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Purpose: To assess the ability of circulating tumor DNA (ctDNA)-based testing to identify patients with HER2 (encoded by ERBB2)-positive gastric/gastroesophageal adenocarcinoma (GEA) who progressed on or after trastuzumab-containing treatments were treated with combination therapy of anti-HER2 and anti-PD-1 agents., Methods: ctDNA analysis was performed retrospectively using plasma samples collected at study entry from 86 patients participating in the phase 1/2 CP-MGAH22-05 study (NCT02689284)., Results: Objective response rate (ORR) was significantly higher in evaluable ERBB2 amplification-positive vs - negative patients based on ctDNA analysis at study entry (37% vs 6%, respectively; P = .00094). ORR was 23% across all patients who were evaluable for response. ERBB2 amplification was detected at study entry in 57% of patients (all HER2 positive at diagnosis), and detection was higher (88%) when HER2 status was determined by immunohistochemistry fewer than 6 months before study entry. ctDNA was detected in 98% (84/86) of patients tested at study entry. Codetected ERBB2-activating mutations were not associated with response., Conclusions: Current ERBB2 status may be more effective than archival status at predicting clinical benefit from margetuximab plus pembrolizumab therapy. ctDNA testing for ERBB2 status prior to treatment will spare patients from repeat tissue biopsies, which may be reserved for reflex testing when ctDNA is not detected.

Background: Margetuximab, a novel, investigational, Fc-engineered, anti-HER2 monoclonal antibody, is designed to more effectively potentiate innate immunity than trastuzumab. We aimed to evaluate the safety, tolerability, and antitumour activity of margetuximab plus pembrolizumab (an anti-PD-1 monoclonal antibody) in previously treated patients with HER2-positive gastro-oesophageal adenocarcinoma., Methods: CP-MGAH22-05 was a single-arm, open-label, phase 1b-2 dose-escalation and cohort expansion study done at 11 academic centres in the USA and Canada and 15 centres in southeast Asia (Korea, Taiwan, and Singapore) that enrolled men and women aged 18 years or older with histologically proven, unresectable, locally advanced or metastatic, HER2-positive, PD-L1-unselected gastro-oesophageal adenocarcinoma, with an Eastern Cooperative Oncology Group performance status of 0 or 1, who had progressed after at least one previous line of therapy with trastuzumab plus chemotherapy in the locally advanced unresectable or metastatic setting. In the dose-escalation phase, nine patients were treated: three received margetuximab 10 mg/kg intravenously plus pembrolizumab 200 mg intravenously every 3 weeks and six received the recommended phase 2 dose of margetuximab 15 mg/kg plus pembrolizumab 200 mg intravenously every 3 weeks. An additional 86 patients were enrolled in the phase 2 cohort expansion and received the recommended phase 2 dose. The primary endpoints were safety and tolerability, assessed in the safety population (patients who received at least one dose of either margetuximab or pembrolizumab) and the objective response rate as assessed by the investigator according to both Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1, in the response-evaluable population (patients with measurable disease at baseline and who received the recommended phase 2 dose of margetuximab and pembrolizumab). This trial is registered with ClinicalTrials.gov, NCT02689284. Recruitment for the trial has completed and follow-up is ongoing., Findings: Between Feb 11, 2016, and Oct 2, 2018, 95 patients were enrolled. Median follow-up was 19·9 months (IQR 10·7-23·1). The combination therapy showed acceptable safety and tolerability; there were no dose-limiting toxicities in the dose-escalation phase. The most common grade 3-4 treatment-related adverse events were anaemia (four [4%]) and infusion-related reactions (three [3%]). Serious treatment-related adverse events were reported in nine (9%) patients. No treatment-related deaths were reported. Objective responses were observed in 17 (18·48%; 95% CI 11·15-27·93) of 92 evaluable patients., Interpretation: These findings serve as proof of concept of synergistic antitumour activity with the combination of an Fc-optimised anti-HER2 agent (margetuximab) along with anti-PD-1 checkpoint blockade (pembrolizumab)., Funding: MacroGenics., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Introduction: The specific aims of the study were to evaluate the 2-year overall survival (OS) and progression-free survival (PFS), toxicity profile, and best objective response rate in patients with locally advanced, clinically unresectable esophageal cancer receiving cetuximab, cisplatin, irinotecan, and thoracic radiotherapy (TRT) within a multi-institutional cooperative-group setting., Methods: Eligible patients (cT4 M0 or medically unresectable, biopsy proven, and noncervical esophageal cancer) were to receive four 21-day cycles of cetuximab 400 mg/m (day 1, cycle 1), cetuximab 250 mg/m (day 8, 15, cycle 1; then days 1, 8, and 15 for subsequent cycles), cisplatin 30 mg/m (days 1 and 8, all cycles), and irinotecan 65 mg/m (days 1 and 8, all cycles). TRT was administered at 1.8 Gy in 28 daily fractions to a total dose of 50.4 Gy, to begin with on day 1 of cycle 3. The primary endpoint was 2-year OS, with an accrual goal of 75 patients with adenocarcinoma., Results: The study was closed because of slow accrual, with 21 eligible patients (11 squamous, 10 adenocarcinoma) enrolled from May 2005 to September 2007. Two-year OS and PFS (95% confidence interval [CI]) were 33.3% (14.6-57.0%) and 23.8% (8.2-47.2%), respectively. Kaplan-Meier estimates of median (95% CI) OS and PFS were 11.2 (6.4-43.6) and 6.4 (3.7-12.0) months, respectively. The overall response rate (95% CI) among 17 evaluable patients was 17.6% (3.8-43.4%), including 6% confirmed complete responders and 12% unconfirmed partial responders. Two deaths resulted from protocol treatment (sudden death and gastrointestinal necrosis). Ten (47.6%) and 6 (28.6%) patients had grade-3 or -4 toxicity, respectively: 52.4% were hematologic, 23.8% had fatigue, 19.0% had nausea, 19.0% had dehydration, and 19.0% had anorexia., Conclusions: Concomitant cetuximab, cisplatin, irinotecan, and TRT were poorly tolerated in the first North American cooperative group trial testing this regimen for locally advanced esophageal cancer as treatment-related mortality approached 10%. Single-institution phase-II cetuximab-based combined modality trials have yielded encouraging results in preliminary analyses. The SWOG GI Committee endorses enrollment to open clinical trials to clarify the therapeutic ratio of cetuximab-based combined modality approaches for esophageal cancer.

Purpose: Pathologic complete response (pCR) after neoadjuvant therapy for locally advanced esophageal adenocarcinoma is associated with improved survival. The Southwest Oncology Group designed a trimodality, phase II, single-arm trial with objectives of achieving a pCR rate of 40% with prospective exploratory analyses of intratumoral molecular markers postulated to affect response and survival., Patients and Methods: Patients with clinically staged II or III esophageal adenocarcinoma received oxaliplatin 85 mg/m(2) on days 1, 15, and 29; protracted-infusion fluorouracil (PI-FU) 180 mg/m(2)/d on days 8 through 43; and external-beam radiation therapy (EBRT) 5 days a week at 1.8 Gy/d for 25 fractions; surgery was performed 28 to 42 days after neoadjuvant therapy. Chemotherapy was planned after surgery. Tumors were analyzed for mRNA expression and polymorphisms in genes involved in drug metabolism and DNA repair., Results: Ninety-three patients were evaluable. Two deaths (2.2%) were attributable to preoperative therapy, and two deaths (2.2%) were attributable to surgery. Grade 3 and 4 toxicities were recorded for 47.3% and 19.4% of patients, respectively. Seventy-nine patients (84.9%) underwent surgery; 67.7% of patients had R0 resections. Twenty-six patients (28.0%) had confirmed pCR (95% CI, 19.1% to 38.2%). At a median follow-up of 39.2 months, estimates of median and 3-year overall survival (OS) were 28.3 months and 45.1%, respectively. Intratumoral ERCC-1 gene expression was inversely related to progression-free survival and OS., Conclusion: Neoadjuvant oxaliplatin, PI-FU, and EBRT for esophageal adenocarcinoma is active and tolerable. Because the regimen failed to meet the primary end point, it does not define a new standard. However, future trials can be built on this platform to validate the role of ERCC-1 in determining the best systemic regimen for individual patients.

Introduction: Esophageal adenocarcinomas commonly express the epidermal growth factor receptor. This trial assessed the 6-month overall survival probability in metastatic esophageal cancer patients treated with cetuximab as second-line therapy., Methods: This was a multicenter, open-label phase II study of single-agent cetuximab for metastatic esophageal adenocarcinoma patients who failed one prior chemotherapy regimen. Adequate organ function and Zubrod performance status of 0 to 2 were required. Patients received cetuximab 400 mg/m intravenously (IV) on week 1 and 250 mg/m IV weekly thereafter. The primary objective was to determine 6-month overall survival. Secondary end points included progression-free survival, response rate, and toxicity. Tumor tissue was collected for correlative studies., Results: Sixty-three patients were registered, with eight ineligible or never treated. Fifty-five eligible patients (49 men, 6 women; median age = 61.2 years [range, 30.7-88.5]) were enrolled. Twenty patients survived more than 6 months for a 6-month overall survival rate of 36% (95% confidence interval [CI]: 24-50%). The median overall survival was 4.0 months (95% CI: 3.2-5.9). Median progression-free survival was 1.8 months (95% CI: 1.7-1.9). One partial response and two unconfirmed partial responses were observed. Two patients experienced grade 4 fatigue. There was one treatment-related death due to pneumonitis. Germline polymorphisms of epidermal growth factor receptor, epidermal growth factor, interleukin (IL)-8, cyclooxygenase (COX)-2, vascular epidermal growth factor receptor (VEGF), CCND1, neuropilin 1 (NRP1), and K-ras mutational status were not associated with response or survival., Conclusions: The 6-month overall survival rate of 36% observed on this study failed to meet the primary survival objective. Thus, cetuximab alone cannot be recommended in the second-line treatment of metastatic esophageal cancer.