Evaluating Pembrolizumab, Trastuzumab and FLOT as Perioperative Treatment of HER2-positive, Localized Esophagogastric Adenocarcinoma

Her-2 positive patients suffering from localized esophagogastric adenocarcinoma (≥ T2 any N+ or any T N+) without evidence of metastatic disease will be included in the study. Eligible subjects will receive a combination of pembrolizumab and trastuzumab with FLOT 8 weeks pre- as well as post-surgery, followed by pembrolizumab and trastuzumab treatment for up to one year (maximum of 17 administrations of systemic treatment with pembrolizumab and trastuzumab incl. pre- and postoperative chemo-immunotherapy) or until tumor relapse/progression or occurrence of limiting toxicity.

The primary objective of this phase II study is to demonstrate the efficacy of the FLOT/trastuzumab/pembrolizumab regimen in terms of an improvement in disease free survival (DFS) according to RECIST v1.1 and an increase in the pathological complete response (pCR) rate compared to historical controls (interim read out after surgery of last patient in study with 18 months recruitment after 24 months). Secondary objectives are further efficacy and tolerability parameters, including overall response rate according to RECIST v1.1, R0 resection rate, overall survival, safety, and tolerability (including perioperative morbidity).

The exploratory objective is to assess whether clinical efficacy correlates with molecularly-defined subgroups (PD-L1 expression, MSI subtypes, and others).

30 patients will be enrolled in this trial.