quality DNA and were included in mutation frequency analyses; mass spectrometry genotyping of tumour samples for KRAS, BRAF, NRAS, and PIK3CA was done centrally. We analysed objective response, progression-free survival (PFS), and overall survival in molecularly defined subgroups of the 649 chemotherapy-refractory patients treated with cetuximab plus chemotherapy. FINDINGS: 40.0% (299/747) of the tumours harboured a KRAS mutation, 14.5% (108/743) harboured a PIK3CA mutation (of which 68.5% [74/108] were located in exon 9 and 20.4% [22/108] in exon 20), 4.7% (36/761) harboured a BRAF mutation, and 2.6% (17/644) harboured an NRAS mutation. KRAS mutants did not derive benefit compared with wild types, with a response rate of 6.7% (17/253) versus 35.8% (126/352; odds ratio [OR] 0.13, 95% CI 0.07-0.22; p<0.0001), a median PFS of 12 weeks versus 24 weeks (hazard ratio [HR] 1.98, 1.66-2.36; p<0.0001), and a median overall survival of 32 weeks versus 50 weeks (1.75, 1.47-2.09; p<0.0001). In KRAS wild types, carriers of BRAF and NRAS mutations had a significantly lower response rate than did BRAF and NRAS wild types, with a response rate of 8.3% (2/24) in carriers of BRAF mutations versus 38.0% in BRAF wild types (124/326; OR 0.15, 95% CI 0.02-0.51; p=0.0012); and 7.7% (1/13) in carriers of NRAS mutations versus 38.1% in NRAS wild types (110/289; OR 0.14, 0.007-0.70; p=0.013). PIK3CA exon 9 mutations had no effect, whereas exon 20 mutations were associated with a worse outcome compared with wild types, with a response rate of 0.0% (0/9) versus 36.8% (121/329; OR 0.00, 0.00-0.89; p=0.029), a median PFS of 11.5 weeks versus 24 weeks (HR 2.52, 1.33-4.78; p=0.013), and a median overall survival of 34 weeks versus 51 weeks (3.29, 1.60-6.74; p=0.0057). Multivariate analysis and conditional inference trees confirmed that, if KRAS is not mutated, assessing BRAF, NRAS, and PIK3CA exon 20 mutations (in that order) gives additional information about outcome. Objective response rates in our series were 24.4% in the unselected population, 36.3% in the KRAS wild-type selected population, and 41.2% in the KRAS, BRAF, NRAS, and PIK3CA exon 20 wild-type population. INTERPRETATION: While confirming the negative effect of KRAS mutations on outcome after cetuximab, we show that BRAF, NRAS, and PIK3CA exon 20 mutations are significantly associated with a low response rate. Objective response rates could be improved by additional genotyping of BRAF, NRAS, and PIK3CA exon 20 mutations in a KRAS wild-type population. FUNDING: Belgian Federation against Cancer (Stichting tegen Kanker).
Abstract: The introduction of KRAS testing as a diagnostic tool to select patients for epidermal growth factor receptor (EGFR)-targeted cetuximab- or panitumumab-based therapies for metastatic colorectal cancer is widely regarded as a key advance in the field of personalized cancer medicine. Oncologists are now facing emerging issues in the treatment of metastatic colorectal cancer, including: (i) the identification of additional genetic determinants of primary resistance to EGFR-targeted therapy for further improving selection of patients; (ii) the explanation of rare cases of patients carrying KRAS-mutated tumors who have been reported to respond to either cetuximab or panitumumab and (iii) the discovery of mechanisms of secondary resistance to anti-EGFR antibody therapies. Here we discuss the potential role of comprehensive dissection of the key oncogenic nodes in the EGFR signaling cascade to predict resistance and sensitivity to EGFR monoclonal antibodies in metastatic colorectal cancer. Current data suggest that, together with KRAS mutations, the evaluation of BRAF and PIK3CA/PTEN alterations could also be useful for selecting patients with reduced chance to benefit from EGFR-targeted therapy. Furthermore, measuring EGFR gene copy number also appears relevant to positively identify responders. Up until now, each of these markers has been mainly assessed as a single event, often in retrospective analyses and patients' series. As these molecular alterations display overlapping patterns of occurrence, this adds considerable complexity to the drawing of an algorithm suitable for clinical decision-making. We suggest that in the near future comprehensive molecular analysis of the entire oncogenic pathway triggered by the EGFR should be performed, thus enhancing the prediction ability of individual markers.
Abstract: Clinical studies showed that only 10% of patients
with metastatic colorectal cancer (mCRC) respond to
treatment with the anti-epidermal growth factor receptor
(EGFR) monoclonal antibodies panitumumab or cetuximab,
regardless of the line of treatment. The current tool used to
select patients, i.e. immunohistochemistry (IHC) evaluation
of EGFR expression by EGFR pharmDxâ„¢ Kit, is not
reliable in predicting response. Retrospective analyses of
factors such as increased EGFR gene copy number and
KRAS and/or BRAF mutations showed that such molecular
changes could affect clinical benefit from anti-EGFR
monoclonal antibodies. We report here the case of a 66-
year-old man with chemorefractory mCRC, considered not
eligible to salvage treatment with the anti-EGFR monoclonal
antibody cetuximab and irinotecan because the primary
adenocarcinoma of the rectum was found not expressing
EGFR protein by IHC. However, FISH analysis of EGFR
gene copy number and evaluation of KRAS and/or BRAF
specific mutations by gene sequencing showed characteristics
associated with favourable clinical outcome to anti-
EGFR therapy. Based on the EGFR protein expression by
IHC in a liver metastasis, the patient was then treated with
cetuximab plus irinotecan, obtaining symptoms improvement
and a dramatic objective tumor response in all sites of
disease, lasting 4.2 months. We also discuss literature
findings about the role of different biological characteristics
in predicting clinical benefit from anti-EGFR therapy in
patients with mCRC.
Abstract: PURPOSE: Purpose of this study has been the assessment of nuclear factor-kappaB (NF-kappaB) as a survival factor in human mesothelial cells (HMC), transformed HMC and malignant mesothelioma (MMe) cells. We aimed at verifying whether the proteasome inhibitor Bortezomib could abrogate NF-kappaB activity in MMe cells, leading to tumor cell death and may be established as a novel treatment for this aggressive neoplasm. EXPERIMENTAL DESIGN: In HMC and MMe cells, NF-kappaB nuclear translocation and DNA binding were studied by electrophoretic mobility shift assay, following treatment with tumor necrosis factor-alpha (TNF-alpha). The IKK inhibitor Bay11-7082 was also tested to evaluate its effects on HMC, transformed HMC, and MMe cell viability upon exposure to asbestos fibers. Following Bortezomib treatment, cytotoxicity of MMe cells was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, whereas apoptosis and cell-cycle blockade were investigated by high-content analysis. Bortezomib was also given to mice bearing i.p. xenografts of MMe cells, and its effects on tumor growth were evaluated. RESULTS: Here, we show that NF-kappaB activity is a constitutive survival factor in transformed HMC, MMe cells, and acts as a survival factor in HMC exposed to asbestos fibers. Bortezomib inhibits NF-kappaB activity in MMe cells and induces cell cycle blockade and apoptosis in vitro as well as tumor growth inhibition in vivo. CONCLUSIONS: Inhibition of NF-kappaB constitutive activation in MMe cells by Bortezomib resulted in in vitro cytotoxicity along with apoptosis and in vivo tumor regression. Our results support the use of Bortezomib in the treatment of MMe and has led to a phase II clinical trial currently enrolling in Europe.
Abstract: PURPOSE: In a previous cohort study, we proposed that responsiveness of metastatic colorectal cancer (mCRC) to anti-epidermal growth factor receptor (EGFR) monoclonal antibodies has a genetic basis, being associated with increased EGFR gene copy number (GCN) as measured by fluorescence in situ hybridization (FISH) in individual tumors. The present study was aimed at assessing the predictive role of EGFR GCN, in terms of clinical outcome, in patients treated with panitumumab. PATIENTS AND METHODS: Patients with mCRC refractory to standard therapies were a subset of patients from a phase III trial of panitumumab plus best supportive care (BSC; n = 58) versus BSC alone (n = 34) who were selected on the basis of availability of tumor samples adequate for FISH. RESULTS: In patients treated with panitumumab, a mean EGFR GCN of less than 2.5/nucleus or less than 40% of tumor cells displaying chromosome 7 polysomy within the tumor predicted for shorter progression-free survival (PFS; P = .039 and P = .029, respectively) and overall survival (P = .015 and P = .014, respectively). None of the treated patients with mean EGFR GCN of less than 2.47/nucleus or less than 43% of tumor cells displaying chromosome 7 polysomy obtained objective response compared with six of 20 and six of 19 patients with values greater than these cutoff limits, respectively (P = .0009 and P = .0007, respectively). Evaluation of BSC-treated patients showed no correlation between EGFR GCN or chromosome 7 polysomy status and PFS. CONCLUSION: In a larger and more homogeneous series than in previous studies, present exploratory data suggest that mCRC patients with tumors distinguishable by FISH analysis of EGFR as homogenously disomic or with low chromosome 7 polysomy have a reduced likelihood of response to panitumumab.
Abstract: During the last 10 years, the concept of targeted biological therapy for the treatment of cancer has emerged. Targeted agents entered clinical practice only recently, and the first drugs with demonstrated clinical efficacy were mainly inhibitors of the ErbB family of receptors (i.e., EGFR and HER-2), either monoclonal antibodies (MAbs) or tyrosine kinase inhibitors (TKIs). After the proof of concept for the clinical efficacy and tolerability of these selective agents, it was conceived that most tumors will depend on more than one signaling pathway for their growth and survival. As a consequence, different strategies were pursued to inhibit multiple signaling pathways or multiple steps in the same pathway, either by the development of multi-targeted agents or the combination of single targeted drugs. The recent FDA and EMEA approval of sorafenib and sunitinib, both multi-targeted TKIs, marked the coming of age of this new generation of drugs. Now a whole new wave of multi-targeted compounds is moving into clinical trials, raising in the minds of investigators important questions about the best strategies to pursue in their use and many doubts about their differences and the seeming redundancies in the pipelines of pharmaceutical companies. This review will deal with the rationale underlying the multi-targeted approach and with the available clinical experience with multi-targeted agents, especially focusing on molecules with anti- EGFR mechanisms of action.
Abstract: Monoclonal antibodies (mAbs) against the extracellular domain of the epidermal growth factor receptor (EGFR) have been introduced for the treatment of metastatic colorectal cancer (mCRC). We have reported recently that increased copy number of the EGFR can predict response to anti-EGFR mAbs and that patients might be selected for treatment based on EGFR copy number. Here, we show that mutations activating the RAS/RAF signaling pathway are also predictive and prognostic indicators in mCRC patients, being inversely correlated with response to anti-EGFR mAbs. In cellular models of CRCs, activation of the RAS signaling pathway by introduction of an activated K-RAS allele (Gly(12)Val) impairs the therapeutic effect of anti-EGFR mAbs. In cancer cells carrying constitutively active RAS, the pharmacologic inhibition of the mitogen-activated protein kinase (MAPK) signaling cascade improves anti-EGFR treatment based on mAbs. These results have implications for the identification of patients who are likely to respond to anti-EGFR treatment. They also provide the rationale for combination therapies, targeted simultaneously to the EGFR and RAS/RAF/MAPK signaling pathways in CRC patients.
Abstract: In the past decade the median overall survival of patients with metastatic colorectal cancer has increased from 12 to more than 20 months, mostly due to the new chemotherapeutic agents, irinotecan and oxaliplatin. Most recently, targeted therapies, that inhibit specific cancer pathways and molecules, have shown promising results in the treatment of patients with metastatic colorectal cancer and other solid tumors. One of the most studied targets for anticancer therapy is the epidermal growth factor receptor (EGFR), which is overexpressed in a variety of malignancies. Cetuximab, an anti-EGFR chimeric monoclonal antibody, has shown clinically meaningful antitumor activity in patients with metastatic colorectal cancer in several clinical trials. Efforts of physicians and researchers are currently directed towards the identification of predictive factors (clinical or molecular) of clinical outcome, with the aim of both optimizing the therapeutic index and dealing with increasing costs of these new compounds.
Abstract: BACKGROUND: The antiepidermal growth factor receptor (antiEGFR) monoclonal antibodies cetuximab and panitumumab have good clinical activity in about 10% of patients with metastatic colorectal cancer that is resistant to chemotherapy. The molecular mechanisms underlying clinical response or resistance to these agents are unknown. METHODS: Tumours from 31 patients with metastatic colorectal cancer who had either an objective response (n=10) or stable disease or progressive disease (n=21) after treatment with cetuximab or panitumumab were screened for genetic changes in EGFR or its immediate intracellular effectors. Specifically, we assessed the EGFR copy number and the mutation profile of the EGFR catalytic domain and of selected exons in KRAS, BRAF, and PIK3CA. RESULTS: Eight of nine of patients with objective responses who were assessable by fluorescence in-situ hybridisation (FISH) had an increased EGFR copy number. By contrast, one of 21 non-responders assessable by FISH had an increased EGFR copy number (p<0.0001 for responders vs non-responders, Fisher's exact test). The mutation status of the EGFR catalytic domain and its immediate downstream effectors PIK3CA, KRAS, and BRAF did not correlate with disease response. In colorectal-cancer cell lines, the concentration of cetuximab that completely inhibited proliferation of cells with amplified EGFR copy number did not affect proliferation of cells with unamplified EGFR. INTERPRETATION: We propose that the response to antiEGFR treatment has a genetic basis and suggest that patients might be selected for treatment on the basis of EGFR copy number.
Abstract: Within a single-institution phase II trial, we investigated the antitumor activity of the Raltitrexed-Oxaliplatin combination as second-line therapy for malignant pleural mesothelioma (MPM). Fourteen patients were enrolled and all were assessable for response. The trial was then closed because chemotherapy, though well tolerated, yielded no objective responses. The best response observed was disease stabilization in 4 patients only (28.57%), while the other 10 patients (71.42%) progressed despite treatment. Median time to progression (TTP) was 8 weeks (average: 9.85, range: 7-20), while median overall survival was just 14 weeks (average: 21.69, range: 9-66+).
Abstract: Using a commercial ELISA assay, we evaluated circulating VEGF and bFGF levels in 203 consecutive patients with solid tumors, and sought a correlation between them and with the grade of anemia. Serum VEGF values were within the normal range in 128 patients (63.05%), with a mean value of 675.04 pg/ml (median, 571.00; range, 0-2796.54). The analysis of VEGF values per tumor group did not provide any statistically significant difference. Regarding bFGF, 143 patients (70.44%) had measurable, and thus abnormal, bFGF values. Overall, mean bFGF serum value was 57.14 pg/ml (median, 8.30; range, 0-4334.71), with the highest bFGF levels found in breast carcinoma patients. As expected, a large number of our patients was fairly anemic, mean hemoglobin level being 11.47 g/dl (median, 11.30; range, 7.1-19.20), the lowest titers being observed in prostate carcinoma patients. No statistically significant correlation was found between serum VEGF and hemoglobin values (r=0.004) but a significant negative correlation was seen between serum bFGF and hemoglobin (r=-0.22, p<0.05). Considering the different tumor groups, a statistically significant negative correlation between bFGF and hemoglobin becomes even more apparent in the subgroup of renal carcinoma patients (r=-0.55, p<0.05). In conclusion, our results demonstrate that there is a statistically significant correlation between systemic hypoxia (evaluated in terms of hemoglobin levels) and circulating bFGF values, but not VEGF; this correlation may lead to therapeutic interventions.
Abstract: BACKGROUND: Currently, there is no standard treatment for patients with advanced renal cell carcinoma (RCC) who do not experience a response to first-line immunotherapy. In the current Phase II study, the authors explored the antitumor activity of a combination of gemcitabine and oxaliplatin (L-OHP) in this setting. METHODS: Forty-two patients with RCC who had progressive disease following immunotherapy received gemcitabine (1000 mg/m2 intravenously on Days 1 and 8 every 21 days) and L-OHP (90 mg/m2 intravenously on Day 1 every 21 days) for a minimum of 2 cycles before responses were evaluated. Responses to treatment and toxicity were recorded according to the Response Evaluation Criteria in Solid Tumors and the National Cancer Institute Common Toxicity Criteria, respectively. RESULTS: No complete responses were recorded; however, 6 patients experienced a partial response (14.28%; 95% confidence interval, 5.43-28.5%), 11 patients (26.19%) had temporary stable disease as a best response, and the remaining 25 patients (59.52%) experienced progression despite receiving treatment. The median time to disease progression was 2.5 months (mean, 3.86 months; range, 1.5-11.0 months), whereas the median overall survival was 9.5 months (mean, 10.46 months; range, 4.0-22.5 months). With regard to toxicity, treatment generally was well tolerated, with only one episode of Grade 4 toxicity and expected episodes of Grade 3 toxicity, including myelosuppression and neuropathy. CONCLUSIONS: The current results suggest that the combination of gemcitabine and L-OHP possesses a certain level of activity and an acceptable toxicity profile in patients with immunotherapy-resistant advanced RCC.
Abstract: The incidence of thyroid function changes among renal cell carcinoma (RCC) patients treated with high-dose IL-2 plus IFN-alpha ranges from 9 to 59%, independently of the administration route (i.v. or s.c.) of IL-2. Although several studies demonstrated a correlation between high-dose IL-2/IFN-alpha regimens and autoimmune thyroid disease, only very limited data are available when low doses of IL-2 plus IFN-alpha are used. We prospectively studied thyroid function in 52 patients with metastatic RCC undergoing immunotherapy with low-dose IL-2 + IFN-alpha. All patients received treatment cycles consisting of both s.c. IL-2 and i.m. IFN-alpha for 4 consecutive weeks; cycles were repeated at 4-month intervals in all patients, irrespectively of their response. Thyroid stimulating hormone (TSH), 3,3',5-triiodo-L-thyronine (T3), thyroxine (T4), human anti-thyroglobulin antibodies (hTg-Ab) and human anti-thyroid peroxidase antibodies (hTPO-Ab) were assayed in all patients before and after each of the first 3 cycles. None of the patients showed clinical signs of dysthyroidism, nor required replacement or suppressive treatment on thyroid function; specifically, no statistically significant differences were found when the median pre- and post-treatment TSH, T3, T4, hTg-Ab and hTPO-Ab levels of each cycle were compared. The median TSH values after the 3 cycles were, respectively, 1.06 [Inter Quartile Range (IQR) 0.58-1.51], 1.21 (IQR 0.58-1.51) and 1.05 micro U/ml (IQR 0.67-1.73). As for thyroid hormones, median values after each of the 3 cycles were: 1.38 (IQR 1.19-1.50), 1.46 (IQR 1.17-1.66) and 1.36 (IQR 1.16-1.46) ng/ml for T3, and 8.74 (IQR 7.26-9.45), 8.67 (IQR 7.12-9.18) and 8.40 (IQR 7.12-9.33) micro g/dl for T4. These data show that a regimen of low-dose IL-2 plus IFN-alpha does not seem to affect thyroid function, neither inducing signs or symptoms of dysthyroidism, nor by causing major biochemical changes in TSH and thyroid hormone levels, or an increase in thyroid-specific auto-antibodies.
Abstract: Due to the frequent use of intrapleural interleukin-2 (IL-2) to treat pleural effusions from malignant mesothelioma (MMe), we measured nitric oxide (NO) end product nitrite (NO(2)(-)) in pleural effusions of 12 MMe patients with chronic or chronic-relapsing pleurisy. Through high performance liquid chromatography analysis, NO(2)(-) was found in the initial pleural fluid sample of all patients (156.25 pmol ml(-1)), and increased significantly following IL-2 intrapleural instillation, both at 24 (589.91 pmol ml(-1), P < or = 0.0005) and 48 h (756 pmol ml(-1), P< or = 0.0005). Even though it is difficult to argue if the large amounts of NO end product NO(2)(-) we observed is produced by IL-2-stimulated and recruited immune cells, by MMe cells themselves, or by both, it is possible that NO could contribute to the complex antitumor activity of IL-2.
Abstract: The role of chemotherapy (CT) for brain metastases (BrM) is still controversial. Limited life expectancy and presence of the blood-brain barrier (BBB) have been considered as contraindications for relatively aggressive therapies, such as CT. Nevertheless, more recent studies emphasise the possibility that in addition to historical nitrosoureas, also platinum derivatives, etoposide, teniposide, gemcitabine, irinotecan, topotecan and temozolomide can pass the BBB as they are active against selected BrM. Interaction of cytotoxic agents with other drugs may represent a problem in the treatment of BrM. By far, the most important factor conditioning the response to cytotoxic agents is the chemosensitivity of different tumours. CT proved to be effective in patients with BrM from lung cancer, mainly small cell lung cancer, breast cancer, choriocarcinoma and germ cell tumours. In these malignancies the responses to CT are similar to those observed in other metastatic sites. This observation, confirmed by many studies, contrasts with the theory, emphasised in the past, of the brain as a sanctuary. In fact BBB may be important in protecting normal brain tissue and micrometastases from CT, but not when BrM are symptomatic and clinically evident. The clue to the treatment of chemosensitive tumours is to assess the most active drugs and combinations. Cisplatin and etoposide was confirmed to be the treatment of choice in many situations (BrM from lung and also from breast cancer). Newer drugs are now on study: topotecan and temozolomide seem to be particularly promising (alone or in association with other drugs) in the treatment of various BrM (also from melanoma) and could represent an alternative to more widely-used drugs or as second-line treatments.
