Phase II trial of domatinostat (4SC-202) in combination with avelumab in patients with previously treated advanced mismatch repair proficient oesophagogastric and colorectal adenocarcinoma: EMERGE.

BACKGROUND: Most oesophagogastric adenocarcinomas (OGAs) and colorectal cancers (CRCs) are mismatch repair proficient (MMRp), responding poorly to immune checkpoint inhibition. We evaluated the safety and efficacy of domatinostat (histone deacetylase inhibitor) plus avelumab (anti-PD-L1 antibody) in patients with previously treated inoperable, advanced/metastatic MMRp OGA and CRC. PATIENTS AND METHODS: Eligible patients were evaluated in a multicentre, open-label dose escalation/dose expansion phase II trial. In the escalation phase, patients received escalating doses of domatinostat [100 mg once daily (OD), 200 mg OD, 200 mg twice daily (BD)] orally for 14 days followed by continuous dosing plus avelumab 10 mg/kg administered intravenously 2-weekly (2qw) to determine the recommended phase II dose (RP2D). The trial expansion phase evaluated the best objective response rate (ORR) during 6 months by RECIST version 1.1 using a Simon two-stage optimal design with 2/9 and 1/10 responses required to proceed to stage 2 in the OGA and CRC cohorts, respectively. RESULTS: Patients (n = 40) were registered between February 2019 and October 2021. Patients in the dose escalation phase (n = 12) were evaluated to confirm the RP2D of domatinostat 200 mg BD plus avelumab 10 mg/kg. No dose-limiting toxicities were observed. Twenty-one patients were treated at the RP2D, 19 (9 OGA and 10 CRC) were assessable for the best ORR; 2 patients with CRC did not receive combination treatment and were not assessable for the primary endpoint analysis. Six patients were evaluated in the dose escalation and expansion phases. In the OGA cohort, the best ORR was 22.2% (95% one-sided confidence interval lower bound 4.1) and the median duration of disease control was 11.3 months (range 9.9-12.7 months). No responses were observed in the CRC cohort. No treatment-related grade 3-4 adverse events were reported at the RP2D. CONCLUSIONS: Responses in the OGA cohort met the criteria to expand to stage 2 of recruitment with an acceptable safety profile. There was insufficient signal in the CRC cohort to progress to stage 2. TRIAL REGISTRATION: NCT03812796 (registered 23rd January 2019).

Biomarker analysis in oesophagogastric cancer: Results from the REAL3 and TransMAGIC trials.

BACKGROUND: REAL3 (Randomised ECF for Advanced or Locally advanced oesophagogastric cancer 3) was a phase II/III trial designed to evaluate the addition of panitumumab (P) to epirubicin, oxaliplatin and capecitabine (EOC) in untreated advanced oesophagogastric adenocarcinoma, or undifferentiated carcinoma. MAGIC (MRC Adjuvant Gastric Infusional Chemotherapy) was a phase III study which demonstrated that peri-operative epirubicin, cisplatin and infused 5-fluorouracil (ECF) improved survival in early oesophagogastric adenocarcinoma. PATIENTS AND METHODS: Analysis of response rate (RR; the primary end-point of phase II) and biomarkers in the first 200 patients randomised to EOC or modified dose (m) EOC+P in REAL3 was pre-planned to determine if molecular selection for the on-going study was indicated. KRAS, BRAF and PIK3CA mutations and PTEN expression were assessed in pre-treatment biopsies and results correlated with response to mEOC+P. Association between these biomarkers and overall survival (OS) was assessed in MAGIC patients to determine any prognostic effect. RESULTS: RR was 52% to mEOC+P, 48% to EOC. Results from 175 assessable biopsies: mutations in KRAS (5.7%), BRAF (0%), PIK3CA (2.5%) and loss of PTEN expression (15.0%). None of the biomarkers evaluated predicted resistance to mEOC+P. In MAGIC, mutations in KRAS, BRAF and PIK3CA and loss of PTEN (phosphatase and tensin homolog) were found in 6.3%, 1.0%, 5.0% and 10.9%, respectively, and were not associated with survival. CONCLUSIONS: The RR of 52% in REAL3 with mEOC+P met pre-defined criteria to continue accrual to phase III. The frequency of the mutations was too low to exclude any prognostic or predictive effect.

A multicentre study of capecitabine, oxaliplatin plus bevacizumab as perioperative treatment of patients with poor-risk colorectal liver-only metastases not selected for upfront resection.

BACKGROUND: Perioperative chemotherapy improves outcome in resectable colorectal liver-only metastasis (CLM). This study aimed to evaluate perioperative CAPOX (capecitabine-oxaliplatin) plus bevacizumab in patients with poor-risk CLM not selected for upfront resection. PATIENTS AND METHODS: Poor-risk CLM was defined as follows: more than four metastases, diameter >5 cm, R0 resection unlikely, inadequate viable liver function if undergoing upfront resection, inability to retain liver vascular supply, or synchronous colorectal primary presentation. Patients underwent baseline computed tomography, magnetic resonance imaging, and/or positron emission tomography (PET) for staging and received neoadjuvant CAPOX plus bevacizumab, with resectability assessed every four cycles. Primary end point was radiological objective response rate (ORR). RESULTS: Forty-six patients were recruited, of which 91% underwent PET to ensure metastases confined to liver. Following neoadjuvant CAPOX plus bevacizumab, the ORR was 78% (95% confidence interval 63% to 89%). This allowed 12 of 30 (40%) patients with initial nonsynchronous unresectable CLM to be converted to resectability. In addition, 10 of 15 (67%) patients with synchronous resectable CLM underwent liver resection, with four additional patients being observed alone due to excellent response to neoadjuvant therapy. No grade 3-4 perioperative complications were seen. CONCLUSION: Neoadjuvant CAPOX plus bevacizumab resulted in a high response rate for patients with CLMs with poor-risk features not selected for upfront resection and converted 40% of patients to resectability.