External validity of clinical trials with diverse trastuzumab-based chemotherapy regimens in advanced gastroesophageal adenocarcinoma: data from the AGAMENON-SEOM registry

Background: Trastuzumab combined with cisplatin and fluoropyrimidines, either capecitabine or 5-fluorouracile (XP/FP), is the standard first-line treatment for advanced, HER2-positive, gastric cancer patients based on the ToGA trial. Despite the lack of phase III trials, many clinicians administer t...

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Authors: Jimenez-Fonseca, P, Carmona-Bayonas, A, Martinez-Torron, A, Alsina, M, Custodio, A, Serra, O, Lavin, DC, Limon, ML, Sauri, T, Lopez, F, Visa, L, Granja, M, Lago, NM, Arrazubi, V, Tocino, RV, Hernandez, R, Aguado, G, Cano, JM, Carnicero, AM, Mangas, M, Pimentel, P, Montes, AF, Declara, IM, Longo, F, Ramchandani, A, Richard, MM, Hurtado, A, Azkarate, A, Perez, CH, Serrano, R, Gallego, J
Format: article
Status:Published version
Publication Date:2021
Country:España
Institution:Institut d'Investigació i Innovació Parc Taulí (I3PT)
Repository:r-I3PT. Repositorio Institucional Producción Científica del Institut d'Investigació i Innovació Parc Taulí
OAI Identifier:oai:i3pt.fundanetsuite.com:p2016
Online Access:https://i3pt.portalinvestigacion.com/publicaciones/2016
Access Level:Open access
Keyword:chemotherapy
external validity
gastric cancer
HER2
oxaliplatin
trastuzumab
Description
Summary:Background: Trastuzumab combined with cisplatin and fluoropyrimidines, either capecitabine or 5-fluorouracile (XP/FP), is the standard first-line treatment for advanced, HER2-positive, gastric cancer patients based on the ToGA trial. Despite the lack of phase III trials, many clinicians administer trastuzumab with alternative regimens. One meta-analysis suggests that substituting cisplatin for oxaliplatin might lead to greater efficacy and less toxicity. Methods: 594 patients with HER2-positive gastroesophageal adenocarcinoma were recruited from the AGAMENON-SEOM registry. The objective was to evaluate the external validity of clinical trials with chemotherapy and trastuzumab. Results: The regimens used in at least 5% of the patients were XP (27%), oxaliplatin and capecitabine (CAPOX) (26%), oxaliplatin and 5-fluorouracil (FOLFOX) (14%), FP (14%), triplet with anthracycline/docetaxel (7%), and carboplatin-FU (5%). Median exposure to trastuzumab was longer with FOLFOX (11.4 months, 95% CI, 9.1-21.0) versus ToGA regimens (7.5, 6.4-8.5), p < 0.001. Patients with HER2-IHC 3+ cancers had higher response rates than those with IHC 2+/FISH+, odds-ratio 1.97 (95% CI, 1.25-3.09). The results achieved with CAPOX-trastuzumab were comparable to those attained with ToGA regimens. FOLFOX-trastuzumab was superior to ToGA schemes in terms of overall survival (OS), with a greater magnitude of effect in IHC 2+/FISH+ tumors (HR 0.47, 0.24-0.92) compared with IHC 3+ (HR 0.69, 0.49-0.96), and in diffuse (HR 0.37, 0.20-0.69) versus intestinal-type tumors (HR 0.76, 0.54-1.06). Conclusion: We have updated the external validity of clinical trials with trastuzumab in first-line treatment of gastric cancer. Our data confirm the comparable outcomes of ToGA regimens and CAPOX-trastuzumab in clinical practice and point toward a possible benefit of FOLFOX-trastuzumab, contingent on the subtypes typically less sensitive to trastuzumab, to be confirmed in clinical trials.