Table 2.

Drug class, specific drug, drug target, and current clinical phase of repurposed agents currently undergoing clinical investigation.

Drug Class	Drugs	Targets	Clinical Trial Stage	References
Antiepileptic Drugs	Valproic Acid	HDAC	Phase II	[70,84,85,86,87,88]
Disulfiram	Disulfiram	PLK1, Ubiquitin–Proteasome Pathway, AIF	Phase II/III	[89,90,91]
Antifungals	Azoles	Hexokinase II	Phase I	[92,93,94]
	Clioquinol	BAX, BCL-2	Phase I	[92,95]
Antimalarials	Atovaquone	STAT3	Preclinical	[31]
	Chloroquine	Unclear	Preclinical	[26,41,86,96,97]
	Hydroxychloroquine	LC3-II	Phase I/II	[98]
	Mefloquine	NMDA	Phase I/II	[99,100,101]
Antiparasitics	Mebendazole	Microtubules, VEGF	Phase I	[102,103,104,105,106]
Antihypertensives	ARBs, ACEis	Unclear	Retrospective	[32,44,45,107,108]
Anti-inflammatories	Celecoxib	COX-2	Phase I–II	[109,110,111]
Immunosuppressants	Temsirolimus	mTOR, MCL-1	Phase I	[42]
	Everolimus		Phase I/II	[112,113,114,115,116]
Antineoplastics	Vorinostat	HDAC	Phase I/II	[117]
	Cabozantinib	TK	Phase II	[118]
	Arsenic Trioxide	Cytochrome C	Phase I/II	[119]
	Marizomib	Proteasome	Phase I	[120,121]
	Fimepinostat	PI3K, HDAC	Phase I	[122]
Carbonic-Anhydrase Inhibitors	Acetazolamide	CA, BCL3	Phase I	[123,124,125]
Checkpoint Inhibitors	Nivolumab	PD-1	Phase II–III	[126,127,128,129,130,131]
	Pembrolizumab	PD-1	Phase I–II	[132,133,134]
	Ipilimumab	CTLA-4	Phase I	[129]
Diabetic Agents	Metformin	AMPK, Cl-Channels, mTOR	Phase I/II	[46,135,136,137,138,139,140,141,142,143,144,145,146,147]
Small Molecules and Biologics	Cetuximab	EGFR	Phase I	[148]
	5-ALA	Not Applicable	Phase III	[149,150,151,152]
Cocktails	CUSP-9	Survival Pathways	Phase I	[5,153,154,155,156,157]
	CLOVA	GSK-3B	Phase I	[153]
	Celecoxib, Vinblastine, Cyclophosphamide	COX-2, Microtubules, DNA	Phase I	[158]

Abbreviations: Histone deacetylase (HDAC); polo-like kinase 1 (PLK1); apoptosis inducing factor (AIF); Bcl-2-associated X protein (BAX); B-cell lymphoma 2 (BCL2); signal transducer and activator of transcription 3 (STAT3); light chain 3 phosphatidylethanolamine conjugate (LC3-II); N-methyl-D-aspartate receptor (NMDAR); vascular-endothelial growth factor 2 (VEGF); cyclooxygenase 2 (COX2); mechanistic target of rapamycin (mTOR); myeloid cell leukemia-1 (MCL-1); tyrosine kinase (TK); phosphoinositide 3-kinase (PI3K); carbonic anhydrase (CA); B-cell lymphoma 3-encoded protein (BCL-3); programmed cell death 1 (PD-1); cytotoxic T-lymphocyte-associated protein 4 (CTLA4); AMP-activated protein kinase (AMPK); epidermal growth factor receptor (EGFR); glycogen synthase kinase (GSK) 3β; deoxyribonucleic acid (DNA).