This is an investigator-initiated study with currently 4 St: i.t. (A) or i.p. IMP321 (B); s.c. IMP321 with SOC (C) or combined with avelumab (D)...The SD gastric cancer pt of St A with PFS of 3 mo had an OS of 28 mo with increase of PD-L1 in the immune cells from 20% at baseline (BL) to 30% (D29 + D71). 3 SD pts with gastric cancer showed high CD45, CD163 expression at BL (tissue)...Intratumoral and intraperitoneal IMP321 can be safely administered up to 30 mg with signals of clinical and cytokine activity.