M. Di Bartolomeo

PI3KCA/PTEN deregulation contributes to impaired responses to cetuximab in metastatic colorectal cancer patients

BACKGROUND It has been reported that KRAS mutations (and to a lesser extent KRAS mutations with the BRAF V600E mutation) negatively affect response to anti-epidermal growth factor receptor (EGFR) mAbs in metastatic colorectal cancer (mCRC) patients, while the biological impact of the EGFR pathway represented by PI3K/PTEN/AKT on anti-EGFR treatment is still not clear. PATIENTS AND METHODS We analysed formalin-fixed samples from a cohort of 32 mCRC patients treated with cetuximab by means of EGFR immunohistochemistry, EGFR and PTEN FISH analysis, and KRAS, BRAF, PI3KCA, and PTEN genomic sequencing. RESULTS Ten (31%) of 32 patients showed a partial response to cetuximab and 22 (69%) did not [nonresponder (NR)]. EGFR immunophenotype and FISH-based gene status did not predict an anti-EGFR mAb response, whereas KRAS mutations (24%) and PI3K pathway activation, by means of PI3KCA mutations (13%) or PTEN mutation (10%)/loss (13%), were significantly restricted to, respectively, 41% and 37% of NRs. CONCLUSION These findings suggested that KRAS mutations and PI3KCA/PTEN deregulation significantly correlate with resistance to cetuximab. In line with this, patients carrying KRAS mutations or with activated PI3K profiles can benefit from targeted treatments only by switching off molecules belonging to the downstream signalling of activated EGFR, such as mammalian target of rapamycin.

BRAF codons 594 and 596 mutations identify a new molecular subtype of metastatic colorectal cancer at favorable prognosis

BACKGROUND While the negative prognostic role of BRAF V600E mutation in metastatic colorectal cancer (mCRC) is well established, the impact of BRAF codons 594 and 596 mutations, occurring in <1% of CRCs, is completely unknown. The present work aims to describe clinical, pathological and molecular features and prognosis of BRAF codons 594 and 596 mutant mCRCs, compared with BRAF V600E mutant and wild-type ones. PATIENTS AND METHODS Patients treated for mCRC at three Italian Institutions between October 2006 and October 2014, with available KRAS and NRAS codon 12, 13, 59, 61, 117 and 146 and BRAF codon 594, 596 and 600 mutational status, as detected by means of direct sequencing or matrix assisted laser desorption ionization time-of-flight MassArray, were included. RESULTS Ten patients bearing BRAF codons 594 or 596 mutated tumors were identified and compared with 77 and 542 patients bearing BRAF V600E mutated and BRAF wild-type tumors, respectively. While BRAF V600E mutated tumors were more frequently right-sided, mucinous and with peritoneal spread, BRAF 594 or 596 mutated were more frequently rectal, nonmucinous and with no peritoneal spread. All BRAF 594 or 596 mutated tumors were microsatellite stable. Patients with BRAF codons 594 or 596 mutated tumors had markedly longer overall survival (OS) when compared with BRAF V600E mutated [median OS: 62.0 versus 12.6 months; hazard ratio: 0.36 (95% confidence interval 0.20-0.64), P = 0.002], both at univariate and multivariate analyses. CONCLUSIONS BRAF codon 594 or 596 mutated mCRCs are different from BRAF V600E ones in terms of molecular features, pathological characteristics and clinical outcome. This is consistent with preclinical evidences of a kinase inactivating effect of these mutations. The role of CRAF in transducing the intracellular signal downstream BRAF 594 or 596 mutated proteins opens the way to further preclinical investigation.

Activity of temozolomide in patients with advanced chemorefractory colorectal cancer and MGMT promoter methylation

BACKGROUND No evidence-based treatment options are available for patients with advanced colorectal cancer (CRC) progressing after standard therapies. MGMT is involved in repair of DNA damage and MGMT promoter methylation may predict benefit from alkylating agents such as temozolomide. The aim of our study was to evaluate the activity of temozolomide in terms of response rate in patients with metastatic CRC and MGMT methylation, after failure of approved treatments. PATIENTS AND METHODS Patients were enrolled in a monocentre, open-label, phase II study and treated with temozolomide at a dose of 150 mg/m2/day for 5 consecutive days in 4-weekly cycles. The treatment was continued for at least six cycles or until progressive disease. RESULTS Thirty-two patients were enrolled from August 2012 to July 2013. Treatment was well tolerated with one grade 4 thrombocytopenia and no other grade≥3 toxicities. No complete response occurred. The objective response rate was 12%, reaching the pre-specified level for promising activity. Median progression-free survival and overall survival were 1.8 and 8.4 months, respectively. Patients with KRAS, BRAF and NRAS wild-type CRC showed significantly higher response when compared with those with any RAS or BRAF mutation (44% versus 0%; P=0.004). TP53 status had no influence on the primary end point. CONCLUSIONS Temozolomide is tolerable and active in heavily pre-treated patients with advanced CRC and MGMT promoter methylation. Further studies in biomolecularly enriched populations or in a randomized setting are necessary to demonstrate the efficacy of temozolomide after failure of standard treatments.

Mitoxantrone in Patients Affected by Hepatocellular Carcinoma with Unfavorable Prognostic Factors

Patients affected by hepatocellular carcinoma (HCC) with unfavorable prognostic factors have limited therapeutic options due to moderate responsiveness to chemotherapeutic agents and lack of compliance with such treatments. In this study the feasibility and efficacy were evaluated of a treatment with mitoxantrone(dihydroxyanthracenedione, DHAD), 12 mg/m2 i.v. on day 1 every 3 weeks. We included 18 patients with poor-risk HCC ineligible for our other trials in relation to their performance status [8], pretreatments [6], age over 70 years [5], severe concomitant illness [6], and altered blood count [platelets less than 100,000/mm3) [8]. Of 17 evaluable cases, there were 4 partial remissions (23%) (95% confidence interval, 10-47%), 6 no changes, and 7 progressions. There were no drug-related deaths, and side effects were moderate and documented only in a few cases. Median survival of evaluable patients was 5 months (range, 1-15). The results were comparable with those obtained with adriamycin but without important toxicity. We conclude that DHAD seems to be safe and moderately active in poor-risk HCC.

Medical treatment of neuroendocrine tumors

Background Tumors of the neuroendocrine system are characterized by amine precursor uptake and decarboxylation, and they represent a heterogeneous group of carcinomas including carcinoids, islet cell carcinomas of the pancreas, medullary thyroid carcinomas and Merkel cell carcinomas. Their similar cytochemical and ultrastructural properties sustain the hypothesis of a common embryologic origin within the neural crest. Many of these tumors grow slowly, and reducing tumor burden represents the treatment of choice. However, when surgery is not feasible, medical treatment has to be considered. Therapeutic approaches in metastatic disease often do not consider the different biologic behaviors of these neoplasms. Moreover, efficacy of the treatment is associated with lack of a clear definition of the type of response: objective, symptomatic or biochemical. Methods In this review we have analyzed the different medical approaches used in the treatment of neuroendocrine tumors in an attempt to define their precise role in the different neoplasms. Results In carcinoid tumors, immunotherapy and the somatostatin analogue can be efficaciously used for the control of carcinoid syndrome. For inhibition of tumor growth, chemotherapy should be used only in patients with rapidly progressive disease, and the results are still unsatisfactory. Conclusions Although all these tumors appear to have similar cytochemical properties, the responsiveness of the various neoplasms is very different. In the future, a specific treatment modality and a clear definition of the type of response (objective, symptomatic or biochemical) need to be defined for each type of neuroendocrine tumor.

HER2 loss in HER2-positive gastric or gastroesophageal cancer after trastuzumab therapy : Implication for further clinical research

Mechanisms of acquired resistance to trastuzumab‐based treatment in gastric cancer are largely unknown. In this study, we analyzed 22 pairs of tumor samples taken at baseline and post‐progression in patients receiving chemotherapy and trastuzumab for advanced HER2‐positive [immunohistochemistry (IHC) 3+ or 2+ with in‐situ hybridization (ISH) amplification] gastric or gastroesophageal cancers. Strict clinical criteria for defining acquired trastuzumab resistance were adopted. Loss of HER2 positivity and loss of HER2 over‐expression were defined as post‐trastuzumab IHC score <3+ and absence of ISH amplification, and IHC “downscoring” from 2+/3+ to 0/1+, respectively. HER2 IHC was always performed, while ISH was missing in 3 post‐progression samples. Patients with initial HER2 IHC score 3+ and 2+ were 14 (64%) and 8 (36%), respectively. Loss of HER2 positivity and HER2 over‐expression was observed in 32 and 32% samples, respectively. The chance of HER2 loss was not associated with any of the baseline clinicopathological variables. The only exception was in patients with initial IHC score 2+ versus 3+, for both endpoints of HER2 positivity (80 vs. 14%; p = 0.008) and HER2 over‐expression (63 vs. 14%; p = 0.025). As already shown in breast cancer, loss of HER2 may be observed also in gastric cancers patients treated with trastuzumab‐based chemotherapy in the clinical practice. This phenomenon may be one of the biological reasons explaining the failure of anti‐HER2 second‐line strategies in initially HER2‐positive disease.

Doxifluridine in colorectal cancer patients resistant to 5-fluorouracil (5-FU) containing regimens☆

Doxifluridine (5-dFUR) is a fluoropyrimidine derivative, which is preferentially converted to 5-fluorouracil (5-FU) within tumour tissues. Although the activity of 5-FU in metastatic colorectal cancer is well recognised, resistance to this agent is frequently observed and remains its major limitation. The aim of this phase II study was to evaluate the activity of oral and i.v. 5-dFUR in metastatic or locally advanced colorectal cancer patients, who had been previously treated with a 5-FU containing regimen in either an adjuvant or metastatic setting. We treated 48 patients who, on the basis of tumour progression during, or within 8 weeks of the discontinuation of 5-FU therapy, were considered 5-FU resistant, 14 of the patients received 5-dFUR 3000 mg/m2 as a 1-h i.v. infusion, combined with L-leucovorin 25 mg/dose on days 1-5, every 3 weeks; the remaining 34 received oral 5-dFUR 1200 mg/m2 for 5 days followed by 5 days off. Oral L-leucovorin 25 mg/dose was administered 2 h before 5-dFUR. On the basis of WHO criteria, 4/14 (29%, 95% CI 4-51) partial responses were noted in the i.v. treated patients, and 4/34 (12%, 95% CI 1-23) in those treated orally. The radiological examinations documenting the response were a CT scan in 4 cases, ultrasound in 2 and NMR in 2. The median response duration was 6 months (range 3-11+), whereas the median time to treatment failure was 4 months (range 2-17). The responses were achieved in cases previously treated with a median of 9250 mg/m2 (range 5500-18,650) of 5-FU. No CTC-NC1 grade 4 toxicity was observed, although grade 3 diarrhoea occurred in 5 of the orally treated and in 3 of the intravenously treated patients. This is the first report documenting the efficacy of 5-dFUR in patients resistant to 5-FU therapy, and suggests that there is an absence of complete cross-resistance between these two fluoropyrimidines.

Etoposide, doxorubicin and cisplatin (EAP) treatment in advanced gastric carcinoma: a multicentre study of the Italian Trials in Medical Oncology (I.T.M.O.) Group

Various reports have documented the efficacy of the combination of etoposide, doxorubicin and cisplatin (EAP) in the treatment of advanced gastric cancer, although other studies have not confirmed such results. This multicentre phase II study was designed to try to define the efficacy and tolerability of the original EAP regimen. From January 1990 to May 1992, 96 patients with locally advanced or metastatic gastric cancer were treated every 3 weeks with etoposide (120 mg/m2) on days 4, 5 and 6, doxorubicin (20 mg/m2) on days 1 and 7, and cisplatin (40 mg/m2) on days 2 and 8. All of the patients had measurable lesions, and were to receive a maximum of six cycles. A total of 416 courses was given (median four/patient), 27% with a delay of > or = 2 weeks. Objective responses were achieved in 34 of the 91 evaluable patients (37%: confidence interval 27-47%), with complete response (CR) in 11 (12%) and partial response (PR) in 23 (25%). The median duration of response was 6 months (range 1-19), and the median survival of the 96 eligible patients was 9 months. Side-effects (WHO grade 3-4) were leucopenia (30%), thrombocytopenia (9%) and mucositis (10%). We conclude that the EAP regimen is active in inducing major objective responses (12% of CR), and that treatment is feasible in patients with good performance status.

Feasibility of intraportal chemotherapy with fluorouracil and folinic acid immediately after hepatic resection for colorectal metastases.

Background About 50% of recurrence after resection of hepatic metastases from colorectal cancer remain confined to the liver. Adjuvant locoregional treatments could reduce the failure rate, but these treatments have been scantily investigated. Experimental models have shown that both intra-arterial chemotherapy (IAC) and intraportal chemotherapy (IPC) in adjuvant setting were able to reduce metastatic growth, but IPC should be initiated in the immediate postoperative period. Aims To evaluate the feasibility of immediate postoperative IPC of fluorouracil (5-FU) plus folinic acid (FA) in a consecutive series of patients undergoing hepatic resection for metastatic colorectal cancer. Methods Forty-three consecutive patients underwent hepatic resection. The first 25 (Control Group = CG) received only surgery; the latter 18 (Treated Group = TG) were candidate to postoperative IPC of 5-FU 750 mg/m2 plus FA 20 mg/m2/day continuous infusion for 8 days. One patient was not treated owing to bleeding, thus only 17 received the treatment. Results Postoperative morbidity was 14%, equally distributed in both groups. Biochemical hepatic parameters of TG were not statistically different from those of CG. Five patients (29%) developed systemic toxicity: one hematologic grade 4; 3 mucositis grade 3 and one allergic erythema. Three of these patients had been treated by systemic chemotherapy less than one year before. Discussion IPC of 5-FU plus FA in the immediate postoperative period has not yet been tested. The schedule we have investigated neither affected the postoperative outcome, nor influenced hepatic function and regeneration. Systemic toxicity was evident and severe mainly in patients already pretreated by systemic chemotherapy. In these patients, however, toxicity did not affect further outcome. This study confirms the feasibility of immediate intraportal chemotherapy after hepatic resection.

528PAFLIBERCEPT + FOLFIRI FOR TREATMENT OF METASTATIC COLORECTAL CANCER AFTER OXALIPLATIN FAILURE: 4TH INTERIM SAFETY DATA FROM THE GLOBAL AFLIBERCEPT SAFETY AND QUALITY-OF-LIFE PROGRAM (ASQOP/AFEQT STUDIES)

ABSTRACT Aim: In VELOUR, aflibercept (ziv-aflibercept in the US) + FOLFIRI demonstrated a statistically significant improvement in overall survival vs placebo + FOLFIRI in metastatic colorectal cancer (mCRC) patients (pts) previously treated with an oxaliplatin-containing regimen. Results supported initiation of the global Aflibercept Safety and Quality-of-Life (QoL) Program composed of 2 clinical studies (ASQoP; AFEQT) to capture utility values from QoL instruments and collect safety data from a population similar to that in VELOUR in a real-life setting. We report safety data from the 4th interim analysis of these ongoing studies. Methods: ASQoP and AFEQT are single-arm, open-label trials in mCRC pts previously treated with an oxaliplatin-containing regimen. Eligible pts received aflibercept 4 mg/kg every 2 weeks on day 1 of each cycle followed by FOLFIRI. FOLFIRI starting dose and subsequent additional dose modifications are at discretion of the treating physician. Results: At data cut-off for this interim analysis, the safety population (n = 688) was compared with VELOUR. In 44% of ASQoP vs 33.5% of VELOUR, pts were ≥65 years; 10.8% of ASQoP vs 5.4% of VELOUR were ≥75 years. ASQoP pts received a median of 6 treatment cycles while VELOUR pts received a median of 9. Grade (G) 3/4 adverse events (AEs) were experienced by 72.2% of ASQoP pts vs 83.5% in VELOUR. Most were G3. G4 hypertension or diarrhea was not reported. Table shows selected G3/4 AEs. ASQoP/AFEQT VELOUR Adverse Events, % Aflibercept + FOLFIRI (n = 688) Aflibercept + FOLFIRI (n = 611) Grade 3/4 (%) Grade 3/4 (%) Proteinuria 3.6 7.9 Stomatitis and ulceration (high level term) 9.6 13.8 Diarrhea (preferred term) 14.1 19.3 Infections and infestations (system organ class) 9.6 12.3 Hypertension 23.0 19.3 Arterial thromboembolic event 0.6 1.8 Venous thromboembolic event 4.4 7.9 Fistula (gastrointestinal [GI] origin) 0.6 0.3 GI perforation 1.3 0.5 Conclusions: Interim safety analysis from ASQoP/AFEQT has identified no new safety signals. Despite a greater % of elderly pts in ASQoP/AFEQT, reported incidence of toxicity is generally similar or less than VELOUR. Differences in AE incidence in ASQoP/AFEQT vs VELOUR may be related to the VELOUR protocol requirement of full-dose FOLFIRI initiation and current overall exposure differences. Disclosure: J. Taieb: has conflicts of interest related to advisory boards for Sanofi and for corporate-sponsored research for Sanofi; Y. Moore: formerly held a leadership position at Sanofi at the time this study was conducted and has stock ownership in Sanofi; C. Zilocchi: is an employee of Sanofi and has stock ownership; S. Brette: is an employee (biostatistician) of Lincoln, which is a consultant for Sanofi. A. Sobrero: has received honoraria for participating in advisory boards for Bayer, Roche, Sanofi, Celgene, Merck, and Amgen. All other authors have declared no conflicts of interest.