pharmaceuticals Review Drug Repurposing Opportunities in Pancreatic Ductal Adenocarcinoma Rita Rebelo 1,2,† ,Bárbara Polónia 1,2,†,Lúcio Lara Santos 3,4, M. Helena Vasconcelos 1,2,5,* and Cristina P. R. Xavier 1,2,5,* 1 Cancer Drug Resistance Group, IPATIMUP—Institute of Molecular Pathology and Immunology, University of Porto, 4200-135 Porto, Portugal;
[email protected] (R.R.);
[email protected] (B.P.) 2 i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal 3 Experimental Pathology and Therapeutics Group, IPO—Instituto Português de Oncologia, 4200-072 Porto, Portugal;
[email protected] 4 ICBAS—Biomedical Sciences Institute Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal 5 Department of Biological Sciences, FFUP—Faculty of Pharmacy of the University of Porto, 4200-135 Porto, Portugal * Correspondence:
[email protected] (M.H.V.);
[email protected] (C.P.R.X.) † These authors equally contributed to this work. Abstract: Pancreatic ductal adenocarcinoma (PDAC) is considered one of the deadliest tumors worldwide. The diagnosis is often possible only in the latter stages of the disease, with patients already presenting an advanced or metastatic tumor. It is also one of the cancers with poorest prognosis, presenting a five-year survival rate of around 5%. Treatment of PDAC is still a major challenge, with cytotoxic chemotherapy remaining the basis of systemic therapy. However, no major advances have been made recently, and therapeutic options are limited and highly toxic. Thus, novel therapeutic options are urgently needed. Drug repurposing is a strategy for the development of novel treatments using approved or investigational drugs outside the scope of the original clinical indication.