Showing papers by "Salvatore Siena published in 2019"

Atezolizumab with or without cobimetinib versus regorafenib in previously treated metastatic colorectal cancer (IMblaze370): a multicentre, open-label, phase 3, randomised, controlled trial

Abstract: Summary Background Microsatellite-stable metastatic colorectal cancer is typically unresponsive to immunotherapy. This phase 3 study was designed to assess atezolizumab plus cobimetinib in metastatic colorectal cancer. Here, we report the comparison of atezolizumab plus cobimetinib or atezolizumab monotherapy versus regorafenib in the third-line setting. Methods IMblaze 370 is a multicentre, open-label, phase 3, randomised, controlled trial, done at 73 academic medical centres and community oncology practices in 11 countries. Patients aged at least 18 years with unresectable locally advanced or metastatic colorectal cancer, baseline Eastern Cooperative Oncology Group performance status of 0–1, and disease progression on or intolerance to at least two previous systemic chemotherapy regimens were enrolled. We used permuted-block randomisation (block size four) to assign patients (2:1:1) via an interactive voice and web response system to atezolizumab (840 mg intravenously every 2 weeks) plus cobimetinib (60 mg orally once daily for days 1–21 of a 28-day cycle), atezolizumab monotherapy (1200 mg intravenously every 3 weeks), or regorafenib (160 mg orally once daily for days 1–21 of a 28-day cycle). Stratification factors were extended RAS status (wild-type vs mutant) and time since diagnosis of first metastasis ( ClinicalTrials.gov , number NCT02788279 . Findings Between July 27, 2016, and Jan 19, 2017, 363 patients were enrolled (183 patients in the atezolizumab plus cobimetinib group, 90 in the atezolizumab group, and 90 in the regorafenib group). At data cutoff (March 9, 2018), median follow-up was 7·3 months (IQR 3·7–13·6). Median overall survival was 8·87 months (95% CI 7·00–10·61) with atezolizumab plus cobimetinib, 7·10 months (6·05–10·05) with atezolizumab, and 8·51 months (6·41–10·71) with regorafenib; the hazard ratio was 1·00 (95% CI 0·73–1·38; p=0·99) for the combination versus regorafenib and 1·19 (0·83–1·71; p=0·34) for atezolizumab versus regorafenib. Grade 3–4 adverse events were reported in 109 (61%) of 179 patients in the atezolizumab plus cobimetinib group, 28 (31%) of 90 in the atezolizumab group, and 46 (58%) of 80 in the regorafenib group. The most common all-cause grade 3–4 adverse events in the combination group were diarrhoea (20 [11%] of 179), anaemia (ten [6%]), increased blood creatine phosphokinase (12 [7%]), and fatigue (eight [4%]). Serious adverse events were reported in 71 (40%) of 179 patients in the combination group, 15 (17%) of 90 in the atezolizumab group, and 18 (23%) of 80 in the regorafenib group. Two treatment-related deaths occurred in the combination group (sepsis) and one in the regorafenib group (intestinal perforation). Interpretation IMblaze370 did not meet its primary endpoint of improved overall survival with atezolizumab plus cobimetinib or atezolizumab versus regorafenib. The safety of atezolizumab plus cobimetinib was consistent with those of the individual drugs. These results underscore the challenge of expanding the benefit of immunotherapy to patients whose tumours have lower baseline levels of immune inflammation, such as those with microsatellite-stable metastatic colorectal cancer. Funding F Hoffmann-La Roche Ltd/Genentech Inc.

Adaptive mutability of colorectal cancers in response to targeted therapies

Abstract: The emergence of drug resistance limits the efficacy of targeted therapies in human tumors. The prevalent view is that resistance is a fait accompli: when treatment is initiated, cancers already contain drug-resistant mutant cells. Bacteria exposed to antibiotics transiently increase their mutation rates (adaptive mutability), thus improving the likelihood of survival. We investigated whether human colorectal cancer (CRC) cells likewise exploit adaptive mutability to evade therapeutic pressure. We found that epidermal growth factor receptor (EGFR)/BRAF inhibition down-regulates mismatch repair (MMR) and homologous recombination DNA-repair genes and concomitantly up-regulates error-prone polymerases in drug-tolerant (persister) cells. MMR proteins were also down-regulated in patient-derived xenografts and tumor specimens during therapy. EGFR/BRAF inhibition induced DNA damage, increased mutability, and triggered microsatellite instability. Thus, like unicellular organisms, tumor cells evade therapeutic pressures by enhancing mutability.

HER2 Positivity Predicts Unresponsiveness to EGFR-Targeted Treatment in Metastatic Colorectal Cancer

Abstract: BACKGROUND HER2 amplification is detected in 3% of patients with colorectal cancer (CRC), making tumors in the metastatic setting vulnerable to double pharmacological HER2 blockade. Preclinical findings show that it also might impair response to anti-epidermal growth factor receptor (EGFR) treatment. SUBJECTS AND METHODS Patients with KRAS exon 2 wild-type metastatic CRC underwent molecular screening of HER2 positivity by HERACLES criteria (immunohistochemistry 3+ or 2+ in ≥50% of cells, confirmed by fluorescence in situ hybridization). A sample of consecutive HER2-negative patients was selected as control. A regression modeling strategy was applied to identify predictors explaining the bulk of HER2 positivity and the association with response to previous anti-EGFR treatment. RESULTS From August 2012 to April 2018, a total of 100 HER2-positive metastatic CRC tumors were detected out of 1,485 KRAS exon 2 wild-type screened patients (6.7%). HER2-positive patients show more frequently lung metastases (odds ratio [OR], 2.04; 95% confidence interval [CI], 1.15-3.61; p = .014) and higher tumor burden (OR, 1.48; 95% CI, 1.10-2.01; p = .011), and tumors were more likely to be left sided (OR, 0.50; 95% CI, 0.22-1.11; p = .088). HER2-positive patients who received treatment with anti-EGFR agents (n = 79) showed poorer outcome (objective response rate, 31.2% vs. 46.9%, p = .031; progression-free survival, 5.7 months vs. 7 months, p = .087). CONCLUSION Testing for HER2 should be offered to all patients with metastatic CRC because the occurrence of this biomarker is unlikely to be predicted based on main clinicopathological features. Patients with HER2-amplified metastatic CRC are less likely to respond to anti-EGFR therapy. IMPLICATIONS FOR PRACTICE Patients with HER2-amplified/overexpressed metastatic colorectal cancer (mCRC) harbor a driver actionable molecular alteration that has been shown in preclinical models to hamper efficacy of the anti-epidermal growth factor receptor (EGFR) targeted therapies. The present study confirmed that this molecular feature was associated with worse objective tumor response and shorter progression-free survival in response to previous anti-EGFR therapies. Moreover, it was found that the occurrence of this biomarker is unlikely to be predicted based on main clinicopathological features. Therefore, HER2 status assessment should be included in the molecular diagnostic workup of all mCRC for speedy referral to clinical trials encompassing HER2-targeted double blockade independently of previous anti-EGFR treatment.

Plasma HER2 (ERBB2) Copy Number Predicts Response to HER2-targeted Therapy in Metastatic Colorectal Cancer.

Abstract: Purpose: ERBB2 (HER2) amplification is an emerging biomarker in colon cancer, conferring sensitivity to combination anti-HER2 therapy. Measurement of HER2 copy number is typically performed using surgical specimens, but cell-free circulating tumor DNA (ctDNA) analysis may be a noninvasive alternative. We determined the sensitivity of plasma copy number (pCN) for detecting ERBB2 amplifications and whether pCN correlated with tissue-detected copy number. We also assessed response to HER2-targeted therapy based on pCN and suggest a pCN threshold predictive of response. Experimental Design: Forty-eight pretreatment and progression plasma samples from 29 HER2-positive patients in the HERACLES A clinical trial were tested using the Guardant360 cfDNA assay. We correlated ERRB2 pCN with progression-free survival (PFS) and best objective response (BOR) and applied an adjustment method based on tumor DNA shedding using the maximum mutant allele fraction as a surrogate for tumor content to accurately determine the pCN threshold predictive of response. Results: Forty-seven of 48 samples had detectable ctDNA, and 46 of 47 samples were ERBB2-amplified on the basis of cfDNA [2.55–122 copies; 97.9% sensitivity (95% confidence interval, 87.2%–99.8%)]. An adjusted ERBB2 pCN of ≥25.82 copies correlated with BOR and PFS (P = 0.0347). Conclusions: cfDNA is a viable alternative to tissue-based genotyping in the metastatic setting. The cfDNA platform utilized correctly identified 28 of 29 (96.6%) of pretreatment samples as ERBB2-amplified and predicted benefit from HER2-targeted therapy. In this study, an observed pCN of 2.4 and an adjusted pCN of 25.82 copies of ERBB2 are proposed to select patients who will benefit from HER2-targeted therapy.

A Multicenter Phase II Study of AMG 337 in Patients with MET-Amplified Gastric/Gastroesophageal Junction/Esophageal Adenocarcinoma and Other MET-Amplified Solid Tumors

Abstract: Purpose: MET gene amplification is associated with poor prognosis in gastric/gastroesophageal junction/esophageal (G/GEJ/E) cancers. We determined antitumor activity, safety, and pharmacokinetics of the small-molecule MET inhibitor AMG 337 in MET-amplified G/GEJ/E adenocarcinoma or other solid tumors. Patients and Methods: In this phase II, single-arm study, adults with MET-amplified G/GEJ/E adenocarcinoma (cohort 1) or other MET-amplified solid tumors (cohort 2) received AMG 337 300 mg/day orally in 28-day cycles. The primary endpoint was objective response rate (ORR; cohort 1). Secondary endpoints included ORR (cohort 2), progression-free survival (PFS), overall survival (OS), and safety. Results: Of 2101 patients screened for MET amplification, 132 were MET-amplified and 60 were enrolled: 45 in cohort 1, and 15 in cohort 2. Fifty-six patients (97%) had metastatic disease; 57 had prior lines of therapy (1 prior line, 29%; ≥2 prior lines, 69%). A protocol-permitted review showed efficacy that was lower-than-expected based on preliminary data from a first-in-human study, and enrollment was stopped. Fifty-eight patients received ≥1 AMG 337 dose. ORR in cohort 1 was 18% (8 partial responses). No responses were observed in cohort 2. Of 54 evaluable patients, median (95% CI) PFS and OS were 3.4 (2.2–5.0) and 7.9 (4.8–10.9) months, respectively. The most frequent adverse events (AEs) were headache (60%), nausea (38%), vomiting (38%), and abdominal pain, decreased appetite, and peripheral edema (33% each); 71% had grade ≥3 AEs and 59% had serious AEs. Conclusions: AMG 337 showed antitumor activity in MET-amplified G/GEJ/E adenocarcinoma but not in MET-amplified non–small-cell lung cancer. See related commentary by Ma, p. 2375

A Comprehensive PDX Gastric Cancer Collection Captures Cancer Cell–Intrinsic Transcriptional MSI Traits

Abstract: Gastric cancer is the world's third leading cause of cancer mortality. In spite of significant therapeutic improvements, the clinical outcome for patients with advanced gastric cancer is poor; thus, the identification and validation of novel targets is extremely important from a clinical point of view. We generated a wide, multilevel platform of gastric cancer models, comprising 100 patient-derived xenografts (PDX), primary cell lines, and organoids. Samples were classified according to their histology, microsatellite stability, Epstein-Barr virus status, and molecular profile. This PDX platform is the widest in an academic institution, and it includes all the gastric cancer histologic and molecular types identified by The Cancer Genome Atlas. PDX histopathologic features were consistent with those of patients' primary tumors and were maintained throughout passages in mice. Factors modulating grafting rate were histology, TNM stage, copy number gain of tyrosine kinases/KRAS genes, and microsatellite stability status. PDX and PDX-derived cells/organoids demonstrated potential usefulness to study targeted therapy response. Finally, PDX transcriptomic analysis identified a cancer cell-intrinsic microsatellite instability (MSI) signature, which was efficiently exported to gastric cancer, allowing the identification, among microsatellite stable (MSS) patients, of a subset of MSI-like tumors with common molecular aspects and significant better prognosis. In conclusion, we generated a wide gastric cancer PDX platform, whose exploitation will help identify and validate novel "druggable" targets and optimize therapeutic strategies. Moreover, transcriptomic analysis of gastric cancer PDXs allowed the identification of a cancer cell-intrinsic MSI signature, recognizing a subset of MSS patients with MSI transcriptional traits, endowed with better prognosis. SIGNIFICANCE: This study reports a multilevel platform of gastric cancer PDXs and identifies a MSI gastric signature that could contribute to the advancement of precision medicine in gastric cancer.

Patient-derived xenografts and matched cell lines identify pharmacogenomic vulnerabilities in colorectal cancer

Abstract: Purpose: Patient-derived xenograft (PDX) models accurately recapitulate the tumor of origin in terms of histopathology, genomic landscape, and therapeutic response, but some limitations due to costs associated with their maintenance and restricted amenability for large-scale screenings still exist. To overcome these issues, we established a platform of 2D cell lines (xeno-cell lines, XL), derived from PDXs of colorectal cancer with matched patient germline gDNA available. Experimental Design: Whole-exome and transcriptome sequencing analyses were performed. Biomarkers of response and resistance to anti-HER therapy were annotated. Dependency on the WRN helicase gene was assessed in MSS, MSI-H, and MSI-like XLs using a reverse genetics functional approach. Results: XLs recapitulated the entire spectrum of colorectal cancer transcriptional subtypes. Exome and RNA-seq analyses delineated several molecular biomarkers of response and resistance to EGFR and HER2 blockade. Genotype-driven responses observed in vitro in XLs were confirmed in vivo in the matched PDXs. MSI-H models were dependent upon WRN gene expression, while loss of WRN did not affect MSS XLs growth. Interestingly, one MSS XL with transcriptional MSI-like traits was sensitive to WRN depletion. Conclusions: The XL platform represents a preclinical tool for functional gene validation and proof-of-concept studies to identify novel druggable vulnerabilities in colorectal cancer.

Combined Low Densities of FoxP3+ and CD3+ Tumor-Infiltrating Lymphocytes Identify Stage II Colorectal Cancer at High Risk of Progression

Abstract: The densities of CD3+ and CD8+ tumor-infiltrating lymphocytes (TILs), combined with tumor-node-metastasis (TNM) staging, have prognostic value for patients with nonmetastatic colorectal cancer. We compared the prognostic value of CD3+ and FoxP3+ TILs at the invasive front, TNM classifiers, and microsatellite (MS) status in a trial set of patients with stage II and III colorectal cancer (n = 413), by recursive partitioning with a classification and regression tree (CART). Significant prognostic factors and interactions were reassessed by logistic regression and Cox proportional-hazards modeling in the trial and a validation set (n = 215) of patients with stage II colorectal cancer. In the trial set, CART indicated that TIL numbers were of value only in predicting recurrence risk for stage II cancers, where low densities of FoxP3+ TILs ranked first and low densities of CD3+ TILs further stratifying risk. Multivariate analysis showed that TILs interacted with tumor stage (FoxP3+, P = 0.06; CD3+, P = 0.02) and MS instability (MSI; FoxP3+; P = 0.02). In stage II MS-stable cancers, concomitant low densities of both FoxP3+ and CD3+ TILs identified patients with the highest progression risk in the trial [HR 7.24; 95% confidence interval (CI), 3.41-15.4; P < 0.001] and the validation (HR 15.16; 95% CI, 3.43-66.9; P < 0.001) sets. FoxP3+ and CD3+ TIL load in colorectal cancer was more informative than other prognostic factors before the cancer progressed to lymph nodes. This prognostic information about TILs, including FoxP3+ cells, suggests that randomized controlled trials might be refined to include interactions between TNM status, molecular classifiers, and postsurgical treatments.

Whole exome sequencing analysis of urine trans-renal tumour DNA in metastatic colorectal cancer patients

Abstract: Background The analysis of circulating free tumour DNA (ctDNA) in blood, commonly referred as liquid biopsy, is being used to characterise patients with solid cancers. Tumour-specific genetic variants can also be present in DNA isolated from other body fluids, such as urine. Unlike blood, urine sampling is non-invasive, can be self-performed, and allows recurrent longitudinal monitoring. The features of tumour DNA that clears from the glomerular filtration barrier, named trans-renal tumour DNA (trtDNA), are largely unexplored. Patients and methods Specimens were collected from 24 patients with KRAS or BRAF mutant metastatic colorectal cancer (mCRC). Driver mutations were assessed by droplet digital PCR (ddPCR) in ctDNA from plasma and trtDNA from urine. Whole exome sequencing (WES) was performed in DNA isolated from tissue, plasma and urine. Results Out of the 24 CRC cases, only four had sufficient DNA to allow WES analyses in urine and plasma. We found that tumour alterations primarily reside in low molecular weight fragments (less than 112 bp). In patients whose trtDNA was more than 2.69% of the urine derived DNA, cancer-specific molecular alterations, mutational signatures and copy number profiles identified in urine DNA are comparable with those detected in plasma ctDNA. Conclusions With current technologies, WES analysis of trtDNA is feasible in a small fraction of mCRC patients. Tumour-related genetic information is mainly present in low molecular weight DNA fragments. Although the limited amounts of trtDNA poses analytical challenges, enrichment of low molecular weight DNAs and optimised computational tools can improve the detection of tumour-specific genetic information in urine.

High Circulating Methylated DNA Is a Negative Predictive and Prognostic Marker in Metastatic Colorectal Cancer Patients Treated With Regorafenib.

Abstract: Background: Regorafenib improves progression free survival (PFS) in a subset of metastatic colorectal cancer (mCRC) patients, although no biomarkers of efficacy are available. Circulating methylated DNA (cmDNA) assessed by a five-gene panel was previously associated with outcome in chemotherapy treated mCRC patients. We hypothesized that cmDNA could be used to identify cases most likely to benefit from regorafenib (i.e., patients with PFS longer than 4 months). Methods: Plasma samples from mCRC patients were collected prior to (baseline samples N = 60) and/or during regorafenib treatment (N = 62) for the assessment of cmDNA and total amount of cell free DNA (cfDNA). Results: In almost all patients, treatment with regorafenib increased the total cfDNA, but decreased cmDNA warranting the normalization of cmDNA to the total amount of circulating DNA (i.e., cmDNA/ml). We report that cmDNA/ml dynamics reflects clinical response with an increase in cmDNA/ml associated with higher risk of progression (HR for progression = 1.78 [95%CI: 1.01-3.13], p = 0.028). Taken individually, high baseline cmDNA/ml (above median) was associated with worst prognosis (HR for death = 3.471 [95%CI: 1.83-6.57], p < 0.0001) and also predicted shorter PFS (<16 weeks with PPV 86%). In addition, high cmDNA/ml values during regorafenib treatment predicted with higher accuracy shorter PFS (<16 weeks with a PPV of 96%), therefore associated with increased risk of progression (HR for progression = 2.985; [95%CI: 1.63-5.46; p < 0.0001). Conclusions: Our data highlight the predictive and prognostic value of cmDNA/ml in mCRC patients treated with regorafenib.

Efficacy of entrectinib in patients (pts) with solid tumors and central nervous system (CNS) metastases: Integrated analysis from three clinical trials.

Abstract: 3017Background: Entrectinib potently inhibits kinases encoded by the NTRK and ROS1 genes. It achieves therapeutic levels in the CNS with antitumor activity in intracranial tumor models. We report i...

Pembrolizumab in MMR-proficient metastatic colorectal cancer pharmacologically primed to trigger dynamic hypermutation status: The ARETHUSA trial.

Abstract: TPS2659Background: Metastatic colorectal cancer (CRC) harbouring genetic defects in the mismatch-repair pathway (MMRd) presents with a high tumor mutational burden (TMB), and is highly sensitive to...