Correction to Identification of Quinoline-Based RIP2 Kinase Inhibitors with an Improved Therapeutic Index to the hERG Ion Channel

[This corrects the article DOI: 10.1021/acsmedchemlett.8b00344.].

Discovery of a First-in-Class Receptor Interacting Protein 2 (RIP2) Kinase Specific Clinical Candidate, 2-((4-(Benzo[d]thiazol-5-ylamino)-6-(tert-butylsulfonyl)quinazolin-7-yl)oxy)ethyl Dihydrogen Phosphate, for the Treatment of Inflammatory Diseases

RIP2 kinase has been identified as a key signal transduction partner in the NOD2 pathway contributing to a variety of human pathologies, including immune-mediated inflammatory diseases. Small-molecule inhibitors of RIP2 kinase or its signaling partners on the NOD2 pathway that are suitable for advancement into the clinic have yet to be described. Herein, we report our discovery and profile of the prodrug clinical compound, inhibitor 3, currently in phase 1 clinical studies. Compound 3 potently binds to RIP2 kinase with good kinase specificity and has excellent activity in blocking many proinflammatory cytokine responses in vivo and in human IBD explant samples. The highly favorable physicochemical and ADMET properties of 3 combined with high potency led to a predicted low oral dose in humans.

Identification of Quinoline-Based RIP2 Kinase Inhibitors with an Improved Therapeutic Index to the hERG Ion Channel

RIP2 kinase was recently identified as a therapeutic target for a variety of autoimmune diseases. We have reported previously a selective 4-aminoquinoline-based RIP2 inhibitor GSK583 and demonstrated its effectiveness in blocking downstream NOD2 signaling in cellular models, rodent in vivo models, and human ex vivo disease models. While this tool compound was valuable in validating the biological pathway, it suffered from activity at the hERG ion channel and a poor PK/PD profile thereby limiting progression of this analog. Herein, we detail our efforts to improve both this off-target liability as well as the PK/PD profile of this series of inhibitors through modulation of lipophilicity and strengthening hinge binding ability. These efforts have led to inhibitor 7, which possesses high binding affinity for the ATP pocket of RIP2 (IC₅₀ = 1 nM) and inhibition of downstream cytokine production in human whole blood (IC₅₀ = 10 nM) with reduced hERG activity (14 μM).

Discovery of GSK2193874: An Orally Active, Potent, and Selective Blocker of Transient Receptor Potential Vanilloid 4

Transient Receptor Potential Vanilloid 4 (TRPV4) is a member of the Transient Receptor Potential (TRP) superfamily of cation channels. TRPV4 is expressed in the vascular endothelium in the lung and regulates the integrity of the alveolar septal barrier. Increased pulmonary vascular pressure evokes TRPV4-dependent pulmonary edema, and therefore, inhibition of TRPV4 represents a novel approach for the treatment of pulmonary edema associated with conditions such as congestive heart failure. Herein we report the discovery of an orally active, potent, and selective TRPV4 blocker, 3-(1,4'-bipiperidin-1'-ylmethyl)-7-bromo-N-(1-phenylcyclopropyl)-2-[3-(trifluoromethyl)phenyl]-4-quinolinecarboxamide (GSK2193874, 28) after addressing an unexpected off-target cardiovascular liability observed from in vivo studies. GSK2193874 is a selective tool for elucidating TRPV4 biology both in vitro and in vivo.

The Identification and Pharmacological Characterization of 6-(tert-Butylsulfonyl)-N-(5-fluoro-1H-indazol-3-yl)quinolin-4-amine (GSK583), a Highly Potent and Selective Inhibitor of RIP2 Kinase

RIP2 kinase is a central component of the innate immune system and enables downstream signaling following activation of the pattern recognition receptors NOD1 and NOD2, leading to the production of inflammatory cytokines. Recently, several inhibitors of RIP2 kinase have been disclosed that have contributed to the fundamental understanding of the role of RIP2 in this pathway. However, because they lack either broad kinase selectivity or strong affinity for RIP2, these tools have only limited utility to assess the role of RIP2 in complex environments. We present, herein, the discovery and pharmacological characterization of GSK583, a next-generation RIP2 inhibitor possessing exquisite selectivity and potency. Having demonstrated the pharmacological precision of this tool compound, we report its use in elucidating the role of RIP2 kinase in a variety of in vitro, in vivo, and ex vivo experiments, further clarifying our understanding of the role of RIP2 in NOD1 and NOD2 mediated disease pathogenesis.

Discovery of potent, selective sulfonylfuran urea endothelial lipase inhibitors

Endothelial lipase (EL) activity has been implicated in HDL catabolism, vascular inflammation, and atherogenesis, and inhibitors are therefore expected to be useful for the treatment of cardiovascular disease. Sulfonylfuran urea 1 was identified in a high-throughput screening campaign as a potent and non-selective EL inhibitor. A lead optimization effort was undertaken to improve potency and selectivity, and modifications leading to improved LPL selectivity were identified. Radiolabeling studies were undertaken to establish the mechanism of action for these inhibitors, which were ultimately demonstrated to be irreversible inhibitors.

Chemo-biotherapy with 5-fluorouracil, leucovorin, and alpha interferon in metastatic carcinoma of the colon--a Cancer Biotherapy Research Group [CBRG] phase II study

BACKGROUND

Biochemical modulation of 5-Fluorouracil activity with Leucovorin has been well documented in colorectal cancer. Several studies have shown increased efficacy of 5-fluorouracil in combination with alpha interferon. We therefore initiated a phase II trial of dual modulation of 5-fluorouracil with leucovorin and alpha interferon to evaluate outcomes in patients with metastatic carcinoma of the colon.

METHODS

Patients with metastatic colon carcinoma with expected survival > 4 months and performance status of ECOG < or = 2 were treated weekly with Leucovorin 400 mg i.v. followed by 5-FU 600 mg/m2 i.v. bolus. Alpha interferon 3-9 million units was administered subcutaneously every Monday, Wednesday and Friday. Patients were analyzed for toxicity, tumor response and survival.

RESULTS

Sixteen patients with a median age of 66 years were treated. Three patients were not evaluable for response but were evaluable for toxicity. Grades 3 and 4 toxicities were neutropenia, diarrhea, mucositis, nausea and vomiting, fatigue, fever, asthenia and elevated hepatic enzymes. One patient died from complications associated with diverticulitis and neutropenia. Objective response rate was 23% (95% confidence interval 4-46%) and median survival was 11.5 months (95% confidence interval 6.3-19 months). Thirty-eight percent of the patients were alive at one year and 19% at two years.

CONCLUSION

The combination of 5-fluorouracil, leucovorin and alpha interferon as administered in this phase II study did not result in enhanced response rate or survival. However this regimen was associated with considerable toxicity.

Hybrid high-dose bolus/continuous infusion interleukin-2 in patients with metastatic melanoma: a phase II trial of the Cancer Biotherapy Research Group (formerly the National Biotherapy Study Group)

PURPOSE

Interleukin-2 (IL-2) is an active agent for the treatment of melanoma. In animal studies, polyethylene glycol conjugated (PEG) IL-2 was found to be effective in certain IL-2-resistant models. Bolus/infusional IL-2 administered to approximate the pharmacokinetics of PEG-IL-2 also overcame resistance in these models. Based on these observations, the Cancer Biotherapy Research Group (CBRG) [formerly the National Biotherapy Study Group (NBSG)] previously had conducted a pilot study and then a phase I trial of bolus IL-2 followed by continuous IL-2 (NBSG 90-01).

METHODS

In the current study, NBSG 92-09, a phase II trial was conducted using IL-2 at a dose of 36 MIU/m2 followed by a 72-hour continuous infusion of IL-2 at 18 MIU/m2/day, so that over 3 days a total of 90 MIU/m2 of IL-2 were delivered; the same amount as previously given during 5 days of continuous i.v. IL-2 at 18 MIU/m2/day. This schedule was repeated every 2 weeks for 2 months, and then monthly for up to 6 months.

RESULTS

Twenty-two patients with metastatic melanoma were enrolled in this trial. Toxicities were qualitatively similar to those seen with other IL-2 regimens, but grade 3 and 4 toxicities were observed only in patients who received at least four cycles of treatment; only one patient went off study because of toxicity. For 18 patients with measurable disease, there were two complete and two partial responses in patients ages 32, 66, 72 and 83 years, for a response rate of 22% (6% to 48%; 95% confidence interval [Ci]). The median survival for all 21 evaluable patients enrolled in the trial was 8.5 months.

CONCLUSION

The hybrid schedule of drug delivery in NBSG 92-09 allowed the same dose and intensity of IL-2 to be delivered over 3 days instead of 5 days, which resulted in fewer days of hospitalization and therefore decreased cost; but with no increase in toxicity and no decrease in efficacy in patients with metastatic melanoma.

Hybrid high-dose bolus/continuous infusion interleukin-2 in patients with metastatic renal cell carcinoma: a phase II trial of the National Biotherapy Study Group

BACKGROUND

Interleukin-2 (IL-2) is an active agent for the treatment of renal cell carcinoma. In animal studies, polyethylene glycol conjugated (PEG) IL-2 was found to be effective in certain IL-2-resistant models. When bolus/infusion IL-2 was administered to approximate the pharmacokinetics of PEG-IL-2, resistance was also overcome in these models. Based on these observations, the National Bio-therapy Study Group (NBSG) previously had conducted a pilot study (NBSG 90-01) and then a phase I trial of a hybrid regimen of bolus IL-2 followed by continuous IL-2 (NBSG 91-04).

METHODS

In the current study, NBSG 92-09, a phase II trial was conducted in patients with metastatic renal cell carcinoma using IL-2 at a dose of 36 MIU/m2 followed by a 72-hour continuous infusion of IL-2 at 18 MIU/m2 per day, so that over 3 days a total of 90 MIU/m2 of IL-2 were delivered; the same amount as previously given during 5 days of continuous intravenous (i.v.) IL-2 at 18 MIU/m2 per day. This was repeated every 2 weeks for 2 months, and then monthly for up to 4 months.

RESULTS

Thirty-one patients with a median age of 62 years were enrolled in this trial. During the first 4 biweekly treatments, the percentages of planned IL-2 administered were 98% for 31 patients, 99% for 27, 98% for 23, and 99% for 20 patients. Toxicities were qualitatively the same as those seen with other IL-2 regimens. During the first 2 months, 4 patients ceased treatment because of rapidly progressive disease while 7 patients stopped because of toxicity; 5 of the 7 were > 65 years of age. At the time of formal reassessment after 2 months of treatment, 7 additional patients had progressive disease for a treatment failure rate of 55% prior to monthly maintenance therapy. There were two partial responses among 22 patients who had measurable disease for a response rate of 9% (1 to 29%, 95% CI). Median survival was 10.2 months and failure-free survival (FFS) 3.4 months for the entire group.

CONCLUSION

The response rate seen with this regimen is similar to those of other schedules of IL-2 requiring more prolonged hospitalization. This hybrid bolus/continuous infusion IL-2 schedule appears to be an equally effective and less expensive schedule of IL-2 administration than previously reported inpatient regimens. However, it is not likely that this regimen is superior to outpatient combination biotherapy regimens which are currently under investigation.

Expression of an activation antigen, Mo3e, associated with the cellular response to migration inhibitory factor by HL-60 promyelocytes undergoing monocyte-macrophage differentiation

HL-60 promyelocytic cells acquire the surface expression of the Mo3e antigenic determinant after exposure to PMA or compounds that raise intracellular concentrations of cyclic AMP (dibutyryl cyclic AMP or a combination of cholera toxin and IBMX). The expression of Mo3e by these stimulated HL-60 cells coincides with the development of features of monocyte-macrophage differentiation (characteristic morphology, nonspecific esterase activity, and respiratory burst activity). During in vitro monocyte-macrophage differentiation, HL-60 cells become responsive to migration inhibitory factor (MIF); the MIF responsiveness of differentiated HL-60 cells is blocked by anti-Mo3e monoclonal antibody. These findings further support the relationship between the expression of Mo3e and the cellular response to MIF.

Regulation of human monocyte surface antigen expression. I. Up-modulation of Mo3e antigen expression on U-937 and HL-60 cells stimulated by pharmacologic activators of protein kinase C

Mo3e is a protein (p 50,80) that is expressed on the surface of human monocytic cells after exposure in vitro to soluble activating factors that include bacterial lipopolysaccharide, muramyl dipeptide, and phorbol myristate acetate (PMA). The surface expression of Mo3e may represent a cellular event that occurs in response to the formation of "secondary messengers" that include diacylglycerol, inositol trisphosphate, and calcium ions. This postulate is based on the stimulatory effect of agents that can mimic the activity of endogenous diacylglycerol (PMA and other biologically active phorbol compounds, mezerein, and L-alpha-1,2 dioctanoylglycerol) and inositol trisphosphate (ionomycin) on Mo3e expression by U-937 and HL-60 cells. The inhibitory effect of phospholipid-active calmodulin inhibitors (trifluoperazine, chlorpromazine, and dibucaine), calcium antagonists (nicardipine and TMB-8), and EGTA further support the involvement of phospholipid- and calcium-dependent protein kinase (protein kinase C) and calcium ions in the up-modulation of Mo3e surface expression.