Off-patent Drugs Research Articles

Alternative Cancer Therapeutics: Unpatentable Compounds and Their Potential in Oncology.

Cancer remains a leading cause of death globally. Cancer patients often seek alternative therapies in addition to, or instead of, conventional treatments like chemotherapy, radiation, and surgery. The progress in medical advancements and early detection provides more treatment options; however, the development of cancer drugs requires a significant amount of time, demands substantial investments, and results in an overall low percent of regulatory approval. The complex relationship between patent protection and pharmaceutical innovation complicates cancer drug development and contributes to high mortality rates. Adjusting patent criteria for alternative cancer therapeutics could stimulate innovation, enhance treatment options, and ultimately improve outcomes for cancer patients. This article explores the potential of alternative cancer therapeutics, chemopreventive agents, natural products, off-patent drugs, generic unpatentable chemicals, and repurposed drugs in cancer treatment, emphasizing the mechanisms and therapeutic potential of these unconventional compounds as combinatorial cancer therapies. The biological pathways, therapeutic effects, and potential to enhance existing therapies are reviewed, demonstrating their cost-effective and accessible options as adjuvant cancer therapies.

Abstract 4549: Combinations of ciclopirox olamine and metformin exert synergistic antitumor activity in triple-negative breast cancer

Abstract Introduction: Triple-negative breast cancer (TNBC) represents a challenging subtype of breast cancer because of its limited treatment options. Recent research has highlighted the potential benefits of combining pharmacological agents to enhance therapeutic outcomes. Studies show that Ciclopirox olamine (CPX), an off-patent anti-fungal drug, induces cell cycle G1-phase arrest and activates the intrinsic apoptosis pathway by downregulating the anti-apoptotic proteins. Meanwhile, metformin, a safe and first-line drug for the treatment of type II diabetes, has been shown to induce cell cycle S-phase arrest and activates the extrinsic apoptosis pathway via induction of endogenous TRAIL in TNBC cells. However, whether the combinations of CPX and metformin would exert potent antitumor activity against TNBC remains unclear. Methods: Cell proliferation (MTS) assays and LIVE/DEAD cell imaging were used to determine the combined inhibitory effects on TNBC cells. IC50s and the combination index (CI) were calculated. Flow cytometry assays were carried out to analyze if the combinations are more potent to block cell cycle progression. Apoptotic-specific ELISA and flow cytometry analysis of Annexin V-PI staining were performed to assess if the combinations are significantly more effective to induce apoptosis. Western blot assays were used to examine if the combinations markedly induced the expression of TRAIL and cleavages of PARP and caspases. Tumor xenograft models will be established to test the in vivo antitumor activity of CPX and metformin either alone or in combinations. Results: Data indicated that both CPX and metformin independently inhibited the proliferation of TNBC cells. A synergistic effect was observed when CPX and metformin were used in combination, resulting in a more potent inhibition of TNBC cell proliferation. The combinatorial treatment effectively suppressed colony formation of TNBC cells. Synergy between CPX and metformin was partially linked to the enhanced activation of the AMPK-mTOR pathway, as the combination significantly enhanced the phosphorylation of AMPKα. The combinations also induced enhanced apoptosis in TNBC cells through both the intrinsic and extrinsic pathways. The combinatorial effects of CPX and metformin on in vivo tumor growth are under investigation. Conclusions: Combinations of CPX and metformin show synergistic effects on inhibiting TNBC cell proliferation. Our studies suggest a potential therapeutic strategy for TNBC, with the combinations of these agents exhibiting an enhanced antitumor activity. Further investigation is warranted to validate the results and explore their clinical applications. Key words: Triple-negative breast cancer, Ciclopirox olamine, Metformin, Combination, Apoptosis Citation Format: Yakun Wu, Hui Lyu, Congcong Tan, Margaret E. Larsen, Shile Huang, Bolin Liu. Combinations of ciclopirox olamine and metformin exert synergistic antitumor activity in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4549.

Abstract B027: Repurposing ion channel drugs: the Na+ channel modifying drug DPI-201-106 significantly enhances the anti-tumor activity of multiple classes of drugs targeting DNA damage repair

Abstract B027: Repurposing ion channel drugs: the Na+ channel modifying drug DPI-201-106 significantly enhances the anti-tumor activity of multiple classes of drugs targeting DNA damage repair

Identification of Keratinocyte Cytoprotectants against Toxicity by the Multikinase Inhibitor Sorafenib Using Drug Repositioning

Hand-foot skin reaction (HFSR) is the most common adverse event of multikinase inhibitors (MKI), such as sorafenib. Although HFSR is not life-threatening, severe cases impair quality of life because of pain and reduced activities of daily living. However, the pathological mechanisms of HFSR have not yet been elucidated in detail, and there is currently no effective treatment. We aimed to identify keratinocyte cytoprotectants against sorafenib toxicity.The screening of cytoprotectants against sorafenib toxicity was performed using cultured normal human epidermal keratinocytes (NHEKs) or a reconstructed human epidermis (RHE) model and off-patent approved drugs in the Prestwick Chemical library. Among 1273 drugs in the chemical library, 8 dose-dependently increased cell viability by more than 200% in the presence of sorafenib. In the presence of sorafenib, the number of proliferating cell nuclear antigen- positive cell was significantly higher in clofazimine-, cyclosporin A-, and itraconazole-treated RHE models than in sorafenib-treated models. And, candidate drugs suppressed sorafenib-induced apoptosis in NHEKs. In addition, clofazimine, itraconazole and pyrvinium pamoate significantly recovered the phosphorylation of ERK1/2 in the presence of sorafenib. Collectively, hit drugs promoted cell viability and normalized keratinocyte proliferation in the presence of sorafenib. These candidate drugs have potential as treatments for MKI-induced HFSR.

Chemical genetic control of cytokine signaling in CAR-T cells using lenalidomide-controlled membrane-bound degradable IL-7.

CAR-T cell therapy has emerged as a breakthrough therapy for the treatment of relapsed and refractory hematologic malignancies. However, insufficient CAR-T cell expansion and persistence is a leading cause of treatment failure. Exogenous or transgenic cytokines have great potential to enhance CAR-T cell potency but pose the risk of exacerbating toxicities. Here we present a chemical-genetic system for spatiotemporal control of cytokine function gated by the off-patent anti-cancer molecular glue degrader drug lenalidomide and its analogs. When co-delivered with a CAR, a membrane-bound, lenalidomide-degradable IL-7 fusion protein enforced a clinically favorable T cell phenotype, enhanced antigen-dependent proliferative capacity, and enhanced in vivo tumor control. Furthermore, cyclical pharmacologic combined control of CAR and cytokine abundance enabled the deployment of highly active, IL-7-augmented CAR-T cells in a dual model of antitumor potency and T cell hyperproliferation.

Accumulation of endogenous free radicals is required to induce titan-like cell formation in Cryptococcus neoformans.

Cryptococcus neoformans is an excellent model to investigate fungal pathogenesis. This yeast can produce "titan cells," which are cells of an abnormally larger size that contribute to the persistence of the yeast in the host. In this work, we have used a new approach to characterize them by identifying drugs that inhibit this process. We have used a repurposing off-patent drug library, combined with an automatic method to image and analyze fungal cell size. In this way, we have identified many compounds that inhibit this transition. Interestingly, several compounds were antioxidants, allowing us to confirm that endogenous ROS and mitochondrial changes are important for titan cell formation. This work provides new evidence of the mechanisms required for titanization. Furthermore, the future characterization of the inhibitory mechanisms of the identified compounds by the scientific community will contribute to better understand the role of titan cells in virulence.

Discovery of New Fusobacterium nucleatum Inhibitors to Attenuate Migratory Capability of Colon Cancer Cells by the Drug Repositioning Strategy.

Recent studies revealed that intestinal microbiota played important roles in colorectal cancer (CRC) carcinogenesis. Particularly, Fusobacterium nucleatum was confirmed to promote the proliferation and metastasis of CRC. Therefore, targeting F. nucleatum may be a potential preventive and therapeutic approach for CRC. Herein, 2,272 off-patent drugs were screened inhibitory activity against F. nucleatum. Among the hits, nitisinone was identified as a promising anti-F. nucleatum lead compound. Further optimization of nitisinone led to the discovery of more potent derivatives. Particularly, compounds 19q and 22c showed potent anti-F. nucleatum activity (MIC50 = 1 and 2 μg/mL, respectively) with low cytotoxicity. Among them, compound 19q effectively attenuated the migratory ability of MC-38 cells induced by F. nucleatum. Preliminary mechanism studies suggested that nitisinone and its derivatives might act by downregulating nitroreductase and tryptophanase. Thus, the development of small molecule F. nucleatum inhibitors represents an effective strategy to treat CRC.

Markups and Fixed Costs in Generic and Off-Patent Pharmaceutical Markets

Abstract Wide dispersion is seen in pharmaceutical prices across countries with comparable quality standards. Under monopoly, off-patent and generic drug prices are at least four times higher in the United States than in comparable English-speaking high-income countries. With five or more competitors, off-patent drug prices are similar or lower. Our analysis shows that differential U.S. markups are largely driven by the market power of drug suppliers and are not due to wholesale intermediaries or pharmacies. Furthermore, we show that the traditional mechanism of reducing market power—free entry—is limited because implied entry costs are substantially higher in the United States.

HPR51 Should Volume-Based Procurement Price of Comparator be Referenced for Innovative Drugs in National Reimbursement Drug List Negotiation in China?

In current China’s National Reimbursement Drug List (NRDL) negotiation, when submitting cost-effectiveness analysis evidence, Volume-based Procurement (VBP) price is referenced for comparator if comparator is off-patent drug with generics. Our study aims to explore whether it is reasonable to reference VBP price of comparator in innovative drugs NRDL negotiation.

Administrative Databases and Diagnostic Therapeutic and Assistance Paths -PDTA- in the Monitoring Treatment of Rheumatoid Arthritis: The Experience of ATS Pavia.

The current flows of the SSN represent the set of interest whose interconnection alone justifies the current study. These flows can be interconnected with other sources, institutional or otherwise, in order to answer well-defined questions. The objective of the study is to verify, through the analysis of administrative databases, any differences in the consumption of health resources between biological off-patent originator drugs and biosimilars in real clinical practice, with particular reference to the rheumatology area. Through the use of assisted databases (BDA) of ATS Pavia we evaluated the differences in terms of consumption of health resources related to the different drugs under analysis. Annual and daily costs were calculated by total patient cost, stratified for different treatments, considering the sum of total costs for the prescriptions of drugs subject to the analysis. Another objective was to evaluate the adherence of the drugs of interest, by utilizing specific indicators (MPR). A total of 145 patients were analyzed. Among enrolled patients, 26.9% of users were treated with a biosimilar drug, while 73.1% with a biologic originator. Adherence is higher if it is considered the population treated with biosimilar drugs (82.1%). Total cost (including drug prescriptions, hospitalizations, outpatient services, tests for any cause) during the observation period of 1 year is 14,274.08. 87.7% of the total is attributable to drugs. Non-hospitalized patients are the least expensive, whether they were treated with biologics or biosimilars. In our sample, biosimilar drugs tend to be underused: the treatment of a patient with a chronic autoimmune disease is a clinical process that involves many health professionals, and a criticality could also derive from the difficult communication between the various professional figures who get involved with the whole patient treatment.

Use of a gene expression signature to identify trimetazidine for repurposing to treat bipolar depression.

The aim of this study was to repurpose a drug for the treatment of bipolar depression. A gene expression signature representing the overall transcriptomic effects of a cocktail of drugs widely prescribed to treat bipolar disorder was generated using human neuronal-like (NT2-N) cells. A compound library of 960 approved, off-patent drugs were then screened to identify those drugs that affect transcription most similar to the effects of the bipolar depression drug cocktail. For mechanistic studies, peripheral blood mononuclear cells were obtained from a healthy subject and reprogrammed into induced pluripotent stem cells, which were then differentiated into co-cultured neurons and astrocytes. Efficacy studies were conducted in two animal models of depressive-like behaviours (Flinders Sensitive Line rats and social isolation with chronic restraint stress rats). The screen identified trimetazidine as a potential drug for repurposing. Trimetazidine alters metabolic processes to increase ATP production, which is thought to be deficient in bipolar depression. We showed that trimetazidine increased mitochondrial respiration in cultured human neuronal-like cells. Transcriptomic analysis in induced pluripotent stem cell-derived neuron/astrocyte co-cultures suggested additional mechanisms of action via the focal adhesion and MAPK signalling pathways. In two different rodent models of depressive-like behaviours, trimetazidine exhibited antidepressant-like activity with reduced anhedonia and reduced immobility in the forced swim test. Collectively our data support the repurposing of trimetazidine for the treatment of bipolar depression.

Repurposing UDCA, an FXR Inhibitor, to Prevent SARS-Cov-2 Infection

Brevini T, Maes M, Webb GJ, et al. FXR Inhibition May Protect From SARS-CoV-2 Infection by Reducing ACE2. Nature 2022 Dec 5. https://doi.org/10.1038/s41586-022-05594-0. Viruses need to access the host’s machinery to replicate and propagate, and do so by binding to their respective receptors on host cells. Angiotensin-converting enzyme 2 (ACE2) was identified early in the pandemic as the entryway for the severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2). Since then, scientists have been exploring ways to prevent SARS-Cov-2 infection by targeting ACE2. In a study published in Nature, Brevini et al identified farnesoid X receptor (FXR) as a regulator of ACE2 expression. FXR is a ubiquitous bile acid sensing protein. Upon its activation by chenodeoxycholic acid, ACE2 increased in biliary, airway, and intestinal organoids. FXR directly bound the ACE2 promoter and activated its transcription. Furthermore, suppressing FXR signaling with ursodeoxycholic acid (UDCA) or Z-guggulsterone–reduced ACE2 expression. To test its relevance to coronavirus disease 2019 (COVID-19) in vitro, organoids were stimulated with chenodeoxycholic acid and infected with SARS-Cov-2 in the presence or absence of UDCA or Z-guggulsterone. Reduced viral infection was measured when drugs were present. In vivo, UDCA treatment decreased ACE2 expression in tissues of mice and hamsters. Furthermore, the Syrian Hamster model showed replication and transmission of SARS-Cov-2 in all untreated animals, whereas only 3 of 9 UDCA-treated animals were infected, and they presented a milder disease course. Interestingly, the authors took several approaches to validate their findings in the human context. They first used donated organs that were unfit for transplantation. They performed ex situ normothermic perfusion on a pair of lungs, whereby 1 lung received UDCA in the perfusate and the other served as a matched control. UDCA treatment decreased ACE2 expression in lung cells and ACE2 activity in the perfusate. Importantly, UDCA treatment decreased infection when lungs were exposed to SARS-Cov-2. Similar observations were seen with liver grafts. Additionally, they determined that UDCA reduced ACE2 expression in the nasal epithelium of healthy volunteers who received UDCA. They also retrospectively found an inverse correlation between UDCA and serum ACE2 levels in a serum proteomics dataset of a patient cohort. Finally, the authors interrogated 2 COVID-19 databases, one composed of patients with chronic liver disease and the other of vaccinated liver transplant recipients. In both scenarios, patients receiving UDCA had better COVID-19 outcomes compared with matched controls. Brevini et al were clever in their approaches. They repurposed donated organs found unfit for transplantation, giving them a new benefit for preclinical drug testing with potentially better predictive power. More important, they repurposed an approved and off-patent drug, UDCA, to prevent SARS-Cov-2 infection, a novel approach against viral infection that is directed toward the host rather than the virus. Because ACE2 is a receptor for many viruses, UDCA may have broader use and is less susceptible to immune escape by viruses. Although the experimental data shown were strong, it remains to be seen how UDCA performs in clinical trials involving larger and controlled cohorts of patients. Nonetheless, the repurposing of a cost-effective and readily available drug to prevent viral infection alongside vaccination is exciting and promising.

The Generic Drug Trilemma

More than 90% of prescriptions dispensed in the United States each year are for off-patent drugs. Yet the bulk of scholarship on prescription drug policy focuses on patented drugs. Discussions of prescription drugs are typically oriented around the “innovation-access dilemma”—the trade-off between stronger patent-based incentives for innovators and higher prices for purchasers of patented products. But for drugs in the “patent afterlife”—the period after patent protection and other forms of market exclusivity have expired—the innovation-access dilemma is not the fundamental policy trade-off. Higher prices do not necessarily redound to the benefit of innovators, and price is not the only significant impediment to access: drug shortages—often triggered by safety concerns—also prevent patients from obtaining the medicines they need.This chapter seeks to provide scholars and policy makers with a unifying framework for analyzing the variegated challenges of the pharmaceutical patent afterlife. We argue that the key trade-offs in off-patent drug policy take the form of a trilemma—the three corners of which are price, quantity, and quality (i.e., safety and efficacy). The generally accepted goal of off-patent drug policy is to facilitate (1) low prices and (2) sufficient quantities of drugs that are (3) equivalent or similar to brand-name drugs approved by the Food and Drug Administration. But policies that improve outcomes along one or two of those dimensions typically entail some sacrifice along the third.The trilemma framing yields several analytical payoffs. First, it sheds light on the root causes of puzzling problems plaguing some off-patent drug markets, such as sudden price spikes and persistent mismatches between supply and demand. Second, it draws attention to the noninnovation costs of recent drug pricing reform proposals—costs that are often overlooked amid the emphasis on innovation versus access. Finally, it motivates a search for solutions that can transcend the trilemma and optimize along all three dimensions of off-patent drug policy. That search brings us, full circle, back to innovation and access—the concerns that dominate discussions of pharmaceutical policy at the beginning of the patent life. But this time, the focus is on innovation—and, specifically, manufacturing innovation—in service of rather than in tension with access.

Improving Drug Therapy for Pediatric Patients: Unfinished History of Pediatric Drug Development.

Improving Drug Therapy for Pediatric Patients: Unfinished History of Pediatric Drug Development.

Drug Repurposing: A New Hope in Drug Discovery for Prostate Cancer.

Prostate cancer (PCA), the most common cancer in men, accounted for 1.3 million new incidences in 2018. An increase in incidences is an issue of concern that should be addressed. Of all the reported prostate cancers, 85% were detected in stages III and IV, making them difficult to treat. Conventional drugs gradually lose their efficacy due to the developed resistance against them, thus requiring newer therapeutic agents to be used as monotherapy or combination. Recent research regarding treatment options has attained remarkable speed and development. Therefore, in this context, drug repurposing comes into the picture, which is defined as the "investigation of the off-patent, approved and marketed drugs for a novel therapeutic indication" which saves at least 30% of the time and cost, reducing the cost of treatment for patients, which usually runs high in cancer patients. The anticancer property of cardiac glycosides in cancers was tested in the early 1980s. The trend then shifts toward treating prostate cancer by repurposing other cardiovascular drugs. The current review mainly emphasizes the advantageous antiprostate cancer profile of conventional CVS drugs like cardiac glycosides, RAAS inhibitors, statins, heparin, and beta-blockers with underlying mechanisms.

Evaluating the benefits of TNF-alfa inhibitor biosimilar competition on off-patent and on-patent drug markets: A Southern European analysis.

Background: The level of competition achieved following biosimilars market availability varies by country, care setting and molecule. Hence, biosimilars contribution to attaining price reductions and extended access to treatments can also vary. Objective: The aim of this study is to capture market dynamics for tumor necrosis factor (TNF)-alpha inhibitors and competing molecules in Southern European markets (2011-2020), and to evaluate the benefits of the competition generated by the availability of biosimilars. Methods: This study is based on a literature review examining market characteristics for TNF-alfa inhibitors and competing immunomodulator molecules, and on the quantitative analysis of market data for these molecules in Italy, Portugal and Spain. Results: Following biosimilars availability in Italian, Portuguese and Spanish markets, there has been an expansion in the overall access to TNF-alfa inhibitor pharmaceuticals. Further, savings have been generated within the TNF-alfa inhibitors class even after the increased use of these molecules. However, the potential of infliximab, etanercept and adalimumab biosimilars to generate price competition outside of their own drug class appeared limited in the studied markets. Considering this limitation and that shifts towards on-patent and higher-cost therapies have occurred after TNF-alfa inhibitor biosimilars availability, the importance of investing in biosimilars development for still on-patent immunology biologics is emphasized. Conclusion: This study highlights the need for policies that do not only seek higher utilization of biosimilars, but that also support a sustainable market for these products. This is expected to foster the future development of biosimilar medicines.

Menadione Potentiates Auranofin-Induced Glioblastoma Cell Death

Glioblastoma (GBM) is the most aggressive primary brain tumor. Recently, agents increasing the level of oxidative stress have been proposed as anticancer drugs. However, their efficacy may be lowered by the cytoprotective activity of antioxidant enzymes, often upregulated in neoplastic cells. Here, we assessed the mRNA and protein expression of thioredoxin reductase 1 (TrxR1), a master regulator of cellular redox homeostasis, in GBM and non-tumor brain tissues. Next, we examined the influence of an inhibitor of TrxR1, auranofin (AF), alone or in combination with a prooxidant menadione (MEN), on growth of GBM cell lines, patient-derived GBM cells and normal human astrocytes. We detected considerable amount of TrxR1 in the majority of GBM tissues. Treatment with AF decreased viability of GBM cells and their potential to form colonies and neurospheres. Moreover, it increased the intracellular level of reactive oxygen species (ROS). Pre-treatment with ROS scavenger prevented the AF-induced cell death, pointing to the important role of ROS in the reduction of cell viability. The cytotoxic effect of AF was potentiated by treatment with MEN. In conclusion, our results identify TrxR1 as an attractive drug target and highlights AF as an off-patent drug candidate in GBM therapy.

FXR inhibition may protect from SARS-CoV-2 infection by reducing ACE2

Preventing SARS-CoV-2 infection by modulating viral host receptors, such as angiotensin-converting enzyme 2 (ACE2)1, could represent a new chemoprophylactic approach for COVID-19 that complements vaccination2,3. However, the mechanisms that control the expression of ACE2 remain unclear. Here we show that the farnesoid X receptor (FXR) is a direct regulator of ACE2 transcription in several tissues affected by COVID-19, including the gastrointestinal and respiratory systems. We then use the over-the-counter compound z-guggulsterone and the off-patent drug ursodeoxycholic acid (UDCA) to reduce FXR signalling and downregulate ACE2 in human lung, cholangiocyte and intestinal organoids and in the corresponding tissues in mice and hamsters. We show that the UDCA-mediated downregulation of ACE2 reduces susceptibility to SARS-CoV-2 infection in vitro, in vivo and in human lungs and livers perfused ex situ. Furthermore, we reveal that UDCA reduces the expression of ACE2 in the nasal epithelium in humans. Finally, we identify a correlation between UDCA treatment and positive clinical outcomes after SARS-CoV-2 infection using retrospective registry data, and confirm these findings in an independent validation cohort of recipients of liver transplants. In conclusion, we show that FXR has a role in controlling ACE2 expression and provide evidence that modulation of this pathway could be beneficial for reducing SARS-CoV-2 infection, paving the way for future clinical trials.

Dynamics of price competition in Italian pharmaceutical off-patent market.

The aim of the study was to evaluate, in a regulated generics market, the effect of the number of manufacturers of generic drugs on the amplitude of off-patent products price reduction and the price evolution of originators and generics after the patent expiry of pharmaceuticals dispensed by community pharmacies and reimbursed by the Italian National Health Service (INHS). The AIFA "transparency list" was utilized to select unbranded and branded off-patent drug dispensed by community pharmacies and reimbursed by the Italian National Health Service between 2012 and 2018. The unbranded drug entry in the transparency list database was considered as a proxy of its patent expiry. A total of 42 different active ingredients were included in the analysis. The relative price per dose at time t of unbranded and branded drugs, considering as common denominator the price per dose a year before the patent expiry, (t-1) decreased with the increase of unbranded manufacturers. At the time of the patent expiry, the price of unbranded drugs was almost 50% less than that of branded drugs at t-1 and the price of branded drugs started to decrease before the first unbranded entry. An inverse relation between the number of generic drug entrants and the price of generics and originators was detected. The patent expiry determines a price decline, more concentrated in the first year of patent expiry.

Drug Repurposing Strategies for Non-cancer to Cancer Therapeutics.

Global efforts invested in the prevention and treatment of cancer need to be repositioned to develop safe, effective, and economic anticancer therapeutics by adopting rational approaches of drug discovery. Drug repurposing is one of the established approaches to reposition old, clinically approved off-patent noncancer drugs with known targets into newer indications. The literature review suggests a key role of drug repurposing in the development of drugs intended for cancer as well as noncancer therapeutics. A wide category of noncancer drugs such as, drugs acting on CNS, anthelmintics, cardiovascular drugs, antimalarial drugs, anti-inflammatory drugs, have come out with interesting outcomes during preclinical and clinical phases. In the present article, a comprehensive overview of the current scenario of drug repurposing for the treatment of cancer has been focused. The details of some successful studies along with examples have been included followed by associated challenges.