From:  Synergistic attack of “old drugs for new uses”: repositioning strategies in cancer combination therapy

 The key characteristics of representative repurposed drugs.

Drug classRepresentative agentsOriginal indicationProposed anticancer mechanismsKey synergistic partnersClinical status/evidence levelRefs.
BiguanidesMetforminType 2 diabetesAMPK/mTOR inhibition; TME modulation; PD-L1 downregulationChemotherapy (temozolomide, cisplatin); ICIsPhase II/III; epidemiological support[3744, 122124]
StatinsAtorvastatin, SimvastatinHypercholesterolemiaMevalonate pathway inhibition; disrupts Ras/Rho prenylationChemotherapy; targeted therapyPhase II ongoing; preclinical[8, 45, 115]
AntimalarialsArtemisinin, CQ, HCQMalariaFerroptosis induction; autophagy inhibition (CQ/HCQ)Chemotherapy (doxorubicin); radiotherapyPhase II (mixed); repurposing challenges[16, 55, 69, 70]
β-BlockersPropranololHypertension, arrhythmiaβ-Adrenergic blockade; anti-angiogenic; immune modulationChemotherapy (5-fluorouracil)Preclinical; retrospective observations[50, 52, 53]
AntihistaminesCetirizine, LoratadineAllergiesHRH1 receptor blockade; restores CD8+ T cell activityICIsObservational; potential ICI adjuvant[54]
NSAIDsAspirin, CelecoxibInflammation, painCOX-2/PGE2 inhibition; converts “cold” tumors to “hot”Immunotherapy (ICIs)Preclinical; combination studies ongoing[57, 125127]
HDAC InhibitorsValproic acidEpilepsyHDAC inhibition; chromatin relaxation; gene reactivationChemotherapy (gemcitabine)Phase II (e.g., VESPA trial)[6264, 112, 115]
AntipsychoticsPimozide, Fluphenazine, SertralinePsychiatric disordersMDR inhibition (P-glycoprotein [P-gp]); apoptosis induction; SHMT inhibition (sertraline)Chemotherapy (paclitaxel); mitochondrial inhibitorsPreclinical; early clinical exploration[7275]
Cardiovascular DrugsDigoxin, VerapamilHeart failure, arrhythmiaNa+/K+-ATPase inhibition; calcium channel blockadeChemotherapyPreclinical[7678]

AMPK: AMP-activated protein kinase; COX-2: cyclooxygenase-2; CQ: chloroquine; HCQ: hydroxychloroquine; HDAC: histone deacetylase; ICIs: immune checkpoint inhibitors; mTOR: mechanistic target of rapamycin; PD-L1: programmed death ligand 1; PGE2: prostaglandin E2; TME: tumor microenvironment.