Fosciclopirox clinical proof of concept in patients with nonmuscle invasive and muscle-invasive bladder cancer

e16557

Background: Fosciclopirox (F) is being developed for the treatment of non-muscle invasive (NMIBC) and muscle invasive (MIBC) bladder cancer. F is a prodrug which is rapidly and completely metabolized in blood to its active metabolite, ciclopirox (CPX). In preclinical models of bladder cancer, CPX acts in part as a γ-secretase inhibitor by binding to γ-secretase complex proteins Presenilin 1 and Nicastrin, resulting in Notch and Wnt inhibition. The F Recommended Phase 2 Dose (RP2D), 900 mg/m2 administered IV over 20 minutes, was identified in the Phase 1 dose escalation trial (NCT03348514) in advanced solid tumor patients. Methods: The F RP2D was investigated in two early phase NMIBC and MIBC clinical proof of concept trials. In NCT04608045, neoadjuvant F was administered as monotherapy in cisplatin-ineligible (C-I) MIBC patients and in combination with gemcitabine + cisplatin in chemotherapy-eligible (C-E) MIBC patients. Clinical stage was assessed in pre-treatment (TURBT/CT) and post-treatment pathological state determined at radical cystectomy, (RC). The steady-state plasma and urine pharmacokinetics of F were also characterized. In NCT04525131, F was administered once daily for five days prior to TURBT. Pre- and post-treatment (at TURBT) bladder tumor samples underwent single cell sequencing to identify treatment effects on gene expression. Plasma, urine, and bladder tumor concentrations of F and its metabolites were determined in samples collected at TURBT. Results: Five C-E and 4 C-I MIBC patients received neoadjuvant F prior to RC. Twelve NMIBC patients received F prior to TURBT. There were no treatment-related serious adverse events observed in either study. Each patient experienced at least one treatment-emergent adverse event (TEAE), none of which resulted in study discontinuation. The most common TEAEs were nausea, fatigue, and constipation. Pathologic downstaging (< ypT2) of bladder tumors was observed in 3 C-E MIBC patients with 2 CRs (ypT0). Two of 4 C-I patients had evident clinical response by CT scan with only microscopic residual ypT2 disease. Treatment-related changes in expression of Notch 1, Notch 2, Hes 1, Hey-1, c-Myc, ß-catenin and survivin were observed in the majority of NMIBC patients. F disappeared from plasma within 2 hours of administration. The mean CPX elimination half-life of CPX, apparent systemic clearance, and volume of distribution values were 8.8 hours, 46 L/hr and 549 L, respectively. Mean plasma, tumor and urine concentrations of CPX at TURBT were approximately 27, 9 and 100 µM, respectively. Conclusions: To date, fosciclopirox is well tolerated and achieves sufficient systemic, tumor, and urine CPX exposure at the RP2D. Evidence of target inhibition was demonstrated in NMIBC tumors and preliminary signs of clinical activity observed in MIBC patients. Safety and efficacy trials are planned to confirm and expand findings in NMIBC and MIBC patients. Clinical trial information: NCT04608045; NCT04525131.

Window of opportunity trial to characterize the safety, pharmacokinetics, and pharmacodynamics of fosciclopirox (CPX-POM) in cisplatin-ineligible muscle invasive bladder cancer patients

TPS604

Background: Fosciclopirox (Ciclopirox Prodrug, CPX-POM) is being developed for the treatment of non-muscle invasive and muscle invasive (MIBC) bladder cancer. CPX-POM selectively delivers its active metabolite, ciclopirox (CPX), to the entire urinary tract following systemic administration. In a validated, chemical carcinogen mouse model of bladder cancer, CPX-POM treatment results in significant decreases in bladder weight, a clear migration to lower stage tumors, dose-dependent reductions in Ki67 and PCNA staining, and inhibition of Notch 1 and Wnt signaling. The safety, dose tolerance, pharmacokinetics and pharmacodynamics of IV CPX-POM have recently been characterized in 19 patients with advanced solid tumors (CPX-POM-001, NCT03348514). The safety and dose tolerance of IV CPX-POM was characterized across a dose range of 30 to 1200 mg/m2. The CPX-POM Recommended Phase 2 Dose (PR2D) of 900 mg/m2 administered IV over 20 minutes on Days 1-5 every 21 days was selected. Methods: Twelve cisplatin ineligible MIBC patients (Stage >T2, NO-N1, M0), scheduled for radical cystectomy (RC) will be enrolled in this window of opportunity study. Patients will receive two 21-day treatment cycles followed by RC within 14 days of completion of the second cycle. Safety and tolerability assessments will be made based on observed adverse and serious adverse events, physical examination, vital signs, electrocardiogram, clinical laboratory tests, and concomitant medications. Assessment of complete and partial pathologic response will be determined at RC. Ki67, Notch and Wnt signaling, and CD8+ lymphocyte tumor infiltration will be determined by immunohistochemistry. An unbiased approach to characterizing CPX-POM mechanisms of action will also be employed using RNAseq and ChIPseq. Serial blood (plasma) and complete urine specimens will be collected on Days 5-6 of Cycle 1 for determination of drug and metabolite concentrations by LC-MS/MS. Plasma and urine steady-state pharmacokinetics of CPX-POM, CPX and ciclopirox glucuronide will be characterized. Urine ß-glucuronidase activity is also being determined by ELISA. Clinical trial information: NCT03348514.

Safety, dose tolerance, pharmacokinetics, and pharmacodynamics of fosciclopirox (CPX-POM) in patients with advanced solid tumors

518

Background: Fosciclopirox (CPX-POM) is being developed for the treatment of non-muscle invasive and muscle invasive bladder cancer. CPX-POM selectively delivers its active metabolite, ciclopirox (CPX), to the entire urinary tract following systemic administration. In a chemical carcinogen mouse model of bladder cancer, CPX-POM treatment resulted in significant decreases in bladder weight, migration to lower stage tumors, inhibition of cell proliferation as well as Notch 1 and Wnt signaling pathways. Methods: Study CPX-POM-001 (NCT03348514) is US multi-site, Phase I, open-label, dose escalation study characterizing the safety, dose tolerance, pharmacokinetics (PK) and pharmacodynamics of IV CPX-POM in advanced solid tumor patients. The PK of CPX-POM, CPX and ciclopirox glucuronide (CPX-G), were characterized in plasma and urine. Circulating biomarkers of Wnt and Notch, IL-6, IL-8 and VEGF were determined. Results: Nineteen patients were enrolled in the study. The starting dose of 30 mg/m2 was administered once daily on Days 1-5 of each 21-day treatment cycle. Doses were escalated to 1200 mg/m2. The MTD was determined to be 900 mg/m2. Overall, the number of treatment-related AE's tended to increase in frequency with dose, nausea and vomiting being the most common. Grade 3 confusion was observed in the 1200 mg/m2 cohort. Four AE's of Grade 1 confusion at 600 and 900 mg/m2. There was no evidence of QTc prolongation or other ECG abnormality. One patient in the 240 mg/m2 dose cohort, with a diagnosis of indolent primary fallopian tube tumor, achieved a partial response per RECIST 1.1. Metabolism of CPX-POM was rapid and complete. The clearance of CPX was dose proportional and time-independent. At MTD, steady-state 24-hour urine CPX concentrations of 215 µM were achieved. Evidence of Notch and Wnt inhibition was observed. Conclusions: IV CPX-POM was well tolerated with treatment-related AEs primarily CNS-related. At MTD, systemic and urinary CPX exposures exceeding in vitro IC50 values by several-fold. The 900 mg/m2 dose is currently being evaluated in an expansion cohort study in cisplatin-ineligible muscle invasive bladder cancer patients scheduled for cystectomy. Clinical trial information: NCT03348514.

Pharmacokinetics of ciclopirox prodrug, a novel agent for the treatment of bladder cancer, in animals and humans

e14705

Background: Ciclopirox Prodrug (CPX-POM) is a novel anticancer agent currently being evaluated in patients with advanced solid tumors participating in a First-in-Human, Phase 1 safety, dose tolerance, pharmacokinetics (PK) and pharmacodynamics trial at four US sites. In vitro and in vivo preclinical proof of principle was established in high grade human urothelial cancer cell lines as well as a mouse model of bladder cancer.Methods: A series of in vivo PK studies were conducted in mice, rats and dogs to characterize the absolute bioavailability of CPX following intravenous (IV), subcutaneous (SC) and oral administration of CPX-POM. The single dose and steady-state plasma and urine pharmacokinetics of CPX-POM are also currently being characterized in patients participating in the ongoing Phase 1 trial. Plasma and urine concentrations of the prodrug and metabolites were determined by LC-MS/MS validated in each specie and matrix. Non-parametric pharmacokinetic parameters were generated from resultant plasma and urine drug and metabolite concentration-time data. Results: CPX-POM is rapidly and completely metabolized to CPX in blood via circulating phosphatases in animals and humans. CPX is completely bioavailable following IV CPX-POM administration in mice, rats and dogs. CPX and its major inactive glucuronide metabolite (CPX-G) are extensively eliminated in urine in all animal species. SC administration of CPX-POM demonstrated excellent bioavailability in rats and dogs. Following IV administration of 30-900 mg/m2CPX-POM to patients, the apparent elimination half-life of CPX ranged from 2 to 8 hours, CPX systemic exposure was dose-proportional and time-independent in cancer patients, and a major portion of the dose was eliminated as CPX-G. Conclusions: IV CPX-POM achieves plasma and urine CPX exposures that exceed in vitro IC50 values several-fold at well tolerated doses in animals and humans. CPX pharmacokinetics observed in animals were predictive of human systemic clearance based on allometric scaling. Clinical trial information: NCT03348514.

Abstract A54: First-in-human study of the first-in-class fatty acid synthase (FASN) inhibitor, TVB-2640 as monotherapy or in combination - final results of dose escalation

Introduction

FASN inhibition is a novel approach to cancer treatment involving the selective disruption of palmitate biosynthesis that, in tumor cells, leads to apoptosis. TVB-2640 is an oral, first-in-class, small-molecule reversible inhibitor of FASN that demonstrates in vitro and in vivo anti-tumor effects. We previously reported (EORTC-NCI-AACR 2014: 3 LBA, AACR/ASCO 2015: CT203/ TPS2615) on the design of this trial (NCT02223247) and now report on the final results of the dose escalation phase.

Methods

Patients from 7 US and 4 UK sites with adequate bone marrow, hepatic and renal function were enrolled. Patients with significant cardiovascular or ophthalmological disease and any conditions that might interfere with oral absorption were excluded. In addition to standard safety assessments and pharmacokinetic (PK) sampling, ophthalmological examinations and 24-hour Holter monitoring for QTc assessments were performed. Blood and tumor tissue (archival and/or fresh) for various pharmacodynamic (PD) assessments were obtained.

Results

Thirty-one patients were enrolled in 6 monotherapy cohorts (60 mg/m2 to 250 mg flat dose) and 13 patients were enrolled in 2 combination cohorts (200 and 250 mg flat dose) in combination with weekly paclitaxel (80 mg/m2, days 1, 8 and 15 q 28 days). Plasma TVB-2640 drug levels increased with dose, with a half-life of approximately 15 hr. The MTD was declared at 100 mg/m2 for both schedules. DLTs observed in both mono- and combination patients were reversible and consisted of corneal edema (Grade 3, n = 2), keratitis and iritis (Grade 2 and 3, n = 1 each), probably a consequence of disrupted tear film lipid metabolism, and palmar-plantar erythrodysesthesia or skin peeling (Grade 3, n = 3 and Grade 1, n = 1). Other toxicities were mild (≤ Grade 2) and only minor GI symptoms were observed; alopecia was reported by 63% of patients overall. No enhancement of known paclitaxel toxicity was observed when given in combination with TVB-2640. Of the 7 NSCLC patients accrued so far, 1 achieved SD for 17 weeks with monotherapy and 2 patients treated in combination with paclitaxel had SD for 24 and 21 weeks respectively. One of three breast cancer patients (histology: triple negative) treated in combination had SD for 20 weeks. One confirmed PR was seen in a combination-treated patient who had peritoneal serous carcinoma with a 42% reduction in tumor load and 58% reduction in CA-125 levels. PD biomarkers have been identified in tumor and in serum. In all four patients with paired tumor biopsies, decreased pAKT S473 was observed after 1 cycle compared to pretreatment biopsies. Global metabolic profiling of serum showed increased levels of malonyl carnitine, a malonyl coA derivative, and decreased tripalmitin, a palmitate derivative, in 9 of 10 patients tested, after 8 days of TVB-2640 treatment. These changes are consistent with FASN inhibition.

Summary

Continuously administered, oral TVB-2640 demonstrated a tolerated dose and schedule with a manageable toxicity profile in association with encouraging signs of preliminary activity both as monotherapy and in combination with paclitaxel. PD analyses reveal engagement of the target in both tumor and surrogate tissue. Further exploration of biological activity in various specific tumor types is now underway in expansion cohorts at the MTD using both schedules.

Citation Format: Andrew Brenner, Jeffrey Infante, Manish Patel, Hendrik-Tobias Arkenau, Mark Voskoboynik, Erkut Borazanci, Gerald Falchook, L.R. Molife, Shubham Pant, Emma Dean, Lorraine Pelosof, Suzanne Jones, Chris Rubino, William McCulloch, Valentina Zhukova-Harrill, George Kemble, Marie O'Farrell, Howard A. Burris, III. First-in-human study of the first-in-class fatty acid synthase (FASN) inhibitor, TVB-2640 as monotherapy or in combination - final results of dose escalation. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A54.