Armando Orlandi

Is there a role for IGF1R and c-MET pathways in resistance to cetuximab in metastatic colorectal cancer?

BACKGROUND The KRAS mutation is not responsible for all cases of resistance to anti-epidermal growth factor receptors (EGFRs) in metastatic colorectal cancer (mCRC), and new predictive and prognostic factors are actively being sought. PATIENTS AND METHODS We retrospectively evaluated the efficacy of a cetuximab-containing treatment in 73 patients with mCRC according to KRAS and BRAF mutational status as well as PTEN, c-MET, and insulin-like growth factor receptor (IGF1R) expression. RESULTS Overall response rate (ORR), median progression-free survival (mPFS), and median overall survival (mOS) were significantly lower in patients with KRAS mutation than in patients with KRAS wild-type; among the population with KRAS wild-type, only 2 patients with BRAF mutations were found and neither of them achieved a response. No significant association was found between PTEN and clinical outcome. Compared with low/normal expression, c-MET overexpression significantly correlated with shorter mPFS and mOS: 3 vs. 5 months (P = .018) and 11 vs. 10 months (P = .037), respectively. In patients with high IGF1R expression, mOS was significantly longer than in those with low/normal expression (14 vs. 8 months; P = .015). CONCLUSION KRAS mutation significantly correlates with a worse outcome in patients treated with cetuximab, whereas no definitive inference can be drawn about the role of BRAF mutation and PTEN loss of expression. Instead, c-MET overexpression might represent a negative prognostic factor in mCRC and may have a role in resistance to anti-EGFR therapy. Interestingly, IGF1R overexpression seems a favorable prognostic factor in mCRC.

Inactivation of DNA repair triggers neoantigen generation and impairs tumour growth

Molecular alterations in genes involved in DNA mismatch repair (MMR) promote cancer initiation and foster tumour progression. Cancers deficient in MMR frequently show favourable prognosis and indolent progression. The functional basis of the clinical outcome of patients with tumours that are deficient in MMR is not clear. Here we genetically inactivate MutL homologue 1 (MLH1) in colorectal, breast and pancreatic mouse cancer cells. The growth of MMR-deficient cells was comparable to their proficient counterparts in vitro and on transplantation in immunocompromised mice. By contrast, MMR-deficient cancer cells grew poorly when transplanted in syngeneic mice. The inactivation of MMR increased the mutational burden and led to dynamic mutational profiles, which resulted in the persistent renewal of neoantigens in vitro and in vivo, whereas MMR-proficient cells exhibited stable mutational load and neoantigen profiles over time. Immune surveillance improved when cancer cells, in which MLH1 had been inactivated, accumulated neoantigens for several generations. When restricted to a clonal population, the dynamic generation of neoantigens driven by MMR further increased immune surveillance. Inactivation of MMR, driven by acquired resistance to the clinical agent temozolomide, increased mutational load, promoted continuous renewal of neoantigens in human colorectal cancers and triggered immune surveillance in mouse models. These results suggest that targeting DNA repair processes can increase the burden of neoantigens in tumour cells; this has the potential to be exploited in therapeutic approaches.

Bevacizumab-based neoadjuvant chemotherapy for colorectal cancer liver metastases: Pitfalls and helpful tricks in a review for clinicians

Bevacizumab added to chemotherapy has shown encouraging efficacy in the neoadjuvant therapy of colorectal cancer liver metastases. In absence of biological predictor factors of efficacy to bevacizumab-based treatment, the assessment of response may be a crucial point to select patients who may benefit the most from surgery. At the same time the pathological response after liver resection could represent a guide for the next therapeutic plan. In the pre-surgical phase, conventional computed tomography and response evaluation with RECIST criteria may underestimate the response to anti-angiogenic drugs. Modified computed tomography criteria of response, morphologic changes as well as novel imaging techniques and metabolic assessment by fluorodeoxyglucose positron emission tomography seem to be promising methods for the assessment of response and for leading the clinical choices. Pathological response at the time of surgery is an important prognostic factor and a surrogate of survival for resected patients. Different classification criteria to assess pathological response have been developed, residual viable tumor, tumor regression grade (TRG), modified TRG and tumor thickness at the tumor-normal interface, but to date a superiority of one approach over the others has not been clearly established. In this review, we evaluate the available data with the aim to help the clinicians in the pre- and post-surgical care of patient with colorectal cancer liver metastases treated with bevacizumab-based neoadjuvant strategy.

Targeted Therapy in Advanced Gastric Carcinoma:the Future is Beginning

Gastric cancer represents one of the most common cancer worldwide. Unfortunately, the majority of patients present in advanced stage and outcome still remains poor with high mortality rate despite decreasing incidence and new diagnostic and therapeutic strategies. Although utility of classical chemotherapy agents has been widely explored, advances have been slow and the efficacy of these agents has reached a plateau of median overall survival not higher than 12 months. Therefore, researchers focused their attention on better understanding molecular biology of carcinogenesis and deeper knowledge of the cancer cell phenotype, as well on development of rationally designed drugs that would target specific molecular aberrancies in signal transduction pathways. These targets include cell surface receptors, circulating growth and angiogenic factors and other molecules involved in downstream intracellular signaling pathways, including receptor tyrosine kinases. However, therapeutic advances in gastric cancer are not so encouraging when compared to other solid organ malignancies such as breast and colorectal cancer. This article reviews the role of targeted agents in gastric cancer as single-agent therapy or in combination regimens, including their rational and emerging mechanism of action, current and emerging data. We focused our attention mainly on published phase III studies, therefore cornerstone clinical trials with trastuzumab and bevacizumab have been largely discussed. Phase III studies presented in important international meetings are also reviewed as well phase II published studies and promising new therapies investigated in preclinical or phase I studies. Today, in first-line treatment only trastuzumab has shown significantly increased survival in combination with chemotherapy, whereas ramucirumab as single agent resulted effective in progressing patients, but - despite several disappointing results - these are the proof of principle that targeting the proper molecular aberration is the best way for implementing outcome of therapy.

A phase 2 study of temozolomide in pretreated metastatic colorectal cancer with MGMT promoter methylation

Background:Presently, few options are available for refractory colorectal cancer (CRC). O6-methyl-guanine-DNA-methyltransferase (MGMT) promoter methylation is a frequent and early event in CRC tumourigenesis. This epigenetic silencing is a predictor of response to the alkylating drug temozolomide in glioblastoma. Preclinical evidences and some case reports showed temozolomide activity in CRC with MGMT silencing, but the available data from clinical trials are inconsistent.Methods:This was a multicentre, phase 2 trial, planned according to a two-stage Simon’s optimal design to investigate activity and safety of temozolomide in refractory CRC harbouring MGMT promoter methylation. The primary end point was overall response rate (ORR). Patients who failed two or more prior treatments received temozolomide at a dose of 150–200 mg m−2 per day on days 1–5 every 28 days.Results:From July 2012 to June 2016, 225 patients were screened, 80 showed MGMT promoter methylation and 41 were enrolled. Overall response rate was 10% and disease control rate was 32%. Median progression-free survival and overall survival were 1.9 and 5.1 months, respectively.Conclusions:Temozolomide showed a modest activity in this heavily pretreated population and the study did not meet its primary end point. The role of temozolomide in CRC remains still controversial and further research is warranted.

BRAF in metastatic colorectal cancer: the future starts now

BRAF mutations are detectable in about 5-15% of metastatic colorectal cancer (mCRC) patients and represent a clear negative prognostic factor. While in BRAF-mutated (BRAFmt) metastatic melanoma TKI target therapies (BRAF and MEK inhibitor), both alone or in combination, have shown significant efficacy, in BRAFmt CRC single-agent BRAF-inhibitors as well as chemotherapy seem to be ineffective. The critical role of EGFR in CRC and its multiple downstreaming pathways seem to be involved in this lack of response. In recent years, preclinical investigations and retrospective studies slowly increased our knowledge on BRAFmt CRC. This review analyses preclinical data and discusses several clinical trials in order to explore new therapeutic strategies targeting BRAFmt mCRC.

ERCC1 Induction after Oxaliplatin Exposure May Depend on KRAS Mutational Status in Colorectal Cancer Cell Line: In Vitro Veritas

Introduction: Oxaliplatin (Oxa) is widely used in metastatic colorectal cancer (mCRC), but currently there are not valid predictors of response to this drug. In the control arms both of OPUS and PRIME studies Oxa seems more active in patients with mCRC with mutated (mt) KRAS than in those with wild type (wt) KRAS. Recently we have retrospectively confirmed this suggestion, therefore we have hypothesized that the mutational status of KRAS could influence the expression of ERCC1, one of the main mechanisms of Oxa resistance. Material and Methods: We used four cell lines of colorectal cancer: two KRAS wild type (wt) (HCT-8 and HT-29) and two KRAS mt (SW620 and SW480). We evaluated the sensitivity of these cell lines to Oxa by MTT-test as well the ERCC1 levels before and after 24 h exposure to Oxa by Real-Time PCR. We silenced KRAS in a KRAS mt cell line (SW620LV) to evaluate the impact on Oxa sensitivity and ERCC1 levels. Lastly, ERCC1 was also silenced in order to confirm the importance of this protein as an Oxa resistance factor. Results: The KRAS mt cell lines resulted more sensitive to Oxa (OR 2.68; IC 95% 1.511-4.757 p<0.001). The basal levels of ERCC1 did not show significant differences between KRAS mt and wt cell lines, however, after 24 h exposure to Oxa, only the wt KRAS lines showed the ability to induce ERCC1, with a statistically significant difference (OR 42.9 IC 95% 17.260-106.972 p<0.0005). By silencing KRAS, sensitivity to Oxa was reduced in mt KRAS cell lines and this effect was associated with the acquisition of ability to induce ERCC1. Silencing of ERCC1, in turn, enhanced the sensitivity to Oxa in wt KRAS cell lines and restored sensitivity to Oxa in SW620LV cell line. Conclusion: KRAS mutated cell lines were more sensitive to Oxa. This feature seems secondary to the inability of these cells to induce ERCC1 after exposure to Oxa. Thus, KRAS mutational status might be a predictor of response to Oxa in CRC surrogating the cell ability to induce ERCC1.

Conversion Chemotherapy for Technically Unresectable Colorectal Liver Metastases: A Retrospective, STROBE-Compliant, Single-Center Study Comparing Chemotherapy Alone and Combination Chemotherapy With Cetuximab or Bevacizumab

Abstract The response rate of patients with unresectable liver-limited metastases of colorectal cancer can be improved by converting inoperable disease to operable disease. However, the benefits of conversion chemotherapy for survival are still controversial. Patients considered to have technically inoperable disease by a multidisciplinary team were retrospectively analyzed. Patients were stratified based on the treatment they received, into the chemotherapy only (G1), chemotherapy plus bevacizumab (G2), or chemotherapy plus cetuximab (G3) groups. The primary endpoint was the resection rate. The secondary endpoint was the overall survival (OS), according to both the treatment received and liver surgery status. In total, 104 patients were included: 30 in the G1, 39 in the G2, and 35 in the G3 groups. All G3 patients had the wild-type KRAS exon 2. The surgical resection rates for patients in the G1, G2, and G3 groups were 43.3% (13/30), 30.7% (12/39), and 51.4% (18/35), respectively. Disease-free survival did not show significant differences among the 3 groups. The median OS was 35.2 months in the G1, 28.8 months in the G2, and 42.1 months in the G3 (P = 0.25) groups. The OS was significantly higher in patients who underwent surgical resection than those who did not. The median OS was 28.4 months in patients who did not undergo resection, whereas it had not been reached after a median follow-up period of 37.5 months for patients who underwent surgical resection (events: 21/43). Our data confirmed that the conversion of initially inoperable disease to operable disease conferred a survival benefit, even in patients who relapsed after surgery. The addition of cetuximab to chemotherapy improved the objective response and resection rates, conferring a potential survival benefit even in patients whose diseases were not converted to operable disease, compared to chemotherapy alone or in combination with bevacizumab.

IL-8 and eNOS polymorphisms predict bevacizumab-based first line treatment outcomes in RAS mutant metastatic colorectal cancer patients

Background Predictive biomarkers of efficacy and toxicity of bevacizumab have not yet been validated. This study assessed the influence of IL-8, eNOS and VEGF-A polymorphisms in RAS mutated metastatic colorectal cancer patients receiving bevacizumab-based chemotherapy. Methods 120 patients treated with first-line combination FOLFOX6 plus bevacizumab were included. A historical cohort of 112 RAS mutated colorectal cancer patients treated with FOLFOX6 alone served as control group. The following SNPs were analyzed: IL-8 c.-251T>A; eNOS c.-786T>C and c.-894G>T; VEGF-A c.936C>T, c.958T>C, c.1154A>G and c.2578C>A. Correlation of SNPs, baseline IL-8 serum levels and bevacizumab-efficacy was done. Results In the bevacizumab group, carriers of the IL-8 alleles c.-251TA+AA showed a shorter PFS (P=0.002) and OS (P=0.03) compared to TT alleles. Patients with pre-treatment IL-8 < 18.25 pg/ml showed significantly longer median PFS and OS (PFS: 10.9 vs 7.6 months, P=0.005; OS: 30.7 vs 18.2 months, P<0.001) compared to patients with IL-8 higher levels (>18,25 pg/ml). IL-8 c.-251TA+AA carriers had significantly higher IL-8 levels (P<0.0001). Multivariate analysis confirmed association of IL-8 polymorphism with PFS, and of IL-8 baseline levels with both PFS and OS. IL-8 SNP did not affect the outcome in the control group. The eNOS polymorphism c.-894G>T was found associated with higher severe toxicity (P=0.0002) in patients carrying the c.-894TT genotype. Conclusions Although our data need prospective validation, IL-8 and eNOS SNPs may be have a role as predictive biomarkers for bevacizumab efficacy and toxicity.

AMAROS Study: Overall Survival in Breast Cancer Subtypes

At a median follow-up of 17 months (range 9e38 months), one patient with liver metastases at presentation had a distant relapse and died without progression within the nasopharynx; 13 patients remain alive with no local regional recurrence, one of whom has developed progression of bone metastases. The 2 year local control and overall survival is 100 and 86%. No patients were feeding tube dependent at 1 year. Although these results are encouraging, they again illustrate the difficulty in drawing conclusions about this group of patients within the UK, as although the radiotherapy protocol and technique in this series were constant, the small numbers of NPC cases presenting in the UK are pathologically heterogeneous. Uncertainty persists as to the optimal timing of chemotherapy in addition to the synchronous component either neoadjuvant or adjuvant. Although adjuvant chemotherapy may remain the international standard, neoadjuvant chemotherapy remains attractive due to early exposure to systemic drugs in a disease with a high rate of distant metastases. Appropriate radiotherapy dose fractionation also remains controversial, with a recent randomised trial suggesting that more toxicity may be seen with accelerated fractionation [2]. Given such controversy, pathological diversity and a small cohort of patients in the UK, we would echo Roques [3] in their call for collaboration at the very least in the contouring of these cases. National UK proton centres offer an opportunity to centralise care for infrequent cancers such as NPC. Proton therapy will allow highly conformal radiotherapy with the additional advantage of a reduced integral dose. Clinical advantages include the potential to reduce long-term neurocognitive toxicity [4]. However, proton therapy is associated with increased vulnerability to uncertainty, including relative biological effectiveness, set-up variation and anatomy change, which can compromise the ability to maintain accurate dosimetry throughout. Strategies are currently under evaluation to tackle such risks and will be necessary to maintain high local control rates while the reduction in morbidity is explored [5].