REGOMA-OSS: a large, Italian, multicenter, prospective, observational study evaluating the efficacy and safety of regorafenib in patients with recurrent glioblastoma

BACKGROUND

In the randomized phase II REGOMA trial, regorafenib showed promising activity in patients with recurrent glioblastoma. We conducted a large, multicenter, prospective, observational study to confirm the REGOMA data in a real-world setting.

PATIENTS AND METHODS

The major inclusion criteria were histologically confirmed diagnosis of glioblastoma according to the World Health Organization (WHO) 2016 classification and relapse after radiotherapy with concurrent/adjuvant temozolomide treatment, good performance status [Eastern Cooperative Oncology Group performance status (ECOG PS 0-1)] and good liver function. Regorafenib was administered at the standard dose of 160 mg/day for 3 weeks on/1 week off. Brain magnetic resonance imaging was carried out within 14 days before starting regorafenib and every 8-12 weeks. The primary endpoint was overall survival (OS). The secondary endpoints were progression-free survival (PFS), objective response rate, disease control rate (DCR), safety and health-related quality of life. The Response Assessment in Neuro-Oncology (RANO) criteria were used for response evaluation and Common Terminology Criteria for Adverse Events (CTCAE) version 5 for assessment of adverse events (AEs).

RESULTS

From September 2020 to October 2022, 190 patients with recurrent glioblastoma were enrolled from 30 cancer centers in Italy: their median age was 58.5 years [interquartile range (IQR) 53-67 years], 68% were male and 85 (44.7%) were in optimal clinical condition (ECOG PS 0). The number of patients taking steroids at baseline was 113 (60%); the second surgery was carried out in 39 (20.5%). O6-methylguanine-DNA methyltransferase (MGMT) was methylated in 80 patients (50.3%) and 147 (92.4%) of the patients analyzed had isocitrate dehydrogenase (IDH) wild type. The median follow-up period was 20 months (IQR 15.6-25.5 months). The median OS was 7.9 months ([95% confidence interval (CI) 6.5-9.2 months] and the median PFS was 2.6 months (95% CI 2.3-2.9 months). Radiological response was partial response and stable disease in 13 (7.3%) and 26 (14.6%) patients, respectively, with a DCR of 21.9%. The median number of regorafenib cycles per patient was 3 (IQR 2.0-4.0). Grade 3-4 drug-related adverse events were reported in 22.6% of patients. A dose reduction due to AEs was required in 36% of patients. No deaths were considered as treatment-related AEs.

CONCLUSIONS

This large, real-world observational study showed similar OS with better tolerability of regorafenib in patients with relapsed glioblastoma compared with the REGOMA study.

Clinical utility of Next Generation Sequencing of plasma cell-free DNA for the molecular profiling of patients with NSCLC at diagnosis and disease progression

BACKGROUND

The present study evaluates the utility of NGS analysis of circulating free DNA (cfDNA), which incorporates small amounts of tumor DNA (ctDNA), at diagnosis or at disease progression (PD) in NSCLC patients.

METHODS

Comprehensive genomic profiling on cfDNA by NGS were performed in NSCLC patients at diagnosis (if tissue was unavailable/insufficient) or at PD to investigate potential druggable molecular aberrations. Blood samples were collected as routinary diagnostic procedures, DNA was extracted, and the NextSeq 550 Illumina platform was used to run the Roche Avenio ctDNA Expanded Kit for molecular analyses. Gene variants were classified accordingly to the ESCAT score.

RESULTS

A total of 106 patients were included in this study; 44 % of cases were requested because of tissue unavailability at the diagnosis and 56 % were requested at the PD. At least one driver alteration was observed in 62 % of cases at diagnosis. Driver druggable variants classified as ESCAT level I were detected in 34 % of patients, including ALK-EML4, ROS1-CD74, EGFR, BRAF, KRAS p.G12C, PI3KCA. In the PD group, most patients were EGFR-positive, progressing to a first line-therapy. Sixty-three percent of patients had at least one driver alteration detected in blood and 17 % of patients had a known biological mechanism of resistance allowing further therapeutic decisions.

CONCLUSIONS

The present study confirms the potential of liquid biopsy to detect tumour molecular heterogeneity in NSCLC patients at the diagnosis and at PD, demonstrating that a significant number of druggable mutations and mechanisms of resistance can be detected by NGS analysis on ctDNA.

Non-pegylated liposomal doxorubicin in older adjuvant early breast cancer patients: cardiac safety analysis and final results of the COLTONE study

AIMS

To explore the cardiac safety of adjuvant Non-Pegylated Liposomal Doxorubicin (NPL-DOX) plus Cyclophosphamide (CTX) followed by weekly Paclitaxel, in elderly women (≥ 65 years) with high-risk breast cancer. Previously, we described no symptomatic cardiac events within the first 12 months from starting treatment. We now reported the updated results after a median follow-up 76 months.

METHODS

The cardiac activity was evaluated with left ventricular ejection fraction (LVEF) echocardiograms assessments, before starting chemotherapy and every 6 months, until 30 months from baseline, then yearly for at least 5 years.

RESULTS

Forty-seven women were recruited by two Units of Medical Oncology (Ethics Committee authorization CESM-AOUP, 3203/2011; EudraCT identification number: 2010-024067-41, for Pisa and Pontedera Hospitals). An episode of grade 3 CHF (NCI-CTCAE, version 3.0) occurred after 18 months the beginning of chemotherapy. The echocardiograms assessments were performed comparing the LVEF values of each patient evaluated at fixed period of time, compared to baseline. We observed a slight changed in terms of mean values at 48, 60, 72 and 84 months. At these time points, a statistically significant reduction of - 3.2%, - 4.6%, - 6.4% and - 7.1%, respectively, was observed. However, LVEF remained above 50% without translation in any relevant clinical signs. No other cardiac significant episodes were reported. To this analysis, in 13 patients (28%) occurred disease relapse and,  of them, 11 (23%) died due to metastatic disease. Eight patients died of cancer-unrelated causes.

CONCLUSIONS

The combination including NPL-DOX in elderly patients revealed low rate of cardiac toxic effects. Comparative trials are encouraged.

Pembrolizumab for First-Line Treatment of Advanced Non-Small-Cell Lung Cancer: Analysis of Prognostic Factors of Outcomes

BACKGROUND

In advanced non-small-cell lung cancer, without activating mutations and with PD-L1≥50%, Pembrolizumab monotherapy is the therapeutic standard in Europe.

OBJECTIVE

to evaluate retrospectively the safety and the efficacy of this drug and to investigate potential prognostic factors in daily clinical practice.

METHODS

From September 2017 to September 2019, 205 consecutive patients from 14 Italian Medical Oncology Units were enrolled in the study. Gender, Age (> or <70 years), ECOG-PS (0-1 or 2), histology (squamous or non-squamous), presence of brain, bone and liver metastases at baseline, PD-L1 score (>90% or <90%), smoking status (never or former or current) were applied to the stratified log-rank. Cox's proportional hazards model was used for multivariate analysis.

RESULTS

At a median follow-up of 15.2 months, median progression-free and overall survival (mPFS and mOS) were 9.2 months (95% C.I., 4.8-13.5) and 15.9 months (95% C.I., not yet evaluable), respectively. Patients with Eastern Cooperative Oncology Group performance status (ECOG-PS) 2 had mPFS of 2.8 months (95% C.I., 2.1-3.4) and mOS of 3.9 months (95% C.I., 2.5-5.3). Patients with liver metastases at diagnosis had an mPFS of 3.2 months (95% C.I., 0.6-5.8) and an mOS of 6.0 months (95% C.I., 3.7-8.4). At multivariate analysis for OS gender, ECOG-PS 2, and presence of liver metastases were independent prognostic factors.

CONCLUSION

Patients with ECOG-PS 2 derived little benefit from the use of first-line pembrolizumab. In patients with liver metastases the association of pembrolizumab with platinum-based chemotherapy could be a better option than pembrolizumab alone.

Endothelial nitric oxide synthase c.-813C>T predicts for proteinuria in metastatic breast cancer patients treated with bevacizumab-based chemotherapy

PURPOSE

To investigate the association between single nucleotide polymorphisms (SNPs) in endothelial nitric oxide synthase (eNOS) and interleukin-8 (IL-8) genes and risk of developing bevacizumab-related adverse events in metastatic breast cancer (mBC) patients.

PATIENTS AND METHODS

mBC patients candidate to receive bevacizumab-based chemotherapy were enrolled in this pharmacogenetic study. eNOS c.-813C>T and c.894G>T, and IL-8 c.-251A>T were analyzed by real time PCR on genomic DNA extracted from peripheral blood. Univariate analysis was performed to test the association between each SNP and treatment-related toxicities.

RESULTS

Seventy-six mBC patients were enrolled in the present study. Patients carrying the homozygous variant eNOS c.-813TT genotype showed a statistically significant occurrence of any grade proteinuria when compared to CT or CC genotypes (p = 0.004). No significant association of proteinuria with IL-8 SNP or hypertension with selected eNOS and IL-8 SNPs was found.

CONCLUSIONS

These findings suggest an association between the eNOS c.-813C>T polymorphism and the development of proteinuria in mBC patients receiving a bevacizumab-based chemotherapy.

Profile of bavituximab and its potential in the treatment of non-small-cell lung cancer

Bavituximab is a an unconjugated, chimeric immunoglobulin G1 (IgG1) monoclonal antibody directed against the phosphatidylserine (PS) expressed on tumor endothelium, with a specific mechanism of action. PS is an anionic membrane phospholipid, physiologically restricted to the internal membrane leaflet; various pathophysiologic processes cause the exposure of PS on the external membrane leaflet. Bavituximab, once bound, starts up host effector activities, such as antibody dependent cellular cytotoxicity, causing vessel destruction and enhancing antitumor immunity. Phase I clinical trials of bavituximab administered as monotherapy or in combination with other chemotherapeutic agents in adults with pretreated solid tumors have been accomplished, indicating that bavituximab can be safely dispensed weekly, with a recommended dose of 1 and 3 mg/kg. A Phase II randomized, placebo-controlled trial of bavituximab plus docetaxel, in the second-line therapy setting of locally advanced or metastatic non-small-cell lung cancer, has been conducted and recently presented, suggesting a clinical benefit of the combination, with an overall response rate of 17% and median overall survival of more than 11 months. A Phase III trial is currently ongoing. Bavituximab has been studied in combination with platinum-based doublets with promising results. In the present paper we summarize the preclinical development and clinical experience with bavituximab in non-small-cell lung cancer.

Second generation tyrosine kinase inhibitors for the treatment of metastatic non-small-cell lung cancer

Backgruond

Since their first description, activating epidermal growth factor receptor (EGFR) mutations identify a distinct clinical entity of patients with non-small-cell lung cancer (NSCLC).

Findings

New targeted therapies for molecularly selected NSCLC are changing the natural history of the disease, with results superior to standard chemotherapy as demonstrated in large phase III studies with first generation EGFR tyrosine kinase inhibitors (TKIs) erlotinib and gefitinib. However, after an initial response, all patients inevitably progress and several mechanisms including a secondary mutation in exon 20 of the EGFR gene (T790M) or MET or HER2 amplifications are responsible for acquired resistance (AR). In clinical practice few options are available for patients with AR, and several new agents or strategies are currently under investigation, including second generation TKIs.

Conclusions

Aim of the present review is to present available data on new EGFR-TKIs and to discuss how these agents could overcome AR to erlotinib or gefitinib.

Abstract P5-17-06: The deficient eNOS c.894G&gt;T genotype is not associated with increased severity of hypertension and proteinuria in breast cancer patients receiving bevacizumab

Background. Tumor angiogenesis is a complex process involving a wide array of effector molecules and stromal cells. In tumor tissue, vasculature is structurally and functionally abnormal, causing elevated interstitial pressure and irregular perfusion. The expression of vascular endothelial growth factor (VEGF), the most important angiogenic factor, is enhanced in many tumors. VEGF may induce nitric oxide (NO) production via up-regulation of the endothelial NO synthase (eNOS, NOS3) and the resultant overproduction of NO is associated with vasodilation and edema within tumors (Goel S et al. Physiol Rev 2011;91:1071). eNOS plays an important physiologic role in maintaining blood pressure homeostasis and vascular integrity by providing constitutive release of NO in endothelial cells. Functional variants of the eNOS gene, including the single-nucleotide polymorphism rs1799983 (c.894G&gt;T, p. Asp298Glu) at codon 298, have been associated with reduced function of eNOS and higher incidence of hypertension (HT) (Niu W, Qi Y. PLoS One 2011;6:e24266).

Purpose. Since suppression of VEGF-eNOS axis by anti-angiogenic therapies is considered a causative factor of HT in patients, the purpose of this study was to examine whether the major eNOS non-synonymous variant c.894G&gt;T may be associated with increased risk of developing hypertension (HT) and proteinuria (PU) in breast cancer patients treated with bevacizumab.

Patients and methods. Forty-one metastatic breast cancer patients given bevacizumab as per standard of care were enrolled. Main characteristics were: median age 49.5 years (range 29–73) at first diagnosis, 53 years (range 34–74) at metastatic disease; PS 0–1 in all patients; 4 subjects with hypertension and 1 patient with compensated cardiovascular disease at diagnosis. Twenty-six subjects had received neoadjuvant or adjuvant chemotherapy based on anthracycline and taxane; first-line chemotherapy for metastatic disease was paclitaxel plus bevacizumab for all patients; 14 subjects received hormone-therapy for metastatic disease (range 1–5 lines). Germline DNA was extracted from peripheral blood and used to screen patients for eNOS c.894G&gt;T variant by automatic sequencing. The study was approved by the local Ethics Committee.

Results. Three patients (7.3%) were homozygous variant c.894TT, 12 (29.3%) homozygous wild-type c.894GG and the remaining 26 (63.4%) were heterozygous c.894GT. The c.894TT patients had no HT or PU at baseline and developed grade (G) 1, 2, 2 HT, respectively, and in one case PU during treatment. G1, 2 and 3 HT developed in 4, 5 and 2 c.894GG subjects, respectively, while PU was observed in 7/12 (58%) patients. The full range of HT grades and PU were observed in heterozygous subjects. Thirty-seven patients achieved one of the following: partial remission, minimal response or stable disease upon treatment with bevacizumab in combination with chemotherapy; 3 subjects had progressive disease and 1 was not evaluable.

Conclusions. The presence of the mutant T allele of c.894G&gt;T is not associated with increased severity of HT and PU; therefore, bevacizumab can be administered at no increased risk in TT patients with respect to the wild-type GG population.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-17-06.

Impact of PIK3CA mutations and p95HER2 expression on the outcome of HER2-positive metastatic breast cancer patients treated with a trastuzumab-based therapy

629

Background: Currently, no biomarkers of trastuzumab (T) clinical resistance have been validated. The aim of this pilot study was to evaluate the impact of PIK3CA mutations and p95HER2 (pHER2 truncated form) expression on the efficacy of a T based-therapy in a HER2-positive metastatic breast cancer (MBC) patients (pts). Methods: 107 HER2-positive MBC pts, treated in the last 10 years, were evaluated. Median age was 54 years (25-79); ECOG performance status was 0 in 56% of pts; all pts received several lines of treatment including T; biomarkers molecular analysis was performed in 70 tumor specimens. The IHC expression of p95HER2 was evaluated by a monoclonal antibody that specifically recognizes only the HER2 external domain; the HER2 integrity was defined by the presence of a homogeneous membrane staining (moderate or intense) in at least 30% of the cells, otherwise the HER2 was defined as p95HER2 positive. PIK3CA mutations in exons 9 and 20 were detected by automated sequencing. The molecular data were correlated to Time to progression (TTP) of the first line treatment including T and the Overall Survival (OS) by using the Kaplan-Meir method and the log-rank-test. Results: p95HER2 positive pts and PIK3CA mutations in exon 9 or 20 were detected in 42% and 22% of tumor specimens, respectively. p95HER2 positive tumors showed a shorter TTP and OS that did not reach statistical significance; PIK3CA mutations correlated with a worse TTP (median 7,6 vs 11,3 months) and OS (median 20,1 vs 41,0 months, p= 0,046). Conclusions: These preliminary results suggest a possible role of PIK3CA mutational status in predicting the outcome of MBC pts treated with T.

Beyond KRAS: perspectives on new potential markers of intrinsic and acquired resistance to epidermal growth factor receptor inhibitors in metastatic colorectal cancer

The monoclonal antibodies cetuximab and panitumumab, directed against the epidermal growth factor receptor (EGFR), are licensed for the treatment of KRAS wild-type metastatic colorectal cancer (mCRC). Such 'molecular restriction' derived from post-hoc analyses of randomized trials and from other retrospective series all indicate how tumors bearing KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog) mutations are resistant to EGFR inhibition. Even if highly sensitive for nonresponse, KRAS testing is not very specific. In fact, a limited but still considerable proportion of KRAS wild-type patients rapidly progress on treatment with an EGFR inhibitor. New potential molecular determinants of benefit from such treatment are under investigation and may further refine the selection of patients. Pharmacogenomic analyses and translational studies are also ongoing for exploring the field of acquired resistance to anti-EGFRs, since all patients eventually progress. New biological data are awaited for optimizing the use of molecular agents in colorectal cancer and for identifying promising targets that could allow to better understand and, potentially, overcome mechanisms of primary or secondary resistance to EGFR inhibitors.

Randomized trial of two induction chemotherapy regimens in metastatic colorectal cancer: an updated analysis

BACKGROUND

In a randomized trial with a median follow-up of 18.4 months, 6 months of induction chemotherapy with a three-drug regimen comprising 5-fluorouracil (by continuous infusion)-leucovorin, irinotecan, and oxaliplatin (FOLFOXIRI) demonstrated statistically significant improvements in response rate, radical surgical resection of metastases, progression-free survival, and overall survival compared with 6 months of induction chemotherapy with fluorouracil-leucovorin and irinotecan (FOLFIRI).

METHODS

From November 14, 2001, to April 22, 2005, we enrolled 244 patients with metastatic colorectal cancer. To evaluate if the superiority of FOLFOXIRI is maintained in the long term, we updated the overall and progression-free survival data to include events that occurred up to February 12, 2009, with a median follow-up of 60.6 months. We performed a subgroup and a risk-stratified analysis to examine whether outcomes differed in specific patient subgroups, and we analyzed the results of treatment after progression. Survival curves were estimated by the Kaplan-Meier method. Multivariable Cox regression models were fit to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). All statistical tests were two-sided.

RESULTS

FOLFOXIRI demonstrated statistically significant improvements in median progression-free survival (9.8 vs 6.8 months, HR for progression = 0.59, 95% CI = 0.45 to 0.76, P < .001) and median overall survival (23.4 vs 16.7 months, HR for death = 0.74, 95% CI = 0.56 to 0.96, P = .026) with a 5-year survival rate of 15% (95% CI = 9% to 23%) vs 8% (95% CI = 4% to 14%). The improvements in progression-free survival and, to a lesser extent, in overall survival were evident even when the analysis excluded patients who received radical resection of metastases. With regard to the risk-stratified analysis, FOLFOXIRI results in longer progression-free survival and overall survival than FOLFIRI in all risk subgroups.

CONCLUSIONS

Six months of induction chemotherapy with FOLFOXIRI is associated with a clinically significant improvement in the long-term outcome compared with FOLFIRI with an absolute benefit in survival at 5 years of 7%.

Cetuximab plus irinotecan after irinotecan failure in elderly metastatic colorectal cancer patients: clinical outcome according to KRAS and BRAF mutational status

BACKGROUND

Scarce data are available about safety and efficacy of cetuximab in elderly metastatic colorectal cancer (mCRC) patients.

PATIENTS AND METHODS

We retrospectively analysed 54 irinotecan-refractory mCRC patients aged≥70 years treated with cetuximab plus irinotecan and evaluated clinical outcome according to KRAS and BRAF mutational status.

RESULTS

Median age was 73 years (70-82). Main grade 3-4 toxicities were skin rash (15%), diarrhea (19%) and neutropenia (13%). Irinotecan dose reduction was necessary in 39% of patients. Fifty-two (96%) patients were analysed for KRAS and BRAF status. The 29 KRAS wild-type patients achieved better RR (31% vs 4%; p=0.030) and median PFS (4.21 months vs 3.95 months; p=0.034; HR: 0.50, 95% CI: 0.27-0.95) when compared with KRAS mutated ones. RR (41% vs 3%; p=0.001) and mPFS (4.57 months vs 3.78 months, p=0.001; HR: 0.35, 95% CI: 0.19-0.66) were significantly higher among the 22 KRAS and BRAF wild-type patients compared to the 30 KRAS or BRAF mutated ones.

CONCLUSION

Cetuximab plus irinotecan has a favourable safety profile in elderly mCRC patients, but a reduced dose of irinotecan should be considered. Such a combination can be a useful option for elderly KRAS and BRAF wild-type patients.

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.

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.

PTEN expression and KRAS mutations on primary tumors and metastases in the prediction of benefit from cetuximab plus irinotecan for patients with metastatic colorectal cancer

PURPOSE

PTEN, AKT, and KRAS are epidermal growth factor receptor (EGFR) downstream regulators. KRAS mutations confer resistance to cetuximab. This retrospective study investigated the role of PTEN loss, AKT phosphorylation, and KRAS mutations on the activity of cetuximab plus irinotecan in patients with metastatic colorectal cancer (mCRC).

PATIENTS AND METHODS

A cohort of patients with irinotecan-refractory mCRC who were treated with cetuximab plus irinotecan was tested for PTEN immunoreactivity (ie, immunohistochemistry; IHC), pAKT IHC, and KRAS mutations. Analyses were performed both on primary tumors and on related metastases, and the association among IHC, mutational results, and treatment outcomes was investigated.

RESULTS

One-hundred two patients were eligible. Ninety-six primary tumors, 59 metastases, and 53 paired samples were available. Forty-nine primary tumors (58% of assessable samples) had a preserved PTEN expression (PTEN-positive), whereas 35 (40% of assessable samples) were pAKT-positive. Levels of concordance between primary tumors and metastases were 60%, 68%, and 95% for PTEN, pAKT, and KRAS, respectively. PTEN status on primary tumors and pAKT status both on primary tumors and on metastases did not predict response or progression-free survival (PFS). On metastases, 12 (36%) of 33 patients with PTEN-positive tumors were responders compared with one (5%) of 22 who had PTEN-negative tumors (P = .007). The median PFS of patients with PTEN-positive metastases was 4.7 months compared with 3.3 months for those with PTEN-negative metastases (hazard ratio [HR], 0.49; P = .005). Patients with PTEN-positive metastases and KRAS wild type had longer PFS compared with other patients (5.5 months v 3.8 months; HR, 0.42; P = .001).

CONCLUSION

PTEN loss in metastases may be predictive of resistance to cetuximab plus irinotecan. The combination of PTEN IHC and KRAS mutational analyses could help to identify a subgroup of patients with mCRC who have higher chances of benefiting from EGFR inhibition.

Analysis of single nucleotide polymorphisms (SNPs) of cytidine deaminase (CDA) and xeroderma pigmentosum group D (XPD) genes for the prediction of clinical response to gemcitabine and cisplatin in advanced non-small cell lung cancer (NSCLC) patients

7219

Background: Detection of genomic differences predictive of drug response may allow to customize chemotherapy to the characteristics of individual patients. Gemcitabine alone or in combination with cisplatin are two of the most common regimens used in the treatment of advanced NSCLC. We investigated the correlation between selected SNPs of genes encoding enzymes involved in the activity of gemcitabine and cisplatin, including CDA, XPD and ERCC1, and the response to chemotherapy. Methods: Forty advanced NSCLC chemo-naïve patients were enrolled into the study; 16 patients, aged > 70 years, were treated with gemcitabine; 24 patients, aged < 70 years, were treated with cisplatin plus gemcitabine. SNPs CDA A79C, XPD A751C, XPD G312A and ERCC1 C118T were analyzed with the ABI PRISM 7900HT Sequence Detection System using TaqMan probe-based assay in DNA obtained from peripheral blood samples. Statistical analysis was performed using Pearson χ2 test, Kaplan-Meier curve and log rank test. Results: Up to now 31 patients, 11 treated with gemcitabine and 20 with cisplatin plus gemcitabine, are evaluable for response with RECIST criteria; correlation between response and genotype are showed in the table. Actuarial progression free survival (PFS) was longer in patients treated with gemcitabine ± cisplatin with CDA A79A genotype than in others (respectively 11.0 vs 2.5 months, p = 0.0092), while no correlation was found between the SNPs of XPD and ERCC1 and PFS in patients receiving cisplatin and gemcitabine. Conclusions: CDA A79A genotype resulted predictive of response and longer PFS in NSCLC patients treated with gemcitabine ± cisplatin. There was also a trend toward significant correlation between XPD A751A and better response in cisplatin-treated patients, while the SNPs in XPD 312 and ERCC1 118 were not associated with response to chemotherapy.

[Table: see text]

No significant financial relationships to disclose.