1385P Phase II study of neoadjuvant camrelizumab combined with chemoradiation for locally advanced proximal gastric cancer (Neo-PLANET, NCT03631615)

Recent results from several clinical trials evaluating chemoimmunotherapy combination as neoadjuvant therapy have shown improved pathologic complete response (pCR) in some cancer types other than PGC. Thus, the phase II study (Neo-PLANET) was conducted to evaluate the efficacy and safety of camrelizumab plus chemoradiation as neoadjuvant therapy for locally advanced PGC. Eligible patients with proximal gastric adenocarcinoma (cT3-4aN+M0) received sequentially one cycle of XELOX regimen (oxaliplatin 130mg/m2 iv d1 and capecitabine 1000mg/m2 po bid d1-14), chemoradiotherapy (45Gy/25 fractions, capecitabine 850mg/m2 po bid for five weeks) followed by one cycle of XELOX, along with five cycles of camrelizumab (200 mg iv, q3w) throughout neoadjuvant therapy. After radical surgery, they were advised to receive four cycles of XELOX. The primary endpoint was pCR rate. Secondary endpoints included major pathologic response (MPR) rate, progression-free survival,overall survival, and safety profile. A total of 36 patients were included with a median age of 65.5 years (range 35-72). Most of patients (77.8%) were male, 86.1% had cT4a, and 52.8% of primary tumors located at the gastroesophageal junction, others at gastric body. Beyond one patient with liver metastasis, one with peritoneal metastasis and one patient who refused surgery, 33 patients underwent radical surgery. R0 resection rate was 91.7%, 12 patients achieved pCR (33.3%) and MPR rate was 41.7%. The most common treatment emergent adverse events (TEAEs) of any grade included lymphocyte count decreased (97.2%), anemia (88.9%), white blood cell decreased (72.2%), and reactive capillary hyperplasia (69.4%). Twenty-seven patient (75%) experienced grade 3-4 lymphocyte count decreased. Camrelizumab combined chemoradiation in the neoadjuvant setting showed promising results in patients with locally advanced PGC, and further investigation is warranted in a phase III clinical trial.