Phase Ib Study of Wnt Inhibitor Ipafricept with Gemcitabine and nab-paclitaxel in Patients with Previously Untreated Stage IV Pancreatic Cancer.

PURPOSE: The recombinant fusion protein ipafricept blocks Wnt signaling, and in combination with gemcitabine and nab-paclitaxel caused tumor regression in xenografts. This phase Ib study evaluated the combination of ipafricept with nab-paclitaxel + gemcitabine in patients with untreated metastatic pancreatic adenocarcinoma (mPDAC). PATIENTS AND METHODS: Dose escalation started with standard dose nab-paclitaxel + gemcitabine and ipafricept (3.5 mg/kg days 1, 15). Because of fragility fractures seen with different anti-Wnt agents, following cohorts had ≥6 patients treated with ipafricept 3 to 5 mg/kg on day 1, and included bone marker monitoring and prophylactic bisphosphonates as indicated. On the basis of preclinical data, sequential dosing was evaluated in cohort 4 (ipafricept day 1 followed nab-paclitaxel + gemcitabine day 3). Objectives included safety, MTD, recommended phase II dose, pharmacokinetics, immunogenicity, pharmacodynamics, and efficacy. RESULTS: A total of 26 patients were enrolled, five in cohort 1 and seven each in cohorts 2-4. ipafricept-related adverse events (AEs) of any grade included fatigue, nausea, vomiting, anorexia, and pyrexia. ipafricept-related AEs grade ≥3 included two events of aspartate aminotransferase elevation, and one each of nausea, rash, vomiting, and leucopenia. No dose-limiting toxicities or fragility fractures were observed. Nine patients (34.6%) had partial response, 12 (46.2%) stable disease as best response, with clinical benefit rate of 81%. Median progression-free survival was 5.9 m [95% confidence interval (CI), 3.4-18.4], median overall survival was 9.7 m (95% CI, 7.0-14). The study was terminated by the sponsor due to bone-related toxicity within this therapeutic program and concerns for commercial viability. One patient remains on therapy under compassionate use. CONCLUSIONS: Ipafricept can be administered with nab-paclitaxel + gemcitabine with reasonable tolerance. Wnt pathway remains a therapeutic target of interest in mPDAC.

Intranasal administration of a stapled relaxin-3 mimetic has anxiolytic- and antidepressant-like activity in rats.

BACKGROUND AND PURPOSE: Depression and anxiety are common causes of disability, and innovative tools and potential pharmacological targets are actively sought for prevention and treatment. Therapeutic strategies targeting the relaxin-3 peptide or its primary endogenous receptor, RXFP3, for the treatment of major depression and anxiety disorders have been limited by a lack of compounds with drug-like properties. We proposed that a hydrocarbon-stapled mimetic of relaxin-3, when administered intranasally, might be uniquely applicable to the treatment of these disorders. EXPERIMENTAL APPROACH: We designed a series of hydrocarbon-stapled relaxin-3 mimetics and identified the most potent compound using in vitro receptor binding and activation assays. Further, we assessed the effect of intranasal delivery of relaxin-3 and the lead stapled mimetic in rat models of anxiety and depression. KEY RESULTS: We developed an i,i+7 stapled relaxin-3 mimetic that manifested a stabilized α-helical structure, proteolytic resistance, and confirmed agonist activity in receptor binding and activation in vitro assays. The stapled peptide agonist enhanced food intake after intracerebral infusion in rats, confirming in vivo activity. We showed that intranasal delivery of the lead i,i+7 stapled peptide or relaxin-3 had orexigenic effects in rats, indicating a potential clinically translatable route of delivery. Further, intranasal administration of the lead i,i+7 stapled peptide exerted anxiolytic and antidepressant-like activity in anxiety- and depression-related behaviour paradigms. CONCLUSIONS AND IMPLICATIONS: Our preclinical findings demonstrate that targeting the relaxin-3/RXFP3 receptor system via intranasal delivery of an i,i+7 stapled relaxin-3 mimetic may represent an effective treatment approach for depression, anxiety, and related neuropsychiatric disorders.

A phase 1b dose escalation study of ipafricept (OMP54F28) in combination with paclitaxel and carboplatin in patients with recurrent platinum-sensitive ovarian cancer.

OBJECTIVES: The WNT pathway is an important oncologic driver of epithelial ovarian cancer (EOC). The first-in-class recombinant fusion protein ipafricept (IPA) blocks Wnt signaling through binding of Wnt ligands. This phase Ib trial was designed to determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RPh2) for IPA in combination with taxane and platinum therapy (C/P). METHODS: Dose escalation started with a standard 3 + 3 design for IPA/C/P with q3w intravenous IPA on Day 1, in cycles 1 to 6 with C (AUC = 5 mg/ml·min) and P (175 mg/m2). For enhanced bone safety the trial was revised to 6-patient cohorts with a q3w regimen of IPA on Day 1 and C/P on Day 3 (IPA → C/P). RESULTS: 37 patients have been treated; 30 of whom were treated following protocol revision to q3w IPA(D1) → C/P(D3) (2 & 4 mg/kg). IPA-related TEAEs that occurred in ≥15% included: fatigue (40%); nausea (35%); diarrhea and decreased appetite (22%) each; dysgeusia (19%); and vomiting (16.2%). 22% reported ≥1 IPA related TEAE Grade ≥3 the most common of which was neutropenia at 16%. There were no DLTs; the MTD was not reached. The maximum administered dose based on bone safety was 6 mg/kg. The overall response rate (ORR) was 75.7%. Median PFS was 10.3 months (95% CI 8.5-14.2) and OS 33 months (95% CI 23.4-NR). CONCLUSIONS: IPA is well tolerated in combination with sequential C/P. ORR, PFS and OS are comparable to historical data but bone toxicity at efficacy doses of this particular Wnt inhibitor limit further development in EOC.

Ketones and pain: unexplored role of hydroxyl carboxylic acid receptor type 2 in the pathophysiology of neuropathic pain.

The mechanisms underlying neuropathic pain are poorly understood. Here we show the unexplored role of the hydroxyl carboxylic acid receptor type 2 (HCAR2) in 2 models of neuropathic pain. We used an oral treatment with dimethyl fumarate and the HCAR2 endogenous ligand ß-hydroxybutyrate (BHB) in wild-type (WT) and HCAR2-null mice. We found an up-regulation of the HCAR2 in the sciatic nerve and the dorsal root ganglia in neuropathic mice. Accordingly, acute and chronic treatment with dimethylfumarate (DMF) and BHB reduced the tactile allodynia. This effect was completely lost in the HCAR2-null mice after a 2-d starvation protocol, in which the BHB reached the concentration able to activate the HCAR2-reduced tactile allodynia in female WT mice, but not in the HCAR2-null mice. Finally, we showed that chronic treatment with DMF reduced the firing of the ON cells (cells responding with an excitation after noxious stimulation) of the rostral ventromedial medulla. Our results pave the way for investigating the mechanisms by which HCAR2 regulates neuropathic pain plasticity.-Boccella, S., Guida, F., De Logu, F., De Gregorio, D., Mazzitelli, M., Belardo, C., Iannotta, M., Serra, N., Nassini, R., de Novellis, V., Geppetti, P., Maione, S., Luongo, L. Ketones and pain: unexplored role of hydroxyl carboxylic acid receptor type 2 in the pathophysiology of neuropathic pain.

Pharmacokinetics and Safety of DS-8500a, an Antidiabetic Drug, in Japanese Subjects with Hepatic or Renal Impairment: A Single-Center, Open-Label, Single-Dose Study.

INTRODUCTION: The pharmacokinetics, safety, and tolerability of DS-8500a (a G protein receptor 119 agonist) up to 100 mg have been investigated in healthy Japanese adults. The objective of this study was to evaluate the effects of hepatic or renal impairment on the pharmacokinetics of a single 25-mg oral dose of DS-8500a. METHODS: This single-center, open-label study enrolled subjects into eight groups according to hepatic function (normal; mild or moderate impairment) and renal function [normal; mild, moderate, or severe impairment; and end-stage renal disease (ESRD)]. Drug concentrations were measured by liquid-chromatography tandem mass spectrometry. Pharmacokinetic parameters were evaluated by non-compartmental analysis. Adverse events (AEs) were evaluated for safety. RESULTS: The hepatic and renal groups enrolled 15 and 30 subjects, respectively. Pharmacokinetic parameters of DS-8500a were comparable between the normal hepatic function and mild hepatic impairment groups, but the mean area under the concentration-time curve (AUC) was 1.37-fold higher, and the half-life was longer in the moderate hepatic impairment group compared with the normal hepatic function group. The maximum concentration (Cmax) and AUC values were 0.704- and 0.609-fold lower, respectively, in the ESRD group compared with the values in the other renal impairment groups; no clear differences in AUC and time to Cmax were observed in the normal function and mild, moderate, and severe renal impairment groups. There was no relationship between apparent total body clearance and estimated glomerular filtration rate. The incidence of AEs was similar among all groups. CONCLUSION: DS-8500a exposure in the mild hepatic impairment and mild to severe renal impairment groups was similar to that in the corresponding normal hepatic and renal function groups, but dose adjustments may be required in those with moderate hepatic impairment and ESRD. TRIAL REGISTRATION: Japic CTI-No. 163135. FUNDING: Daiichi Sankyo Co. Ltd., Tokyo, Japan.

The role of free-fatty acid receptor-4 (FFA4) in human cancers and cancer cell lines.

A dietary influence on cancer progression has been evident for many decades, and dietary fatty acids, particularly long chain mono- and polyunsaturated fatty acids, have been shown to play significant roles in influencing growth of a variety of human cancers. The discovery of the family of cell-surface free-fatty acid receptors, which include the long-chain fatty acid receptors FFA1 and FFA4, suggest that many of the effects of dietary fats could be receptor-mediated. FFA4 is ubiquitously expressed and has recently been shown to modulate a variety of important anti-inflammatory and metabolic processes. Since FFA4 is currently an attractive drug target for treatment of metabolic disorders such as diabetes and obesity, understanding its role in cancer progression is critical towards the drug discovery process. In this research update, the current body of knowledge on the role of this receptor in regulating cancer cell proliferation, migration, and invasion, as well as in vivo tumorigenesis is reviewed.

A First-in-Human Phase I Study of the Anticancer Stem Cell Agent Ipafricept (OMP-54F28), a Decoy Receptor for Wnt Ligands, in Patients with Advanced Solid Tumors.

Purpose: Wnt signaling is implicated in tumor cell dedifferentiation and cancer stem cell function. Ipafricept (OMP-54F28) is a first-in-class recombinant fusion protein with the extracellular part of human frizzled 8 receptor fused to a human IgG1 Fc fragment that binds Wnt ligands. This trial evaluated ipafricept in patients with solid tumors.Experimental design: A 3+3 design was used; ipafricept was given intravenously every 3 weeks. The objectives were determination of dose-limiting toxicities (DLTs), recommended phase 2 dose (RP2D), safety, pharmacokinetics (PK), immunogenicity, pharmacodynamics (PD), and preliminary efficacy.Results: 26 patients were treated in seven dose-escalation cohorts (0.5, 1, 2.5, 5, 10, 15, and 20 mg/kg). No further dose escalation was pursued as PK modeling indicated that the target efficacious dose was reached at 10 mg/kg, and fragility fractures occurred at 20 mg/kg. Most common related grade 1 and 2 adverse events (AEs; ≥20% of patients) were dysgeusia, decreased appetite, fatigue, and muscle spasms. Ipafricept-related grade 3 TEAEs included hypophosphatemia and weight decrease (1 subject each, 3.8%). Ipafricept half-life was ∼4 days and had low incidence of antidrug antibody formation (7.69%) with no impact on drug exposure. Six patients had ß-C-terminal telopeptide (ß-CTX) doubling from baseline, which was reversible. PD modulation of Wnt pathway genes in hair follicles occurred ≥2.5 mg/kg. Two desmoid tumor and a germ cell cancer patient experienced stable disease for >6 months.Conclusions: Ipafricept was well tolerated, with RP2D of 15 mg/kg Q3W. Prolonged SD was noted in desmoid tumor and germ cell cancer patients. Clin Cancer Res; 23(24); 7490-7. ©2017 AACR.

Evaluation of tolerance to lentiviral LV-RPE65 gene therapy vector after subretinal delivery in non-human primates.

Several approaches have been developed for gene therapy in RPE65-related Leber congenital amaurosis. To date, strategies that have reached the clinical stages rely on adeno-associated viral vectors and two of them documented limited long-term effect. We have developed a lentiviral-based strategy of RPE65 gene transfer that efficiently restored protein expression and cone function in RPE65-deficient mice. In this study, we evaluated the ocular and systemic tolerances of this lentiviral-based therapy (LV-RPE65) on healthy nonhuman primates (NHPs), without adjuvant systemic anti-inflammatory prophylaxis. For the first time, we describe the early kinetics of retinal detachment at 2, 4, and 7 days after subretinal injection using multimodal imaging in 5 NHPs. We revealed prolonged reattachment times in LV-RPE65-injected eyes compared to vehicle-injected eyes. Low- (n = 2) and high-dose (n = 2) LV-RPE65-injected eyes presented a reduction of the outer nuclear and photoreceptor outer segment layer thickness in the macula, that was more pronounced than in vehicle-injected eyes (n = 4). All LV-RPE65-injected eyes showed an initial perivascular reaction that resolved spontaneously within 14 days. Despite foveal structural changes, full-field electroretinography indicated that the overall retinal function was preserved over time and immunohistochemistry identified no difference in glial, microglial, or leucocyte ocular activation between low-dose, high-dose, and vehicle-injected eyes. Moreover, LV-RPE65-injected animals did not show signs of vector shedding or extraocular targeting, confirming the safe ocular restriction of the vector. Our results evidence a limited ocular tolerance to LV-RPE65 after subretinal injection without adjuvant anti-inflammatory prophylaxis, with complications linked to this route of administration necessitating to block this transient inflammatory event.

A G-protein-coupled chemokine receptor: A putative insertion site for a multi-pathogen recombinant capripoxvirus vaccine strategy.

Capripoxviruses (CaPVs) have been shown to be ideal viral vectors for the development of recombinant multivalent vaccines to enable delivery of immunogenic genes from ruminant pathogens. So far, the viral thymidine kinase (TK) gene is the only gene used to generate recombinants. A putative non-essential gene encoding a G-protein-coupled chemokine receptor subfamily homologue (GPCR) was targeted as an additional insertion site. Peste des petits ruminants (PPR) was chosen as a disease model. A new recombinant CaPV expressing the viral attachment hemagglutinin (H) of the PPR virus (PPRV) in the GPCR insertion site (rKS1-HPPR-GPCR) was generated in the backbone North African isolate KS1 strain of lumpy skin disease virus (LSDV). Comparison with the recombinant CaPV expressing the H of PPRV in the TK gene (rKS1-HPPR-TK) shown to induce protection against both PPR and LSD in both sheep and goats was assessed. The suitability of the GPCR gene to be a putative additional insertion site in the CaPV genome is evaluated and discussed.

Estradiol and G1 reduce infarct size and improve immunosuppression after experimental stroke.

Reduced risk and severity of stroke in adult females is thought to depend on normal endogenous levels of estrogen, a well-known neuroprotectant and immunomodulator. In male mice, experimental stroke induces immunosuppression of the peripheral immune system, characterized by a reduction in spleen size and cell numbers and decreased cytokine and chemokine expression. However, stroke-induced immunosuppression has not been evaluated in female mice. To test the hypothesis that estradiol (E2) deficiency exacerbates immunosuppression after focal stroke in females, we evaluated the effect of middle cerebral artery occlusion on infarct size and peripheral and CNS immune responses in ovariectomized mice with or without sustained, controlled levels of 17-beta-E2 administered by s.c. implant or the putative membrane estrogen receptor agonist, G1. Both E2- and G1-replacement decreased infarct volume and partially restored splenocyte numbers. Moreover, E2-replacement increased splenocyte proliferation in response to stimulation with anti-CD3/CD28 Abs and normalized aberrant mRNA expression for cytokines, chemokines, and chemokine receptors and percentage of CD4(+)CD25(+)FoxP3(+) T regulatory cells observed in E2-deficient animals. These beneficial changes in peripheral immunity after E2 replacement were accompanied by a profound reduction in expression of the chemokine, MIP-2, and a 40-fold increased expression of CCR7 in the lesioned brain hemisphere. These results demonstrate for the first time that E2 replacement in ovariectomized female mice improves stroke-induced peripheral immunosuppression.

Kisspeptin-54 at high doses acutely induces testicular degeneration in adult male rats via central mechanisms.

BACKGROUND AND PURPOSE: The kisspeptins are critical regulators of reproduction and a therapeutic target for reproductive disease. Intracerebroventricular (i.c.v.) or peripheral injection of kisspeptin potently stimulates the hypothalamic-pituitary gonadal (HPG) axis via gonadotrophin-releasing hormone (GnRH). However, little is known regarding the effects of kisspeptin administration on testicular function. We investigated the mechanism(s) of kisspeptin-induced testicular degeneration in the rat. EXPERIMENTAL APPROACH: Kisspeptin-54 (50 nmol.day(-1)) was continuously administered subcutaneously (6 h to 3 days) to male Wistar rats and reproductive hormones and testicular histology analysed. We also investigated the effects of a single subcutaneous injection of 0.5, 5 or 50 nmol kisspeptin-54. In order to determine whether the testicular degeneration observed is peripherally or centrally mediated, we investigated effects of i.c.v. injections of 5 nmol kisspeptin-54 and pre-administered a GnRH-receptor antagonist (cetrorelix) to rats peripherally treated with kisspeptin-54. KEY RESULTS: Continuous subcutaneous administration of kisspeptin-54 caused testicular degeneration after only 12 h, when gonadotrophins were still markedly raised, suggesting that the degeneration is independent of the desensitization of the HPG axis to kisspeptin-54. Furthermore, a single subcutaneous injection of kisspeptin-54 caused dose-dependent testicular degeneration. Continuous kisspeptin-54 administration is thus not required to cause testicular degeneration. Pretreatment with cetrorelix blocked kisspeptin-induced testicular degeneration, and a single i.c.v. injection of kisspeptin-54 caused testicular degeneration, suggesting it is GnRH-mediated. CONCLUSIONS AND IMPLICATIONS: Kisspeptin-induced testicular degeneration appears to be centrally mediated, and result from acute hyper-stimulation of the HPG axis. Doses must be carefully considered if kisspeptin is to be used therapeutically.

Fatty acid receptors as new therapeutic targets for diabetes.

G-protein-coupled receptors (GPCRs) are key regulators of several physiological functions. Their roles in cellular signal transduction have made them the target for majority of all currently prescribed drugs. Additionally, there are many orphan GPCRs that provide potential novel therapeutic targets. Several GPCRs are involved in metabolic regulation and glucose homeostasis such as GLP-1 receptor, glucagon receptor, adiponectin receptor and so on. Recently, free fatty acids (FFAs) have been demonstrated as ligands for orphan GPCRs and have been proposed to play a critical role in physiological glucose homeostasis. GPR40 and GPR120 are activated by medium and long-chain FFAs, whereas GPR41 and GPR43 can be activated by short-chain FFAs. GPR40, which is preferentially expressed in pancreatic beta-cells, mediates the majority of the effects of FFAs on insulin secretion. In this review, these findings and also critical analysis of these GPCRs as novel targets for diabetes are discussed.

G protein-coupled receptor 83 overexpression in naive CD4+CD25- T cells leads to the induction of Foxp3+ regulatory T cells in vivo.

Foxp3 functions as a lineage specification factor for the development of naturally occurring thymus-derived CD4+CD25+ regulatory T (Treg) cells. Recent evidence suggests that naive Foxp3-CD4+CD25- T cells can be converted in the periphery into Foxp3+ Treg cells. In this study, we have identified the G protein-coupled receptor (GPR)83 to be selectively up-regulated by CD4+CD25+ Treg cells of both murine and human origin in contrast to naive CD4+CD25- or recently activated T cells. Furthermore, GPR83 was induced upon overexpression of Foxp3 in naive CD4+CD25- T cells. Transduction of naive CD4+CD25- T cells with GPR83-encoding retroviruses did not confer in vitro suppressive activity. Nevertheless, GPR83-transduced T cells were able to inhibit the effector phase of a severe contact hypersensitivity reaction of the skin, indicating that GPR83 itself or GPR83-mediated signals conferred suppressive activity to conventional CD4+ T cells in vivo. Most strikingly, this in vivo acquisition of suppressive activity was associated with the induction of Foxp3 expression in GPR83-transduced CD4+ T cells under inflammatory conditions. Our results suggest that GPR83 might be critically involved in the peripheral generation of Foxp3+ Treg cells in vivo.