From:  Macrophages as predictors and new targets for immunotherapy in colorectal cancer

 Ongoing clinical trials based on combination immunotherapy for CRC treatment.

TherapyTargetsType of cancer, sample sizeEfficiency of therapyMacrophages as indicators of response to therapyID clinical trialsAdverse events (rates)
Regorafenib plus nivolumab [117, 124]Kinase, PD-1MSS/pMMR CRC, n = 22ORR in 36% of cases (in clinical trial)CD206+CD11b+ M2-like macrophages within the tumor were significantly higher in responders before treatmentPhase Ib (NCT03406871)Liver transaminase increased, creatinine increased, and platelet count decreased (the most common, 70% in the clinical trial)
Pimitespib plus nivolumab [117, 125]Hsp90, PD-1MSS CRC, n = 23ORR in 16% of cases (in clinical trial)CD206+CD11b+ M2-like macrophages within the tumor were significantly higher in non-responders before treatmentPhase Ib (UMIN000032801)Rash, proteinuria, palmar-plantar erythrodysesthesia (the most common, grade 3 or worse, 7% in clinical trial)
Pembrolizumab (KEYNOTE 177 clinical trial) or nivolumab (group with first-line therapy) [118, 123]PD-1hypermutated CRC, n = 16Persistent response in 56% of casesCD68+CD74+ cells were observed in CRC tumors with a durable response. 80% of CD68+CD74+ cells expressed markers HLA-ABC, HLA-DR, CD40, CD16, and CD163Phase 3 (NCT02563002) + patients with first-line therapyDiarrhea, fatigue, nausea, abdominal pain, anemia, hypertension (97% patients in clinical trial)
Oncolytic virotherapy plus LP002 [99]Tumor cells, PD-1MSS CRC with liver metastasis, n = 4One out of four patients demonstrated a durable responseResponder had elevated levels of both M1-like and M2-like macrophagesPhase I (NCT04755543)Fever, nausea, fatigue, constipation, dry mouth (100% patients)
Pembrolizumab with or without XL888 [119]PD-1, Hsp90Advanced CRC with liver metastasis, n = 18No ORR with combination therapy. 25% of patients had stable diseaseDecreased CD68+ and CD68+IL6+ in liver metastasis with combination therapyPhase Ib/II (NCT03095781)Diarrhea, fatigue, abdominal pain, constipation, nausea, vomiting, eye disorders, anorexia, hypomagnesemia, cough, increased liver enzymes (grade 3–4, 12.5% patients in combination therapy)
Pembrolizumab plus maraviroc [121]CCR5, PD-1pMMR CRC, n = 20One patient achieved a partial response, 94.7% patients had disease progression (ORR in 5.3% of cases)Anti-tumor macrophage activationPhase I (NCT03274804)Hyperglycemia (1 case, grade 4)
Sintilimab plus chidamide with or without bevacizumab [122]PD-1, HDAC, VEGFUnresectable chemotherapy-refractory locally advanced or MSS/pMMR CRC, n = 4818-week PFS of triple combination therapy vs. double combination (64.0% vs. 21.7%) ORR of triple combination therapy vs. double combination (44.0% vs. 13.0%)Increased the number of monocytic lineage cells in triple therapy respondersPhase 2 (NCT04724239)Proteinuria, thrombocytopenia, neutropenia, anemia, leukopenia, diarrhea (96% patients in triple combination therapy, 100% patients in double combination therapy)

CCR5: C-C motif chemokine receptor 5; CRC: colorectal cancer; HDAC: histone deacetylase; MSS: microsatellite stable; ORR: objective response rate; PD-1: programmed cell death-1; PFS: progression-free survival; pMMR: mismatch repair proficient; VEGF: vascular endothelial growth factor.