Clinical activity of FOLFIRI plus cetuximab according to extended gene mutation status by next-generation sequencing: findings from the CAPRI-GOIM trial

BACKGROUND

Treatment with antiepidermal growth factor receptor (anti-EGFR) monoclonal antibodies has been restricted to metastatic colorectal cancer (mCRC) patients with RAS wild-type tumors. Next-generation sequencing (NGS) allows the assessment in a single analysis of a large number of gene alterations and might provide important predictive and prognostic information.

PATIENTS AND METHODS

In the CAPRI-GOIM trial, 340 KRAS exon 2 wild-type mCRC patients received first-line FOLFIRI plus cetuximab. Tumor samples (182/340, 53.5%) were assessed by NGS to search for mutations in 22 genes involved in colon cancer.

RESULTS

Objective responses in the NGS cohort were observed in 104/182 patients [overall response rate (ORR) 57.1%; 95% confidence interval (95% CI) 52% to 66.4%] with a median progression-free survival (mPFS) of 9.8 (95% CI 8.7-11.5) months. NGS analysis was successfully completed in all 182 samples. One or more gene mutations (up to five) were detected in 124/182 (68.1%) tumors within 14/22 genes for a total of 206 mutations. KRAS exon 2 mutations were identified in 29/182 (15.9%) samples, defined as wild type by local laboratory assessment. Frequently mutated genes were: TP53 (39.6%), KRAS exons 3/4 (8.8%), NRAS exons 2/3 (7.1%), PIK3CA exons 9/20 (13.2%), BRAF (8.2%). FOLFIRI plus cetuximab treatment determined ORR of 62.0% (95% CI 55.5% to 74.6%) with mPFS of 11.1 (95% CI 9.2-12.8) months in patients with KRAS and NRAS wild-type tumors. Conversely, ORR was 46.6% (95% CI 39.9-57.5%) with mPFS of 8.9 (95% CI 7.4-9.6) months in patients with KRAS or NRAS mutations. Similarly, the subgroup of patients carrying KRAS, NRAS, BRAF, or PIK3CA mutations showed a worse outcome, although this might be due to a prognostic effect.

CONCLUSIONS

This study demonstrates that NGS analysis in mCRC is feasible, reveals high level of intra and intertumor heterogeneity, and identifies patients that might benefit of FOLFIRI plus cetuximab treatment.

Abstract P5-04-13: Antibody-based therapy targeting integrin a5 is an effective strategy to treat experimental breast cancer bone metastasis

Background: Integrin a5β1 is a specific fibronectin receptor that is often upregulated in breast cancer cells undergoing epithelial-to-mesenchymal transition. Preclinical evidence showed that α5β1-fibronectin interaction promotes in vitro the survival of growth-arrested breast cancer cells in the bone marrow. This is in line with the observation that disseminated tumor cells (DTCs) in the bone marrow, that are the earliest sign of development of metastatic disease in patients, express α5β1 integrin. However, the role of α5β1 in bone marrow micrometastasis formation remains unknown. Here, we investigated its role in experimental breast cancer bone metastasis, using an antibody-based strategy targeting the α5 subunit.

Methods: Integrin α5 mRNA expression levels were quantified by qRT-PCR, using radically resected primary tumors of 427 breast cancer patients. Comparison between Kaplan-Meier curves was performed using the log-rank test. The Cox model was used for multivariate analysis. For experimental metastasis, female BALB/c immunodeficient mice were treated with a chimeric IgG4 monoclonal antibody that specifically binds to human integrin subunit α5 (M200;15mg/kg) or the vehicle. Treatment was performed 3 times per week starting the day before intra-arterial inoculation with luciferase-expressing human MDA-MB-231/B02 breast cancer cells, which selectively metastasize to bone. Vehicle and M200-treated mice were analyzed by radiography and bioluminescence. On day 28 after tumor cell inoculation, animals were sacrificed and histomorphometric analysis of metastatic legs was performed. Alternatively, animals were culled on day 7 after tumor cell inoculation, and the bone marrow was flushed for DTC colony assay. In-vitro cell-based assays were conducted to explore the functions of α5β1 on adhesion, invasion and survival. Statistical analysis was carried out by performing a Mann-Whitney U test.

Results: Median durations of metastasis-free survival were 6.2 (high α5 expression) and 9.5 years (low α5 expression) (P = 0.0008). Additionally, compared with low expression, a high α5 expression was associated with shorter bone metastasis-free survival, both in univariate (P = 0.024) and multivariate analysis (HR = 1.65,95%CI = 1.02 to 2.67; P = 0.04).The treatment of tumor-bearing animals with M200 antibody statistically significantly delayed the onset of skeletal lesions (P = 0.02) and caused a 50% reduction in the extent of osteolytic lesions (P = 0.038), compared with vehicle. This difference was accompanied with a sharp reduction of tumor burden (P = 0.02), as determined by bioluminescence. Histomorphometric analysis of metastatic legs showed that M200 treatment decreased skeletal tumor burden (P = 0.027) and increased the bone volume (P = 0.02), compared with vehicle. Additionally, the number of DTC colonies in the bone marrow from M200-treated mice was dramatically decreased compared with vehicle (P<0.001). In vitro, M200 antibody did not affect tumor cell survival. By contrast, it specifically inhibited fibronectin-mediated tumor cell adhesion and invasion.

Conclusion: Our results suggest that α5β1 integrin expression in breast cancer cells facilitates bone marrow micrometastasis formation and the subsequent development of osteolytic lesions.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-04-13.

The bone anabolic therapy

Teriparatide (TPTD), the amino-terminal parathyroid hormone recombinant peptide [PTH (1–34)], is a drug with a proven anabolic action on the bone, effective in preventing vertebral and non-vertebral fragility fractures. Recent publications have investigated in great detail the TPTD action on the cortical bone, highlighting the increased strength in the critical zone of the hip with high risk of fracture in osteoporotic patients Poole (PLoS ONE 6:e16190, 2011). In November 2002, TPTD was approved by the FDA for use in post-menopausal women and men with osteoporosis at high risk of fracture and in patients with glucocorticoid-induced osteoporosis and, since then, has been used to treat more than 1 million patients worldwide (J Bone Miner Res 27(12):2429-2437, 2012). The unchanged safety profile and the well-known mechanism of action of this drug have led doctors to explore the use of TPTD in other conditions such as delayed fracture healing, non-union, osteonecrosis of the jaw, etc. The positive reports that have resulted from these studies are helping to hypothesize a new perspective on the wider use of this drug, but warrant further clinical investigation to consolidate these results.

Tryptophan hydroxylase autoantibodies as markers of a distinct autoimmune gastrointestinal component of autoimmune polyendocrine syndrome type 1

BACKGROUND

Autoantibodies to tryptophan hydroxylase (TPHAbs) directed against serotonin-producing enterochromaffin cells (EC) have been reported in autoimmune-polyendocrine-syndrome type 1 (APS-1) patients with gastrointestinal dysfunction (GID). Serotonin plays a critical role in enteric function and its peripheral blood levels reflect serotonin release from the gastrointestinal tract.

AIMS

We test the hypothesis that TPHAbs mark a distinct autoimmune component of APS-1 characterized by an autoimmune attack toward EC, which results in clinical GID.

METHODS

TPHAbs were measured in 64 APS-1 patients. Endoscopy with gastric (antrum/body) and duodenal biopsy was carried in 16 TPHAbs+ patients (8 with and 8 without GID) and in 2 TPHAbs- patients (without GID). Immunohistochemistry of biopsy specimens was carried out using antibodies to serotonin, chromogranin-A, CD3, CD4, CD8, and CD20. Serotonin serum levels were measured in TPHAbs+ and TPHAbs- patients who had endoscopy.

RESULTS

Thirty-seven of 64 patients were TPHAbs+ (11/12 with GID and 26/52 without GID; P < .001). Gastric and duodenal biopsies in all 8 TPHAb+ patients with GID showed lymphocytic infiltration with increased CD3+CD8+ intraepithelial lymphocytes and absence of EC. Furthermore, mean serotonin serum levels were below the normal range in TPHAb+ patients with GID (P < .01). In 8 TPHAb+ patients without GID gastric and duodenal biopsies showed different grades of inflammatory infiltration and reduced number of EC. Mean serotonin serum levels were near the lower limit of the normal range. In all TPHAbs+ patients the biopsies showed a reduced number of chromogranin-A positive cells consistent with enteroendocrine cells depletion. TPHAbs- patients without GID showed normal gastrointestinal mucosa and serotonin serum levels.

CONCLUSIONS

TPHAbs appear to be markers of a distinct autoimmune component of APS-1. Progressive involvement of the gastrointestinal EC leads to the transition from preclinical to clinical disease, characterized by GID and reduced serotonin serum levels.

Autoimmune-polyendocrinopathy-candidiasis-ectodermal-dystrophy in Calabria: clinical, immunological and genetic patterns

Autoimmune polyendocrinopathy-candidiasis-ectodermal- dystrophy (APECED), also known as autoimmune polyendocrine syndrome type 1 (APS-1), is a very rare disease. Diagnosis requires the presence of at least two of three major clinical features: chronic mucocutaneous candidiasis, chronic hypoparathyroidism, and Addison's disease.

DESIGN

In this study, we analyzed Autoimmune Regulator (AIRE) gene mutations and genotype-phenotype correlation in APECED patients originating from Calabria, a region in the south of Italy.

PATIENTS AND METHODS

Four patients and their first-degree relatives were evaluated for clinical manifestations, autoantibody presence and AIRE gene mutations.

RESULTS

Three patients carried a homozygous W78R mutation on exon 2, typical of patients with APECED from Apulia; the fourth patient had a homozygous R203X mutation on exon 5, typical of APECED patients from Sicily. Clinical disease expression showed wide variability. Analysis of relatives allowed the identification of 6 heterozygotes, none of whom showed major findings of APECED.

CONCLUSIONS

No AIRE gene mutations specific to Calabria were found in patients with APS-1, but mutations similar to those in patients from Apulia and Sicily. Heterozygosity for AIRE gene mutation is not associated with major findings of APECED.

Rare frequencey of point mutations for codon 12, 13 and 61 of ras gene in italian neuroblastoma

Single point mutations of ras oncogenes are found in many tumors and contribute to the pathogenesis of the cancer. The product of the ras gene, p21 protein, was found expressed in several neuroblastoma tissues. However, the role of ras gene in this tumor has yet to be clarified. To contribute to the understanding of the ras activation, 79 fresh biopsies of neuroblastoma were studied to investigate the possibility that ras would be activated by point mutation. Analysis of H-ras and N-ras was performed by means of PCR and SSO, while K-ras mutations were detected by multiplex-ASPCR. None of the neuroblastomas examined showed H- or K-ras activation, while N-ras mutations were demonstrated in only three patients (3,7%). N-myc oncogene is amplified in a substantial number of patients with neuroblastoma. N-myc amplification was studied by Southern blot technique. N-myc amplification was demonstrated in 13.2% of patients less than 1 year of age at diagnosis and 23% of older children. Two of the patients (one stage I and one stage IVs) with N-ras mutation and without N-myc amplification had a good outcome, while the third (stage IVs) with N-myc amplification had a poor prognosis. These results suggest that ras activation is a rare event in both amplified and non-amplified neuroblastoma tumors and that N-ras activation was not involved in the clinical outcome of these patients. Moreover, our data suggest that p21 expression is induced by a post-transcriptional activation.

Distribution of retinoic Acid receptor-alpha, receptor-Beta and receptor-gamma messenger-rnas in neuroblastoma-derived cell-lines and in fresh tumors

The expression of alpha, beta and gamma retinoic acid receptors (RAR) was analyzed by reverse transcription polymerase chain reaction (RT/PCR) in several neuroblastoma derived cell lines before and after exposure to 10 nM retinoic acid. Each cell line shows a different receptor pattern: RAR alpha mRNA is ubiquitously present, whereas RAR beta and RAR gamma mRNAs are not always expressed. After retinoic acid treatment at physiological concentration, the majority of cell lines shows expression of all three receptors but two are resistant to the retinoid in expressing RAR beta mRNA. These data suggest that each NB cell line follows a particular retinoic acid-dependent differentiation route, at least with regard to the expression of RAR alpha, beta and gamma receptors. In an attempt to develop a biochemical classification of neuroblastomas, which could also be useful in the prognosis of the disease, we have screened biopsies belonging to patients in different clinical stages for the distribution of RAR receptors. The results show that the pattern of RAR alpha, beta and gamma mRNAs expression is rather variable in fresh tumors even if they are classified at the same stage. This may account for heterogeneous tumor cell composition which has in turn its own complement of RA receptors.

Cetuximab rechallenge in metastatic colorectal cancer patients: how to come away from acquired resistance?

BACKGROUND

Scientific data provide the evidence that secondary K-RAS mutations do not occur during anti-epidermal growth factor receptor therapy in colorectal cancer patients. This multicenter phase II prospective study aims to investigate the activity of a retreatment with a cetuximab-based therapy.

PATIENTS AND METHODS

We enrolled 39 irinotecan-refractory patients who had a clinical benefit after a line of cetuximab- plus irinotecan-based therapy and then a progression of disease for which underwent a new line chemotherapy and finally, after a clear new progression of disease, were retreated with the same cetuximab- plus irinotecan-based therapy.

RESULTS

Median number of therapeutic lines before accrual was 4. Median interval time between last cycle of first cetuximab-based therapy and first cycle of the retreatment was 6 months. Overall response rate was 53.8% with 19 partial responses (48.7%) and 2 complete responses (5.1%). Disease stabilization was obtained in 35.9% of patients and progression in four patients (10.2%). Median progression-free survival was 6.6 months. The correlation between skin toxicity during first cetuximab therapy and during cetuximab rechallenge was significant (P = 0.01).

CONCLUSION

Rechallenge with the same cetuximab-based therapy may achieve a new important clinical benefit further delaying the progression of disease and improving the therapeutic options.

Natural history of bone metastasis in colorectal cancer: final results of a large Italian bone metastases study

BACKGROUND

Data are limited regarding bone metastases from colorectal cancer (CRC). The objective of this study was to survey the natural history of bone metastasis in CRC.

PATIENTS AND METHODS

This retrospective, multicenter, observational study of 264 patients with CRC involving bone examined cancer treatments, bone metastases characteristics, skeletal-related event (SRE) type and frequency, zoledronic acid therapy, and disease outcomes.

RESULTS

Most patients with bone metastases had pathologic T3/4 disease at CRC diagnosis. The spine was the most common site involved (65%), followed by hip/pelvis (34%), long bones (26%), and other sites (17%). Median time from CRC diagnosis to bone metastases was 11.00 months; median time to first SRE thereafter was 2.00 months. Radiation and pathologic fractures affected 45% and 10% of patients, respectively; 32% of patients had no reported SREs. Patients survived for a median of 7.00 months after bone metastases diagnosis; SREs did not significantly affect survival. Subgroup analyses revealed that zoledronic acid significantly prolonged median time to first SRE (2.00 months versus 1.00 month, respectively, P=0.009) and produced a trend toward improved overall survival versus no zoledronic acid.

CONCLUSION

This study illustrates the burden of bone metastases from CRC and supports the use of zoledronic acid in this setting.