Table 1.

Timing of oncolytic virotherapy and immune checkpoint inhibitor combinations in selected preclinical studies

Virus family	Virus	Indication	Combination drug	Virus RoA	Dosing schedule	Timing comment	References
Adenovirus	Ad-TK	GL261Luc2 glioma	Anti-PD1	IC	Virus day 7, ICI days 10, 13, 16, 19	Delayeda ICI administration improved survival	[105]
	Ad5 TNF-α or IL-2	B16-OVA melanoma	Anti-PD1	IT	Virus day 10, ICI day 10, q3d Virus days 11, 12, 14, q3d, ICI days 11, 12, 14, q3d Virus days 11, 12, 14, q3d, ICI day 14, q3d	Simultaneous or delayeda ICI (or ICI and ACT) administration improved survival over virus alone	[106]
	hTertAd	CMT64 lung adenocarcinoma	Anti-PD1	IT	Virus day 0, ICI days 0, 3, 6, 9	Simultaneous administration improved survival and broadened T cell neoantigen response	[65]
	ONCOS-102: GM-CSF and Ad5/3 capsid	A2058 melanoma	Pembrolizumab	IT	Virus days 15, 17, 19, ICI days 15, 17, 19, then q3–4d	Simultaneous ICI synergistically reduced tumor volume, no significance comparisons between combination and virus alone	[107]
HSV-1	HSV-G47Δ IL-12	005 GSC glioma	Anti-PD1 Anti-PDL1 Anti-CTLA4	IT	Virus day 12, anti-PD1 or anti-PD-L1 days 15, 18, 21 Virus day 8, anti-CTLA4 days 8, 11, 14 Virus day 8, combination anti-PD1 anti-CTLA4 days 8, 11, 14	Earlier (day 8) virus and simultaneous ICI administration yielded best outcomes	[108]
	HSV1716	M3-9-M and 76-9 rhabdomyosarcoma	Anti-PD1	IT	Virus days 0, 2, 4, ICI days 4, 7, 11	Delayeda ICI administration improved survival	[109]
Maraba	MG1	4T1, EMT6, E0771 breast cancer	Anti-CTLA4 Anti-PD1	IT neoadjuvant	Virus days 7–11 (daily), combination anti-CTLA4 and anti-PD1 days 21–29 (q2d)	Delayedb combination anti-CTLA4 and anti-PD1 ICI administration improved survival	[71]
NDV	NDV LaSota	B16 melanoma	Anti-CTLA4	IT	Virus and ICI days 7, 10, 13, 16	Simultaneous ICI administration improved survival	[64]
	NDV LaSota	B16F10 melanoma and CT26 colon cancer	Anti-PD1 Anti-PDL1	IT	B16F10 model: virus and ICI days 3, 5, 7, 9 CT26 model: virus and ICI days 7, 9, 11, 13	Simultaneous ICI administration improved survival	[110]
Reovirus	Reovirus	5TGM1-luc multiple myeloma	Anti-PDL1	IV	Virus days 7, 14, 21, ICI day 22, q2d × 8	Delayedb ICI administration improved survival	[111]
	Reovirus	GL261 glioma	Anti-PD1	IV	Virus days 5–10, 12–17, ICI days 19, 21, 23	Delayedb ICI administration combined with GM-CSF improved survival over virus + GM-CSF	[14]
Vaccinia	vvDD-Fcu1	MCA205 sarcoma	Anti-PD1 Anti-CTLA4	IT	Virus days 0, 3, ICI days 6, 9, 12 or ICI days 0, 3, 6, virus days 7, 10	Delayeda ICI administration and anti-PD1 pretreatment improved survival	[76]
	vvDD-fused IL-15/IL-15Rα	MC38-luc colon cancer	Anti-PD1	IP	Virus day 7, ICI days 7, 9 11, 13	Simultaneous ICI administration improved survival	[112]
	vvDD-mIL2	MC38-luc colon cancer	Anti-PD1 Anti-PDL1 Anti-CTLA4	IP	Virus day 9, ICI days 9, 11, 13, 15	Simultaneous ICI administration improved efficacy (not for anti-CTLA4 antibody)	[69]
	vvDD or B18R	Renca renal adenocarcinoma	Anti-CTLA4	IV	Virus day 0, ICI days 4, 7, 10 or ICI days 0, 3, 6	Only delayeda ICI administration improved efficacy	[75]
VSV	VSV gp100 or OVA	B16 or B16-OVA melanoma	Anti-PD1 Anti-TIM3	IV	Virus days 8–28 (3 ×/week), ICI days 14–28 (3 ×/week), ACT days 7, 21	Delayeda/overlapping ICI administration had no effect on survival vs. virus + ACT	[73]
	VSV-HIF2a, Sox-10,or c-Myc	GL261 glioma	Anti-PD1 Anti-CTLA4	IV	Virus days 6, 8, 10, 13, 15, 17, ICI days 13, 15, 17	Delayedb dual-ICI combination with all 3 TAA-expressing viruses improved survival over virus or virus + a single ICI	[66]
	VSV-IFNβ-NIS	C1498.GFP AML	Anti-PDL1	IV	Virus day 12, ICI days 15, 18, 21	Delayeda ICI administration improved survival	[68]

ACT adoptive T cell therapy, Ad-TK adenovirus expressing the herpes simplex virus thymidine kinase gene, AML acute myeloid leukemia, CTLA4 cytotoxic T cell lymphocyte antigen 4, GFP green fluorescent protein, GM-CSF granulocyte–macrophage colony-stimulation factor, GSC glioblastoma stem-like cell, HSV1 herpes simplex virus 1, hTertAd human telomerase reverse transcriptase promoter-regulated adenovirus, IC intracoelomic, ICI immune checkpoint inhibitor, IL interleukin, IL-15Rα interleukin-15 receptor α, IP intraperitoneal, IT intratumoral, IV intravenous, NDV Newcastle disease virus, OV oncolytic virus, OVA ovalbumin, PD1 programmed death 1, PDL1 programmed death 1 ligand, qxd every x days, RoA route of administration, TIM3 T cell immunoglobin and mucin-domain containing-3 protein, TNF tumor necrosis factor, VSV vesicular stomatitis virus, VSV-IFNβ-NIS vesicular stomatitis virus expressing both interferon β and sodium iodide symporter genes

^a First administration of ICI between 1 and 6 days after the first OV administration

^b First administration of ICI ≥ 7 days after the first OV administration