A study by Hofheinz and colleagues evaluated whether targeting the human epidermal growth factor receptor 2 (HER2) pathway can improve outcomes in early-stage esophagogastric adenocarcinoma (EGA).1 About 15%-20% of EGA overexpress HER2. In the metastatic setting, anti-HER2 therapies have an established role. Trastuzumab in combination with chemotherapy has been part of standard treatment for these tumors for over a decade and now immunotherapy, based on the ongoing KEYNOTE-811 study, has been proven effective as well.2,3 However, prior attempts to effectively target HER2 in the early stage have not been successful.4
A phase 2 trial conducted by the AIO EGA Study Group evaluated the addition of trastuzumab and pertuzumab to FLOT (fluorouracil, leucovorin, oxaliplatin, docetaxel) chemotherapy in resectable HER2-positive EGA. The trial closed early, before planned full accrual, when the results of the JACOB trial, which evaluated the addition of pertuzumab in the metastatic setting, came out as negative.5 However, the results are still worth discussing here. A total of 81 patients were enrolled in this study (40 in the experimental arm and 41 in the chemotherapy-only control arm). Pathologic complete response was significantly improved with the addition of anti-HER2 therapy (35% vs 12%; P = .02). The rates of R0 resection and surgical complications were similar. Median disease-free survival was not reached in the experimental arm (26 months in the control arm). This study suggests that evaluation of anti-HER2 agents in combination with chemotherapy is warranted. Given the promising results of the KEYNOTE-811 study, future studies should consider incorporative immunotherapy as well.
The Neo-PLANET phase 2 study by Tang and colleagues evaluated the addition of camrelizumab (anti-PD1 antibody) to concurrent chemoradiation in the treatment of advanced EGA.6 The 36 patients enrolled in this study received induction chemotherapy with capecitabine and oxaliplatin followed by chemoradiation with the same chemotherapy backbone. Camrelizumab was added from the time of all chemotherapy initiation. The pathologic complete response observed (33.3%) compared favorably to historical references. No new safety signals were identified. Current standards for resectable EGA include adjuvant nivolumab in patients who have residual disease at the time of resection post chemoradiation. This study demonstrated that the addition of immunotherapy earlier in the treatment course is safe and possibly efficacious. The prospective randomized phase 2/3 ECOG-ACRIN 2174 study will evaluate the addition of nivolumab to chemoradiation, as well as the addition of ipilimumab to nivolumab in the adjuvant setting, and will answer the question regarding the benefits of immunotherapy used earlier in the course of disease in a prospective randomized manner (NCT03604991).
The study by de Jongh and colleagues evaluated the pattern of lymph node metastasis after neoadjuvant chemotherapy with relation to the location of the primary gastric tumor. Tumors from 212 patients who were previously enrolled in the Dutch LOGICA trial comparing laparoscopy vs open D2 gastrectomy were included in this analysis. Although the primary tumor location (proximal vs distal) was associated with a higher frequency of metastasis to certain lymph node groups, this relationship was not exclusive. As such, the extent of lymphadenectomy should not depend on the primary location of the tumor and is not affected by neoadjuvant chemotherapy.
Additional References
1. Hofheinz R-D, Merx K, Haag GM, et al. FLOT versus FLOT/trastuzumab/pertuzumab perioperative therapy of human epidermal growth factor receptor 2–positive resectable esophagogastric adenocarcinoma: A randomized phase II trial of the AIO EGA Study Group. J Clin Oncol. 2022;40:3750-3761. Doi: 10.1200/JCO.22.00380
2. Janjigian YY, Kawazoe A, Yañez P, et al. The KEYNOTE-811 trial of dual PD-1 and HER2 blockade in HER2-positive gastric cancer. Nature. 2021;600:727-730. Doi: 10.1038/s41586-021-04161-3
3. Bang Y-J, Van Cutsem E, Feyereislova A, et al. Trastuzumab in combination with chemotherapy versus chemotherapy alone for treatment of HER2-positive advanced gastric or gastro-oesophageal junction cancer (ToGA): A phase 3, open-label, randomised controlled trial. Lancet. 2010;376:687-697. Doi: 10.1016/S0140-6736(10)61121-X
4. Safran HP, Winter K, Hilson D, et al. Trastuzumab with trimodality treatment for oesophageal adenocarcinoma with HER2 overexpression (NRG Oncology/RTOG 1010): A multicentre, randomised, phase 3 trial. Lancet Oncol. 2022;23:259-269. Doi: 10.1016/S1470-2045(21)00718-X
5. Tabernero J, Hoff PM, Shen L, et al. Pertuzumab plus trastuzumab and chemotherapy for HER2-positive metastatic gastric or gastro-oesophageal junction cancer (JACOB): Final analysis of a double-blind, randomised, placebo-controlled phase 3 study. Lancet Oncol. 2018:19:1372-1384. Doi: 10.1016/S1470-2045(18)30481-9
6. Tang Z, Wang Y, Liu D, et al. The Neo-PLANET phase II trial of neoadjuvant camrelizumab plus concurrent chemoradiotherapy in locally advanced adenocarcinoma of stomach or gastroesophageal junction. Nat Commun 2022;13:6807. Doi: 10.1038/s41467-022-34403-5