The antimycotic ciclopirox olamine is an intracellular iron chelator that has anticancer activity in vitro and in vivo. We developed an oral formulation of ciclopirox olamine and conducted the first-in-human phase I study of this drug in patients with relapsed or refractory hematologic malignancies (Trial registration ID: NCT00990587). Patients were treated with 5-80 mg/m 2 oral ciclopirox olamine once daily for five days in 21-day treatment cycles. Pharmacokinetic and pharmacodynamic companion studies were performed in a subset of patients. Following definition of the half-life of ciclopirox olamine, an additional cohort was enrolled and treated with 80 mg/m 2 ciclopirox olamine four times daily. Adverse events and clinical response were monitored throughout the trial. Twenty-three patients received study treatment. Ciclopirox was rapidly absorbed and cleared with a short half-life. Plasma concentrations of an inactive ciclopirox glucuronide metabolite were greater than those of ciclopirox. Repression of survivin expression was observed in peripheral blood cells isolated from patients treated once daily with ciclopirox olamine at doses greater than 10 mg/m 2 , demonstrating biological activity of the drug. Dose-limiting gastrointestinal toxicities were observed in patients receiving 80 mg/m 2 four times daily, and no dose limiting toxicity was observed at 40 mg/m 2 once daily. Hematologic improvement was observed in two patients. Once-daily dosing of oral ciclopirox olamine was well tolerated in patients with relapsed or refractory hematologic malignancies, and further optimization of dosing regimens is warranted in this patient population.

What is known and Objective: 6-Cyclohexyl-1-hydroxy-4-methyl-2(1H)-pyridone (ciclopirox) and specifically its olamine salt 6-cyclohexyl-1-hydroxy-4-methyl-2(1H)-pyridone 2-aminoethanol salt (ciclopirox olamine) are anti-fungal agents currently used for the treatment of mild to moderate cutaneous fungal infection. Our objective is to comment on the opportunity to rapidly reposition ciclopirox and its olamine for the treatment of haematologic malignancy by leveraging its prior published toxicology and pharmacology data. Comment: Ciclopirox olamine chelates intracellular iron and displays preclinical efficacy in the treatment of haematologic malignancy. Currently, an ongoing study is evaluating topical ciclopirox olamine for the treatment of cervical cancer. Doses of ciclopirox olaine required for a systemic anti-cancer effect appear pharmacologically achievable. However, caution is required as at the highest doses tested in animal toxicology studies, irreversible cardiac degeneration was observed. What is new and Conclusion: The existing pharmacology and toxicology data suggest that systemic ciclopirox olamine could be repositioned as a new investigational anti-cancer agent.The available pharmacology and toxicology data should aid in the design of phase I clinical trials of this agent in patients with refractory haematologic malignancies. Keywords: drug repositioning, intracellular iron chelation, leukemia WHAT I S KN OWN AND BAC KGRO UNDOff-patent drugs with previously unrecognized anti-cancer activity could be rapidly repurposed for this new indication by leveraging their prior pharmacokinetic and toxicology data. Recently, we and others have demonstrated that the topical anti-fungal agent 6-cyclohexyl-1-hydroxy-4-methyl-2(1H)-pyridone (ciclopirox) and specifically its olamine salt 6-cyclohexyl-1-hydroxy-4-methyl-2(1H)-pyridone 2-aminoethanol salt (ciclopirox olamine) (Fig. 1) have preclinical efficacy in the treatment of haematologic malignancy. Ciclopirox olamine is an alpha hydroxypyridone that is currently used for the treatment of cutaneous fungal infection and available in a variety of topical formulations including gels, creams, lacquers and shampoos (1-6). However, an oral formulation is not currently available. Our objective is to comment on the potential for a clinical trial of systemic ciclopirox olamine in patients with relapsed and refractory malignancy with the help of a review of published literature as well as FDA submissions. The published information was used to understand the drug's preclinical efficacy as an anti-cancer agent and its mechanism of action as well as pharmacokinetics and toxicology profile in animals and humans.

Opioid peptides are key regulators in cellular and intercellular physiological responses, and could be therapeutically useful for modulating several pathological conditions. Unfortunately, the use of peptide-based agonists to target centrally located opioid receptors is limited by poor physicochemical (PC), distribution, metabolic, and pharmacokinetic (DMPK) properties that restrict penetration across the blood-brain barrier via passive diffusion. To address these problems, the present paper exploits fluorinated peptidomimetics to simultaneously modify PC and DMPK properties, thus facilitating entry into the central nervous system. As an initial example, the present paper exploited the Tyr-ψ[( Z)CF═CH]-Gly peptidomimetic to improve PC druglike characteristics (computational), plasma and microsomal degradation, and systemic and CNS distribution of Leu-enkephalin (Tyr-Gly-Gly-Phe-Leu). Thus, the fluoroalkene replacement transformed an instable in vitro tool compound into a stable and centrally distributed in vivo probe. In contrast, the Tyr-ψ[CFCH-NH]-Gly peptidomimetic decreased stability by accelerating proteolysis at the Gly-Phe position.

Ewing sarcoma (ES) are aggressive pediatric bone and soft tissue tumors driven by EWS-ETS fusion oncogenes, most commonly EWS-FLI1. Treatment of ES patients consists of up to 9 months of alternating courses of 2 chemotherapeutic regimens. Furthermore, EWS-ETS-targeted therapies have yet to demonstrate clinical benefit, thereby emphasizing a clinical responsibility to search for new therapeutic approaches. Our previous in silico drug screening identified entinostat as a drug hit that was predicted to reverse the ES disease signatures and EWS-FLI1mediated gene signatures. Here, we establish preclinical proof of principle by investigating the in vitro and in vivo efficacy of entinostat in preclinical ES models, as well as characterizing the mechanisms of

Pharmacokinetic studies in rats and dogs were performed to characterize the in vivo performance of a novel prodrug, fosciclopirox. Ciclopirox olamine (CPX-O) is a marketed topical antifungal agent with demonstrated in vitro and in vivo preclinical anticancer activity in several solid tumor and hematologic malignancies. The oral route of administration for CPX-O is not feasible due to low bioavailability and dose-limiting gastrointestinal toxicities. To enable parenteral administration, the phosphoryl-oxymethyl ester of ciclopirox (CPX), fosciclopirox (CPX-POM), was synthesized and formulated as an injectable drug product. In rats and dogs, intravenous CPX-POM is rapidly and completely metabolized to its active metabolite, CPX. The bioavailability of the active metabolite is complete following CPX-POM administration. CPX and its inactive metabolite, ciclopirox glucuronide (CPX-G), are excreted in urine, resulting in delivery of drug to the entire urinary tract. The absolute bioavailability of CPX following subcutaneous administration of CPX-POM is excellent in rats and dogs, demonstrating the feasibility of this route of administration. These studies confirmed the oral bioavailability of CPX-O is quite low in rats and dogs compared with intravenous CPX-POM. Given its broad-spectrum anticancer activity in several solid tumor and hematologic cancers and renal elimination, CPX-POM is being developed for the treatment of urothelial cancer. The safety, dose tolerance, pharmacokinetics, and pharmacodynamics of intravenous CPX-POM are currently being characterized in a United States multicenter first-inhuman Phase 1 clinical trial in patients with advanced solid tumors (NCT03348514).