Chemotherapy toxicity and activity in patients with pancreatic ductal adenocarcinoma and germline BRCA1-2 pathogenic variants (gBRCA1-2pv): a multicenter survey

BACKGROUND

Germline BRCA1-2 pathogenic variants (gBRCA1-2pv)-related pancreatic ductal adenocarcinoma (PDAC) showed increased sensitivity to DNA cross-linking agents. This study aimed at exploring safety profile, dose intensity, and activity of different chemotherapy regimens in this setting.

PATIENTS AND METHODS

gBRCA1-2pv PDAC patients of any age and clinical tumor stage who completed a first course of chemotherapy were eligible. A descriptive analysis of chemotherapy toxicity, dose intensity, response, and survival outcomes was performed.

RESULTS

A total of 85 gBRCA1-2pv PDAC patients treated in 21 Italian centers between December 2008 and March 2021were enrolled. Seventy-four patients were assessable for toxicity and dose intensity, 83 for outcome. Dose intensity was as follows: nab-paclitaxel 72%, gemcitabine 76% (AG); cisplatin 75%, nab-paclitaxel 73%, capecitabine 73%, and gemcitabine 65% (PAXG); fluorouracil 35%, irinotecan 58%, and oxaliplatin 64% (FOLFIRINOX). When compared with the literature, grade 3-4 neutropenia, thrombocytopenia, and diarrhea were increased with PAXG, and unmodified with AG and FOLFIRINOX. RECIST responses were numerically higher with the three- (81%) or four-drug (73%) platinum-containing regimens that outperformed AG (41%) and oxaliplatin-based doublets (56%). Carbohydrate antigen 19.9 (CA19.9) reduction >89% at nadir was reported in two-third of metastatic patients treated with triplets and quadruplets, as opposed to 33% and 45% of patients receiving oxaliplatin-based doublets or AG, respectively. All patients receiving AG experienced disease progression, with a median progression-free survival (mPFS) of 6.4 months, while patients treated with platinum-containing triplets or quadruplets had an mPFS >10.8 months. Albeit still immature, data on overall survival seemed to parallel those on PFS.

CONCLUSIONS

Our data, as opposed to figures expected from the literature, highlighted that platinum-based regimens provoked an increased toxicity on proliferating cells, when dose intensity was maintained, or an as-expected toxicity, when dose intensity was reduced, while no change in toxicity and dose intensity was evident with AG. Furthermore, an apparently improved outcome of platinum-based triplets or quadruplets over other regimens was observed.

Tropomyosin receptor kinase (TRK) biology and the role of NTRK gene fusions in cancer

The tropomyosin receptor kinase (TRK) family of receptor tyrosine kinases are encoded by NTRK genes and have a role in the development and normal functioning of the nervous system. Since the discovery of an oncogenic NTRK gene fusion in colorectal cancer in 1986, over 80 different fusion partner genes have been identified in a wide array of adult and paediatric tumours, providing actionable targets for targeted therapy. This review describes the normal function and physiology of TRK receptors and the biology behind NTRK gene fusions and how they act as oncogenic drivers in cancer. Finally, an overview of the incidence and prevalence of NTRK gene fusions in various types of cancers is discussed.

Tumor MGMT promoter hypermethylation changes over time limit temozolomide efficacy in a phase II trial for metastatic colorectal cancer

BACKGROUND

Objective response to dacarbazine, the intravenous form of temozolomide (TMZ), in metastatic colorectal cancer (mCRC) is confined to tumors harboring O(6)-methylguanine-DNA-methyltransferase (MGMT) promoter hypermethylation. We conducted a phase II study of TMZ enriched by MGMT hypermethylation in archival tumor (AT), exploring dynamic of this biomarker in baseline tumor (BT) biopsy and plasma (liquid biopsy).

PATIENTS AND METHODS

We screened 150 mCRC patients for MGMT hypermethylation with methylation-specific PCR on AT from FFPE specimens. Eligible patients (n = 29) underwent BT biopsy and then received TMZ 200 mg/m(2) days 1-5 q28 until progression. A Fleming single-stage design was used to determine whether progression-free survival (PFS) rate at 12 weeks would be ≥35% [H0 ≤ 15%, type I error = 0.059 (one-sided), power = 0.849]. Exploratory analyses included comparison between MGMT hypermethylation in AT and BT, and MGMT methylation testing by MethylBEAMing in solid (AT, BT) and LB with regard to tumor response.

RESULTS

The PFS rate at 12 weeks was 10.3% [90% confidence interval (CI) 2.9-24.6]. Objective response rate was 3.4% (90% CI 0.2-15.3), disease control rate 48.3% (90% CI 32.0-64.8), median OS 6.2 months (95% CI 3.8-7.6), and median PFS 2.6 months (95% CI 1.4-2.7). We observed the absence of MGMT hypermethylation in BT in 62.7% of tumors.

CONCLUSION

Treatment of mCRC with TMZ driven by MGMT promoter hypermethylation in AT samples did not provide meaningful PFS rate at 12 weeks. This biomarker changed from AT to BT, indicating that testing BT biopsy or plasma is needed for refined target selection.

A randomized, multicenter, phase II study of vandetanib monotherapy versus vandetanib in combination with gemcitabine versus gemcitabine plus placebo in subjects with advanced biliary tract cancer: the VanGogh study

BACKGROUND

The management of biliary tract cancers (BTCs) is complex due to limited data on the optimal therapeutic approach. This phase II multicenter study evaluated the efficacy and tolerability of vandetanib monotherapy compared with vandetanib plus gemcitabine or gemcitabine plus placebo in patients with advanced BTC.

PATIENTS AND METHODS

Patients were randomized in a 1 : 1 : 1 ratio to three treatment groups: vandetanib 300 mg monotherapy (V), vandetanib 100 mg plus gemcitabine (V/G), gemcitabine plus placebo (G/P). Vandetanib (300 mg or 100 mg) or placebo was given in single oral daily doses. Gemcitabine 1000 mg/m(2) was i.v. infused on day 1 and day 8 of each 21-day cycle. The primary end point was progression-free survival (PFS). Secondary end points were: objective response rate (ORR), disease control rate, overall survival, duration of response, performance status and safety outcomes.

RESULTS

A total of 173 patients (mean age 63.6 years) were recruited at 19 centers across Italy. Median (95% confidence intervals) PFS (days) were 105 (72-155), 114 (91-193) and 148 (71-225), respectively, for the V, V/G and G/P treatment groups, with no statistical difference among them (P = 0.18). No statistical difference between treatments was observed for secondary end points, except ORR, which slightly favored the V/G combination over other treatments. The proportion of patients reporting adverse events (AEs) was similar for the three groups (96.6% in V arm, 91.4% in the V/G arm and 89.3% in the G/P arm).

CONCLUSIONS

Vandetanib treatment did not improve PFS in patients with advanced BTC. The safety profile of vandetanib did not show any additional AEs or worsening of already known AEs.

CLINICAL TRIAL NUMBER

NCT00753675.

Colorectal liver metastases: hepatic pedicle clamping during hepatectomy reduces the incidence of tumor recurrence in selected patients. Case-matched analysis

BACKGROUND

Hepatic pedicle clamping (HPC) during Liver Resection (LR) is a vascular procedure designed to prevent bleeding from the liver during hepatectomy. Outgrowth of pre-existing colorectal micrometastases may occur 5-6 times faster in occluded liver lobes than in non-occluded lobes. We conducted a case-matched analysis at our Institution to assess the effects of HPC on overall and recurrence-free survival in highly selected patients, who underwent LR due to Colorectal liver metastases (CLM).

MATERIALS AND METHODS

From January 2002 to December 2010, 120 patients operated for CLM were included into this case-matched study. Patients were allocated to two groups: Group-A patients who underwent HPC during LR; Group-B patients who underwent LR without HPC.

RESULTS

HPC during liver resection was associated with better overall patient 5-year survival (47.2% in Group-A and 32.1% in Group-B) (P-value = 0.06), and significantly better 5-year recurrence-free survival (49.9% in Group-A vs 18.3% in Group-B) (P-value = 0.010) The Cox regression model identified the following risk factors for worse prognosis in terms of shorter recurrence-free survival and higher incidence of tumor recurrence: no HPC (Group-B) (P-value = 0.032) and positive lymph nodes at the time of LR (P-value = 0.018).

CONCLUSION

Lack of HPC in selected patients who underwent LR for CLM results to be a strong independent risk factor for higher patient exposure to tumor recurrence. We suggest that hepatic hilum clamping should be seriously taken into consideration in this patient setting.

MINI-ABSTRACT

A case-matched study was performed in 120 patients undergoing liver resection due to colorectal liver metastases, comparing patients who received intermittent hepatic pedicle clamping (HPC) with those who did not. The 5-year overall survival rate was similar, but the 5-year recurrence-free rate was significantly higher with no HPC (p = 0.012).

Therapeutic implications of resistance to molecular therapies in metastatic colorectal cancer

Metastatic colorectal cancer (mCRC) patients carrying KRAS mutated tumors do not benefit from epidermal growth factor receptor (EGFR)-targeted cetuximab- or panitumumab-based therapies. Indeed, the mutational status of KRAS is currently a validated predictive biomarker employed to select mCRC patients for EGFR targeted drugs. When patients fail standard 5-fluorouracil-, oxaliplatin-, irinotecan- and bevacizumab-based therapies, EGFR-targeted salvage therapy can be prescribed only for those individuals with KRAS wild-type cancer. Thus, clinicians are now facing the urgent issue of better understanding the biology of KRAS mutant disease, in order to devise novel effective therapies in such defined genetic setting. In addition to KRAS, recent data point out that BRAF and PIK3CA exon 20 mutations hamper response to EGFR-targeted treatment in mCRC, potentially excluding from treatment also patients with these molecular alterations in their tumor. This review will focus on current knowledge regarding the molecular landscape of mCRC including and beyond KRAS, and will summarize novel rationally-developed combinatorial regimens that are being evaluated in early clinical trials.

Circulating endothelial cells and endothelial progenitors as predictive markers of clinical response to bevacizumab-based first-line treatment in advanced colorectal cancer patients

BACKGROUND

Despite the consistent clinical results demonstrated by studies on anti-angiogenic drugs targeted against the vascular endothelial growth factor in metastatic colorectal cancer (mCRC) patients, no specific direct/indirect biomarker of their efficacy has been validated. In this field, circulating endothelial cells (CECs) and endothelial progenitor cells (CEPs) have recently been proposed as noninvasive biomarkers.

PATIENTS AND METHODS

The absolute numbers of CEPs, total CECs (tCECs) and their resting (rCECs) and activated subsets were evaluated by multiparameter flow cytometry in 40 mCRC patients at baseline and before the administration of the third and sixth course of a bevacizumab-based first-line treatment. Fifty healthy subjects were utilized as control.

RESULTS

The overall response rate was 80%, overall clinical benefit was 90% and median progression-free survival (PFS) was 13.8 months. In our patients, tCECs and rCECs were significantly increased compared with healthy subjects. The patients who achieved a radiological response showed, at baseline, a significant decrease of rCECs and a trend in decrease of tCECs in comparison with patients not achieving response. Finally, a baseline absolute number of tCEC and rCEC <40 cells/ml was evidenced in patients with a longer PFS. No correlation was found regarding CEP.

CONCLUSIONS

Our study suggests significant correlations between both tCEC and rCEC baseline levels and the antitumor efficacy of a bevacizumab-based combination therapy in mCRC patients, thus confirming that these biomarkers could be used in the clinical setting as an early predictor of tumor response.

KRAS codon 61, 146 and BRAF mutations predict resistance to cetuximab plus irinotecan in KRAS codon 12 and 13 wild-type metastatic colorectal cancer

Background:

KRAS codons 12 and 13 mutations predict resistance to anti-EGFR monoclonal antibodies (moAbs) in metastatic colorectal cancer. Also, BRAF V600E mutation has been associated with resistance. Additional KRAS mutations are described in CRC.

Methods:

We investigated the role of KRAS codons 61 and 146 and BRAF V600E mutations in predicting resistance to cetuximab plus irinotecan in a cohort of KRAS codons 12 and 13 wild-type patients.

Results:

Among 87 KRAS codons 12 and 13 wild-type patients, KRAS codons 61 and 146 were mutated in 7 and 1 case, respectively. None of mutated patients responded vs 22 of 68 wild type (P=0.096). Eleven patients were not evaluable. KRAS mutations were associated with shorter progression-free survival (PFS, HR: 0.46, P=0.028). None of 13 BRAF-mutated patients responded vs 24 of 74 BRAF wild type (P=0.016). BRAF mutation was associated with a trend towards shorter PFS (HR: 0.59, P=0.073). In the subgroup of BRAF wild-type patients, KRAS codons 61/146 mutations determined a lower response rate (0 vs 37%, P=0.047) and worse PFS (HR: 0.45, P=0.023). Patients bearing KRAS or BRAF mutations had poorer response rate (0 vs 37%, P=0.0005) and PFS (HR: 0.51, P=0.006) compared with KRAS and BRAF wild-type patients.

Conclusion:

Assessing KRAS codons 61/146 and BRAF V600E mutations might help optimising the selection of the candidate patients to receive anti-EGFR moAbs.

A six-colour flow cytometric method for simultaneous detection of cell phenotype and apoptosis of circulating endothelial cells

Blood circulating endothelial cells (CECs), with their resting and activated subsets, (rCECs and aCECs) and circulating progenitors cells (CEPs) are two extremely rare cell populations that are important in tissue vascularization. Their number and function are modulated in diseases involving vascular injury, such as human tumours. Although a consensus on the phenotypic definition of endothelial cells, as well as on the optimal enumeration technique, is still lacking, the number of clinical studies based on assessment of these cells is rapidly expanding, as well as the analytical methods employed. The present study aimed to develop a rapid and sensitive flow cytometric method of quantifying and characterizing CECs (with both their subsets and the apoptotic fraction) and CEPs. We analysed peripheral blood samples from 21 subjects with a six-colour flow cytometric approach allowing detection of the cell phenotype of CECs and CEPs using a monoclonal antibodies panel and a dedicated gating strategy. Apoptotic CECs were detected with Annexin V and dead cells with 7-amino-actinomycin D staining. The described technique proved to be a new, reliable, tool increasing our knowledge of the biology of CECs and CEPs and can readily be applied in the study of many pathological conditions characterized by endothelial damage.

Correlation of immunological effects of anti-VEGF therapy with progression-free survival of advanced colorectal cancer patients

e14559

Background: The clinical efficacy of Bevacizumab (BEV) in advanced colorectal cancer (mCRC) could be related not only to its well-established effect on tumor neoangiogenesis but also to a counteraction of VEGF-mediated dendritic cell (DC) abnormalities. The addition of BEV to chemotherapy (CT) may improve the number and function of blood DCs in cancer pts. We have focused on the correlation between this effect and the clinical efficacy of a BEV-based, 1st-line treatment for mCRC. Methods: Starting from January 2007 we performed a flow cytometric analysis of PB lymphocytes and DC subsets in 53 mCRC pts who had not received prior CT for metastatic disease or for whom 6 months had elapsed since adjuvant CT (M/F: 31/22, median age: 59yrs; range 32–75; ECOG PS <2), before and every 3 courses of a BEV+CT (5-FU± CPT11± Oxaliplatin) program. Biological data of the 42 evaluable pts that received all the planned treatment were correlated to both tumor response (OR) and progression free survival (PFS). Results: During treatment, DCs and their subsets showed a progressive, significant increase in absolute number, with respect to baseline, both in responder (CR,PR,SD) (67%) and in non responder pts. This effect on the DC profile was evidenced in responder pts up to 4 weeks since the last treatment course. After therapy completion, pts with PFS > 15 months (58%) showed DC and DC1 absolute number significantly higher with respect to pts with shorter PFS (p< .02). Conclusions: The recovery of blood DCs induced by 1st- line, BEV-based therapy in mCRC pts indicates a potential additional anticancer mechanism of this drug. The improvement of DC number does not influence OR but correlates with longer PFS. This suggests that BEV can influence tumor regrowth by contributing to overcome the impairement of the host immune surveillance induced by VEGF.

No significant financial relationships to disclose.

Amphiregulin (AR) expression in the prediction of benefit from cetuximab plus irinotecan in KRAS wild-type metastatic colorectal cancer (mCRC) patients

4021

Background: AR is an endogenous ligand of Epidermal Growth Factor Receptor (EGFR), whose binding is prevented in the presence of cetuximab. Methods: We retrospectively assessed KRAS mutational status and AR expression at immunohistochemistry (IHC) in 86 irinotecan-refractory EGFR-positive mCRC patients treated with cetuximab plus irinotecan. AR-IHC was performed on tissue sections from paraffin-embedded primary tumors. Specimens were defined AR-low or AR-high according to a score (range 0–300) obtained multiplying intensity (0 to 3+) by percentage of stained cells (0–100%). According to the results of a ROC analysis, we identified a cut-off value of 18. The association between AR-IHC and treatment outcome in terms of response rate (RR), PFS, and OS was investigated in the subgroup of KRAS wild-type patients. Results: Eighty-six consecutive patients were included. M/F = 44/42, median age = 67 (41–78), median number of previous lines of chemotherapy = 2 (1–5). Among 51 (59%) KRAS wild-type patients, 12 PRs and 1 CR were observed, for an overall RR of 25% (13/51). AR-IHC was high, low or unconclusive in 27, 22 and 2 cases respectively. AR-low patients reported a significantly worse RR (2/22, 9%) compared with AR-high (10/27, 37%) (p = 0.024) and a trend toward shorter PFS (3.5 vs 5.3 months, HR 0.88 [95%CI: 0.46–1.60], p = 0.628) and OS (8.8 vs 15.1 months, HR 0.60 [95%CI: 0.30–1.10], p = 0.106). Conclusions: These results underline the potential role of endogenous ligands in influencing the activity of anti-EGFR monoclonal antibodies. Absent or low AR expression at IHC may be related to resistance to cetuximab plus irinotecan. Further data regarding the prognostic impact of AR expression are needed.

No significant financial relationships to disclose.

Characterization of innate responses elicited by neoadjuvant radio-chemotherapy for rectal cancer

e15044

Background: The neoadjuvant chemo-radiotherapy (CT-RT) has improved the treatment of locally advanced rectal cancer reducing the local recurrence. However a survival benefit has not been reached yet. In order to increase the rate of pathological complete remissions in our Institution we intensified both the CT schedule adding oxaliplatin to 5-FU and the RT program with tomotherapy. The aim of this study was to verify: whether the pattern of innate response elicited by the neoadjuvant CT-RT is heterogeneous among pts and whether this information can be used to identify which pts will benefit from the treatment. Methods: We collected samples of T3N+M0 rectal cancer pts before, during and after neoadjuvant CT-RT (3 cycles of oxaliplatin + 5-FU; 45 Gy). At each time point we characterized circulating monocytes by flow cytometry, infiltrating macrophages by immunoistochemistry (IHC) and selected inflammatatory molecules by ELISA.Results: We recruited so far 25 pts, of whom 10 have reached the surgery with three pathological complete remission and four down staging. No substantial changes were detectable in the number of circulating monocytes. In contrast we observed a clear expansion of CD14/CD86 and CD14/CD163 double positive subsets. This event was transient and apparently causally related to the treatment since it abated at the later time point. Moreover, it correlated with sensitivity to the treatment: 5/7 pts who underwent disease regression had an early and transitory increase of the number of CD14/CD86 and CD14/CD163 positive cells, which was absent or negligible in non responder pts. The IHC study revealed a massive tumoral infiltration by macrophages which displayed clear features of alternative M2 polarization as assessed by expression of the CD163 and 206 scavenger receptors. A subset of pts had elevated PTX3 and low CRP concentration at the onset of treatment. PTX3 concentration abated after the first CT cycle. Conclusions: These data suggest that neoadjuvant CT-RT modulates the cellular components of innate immune responses, that could represent valuable predictive factors.

No significant financial relationships to disclose.

Flow cytometric detection of circulating dendritic cells in healthy subjects

Dendritic cells (DCs) are the key antigen-presenting cells controlling the initiation of the T cell- dependent immune response. Currently, two peripheral blood DC subsets have been identified on the basis of their CD11c expression. The CD11c-negative (CD11c-) DCs (expressing high levels of CD123) are designated as lymphoid-derived DCs (DC2), whereas the CD11c+/CD123- cells, do identify the myeloid-derived DCs (DC1). A growing number of studies have been conducted in recent years on both the quantitative and functional alterations of DCs and their subsets in different pathological conditions. In the present study we assessed, using two different flow cytometric (FCM) techniques, the normal profile of blood DCs in 50 italian adult healthy subjects (M/F: 25/25, median age 42.5 years, range 20-65). The percentage and the absolute number of DCs and their subsets, were obtained starting from whole blood samples in two ways: 1) by calculating the number of DCs when gated as lineage-negative/ HLA-DR+ and identifing the two subsets as CD11c+ (DC1) and CD123+ (DC2) and 2) by using three specific markers: BDCA.1 (CD11c+ high/CD123+ low, myeloid DCs); BDCA.2 (CD11c-/ CD123+high, lymphoid DCs); BDCA.3 (CD11c+low /CD123-, myeloid DCs). Six parameters, 4-color FCM analysis were perfomed with a BD FACSCanto equipment. The mean values of the percentage and of the absolute number were: 0.5+/-0.2% and 30+/-11 cells/microL for DCs; 0.2+/-0.1% and 15+/-6 cells/microL for DC1; 0.2+/-0.1% and 15+/-7 cells/microL for DC2. The same values were: 0.2+/-0.1% and 16+/-7 cells/microL for BDCA.1; 0.2+/-0.1% and 12+/-7 cells/microL for BDCA.2; 0.02+/-0.01% and 2+/-1 cells/microL for BDCA.3, respectively. Our study confirmes that the two types of FCM analysis are able to identify the DC population. We also provides the first reference values on normal rates and counts of blood DCs in italian adult healthy subjects.

EGFR FISH assay predicts for response to cetuximab in chemotherapy refractory colorectal cancer patients

BACKGROUND

Standardized conditions to distinguish subpopulations of colorectal cancer (CRC) patients more and less sensitive to cetuximab therapy remain undefined.

MATERIALS AND METHODS

We retrospectively analyzed epidermal growth factor receptor (EGFR) copy number by fluorescence in situ hybridization (FISH) in paraffin-embedded tumor blocks from 85 chemorefractory CRC patients treated with cetuximab. Results were analyzed according to different score systems previously reported in colorectal and lung cancers. The primary end point of the study was identification of the EGFR FISH score that best associates with response rate (RR).

RESULTS

Using receiver operating characteristic (ROC) analysis, the cut-off that best discriminated responders versus nonresponders to cetuximab was a mean of 2.92 EGFR gene copies per cell. This model showed sensitivity of 58.6% [95% confidence interval (CI) = 47.1-70.1) and specificity of 93.3% (95% CI = 80.6-100). EGFR FISH-positive patients (N = 43, 50.6%) had significantly higher RR (P = 0.0001) and significantly longer time to disease progression (P = 0.02) than EGFR FISH negative (N = 42, 49.4%). Other scoring systems resulted less accurate in discriminating patients with the highest likelihood of response to cetuximab therapy.

CONCLUSIONS

CRC patients with high EGFR gene copy number have an increased likelihood to respond to cetuximab therapy. Prospective clinical trials with a careful standardization of assay conditions and pattern interpretation are urgently needed.

Lack of effect of pegfilgrastim on anemia in breast cancer patients treated with dose-dense chemotherapy

11071

Background: A greater risk of anemia has been evidenced among breast cancer (BC) pts receiving dose-dense CT. A recent report showed that filgrastim may play a role in worsening anemia in BC pts receiving intensified Epirubicin (E) + Cyclophosphamide (CTX), by inducing stem cells to differentiate into more committed hematopoietic progenitors (Papaldo P. JCO, 2006). No data are available about the impact of pegfilgrastim-induced leucocytosis on Hb levels without prophylactic erythropoietic support. Methods: We have focused on this point in 36 BC pts. 14 N+ pts received 4 cycles of E 90 mg/sqm + CTX 600 mg/sqm every 14 days in adjuvant setting. 22 pts with locally advanced disease received 4 cycles of E 75 mg/sqm + Docetaxel 80 mg/sqm every 14 days as primary CT. All pts received prophylactic pegfilgrastim 6 mg s.c, after CT. Three groups were defined on the basis of WBC: A = <10 x 103/mL; B = between 10 and 20 x 103/mL and C = > 20 x 103/mL. WBC and Hb levels at the beginning of treatment were normal in all pts and were subsequently determined on day 1 of each treatment cycle. Results: All pts received the planned CT dose intensity. Only 3 pts developed G2 anemia and were excluded from the analysis, because of receiving darbepoietin alpha support. Among the 14 pts treated in adjuvant setting, 5 dropped in group A, 6 in group B and 3 in group C. The mean Hb decrease from the baseline to the last CT course was - 1.5 g/dL; -1.4, -1.8 and -1.4 in group A, B and C, respectively. In the primary setting, 4 pts dropped in group A, 12 in group B and 4 in group C. The mean Hb decrease was -1.5 g/dL; -1.3, -1.4 and -1.8 in group A, B and C respectively. No statistically significant correlation was found between the Hb levels and the degree of leukocytosis. Conclusions: Pegfilgrastim does not worsen anemia in BC pts treated with dose- dense CT, even when its use is related to some degree of leucocytosis.

No significant financial relationships to disclose.

EGFR, HER2 and Kras as predictive factors for cetuximab sensitivity in colorectal cancer

4021

Background: In colorectal cancer, biological mechanisms underlying response or resistance to cetuximab, a monoclonal antibody against the extracellular domain of the EGFR are not defined. Small retrospective studies suggested that EGFR increased gene copy number measured by fluorescence in situ hybridization (FISH) or presence of KRAS mutations were associated with cetuximab response or resistance, respectively. This study aimed to identify biological predictors for sensitivity/resistance to cetuximab treatment in colorectal cancer. We also compared biomarker results in primary tumors and corresponding metastases. Methods: We analyzed EGFR (IHC, FISH), HER2 (FISH), and KRAS (mutation) in paraffin embedded tumor blocks from 85 colorectal cancer patients treated with cetuximab. For FISH analyses, a positive result was defined according to criteria described in breast (Wolff et al. J Clin Oncol 2007), lung (Cappuzzo et al. JNCI 2005) and colorectal cancer (Moroni et al. Lancet Oncology 2005). EGFR, HER2 and PIK3CA mutation analyses are ongoing. Results: EGFR FISH positive patients (N=41), defined as ratio EGFR/nucleus =3, had a significantly higher RR (29.3% versus 6.8%, p=0.007) and TTP (6.6 versus 3.7 months, p=0.053) than EGFR FISH negative (N=44). No difference for clinical endpoints was observed using other scoring systems. EGFR expression assessed by IHC was not associated with any clinical end-point. Increased HER2 gene copy number was associated with shorter TTP (p=0.09) and survival (p=0.03). Compared to patients with wild type KRAS (N=49), KRAS mutation carriers (N=32) had a significantly lower RR (6.3% versus 26.5%, p= 0.02), shorter TTP (3.7 versus 6.3 months, p=0.07) and shorter survival (8.3 versus 10.8 months, p=0.2). In 22 patients with available primary and metastatic tumor tissue, there was no difference between these sites for EGFR FISH, HER2 FISH and KRAS results. Conclusions: This study, the largest biomarker analysis in colorectal cancer patients treated with cetuximab, shows a significant benefit in response and TTP for EGFR FISH positive patients. KRAS mutation analysis identifies a group of patients with the lowest chance to benefit from the therapy. Increased HER2 gene copy number predicts early escape from cetuximab therapy.

No significant financial relationships to disclose.

New agents in medical oncology and the risk of venous thromboembolism

Over the past several years the medical approach to cancer patients has made important steps forward both in the field of novel, selective, antiproliferative agents and more effective supportive therapies. A greater understanding of the molecular pathways regulating cell proliferation and metastasis has led to the identification of a range of targets specifically inhibited by these new drugs. The clinical development of these compounds (the so called "targeted therapies") has shown distinctive adverse effects with respect to standard chemotherapeutic agents but the potential increasing risk of venous thromboembolism remains unvaried. In fact, the incidence of this potentially life-threatening complication in patients receiving standard chemotherapy ranges from about 11% to 20% and even more depending on the type of drug administered and on the possible association with other anti-neoplastic and supportive therapies. In this paper we reviewed all the available evidences concerning the increasing risk of venous thromboembolism in cancer patients during treatment with new agents currently used in medical oncology together with data concerning the clinical value of a concomitant prophylactic anticoagulation. At present, additional information concerning safety in terms of thromboembolic risk of novel biological and molecular therapies should be collected from specifically designed original basic science studies and clinical trials in order to optimize their use in current oncology practice.

Epidermal growth factor receptor tyrosine kinase inhibitors for the treatment of non-small-cell lung cancer: results and open issues

The medical treatment of non-small-cell lung cancer (NSCLC) has progressively changed since the introduction of "targeted therapy". The development of one of these molecular drug categories, e. g., the epidermal growth factor receptor (EGFR) tyrosine-kinase (TK) selective inhibitors, such as the orally active gefitinib and erlotinib, offers an interesting new opportunity. The clinical response rates obtained with their employment in unselected patient populations only account for approximately 10%. Because of this, over the last two years numerous studies have been performed in order to identify the patient subsets that could better benefit from these agents. Not only patient characteristics and clinical-pathological features, such as never-smoking status, female gender, East Asian origin, adenocarcinoma histology, bronchioloalveolar subtype, but also molecular findings, such as somatic mutations in the EGFR gene, emerge as potentially useful prognostic and predictive factors in advanced NSCLC. Further, specifically designed clinical trials are still needed to completely clarify these and other open issues that are reviewed in this paper, in order to clarify all the interesting findings available in the clinical practice.

Biological effects of pegfilgrastim after myelosuppressive chemotherapy in breast cancer

10521

Background: The dose and schedule of chemotherapy (CT), that play a crucial role in the outcome of pts with chemosensitive tumors, were made feasible with the primary use of colony stimulating factors. Few data are available on the in vivo biological effects of the “long-lasting” cytokine pegfilgrastim. We have focused on the cytokinetic effects on the CD34+/38+ peripheral blood (PB) progenitor cell subset and on its influence on neutrophils functional parameters. Methods: We studied PB samples from 14 breast cancer pts (median age 47 yrs; 35–61 yrs), treated with Docetaxel (80 mg/sqm, d 1) + Epirubicin (75 mg/sqm, d 1) + pegfilgrastim (6 mg s.c. on d +1). The % of CD34+/38+ circulating progenitor cells (CPCs) (sorted with immunomagnetic procedure) undergoing G0/G1, S and G2/M phases of the cell cycle or showing apoptotic features were evaluated using flow cytometry. Annexin V was quantitated at a single cell level and correlated with cell cycle phases. On PB buffy coat smears, alkaline phosphatase activity by cytochemistry, actin polymerization using FITC-labelled phalloidin and apoptosis by TUNEL technique, were evaluated on neutrophils. Results: Seven days following CT + pegfilgrastim the CD34+/38+ absolute numbers were: 46 (27–74) and 41 (25–66) on day 14+ from CT.On day 7+ the % of CD34+/38+ CPCs in S-phase was 13.0 ± 9 while 3.7% ± 6 of this cell subset showed apoptotic features. One week later, these values were 8.4% ± 7 and 7.7% ± 5, respectively. We also observed: stability of the absolute neutrophil count for all the duration of treatment; a significant increase of the leucocyte alkaline phosphatase; abnormalities of actin assembly in neutrophils, indicative of changes in cytoskeleton organization, and a significant reduction of neutrophil apoptosis. Conclusions: 1) pegfilgrastim exerts stimulatory effects on cell cycle status of PB CD34+/38+ CPCs, protecting them from apoptosis; this is evident 7 days after its administration and tends to decrease one week later 2) pegfilgrastim improves the neutrophil function by inhibiting their accelerated apoptosis and prolonging survival. These data could be useful when dose-dense CT is planned with pegfilgrastim support.

No significant financial relationships to disclose.