P-30 First-line (1L) treatment patterns in advanced gastric, gastroesophageal junction, and esophageal adenocarcinoma (GC/GEJC/EAC): Data from the Spanish AGAMENON-SEOM registry

Data on treatment patterns and outcomes in patients with advanced gastroesophageal adenocarcinoma in daily clinical practice are scarce. Using real-world data from the Spanish AGAMENON-SEOM registry, this retrospective study assessed patient characteristics, treatment patterns, and outcomes for 1L advanced GC/GEJC/EAC. Adult patients diagnosed with locally advanced unresectable or metastatic GC/GEJC/EAC between 2008 and 2021 were identified from 34 centers. This analysis only included patients who received ≥1 cycle of 1L polychemotherapy. Primary endpoints included description of demographic and clinical characteristics at initial diagnosis (equivalent to 1L therapy initiation), 1L treatment patterns, progression-free survival (PFS) and overall survival (OS) from 1L therapy initiation. Secondary endpoints included subgroup analyses in patients with human epidermal growth factor receptor 2 (HER2)-negative status and in patients who met the eligibility criteria of the CheckMate 649 study (Janjigian YY et al, Lancet 2021;398:27-40) and were treated with FOLFOX or XELOX (hereafter, CheckMate 649-matched subgroup). The proportion of patients who received second-line (2L) or third-line (3L) therapy and the reasons for not receiving subsequent therapy were explored. Overall, patients initiating 1L treatment (n=3,110) had a median (range) age of 65 (20–89) years, were mostly male (71.0%), had an ECOG performance status (PS) of 1 (61.7%) or 0 (23.7%), and had normal (>35 g/dL) basal albumin levels (64.8%). The most prevalent comorbidities were diabetes (15.3%) and chronic cardiopathy (11.6%). The most common primary tumor location was the stomach (77.7%) versus GEJ (13.4%) or esophagus (8.7%). 5.6% of patients had unresectable locally advanced disease and 94.4% of patients had metastatic disease, primarily synchronous (77.6%); the number of metastastic sites was unknown in 13 (synchronous) and 4 (metachronous) patients. The most frequent metastatic locations were lymph nodes (46.4%) or peritoneum (43.7%). In the HER2-evaluable population (n=2,650), 73.3% of patients had HER2-negative tumors. Clinical characteristics of patients in the HER2-negative (n=2,385; includes 460 patients with unknown HER2 status) and CheckMate 649-matched (n=383) subgroups were generally similar to those of the overall population. The most common 1L treatments for HER2-negative tumors were FOLFOX6 (20%) and XELOX (19%). In the overall population, 1,588 patients received 2L therapy and 218 patients received 3L therapy. The primary reason for patients not receiving 2L or 3L therapy was poor ECOG PS (68.0% and 79.8%, respectively). At a median follow-up of 57.0 months in the overall population (n=3,037), the median (95% confidence interval [CI]) PFS and OS were 6.0 (5.8–6.2) and 10.8 (10.4–11.2) months, respectively. Median OS was 10.1 (95% CI 9.7–10.5) months in the HER2-negative subgroup (n=2,346). At a median follow-up of 32 months in the CheckMate 649-matched subgroup, median (95% CI) PFS and OS were 6.4 (5.7–7.2) and 11.7 (10.6–12.8) months, respectively. In this real-world observational study of the Spanish AGAMENON-SEOM registry, PFS and OS outcomes for 1L treatment of advanced GC/GEJC/EAC were comparable to those of historical studies. With an estimated median OS of < 1 year from 1L therapy initiation, better treatment options for patients with advanced GC/GEJC/EAC remain an unmet need and deserve further investigation.