Fenretinide in Young Women at Genetic or Familial Risk of Breast Cancer: A Placebo-Controlled Biomarker Trial.

Fenretinide, a retinoid with a low-toxicity profile that accumulates in the breast, has been shown to prevent second breast cancer in young women. Fenretinide exhibits apoptotic and antiinvasive properties and it improves insulin sensitivity in overweight premenopausal women with insulin resistance. This study aimed to further characterize its role in cancer prevention by measuring circulating biomarkers related to insulin sensitivity and breast cancer risk.Sixty-two women, ages 20 to 46 years, healthy or who had already undergone breast cancer surgery, with a known BRCA1/2 mutation or a likelihood of mutation ≥20% according to the BRCAPRO model, were randomly assigned to receive fenretinide (200 mg/day) or placebo for 5 years (trial registration: EudraCT No. 2009-010260-41). Fasting blood samples were drawn at baseline, 12 and 36 months, and the following biomarkers were analyzed: retinol, leptin, adiponectin, retinol-binding protein 4 (RBP-4), total cholesterol, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol, triglycerides, glucose, insulin, insulin-like growth factor (IGF-1), IGF-binding protein 3, sex hormone binding globulin (SHBG), testosterone, and vascular endothelial growth factor (VEGF).After 12 months of treatment, we observed a favorable effect of fenretinide on glucose (decrease; P = 0.005), insulin (decrease; P = 0.03), homeostatic model assessment index (decrease; P = 0.004), HDL cholesterol (increase; P = 0.002), even though these effects were less prominent after 36 months. Retinol and retinol-binding protein 4 markedly decreased (P < 0.0001) throughout the study. None of the other measured biomarkers changed. PREVENTION RELEVANCE: Fenretinide exhibits beneficial effects on the metabolic profile, supporting its clinical use in breast cancer prevention especially in premenopausal women with a positive family history and pathogenic variants in BRCA1/2 genes. This finding requires further investigations in larger trials to confirm its role in breast cancer prevention.

Microemulsion for Prolonged Release of Fenretinide in the Mammary Tissue and Prevention of Breast Cancer Development.

The need of pharmacological strategies to preclude breast cancer development motivated us to develop a non-aqueous microemulsion (ME) capable of forming a depot after administration in the mammary tissue and uptake of interstitial fluids for prolonged release of the retinoid fenretinide. The selected ME was composed of phosphatidylcholine/tricaprylin/propylene glycol (45:5:50, w/w/w) and presented a droplet diameter of 175.3 ± 8.9 nm. Upon water uptake, the ME transformed successively into a lamellar phase, gel, and a lamellar phase-containing emulsion in vitro as the water content increased and released 30% of fenretinide in vitro after 9 days. Consistent with the slow release, the ME formed a depot in cell cultures and increased fenretinide IC50 values by 68.3- and 13.2-fold in MCF-7 and T-47D cells compared to a solution, respectively. At non-cytotoxic concentrations, the ME reduced T-47D cell migration by 75.9% and spheroid growth, resulting in ∼30% smaller structures. The depot formed in vivo prolonged a fluorochrome release for 30 days without producing any sings of local irritation. In a preclinical model of chemically induced carcinogenesis, ME administration every 3 weeks for 3 months significantly reduced (4.7-fold) the incidence of breast tumors and increased type II collagen expression, which might contribute to limit spreading. These promising results support the potential ME applicability as a preventive therapy of breast cancer.

A phase I study of intravenous fenretinide (4-HPR) for patients with malignant solid tumors.

BACKGROUND: Fenretinide is a synthetic retinoid that can induce cytotoxicity by several mechanisms. Achieving effective systemic exposure with oral formulations has been challenging. An intravenous lipid emulsion fenretinide formulation was developed to overcome this barrier. We conducted a study to establish the maximum tolerated dose (MTD), preliminary efficacy, and pharmacokinetics of intravenous lipid emulsion fenretinide in patients with advanced solid tumors. METHODS: Twenty-three patients with advanced solid tumors refractory to standard treatments received fenretinide as a continuous infusion for five consecutive days in 21-day cycles. Five different dose cohorts were evaluated between doses of 905 mg/m2 and 1414 mg/m2 per day using a 3 + 3 dose escalation design. A priming dose of 600 mg/m2 on day 1 was introduced in an attempt to address the asymptomatic serum triglyceride elevations related to the lipid emulsion. RESULTS: The treatment-related adverse events occurring in ≥ 20% of patients were anemia, hypertriglyceridemia, fatigue, aspartate aminotransferase (AST)/alanine aminotransferase (ALT) increase, thrombocytopenia, bilirubin increase, and dry skin. Five evaluable patients had stable disease as best response, and no patients had objective responses. Plasma steady-state concentrations of the active metabolite were significantly higher than with previous capsule formulations. CONCLUSION: Fenretinide emulsion intravenous infusion had a manageable safety profile and achieved higher plasma steady-state concentrations of the active metabolite compared to previous capsule formulations. Single-agent activity was minimal but combinatorial approaches are under evaluation.

Vorinostat and fenretinide synergize in preclinical models of T-cell lymphoid malignancies.

T-cell lymphoid malignancies (TCLMs) are in need of novel and more effective therapies. The histone deacetylase (HDAC) inhibitors and the synthetic cytotoxic retinoid fenretinide have achieved durable clinical responses in T-cell lymphomas as single agents, and patients who failed prior HDAC inhibitor treatment have responded to fenretinide. We have previously shown fenretinide synergized with the class I HDAC inhibitor romidepsin in preclinical models of TCLMs. There exist some key differences between HDAC inhibitors. Therefore, we determined if the pan-HDAC inhibitor vorinostat synergizes with fenretinide. We demonstrated cytotoxic synergy between vorinostat and fenretinide in nine TCLM cell lines at clinically achievable concentrations that lacked cytotoxicity for non-malignant cells (fibroblasts and blood mononuclear cells). In vivo, vorinostat + fenretinide + ketoconazole (enhances fenretinide exposures by inhibiting fenretinide metabolism) showed greater activity in subcutaneous TCLM xenograft models than other groups. Fenretinide + vorinostat increased reactive oxygen species (ROS, measured by 2',7'-dichlorodihydrofluorescein diacetate dye), resulting in increased apoptosis (via transferase dUTP nick end labeling assay) and histone acetylation (by immunoblotting). The synergistic cytotoxicity, apoptosis, and histone acetylation of fenretinide + vorinostat was abrogated by the antioxidant vitamin C. Like romidepsin, vorinostat combined with fenretinide achieved synergistic cytotoxic activity and increased histone acetylation in preclinical models of TCLMs, but not in non-malignant cells. As vorinostat is an oral agent and not a P-glycoprotein substrate it may have advantages in such combination therapy. These data support conducting a clinical trial of vorinostat combined with fenretinide in relapsed and refractory TCLMs.

Nanomicellar Lenalidomide-Fenretinide Combination Suppresses Tumor Growth in an MYCN Amplified Neuroblastoma Tumor.

PURPOSE: In a previous study, we demonstrated that the combination of fenretinide with lenalidomide, administered by a novel nanomicellar formulation (FLM), provided a strong antitumor effect in a neuroblastoma TrkB-expressing tumor. In this study, we tested the nanomicellar combination in an MYCN amplified neuroblastoma xenograft to assess its efficacy in different tumor genotypes and evaluate the interactions of the nanomicelles with the tumor cells. EXPERIMENTAL DESIGN: FLM was administered to mice bearing human NLF xenografts to evaluate its efficacy in comparison with the nanomicelles containing fenretinide alone (FM). Confocal laser-scanning fluorescence microscopy images of the NLF cells treated with FLM and FM allowed us to estimate the nanomicelle ability to transport the encapsulated drugs inside the tumor cells. Flow cytometric analysis of the cells from treated tumors was performed to assess the effect of treatment on GD2 expression and NK cell infiltration. RESULTS: FLM and FM decreased the growth of NLF xenografts at comparable extents during the treatment period. Afterwards, FLM induced a progressive tumor regression without regrowth, while FM treatment was followed by regrowth within 15-20 days after the end of treatment. Both FLM and FM were able to penetrate the tumor cells transporting the encapsulated drugs. FLM transported higher amount of fenretinide inside the cells. Also, FLM treatment strongly increased GD2 expression in treated tumors and slightly decreased the NK infiltration compared to FM. CONCLUSION: FLM treatment induced a superior antitumor response than FM in NLF xenografts, presumably due to the combined effects of fenretinide cytotoxicity and lenalidomide antiangiogenic activity. The ability of FLM to penetrate tumor cells, transporting the encapsulated drugs, substantially improved the therapeutic efficiency of this system. Moreover, the enhancement of GD2 expression in FLM treated tumors offers the possibility to further increase the antitumor effect by the use of anti-GD2 CAR-T cells and anti-GD2 antibodies in combination with FLM in multimodal therapies.

Microencapsulation of amorphous solid dispersions of fenretinide enhances drug solubility and release from PLGA in vitro and in vivo.

The purpose of this study was to develop solid dispersions of fenretinide(4HPR), incorporate them into poly(lactic-co-glycolic)(PLGA) millicylindrical implants, and evaluate the resulting implants in vitro and in vivo for future applications in oral cancer chemoprevention. Due to the extreme hydrophobicity of 4HPR, 4HPR-polyvinylpyrrolidone (PVP) amorphous solid dispersions(ASDs) were prepared for solubility enhancement. The optimal PVP-4HPR ratio of 9/1(w/w) provided a 50-fold solubility enhancement in aqueous media, which was sustained over 1 week. PVP-4HPR ASD particles were loaded into PLGA millicylinders and drug release was evaluated in vitro in PBST and in vivo by recovery from subcutaneous injection in rats. While initial formulations of PLGA PVP-4HPR millicylinders only released 10% 4HPR in vitro after 28 days, addition of the plasticizer triethyl-o-acetyl-citrate(TEAC) into PVP-4HPR ASDs resulted in a 5.6-fold total increase in drug release. Remarkably, the TEAC-PVP-4HPR PLGA implants demonstrated slow, continuous, and nearly complete release over 1 month in vivo compared to a 25% release for our previously reported formulation incorporating solubilizers and pore-forming agents. Hence, a combination of PLGA plasticizer and ASD formation provides an avenue for long-term controlled release in vivo for the exceptionally difficult drug to formulate, 4HPR, and a suitable formulation for future evaluation in rodent models of oral cancer.

Mixed micelles of TPGS and Soluplus® for co-delivery of paclitaxel and fenretinide: in vitro and in vivo anticancer study.

Fenretinide (4-HPR), as a semi-synthetic retinoid, has apoptosis-promoting effects as a single agent and chemotherapy synergist in vitro. When a human ovarian cancer cells line (A2780s) was treated with both PTX and 4-HPR, there was a synergistic anti-cancer effect demonstrated with a average combination index of 0.44. In this research, a new TPGS-Soluplus® mixed micelles were developed which encapsulation efficiencies of paclitaxel (PTX) and fenretinide (4-HPR) were as high as 98%, and the average diameter of the micelles was 66.26 nm. Cytotoxicity of the mixed micelles co-delivered with PTX and 4-HPR reduced significantly 7.3 and 25.1 times compared with free drug respectively in A2780s cells. More importantly, in vivo pharmacokinetic study, the loaded drugs in mixed micelles exhibited higher AUC and t1/2 values than free drugs. Furthermore, in vivo antitumor efficacy experiments demonstrated that PF-TS exhibited superior in vivo antitumor activity on the inhibition rate of tumor growth than other treatment groups (77.8% corresponding tumor growth inhibition in PF-TS treated group vs 19.9, 12.5, and 26.0% of tumor growth inhibition rate in Taxol®, 4-HPR, and Taxol®+4-HPR, respectively). Therefore, the mixed micelles of co-deliver PTX and 4-HPR successfully constructed may hopefully be applied to the cancer combination treatment with less toxic effect and more antitumor activity.

Fenretinide favorably affects mucins (MUC5AC/MUC5B) and fatty acid imbalance in a manner mimicking CFTR-induced correction.

Cystic fibrosis (CF) is the most common genetic disease in Caucasians. CF is manifested by abnormal accumulation of mucus in the lungs, which serves as fertile ground for the growth of microorganisms leading to recurrent infections and ultimately, lung failure. Mucus in CF patients consists of DNA from dead neutrophils as well as mucins produced by goblet cells. MUC5AC mucin leads to pathological plugging of the airways whereas MUC5B has a protective role against bacterial infection. Therefore, decreasing the level of MUC5AC while maintaining MUC5B intact would in principle be a desirable mucoregulatory treatment outcome. Fenretinide prevented the lipopolysaccharide-induced increase of MUC5AC gene expression, without affecting the level of MUC5B, in a lung goblet cell line. Additionally, fenretinide treatment reversed the pro-inflammatory imbalance of fatty acids by increasing docosahexaenoic acid and decreasing the levels of arachidonic acid in a lung epithelial cell line and primary leukocytes derived from CF patients. Furthermore, for the first time we also demonstrate the effect of fenretinide on multiple unsaturated fatty acids, as well as differential effects on the levels of long- compared to very-long-chain saturated fatty acids which are important substrates of complex phospholipids. Finally, we demonstrate that pre-treating mice with fenretinide in a chronic model of P. aeruginosa lung infection efficiently decreases the accumulation of mucus. These findings suggest that fenretinide may offer a new approach to therapeutic modulation of pathological mucus production in CF.

A Cationic Nanomicellar Complex of the Quaternary Amphiphilic Amine RC16+ with Fenretinide as a New Multitasking System for Antitumor Therapy.

OBJECTIVES: This study investigated the antitumor effect of a new nanomicellar complex obtained by combining the antitumor agent fenretinide with a quaternary amphiphilic amine RC16+ also endowed with antitumor activity. METHODS: The complex (Fen-RC16+) strongly improved the aqueous solubility of fenretinide (from 1,71 ± 0.08 µg/ml, pure fenretinide to 1500 ± 164 µg /ml, Fen-RC16+ complex) and provided a cytotoxic effect on SH-SY5Y neuroblastoma cell lines resulting from the intrinsic activity of both the complex components. Moreover, the mean size of the nanomicellar complex (ranging from 20 ± 1.97 nm to 40 ± 3.05 nm) was suitable for accumulation to the tumor site by the enhanced permeability and retention effect and the positive charge provided by the quaternary RC16+ induced adsorption of the complex on the tumor cell surface improving the intracellular concentration of fenretinide. RESULTS: All these characteristics made the Fen-RC16+ complex a multitasking system for antitumor therapy. CONCLUSION: Indeed its in vivo activity, evaluated on SH-SY5Y xenografts, was strong, and the tumor growth did not resume after the treatment withdrawal.

A novel oral micellar fenretinide formulation with enhanced bioavailability and antitumour activity against multiple tumours from cancer stem cells.

BACKGROUND: An increasing number of anticancer agents has been proposed in recent years with the attempt to overcome treatment-resistant cancer cells and particularly cancer stem cells (CSC), the major culprits for tumour resistance and recurrence. However, a huge obstacle to treatment success is the ineffective delivery of drugs within the tumour environment due to limited solubility, short circulation time or inconsistent stability of compounds that, together with concomitant dose-limiting systemic toxicity, contribute to hamper the achievement of therapeutic drug concentrations. The synthetic retinoid Fenretinide (4-hydroxy (phenyl)retinamide; 4-HPR) formerly emerged as a promising anticancer agent based on pre-clinical and clinical studies. However, a major limitation of fenretinide is traditionally represented by its poor aqueous solubility/bioavailability due to its hydrophobic nature, that undermined the clinical success of previous clinical trials. METHODS: Here, we developed a novel nano-micellar fenretinide formulation called bionanofenretinide (Bio-nFeR), based on drug encapsulation in an ion-pair stabilized lipid matrix, with the aim to raise fenretinide bioavailability and antitumour efficacy. RESULTS: Bio-nFeR displayed marked antitumour activity against lung, colon and melanoma CSC both in vitro and in tumour xenografts, in absence of mice toxicity. Bio-nFeR is suitable for oral administration, reaching therapeutic concentrations within tumours and an unprecedented therapeutic activity in vivo as single agent. CONCLUSION: Altogether, our results indicate Bio-nFeR as a novel anticancer agent with low toxicity and high activity against tumourigenic cells, potentially useful for the treatment of solid tumours of multiple origin.

A Novel Nanomicellar Combination of Fenretinide and Lenalidomide Shows Marked Antitumor Activity in a Neuroblastoma Xenograft Model.

PURPOSE: Currently >50% of high-risk neuroblastoma (NB) patients, despite intensive therapy and initial partial or complete response, develop recurrent NB due to the persistence of minimal residual disease (MRD) that is resistant to conventional antitumor drugs. Indeed, their low therapeutic index prevents drug-dose escalation and protracted administration schedules, as would be required for MRD treatment. Thus, more effective and less toxic therapies are urgently needed for the management of MRD. To address this aim, we evaluated a new combination of fenretinide and lenalidomide, both endowed with antitumor activity and low-toxicity profiles. New nanomicelles were prepared as carriers for this combination to maximize bioavailability and accumulation at the tumor site because of the enhanced permeability and retention (EPR) effect. EXPERIMENTAL DESIGN: New nanomicelles containing the fenretinide-lenalidomide combination (FLnMs) were prepared by a one-step method, providing high drug encapsulation and micelle dimensions suitable for tumor accumulation. Their administration to mice bearing human NB xenografts allowed us to evaluate their efficacy in comparison with the nanomicelles containing fenretinide alone (FnMs). RESULTS: Treatment by FLnMs significantly decreased the tumor growth of NB xenografts. FLnMs were more active than FnMs despite comparable fenretinide concentrations in tumors, and lenalidomide alone did not show cytotoxic activity in vitro against NB cells. The tumor mass at the end of treatment with FLnMs was predominantly necrotic, with a decreased Ki-67 proliferation index. CONCLUSION: FLnMs provided superior antitumor efficacy in NB xenografts compared to FnMs. The enhanced efficacy of the combination was likely due to the antiangiogenic effect of lenalidomide added to the cytotoxic effect of fenretinide. This new nanomicellar combination is characterized by a low-toxicity profile and offers a novel therapeutic option for the treatment of high-risk tumors where the persistence of MRD requires repeated administrations of therapeutic agents over long periods of time to avoid recurrent disease.

Quality of Life in a Randomized Breast Cancer Prevention Trial of Low-Dose Tamoxifen and Fenretinide in Premenopausal Women.

Menopausal symptoms are the main reason for withdrawal in tamoxifen prevention trials. Here, we present Menopause Quality of Life (MenQoL) assessment within a randomized 2 × 2 phase II clinical trial of low-dose tamoxifen and the synthetic retinoid fenretinide. A total of 235 premenopausal women at higher risk for breast cancer were randomized to either tamoxifen 5 mg daily, fenretinide 200 mg daily, their combination, or placebo. Climacteric symptoms were investigated using the MenQoL questionnaire which was self-administered at each visit for 2 years of treatment and for 1 year of follow-up. CYP2D6 was genotyped in subjects taking tamoxifen to study the association with menopausal symptoms. The MenQoL effect size analysis showed no statistically significant difference among the four treatment arms for all four domains (vasomotor, physical, psychosocial, and sexual). Vasomotor symptoms only slightly increased under tamoxifen, with a score at year two of 1.45, 1.21, 0.58, and 1.17 in the combined, tamoxifen, fenretinide, and placebo arms, respectively. Compared with the slow metabolizers, a higher percentage of subjects with CYP2D6 extensive metabolizer genotype complained of a ≥3 score in the vasomotor, psychosocial, and sexual domain in the tamoxifen arms (P value = 0.01, 0.007, and 0.007, respectively). QoL in premenopausal or perimenopausal women was not significantly worsened by low-dose tamoxifen or fenretinide. Our findings suggest that a low dose of tamoxifen may increase its acceptability for breast cancer prevention.

Antiglioma via regulating oxidative stress and remodeling tumor-associated macrophage using lactoferrin-mediated biomimetic codelivery of simvastatin/fenretinide.

Effective treatment of malignant glioma still remains a formidable challenge due to lack of the effective BBB-permeable drugs and efficient brain delivery methods, and the pharmacotherapy options are very limited. Therefore, to develop an effective therapeutic strategy is a pressing need. In this work, a noncytotoxic drug combination (i.e., simvastatin and fenretinide) was revealed to be potent for treating glioma, which was co-encapsulated into a TPGS-TAT-embedded lactoferrin nanoparticle system for achieving brain-targeted biomimetic delivery via the LRP-1 receptor. It was shown that the lactoferrin nanoparticle repolarized the tumor-associated macrophages from the M2 phenotype to M1 via regulating the STAT6 pathway, as well as induced the ROS-mediated mitochondrial apoptosis by inhibiting the Ras/Raf/p-Erk pathway in the glioma cells. The antiglioma efficacy was further demonstrated in both the subcutaneous and orthotopic glioma models. The repolarization of tumor-associated macrophages not only prompted the ROS generation but also induced the innate immunity (e.g., antitumor cytokine release). This delivery and therapeutic strategy provides a novel modality for the glioma treatment.

In vivo controlled release of fenretinide from long-acting release depots for chemoprevention of oral squamous cell carcinoma recurrence.

Local, long-acting release fenretinide (4HPR) millicylindrical implants were prepared and evaluated for their release kinetics in vivo and their ability to suppress oral cancer tumor explant growth. Poly(lactic-co-glycolic acid)(PLGA) implants were prepared as a function of drug loading and the presence of various excipients (pore-formers, solubilizers, crystallization inhibitors) to enhance release of the insoluble 4HPR. Release kinetics and bioerosion of PLGA were monitored both in vitro in a PBS/Tween 80 buffer and in vivo by recovery of the drug remaining at the injection site. 4HPR was released from PLGA implants much slower in vivo than in the drug solubilizing media in vitro, with a 3-week lag phase and continuous release of >2 months, but showed some release enhancement by addition of solubilizers. Water-soluble PVA/sucrose implants for release of 4HPR served to determine if drug dissolution provided suitable controlled release without the PLGA, and this formulation showed continuous drug release over 6 weeks in vivo. Placement of PLGA-4HPR implants adjacent to oral cancer tumor murine xenografts showed inhibition of tumor growth relative to sham implants, indicating the potential for the local 4HPR delivery approach to be useful for oral cancer chemoprevention.

Clinical development of fenretinide as an antineoplastic drug: Pharmacology perspectives.

Fenretinide (4-HPR) is a synthetic retinoid that has cytotoxic activity against cancer cells. Despite substantial in vitro cytotoxicity, response rates in early clinical trials with 4-HPR have been less than anticipated, likely due to the low bioavailability of the initial oral capsule formulation. Several clinical studies have shown that the oral capsule formulation at maximum tolerated dose (MTD) achieved <10 µmol/L concentrations in patients. To improve bioavailability of 4-HPR, new oral powder (LYM-X-SORB®, LXS) and intravenous lipid emulsion (ILE) formulations are being tested in early-phase clinical trials. ILE 4-HPR administered as five-day continuous infusion achieved over 50 µmol/L at MTD with minimal systemic toxicities; multiple complete and partial responses were observed in peripheral T cell lymphomas. The LXS oral powder 4-HPR formulation increased plasma levels approximately two-fold at MTD in children without dose-limiting toxicities and demonstrated multiple complete responses in recurrent neuroblastoma. The clinical activity observed with new 4-HPR formulations is attributed to increased bioavailability. Phase I and II clinical trials of both LXS 4-HPR and ILE 4-HPR are in progress as a single agent or in combination with other drugs. Impact statement One of the critical components in drug development is understanding pharmacology (especially pharmacokinetics) of the drugs being developed. Often the pharmacokinetic properties, such as poor solubility leading to poor bioavailability, of the drug can limit further development of the drug. The development of numerous drugs has often halted at clinical testing stages, and several of them were due to the pharmacological properties of the agents, resulting in increased drug development cost. The current review provides an example of how improved clinical activity can be achieved by changing the formulations of a drug with poor bioavailability. Thus, it emphasizes the importance of understanding pharmacologic characteristics of the drug in drug development.

Phase I Study of Fenretinide Delivered Intravenously in Patients with Relapsed or Refractory Hematologic Malignancies: A California Cancer Consortium Trial.

Purpose: A phase I study was conducted to determine the MTD, dose-limiting toxicities (DLT), and pharmacokinetics of fenretinide delivered as an intravenous emulsion in relapsed/refractory hematologic malignancies.Experimental Design: Fenretinide (80-1,810 mg/m2/day) was administered by continuous infusion on days 1 to 5, in 21-day cycles, using an accelerated titration design.Results: Twenty-nine patients, treated with a median of three prior regimens (range, 1-7), were enrolled and received the test drug. Ninety-seven courses were completed. An MTD was reached at 1,280 mg/m2/day for 5 days. Course 1 DLTs included 6 patients with hypertriglyceridemia, 4 of whom were asymptomatic; 2 patients experienced DLT thrombocytopenia (asymptomatic). Of 11 patients with response-evaluable peripheral T-cell lymphomas, two had complete responses [CR, progression-free survival (PFS) 68+ months; unconfirmed CR, PFS 14+ months], two had unconfirmed partial responses (unconfirmed PR, PFS 5 months; unconfirmed PR, PFS 6 months), and five had stable disease (2-12 cycles). One patient with mature B-cell lymphoma had an unconfirmed PR sustained for two cycles. Steady-state plasma levels were approximately 10 mcg/mL (mid-20s µmol/L) at 640 mg/m2/day, approximately 14 mcg/mL (mid-30s µmol/L) at 905 mg/m2/day, and approximately 22 mcg/mL (mid-50s µmol/L) at 1,280 mg/m2/day.Conclusions: Intravenous fenretinide obtained significantly higher plasma levels than a previous capsule formulation, had acceptable toxicities, and evidenced antitumor activity in peripheral T-cell lymphomas. A recommended phase II dosing is 600 mg/m2 on day 1, followed by 1,200 mg/m2 on days 2 to 5, every 21 days. A registration-enabling phase II study in relapsed/refractory PTCL (ClinicalTrials.gov identifier: NCT02495415) is ongoing. Clin Cancer Res; 23(16); 4550-5. ©2017 AACR.

P450 inhibitor ketoconazole increased the intratumor drug levels and antitumor activity of fenretinide in human neuroblastoma xenograft models.

We previously reported that concurrent ketoconazole, an oral anti-fungal agent and P450 enzyme inhibitor, increased plasma levels of the cytotoxic retinoid, fenretinide (4-HPR) in mice. We have now determined the effects of concurrent ketoconazole on 4-HPR cytotoxic dose-response in four neuroblastoma (NB) cell lines in vitro and on 4-HPR activity against two cell line-derived, subcutaneous NB xenografts (CDX) and three patient-derived NB xenografts (PDX). Cytotoxicity in vitro was assessed by DIMSCAN assay. Xenografted animals were treated with 4-HPR/LXS (240 mg/kg/day) + ketoconazole (38 mg/kg/day) in divided oral doses in cycles of five continuous days a week. In one model, intratumoral levels of 4-HPR and metabolites were assessed by HPLC assay, and in two models intratumoral apoptosis was assessed by TUNEL assay, on Day 5 of the first cycle. Antitumor activity was assessed by Kaplan-Meier event-free survival (EFS). The in vitro cytotoxicity of 4-HPR was not affected by ketoconazole (p ≥ 0.06). Ketoconazole increased intratumoral levels of 4-HPR (p = 0.02), of the active 4-oxo-4-HPR metabolite (p = 0.04), and intratumoral apoptosis (p ≤ 0.0006), compared to 4-HPR/LXS-alone. Concurrent ketoconazole increased EFS in both CDX models compared to 4-HPR/LXS-alone (p ≤ 0.008). 4-HPR + ketoconazole also increased EFS in PDX models compared to controls (p ≤ 0.03). Thus, concurrent ketoconazole decreased 4-HPR metabolism with resultant increases of plasma and intratumoral drug levels and antitumor effects in neuroblastoma murine xenografts. These results support the clinical testing of concurrent ketoconazole and oral fenretinide in neuroblastoma.

Reactive Oxygen Species-Mediated Synergism of Fenretinide and Romidepsin in Preclinical Models of T-cell Lymphoid Malignancies.

T-cell lymphoid malignancies (TCLM) are in need of novel and more effective therapies. The histone deacetylase (HDAC) inhibitor romidepsin and the synthetic cytotoxic retinoid fenretinide both have achieved durable clinical responses in T-cell lymphomas as single agents. We investigated the potential for using these two agents in combination in TCLMs. We demonstrated cytotoxic synergy between romidepsin and fenretinide in 15 TCLM cell lines at clinically achievable concentrations that lacked cytotoxicity for nonmalignant cells (fibroblasts and blood mononuclear cells). In vivo, romidepsin + fenretinide + ketoconazole (enhances fenretinide exposures by inhibiting fenretinide metabolism) showed greater activity in subcutaneous and disseminated TCLM xenograft models than single-agent romidepsin or fenretinide + ketoconazole. Fenretinide + romidepsin caused a reactive oxygen species (ROS)-dependent increase in proapoptotic proteins (Bim, tBid, Bax, and Bak), apoptosis, and inhibition of HDAC enzymatic activity, which achieved a synergistic increase in histone acetylation. The synergistic cytotoxicity, apoptosis, and histone acetylation of fenretinide + romidepsin were abrogated by antioxidants (vitamins C or E). Romidepsin + fenretinide activated p38 and JNK via ROS, and knockdown of p38 and JNK1 significantly decreased the synergistic cytotoxicity. Romidepsin + fenretinide also showed synergistic cytotoxicity for B-lymphoid malignancy cell lines, but did not increase ROS, acetylation of histones, activation of p38 + JNK, or cytotoxicity in nonmalignant cells. Romidepsin + fenretinide achieved synergistic activity in preclinical models of TCLMs, but not in nonmalignant cells, via a novel molecular mechanism. These data support conducting clinical trials of romidepsin + fenretinide in relapsed and refractory TCLMs. Mol Cancer Ther; 16(4); 649-61. ©2017 AACR.

Results of a phase I-II study of fenretinide and rituximab for patients with indolent B-cell lymphoma and mantle cell lymphoma.

Fenretinide, a synthetic retinoid, induces apoptotic cell death in B-cell non-Hodgkin lymphoma (B-NHL) and acts synergistically with rituximab in preclinical models. We report results from a phase I-II study of fenretinide with rituximab for B-NHLs. Eligible diagnoses included indolent B-NHL or mantle cell lymphoma. The phase I design de-escalated from fenretinide at 900 mg/m2 PO BID for days 1-5 of a 7-day cycle. The phase II portion added 375 mg/m2 IV rituximab weekly on weeks 5-9 then every 3 months. Fenretinide was continued until progression or intolerance. Thirty-two patients were treated: 7 in phase I, and 25 in phase II of the trial. No dose-limiting toxicities were observed. The phase II component utilized fenretinide 900 mg/m2 twice daily with rituximab. The most common treatment-related adverse events of grade 3 or higher were rash (n = 3) and neutropenia (n = 3). Responses were seen in 6 (24%) patients on the phase II study, with a median duration of response of 47 months (95% confidence interval, 2-56). The combination of fenretinide and rituximab was well tolerated, yielded a modest overall response rate, but with prolonged remission durations. Further study should focus on identifying the responsive subset of B-NHL.

The involvement of M2 macrophage polarization inhibition in fenretinide-mediated chemopreventive effects on colon cancer.

Clinical studies have shown that fenretinide (4-HPR) is an attractive chemopreventive agent for cancer treatment. However, to date, few studies have demonstrated the mechanism of the preventive effect of 4-HPR. In our current study, we revealed that 4-HPR could significantly suppress IL-4/IL-13 induced M2-like polarization of macrophages, which was demonstrated by the reduced expression of M2 surface markers, the down-regulation of M2 marker genes, and the inhibition of M2-like macrophages promoted angiogenesis. Mechanistically, our study suggested that the inhibition of the phosphorylation of STAT6, rather than the generation of oxidative stress, is involved in the 4-HPR-driven inhibition of M2 polarization. More intriguingly, by utilizing adenomatous polyposis coli (APCmin/+) transgenic mice, we demonstrated that the tumorigenesis was dramatically decreased by 4-HPR treatment accompanied with fewer M2-like macrophages in the tumor tissues, thereby profoundly blocking tumor angiogenesis. These findings, for the first time, reveal the involvement of M2 polarization inhibition in 4-HPR-mediated chemoprevention, which provides a new point of insight and indicates the potential mechanism underlying the chemopreventive effect of 4-HPR.