Safety of ixekizumab in patients with psoriatic arthritis: data from four clinical trials with over 2000 patient-years of exposure.

OBJECTIVES: Ixekizumab, a high-affinity monoclonal antibody that selectively targets interleukin 17A (IL-17A), has shown significant efficacy in the treatment of psoriatic arthritis (PsA) and sustained long-term clinical response without unexpected new safety outcome for an IL-17A inhibitor. Here, we report the updated safety profile of ixekizumab up to 3 years in patients with PsA. METHODS: This is an integrated safety analysis from four clinical trials in patients with PsA who received at least one dose of ixekizumab. Treatment-emergent adverse events (TEAEs) and selected adverse events (AEs) exposure-adjusted incidence rates (EAIRs) per 100 patient-years up to 3 years of exposure are reported. RESULTS: A total of 1401 patients with a cumulative ixekizumab exposure of 2247.7 patient-years were included in this analysis. The EAIR of patients with ≥1 TEAE was 50.3 per 100 patient-years and most TEAEs were mild to moderate in severity. Serious AEs were reported by 134 patients (EAIR=6.0). The most reported TEAEs were nasopharyngitis (EAIR=9.0) and upper respiratory tract infection (EAIR=8.3). Infections in general and injection site reactions were the most common TEAEs; the incidence rates of serious cases were low (EAIR ≤1.2). The EAIRs of malignancies (EAIR=0.7), inflammatory bowel disease (EAIR=0.1) including ulcerative colitis and Crohn's disease, depression (EAIR=1.6), and major adverse cerebro-cardiovascular events (EAIR=0.5) were low. As assessed, based on year of exposure, incidence rates were decreasing or constant over time. CONCLUSIONS: In this analysis, the overall safety profile and tolerability of ixekizumab are consistent with the known safety profile in patients with PsA. No new or unexpected safety events were detected. TRIAL REGISTRATION NUMBER: NCT01695239, NCT02349295, NCT02584855, NCT03151551.

Improvement from ixekizumab treatment in patients with psoriatic arthritis who have had an inadequate response to one or two TNF inhibitors.

OBJECTIVE: To evaluate the efficacy of ixekizumab (IXE), a monoclonal antibody selectively targeting interleukin-17A, in patients with inadequate response to one or two TNF inhibitors (TNFi). METHODS: A phase 3 study (SPIRIT-P2; NCT02349295) randomized patients with PsA with inadequate response or intolerance to one or two TNFi to receive 80-mg IXE every 2 weeks (n = 123) or every 4 weeks (n = 122) after a 160-mg starting dose or placebo (PBO; n = 118) through week 24. This post hoc analysis used data from inadequate responders to one or two TNFi, measuring the percentage achieving: ≥50% improvement in ACR response criteria (ACR50) and 100% improvement from baseline in the Psoriasis Area and Severity Index (PASI 100), ACR50, improvement in HAQ-Disability Index (HAQ-DI) ≥0.35, minimal disease activity (MDA), European League Against Rheumatism (EULAR) Good Response Criteria [improvement in Disease Activity Score 28 CRP (DAS28-CRP) >1.2], and Disease Activity in PsA (DAPSA) ≤14. RESULTS: There were no significant differences in baseline characteristics between inadequate responders to one and two TNFi. At week 24, significantly more patients irrespective of previous TNFi experience receiving IXE than PBO achieved ACR50, HAQ-DI ≥0.35 improvement, MDA, EULAR good response, and DAPSA ≤14, and significantly more patients with inadequate response to one TNFi receiving IXE than PBO achieved ACR50 and PASI 100. Improvement persisted in all measures through week 52. CONCLUSION: IXE improved the signs and symptoms of PsA in a population of difficult-to-treat patients with inadequate response to one or two TNFi.

Rapid and sustained improvements in patient-reported signs and symptoms with ixekizumab in biologic-naive and TNF-inadequate responder patients with psoriatic arthritis.

OBJECTIVES: To analyse the onset and sustainability of patient-reported improvements in symptoms of psoriatic arthritis (PsA) following treatment with ixekizumab (IXE) up to Week 108. METHODS: In patients with active PsA, either naive to biological DMARDs (SPIRIT-P1) or having inadequate response or intolerance to 1 or 2 prior TNF-inhibitors (TNFi­experienced; SPIRIT-P2), we analysed the change from baseline in joint pain visual analogue scale (VAS; 0-100 scale), patient global assessment (PatGA VAS; 0-100 scale), fatigue numerical rating scale (NRS; 0 [no fatigue] to 10 [worst imaginable]), and Health Assessment Questionnaire-Disability Index (HAQ-DI; 0-3), up to Week 108. RESULTS: IXE-treated patients compared to placebo reported rapid and statistically significant improvement in pain VAS, PatGA, and HAQ-DI as early as Week 1 and this benefit was sustained or increased through Week 108. Fatigue scores improved in IXE-treated patients compared to placebo in both studies; results were statistically significant at Week 24 only in SPIRIT-P2. Improvements in fatigue with IXE were sustained over 2 years. The improvements observed in these patient-reported outcomes (PROs) were consistent in biologic-naive or TNFi-experienced patients. CONCLUSIONS: Patients treated with IXE versus PBO achieved significantly greater improvements and showed faster onset of improvements in patient-reported outcomes measuring symptoms and impact of PsA. Responses were sustained over 2 years and were generally consistent regardless of prior TNFi experience.

Sphingosine kinase type 2 inhibition elevates circulating sphingosine 1-phosphate.

S1P (sphingosine 1-phosphate) is a pleiotropic lipid mediator involved in numerous cellular and physiological functions. Of note among these are cell survival and migration, as well as lymphocyte trafficking. S1P, which exerts its effects via five GPCRs (G-protein-coupled receptors) (S1P1-S1P5), is formed by the action of two SphKs (sphingosine kinases). Although SphK1 is the more intensively studied isotype, SphK2 is unique in it nuclear localization and has been reported to oppose some of the actions ascribed to SphK1. Although several scaffolds of SphK1 inhibitors have been described, there is a scarcity of selective SphK2 inhibitors that are necessary to evaluate the downstream effects of inhibition of this isotype. In the present paper we report a cationic amphiphilic small molecule that is a selective SphK2 inhibitor. In the course of characterizing this compound in wild-type and SphK-null mice, we discovered that administration of the inhibitor to wild-type mice resulted in a rapid increase in blood S1P, which is in contrast with our SphK1 inhibitor that drives circulating S1P levels down. Using a cohort of F2 hybrid mice, we confirmed, compared with wild-type mice, that circulating S1P levels were higher in SphK2-null mice and lower in SphK1-null mice. Thus both SphK1 and SphK2 inhibitors recapitulate the blood S1P levels observed in the corresponding null mice. Moreover, circulating S1P levels mirror SphK2 inhibitor levels, providing a convenient biomarker of target engagement.

Biosynthesis of alkyl lysophosphatidic acid by diacylglycerol kinases.

Lysophosphatidic acid (LPA) designates a family of bioactive phosphoglycerides that differ in the length and degree of saturation of their radyl chain. Additional diversity is provided by the linkage of the radyl chain to glycerol: acyl, alkyl, or alk-1-enyl. Acyl-LPAs are the predominate species in tissues and biological fluids. Alkyl-LPAs exhibit distinct pharmacodynamics at LPA receptors, potently drive platelet aggregation, and contribute to ovarian cancer aggressiveness. Multiple biosynthetic pathways exist for alkyl-LPA production. Herein we report that diacylglycerol kinases (DGKs) contribute to cell-associated alkyl-LPA production involving phosphorylation of 1-alkyl-2-acetyl glycerol and document the biosynthesis of alkyl-LPA by DGKs in SKOV-3 ovarian cancer cells, specifically identifying the contribution of DGKα. Concurrently, we discovered that treating SKOV-3 ovarian cancer cell with a sphingosine analog stimulates conversion of exogenous 1-alkyl-2-acetyl glycerol to alkyl-LPA, indicating that DGKα contributes significantly to the production of alkyl-LPA in SKOV-3 cells and identifying cross-talk between the sphingolipid and glycerol lipid pathways.

Sphingosine kinase type 1 inhibition reveals rapid turnover of circulating sphingosine 1-phosphate.

S1P (sphingosine 1-phosphate) is a signalling molecule involved in a host of cellular and physiological functions, most notably cell survival and migration. S1P, which signals via a set of five G-protein-coupled receptors (S1P1-S1P5), is formed by the action of two SphKs (sphingosine kinases) from Sph (sphingosine). Interfering RNA strategies and SphK1 (sphingosine kinase type 1)-null (Sphk1-/-) mouse studies implicate SphK1 in multiple signalling cascades, yet there is a paucity of potent and selective SphK1 inhibitors necessary to evaluate the effects of rapid onset inhibition of this enzyme. We have identified a set of submicromolar amidine-based SphK1 inhibitors and report using a pair of these compounds to probe the cellular and physiological functions of SphK1. In so doing, we demonstrate that our inhibitors effectively lower S1P levels in cell-based assays, but we have been unable to correlate SphK1 inhibition with changes in cell survival. However, SphK1 inhibition did diminish EGF (epidermal growth factor)-driven increases in S1P levels and Akt (also known as protein kinase B)/ERK (extracellular-signal-regulated kinase) phosphorylation. Finally, administration of the SphK1 inhibitor to wild-type, but not Sphk1-/-, mice resulted in a rapid decrease in blood S1P levels indicating that circulating S1P is rapidly turned over.

Responses to Ixekizumab in Male and Female Patients with Psoriatic Arthritis: Results from Two Randomized, Phase 3 Clinical Trials.

INTRODUCTION: Differences in psoriatic arthritis (PsA) treatment response between sexes for ixekizumab, an interleukin-17A antagonist, are largely unexplored. This analysis used data from randomized clinical trials (RCTs) evaluating ixekizumab to study differences in treatment response between male and female patients with PsA. METHODS: We used pooled data from patients enrolled in SPIRIT-P1 and SPIRIT-P2 (NCT01695239 and NCT02349295, respectively), phase 3 RCTs evaluating ixekizumab every 4 and 2 weeks in patients with active PsA. Subgroups of patients were defined by sex (male, female). Efficacy was measured by the proportion of male and female patients achieving American College of Rheumatology 20%/50%/70% improvement criteria (ACR20/50/70), minimal disease activity or very low disease activity (MDA/VLDA), and Disease Activity Index for Psoriatic Arthritis (DAPSA) scores representing low disease activity (LDA) or remission through week 156. Changes from baseline in components of the above measures were also assessed through week 156. RESULTS: Compared to male patients at baseline, female patients were older, had higher body mass index and lower C-reactive protein levels, and had worse tender joint count, Health Assessment Questionnaire Disability Index, and Leeds Enthesitis Index scores. Through week 156, female patients in all treatment arms had lower response rates than male patients in all analyzed composite measures (ACR20/50/70; MDA/VLDA; DAPSA LDA/remission), with significant differences observed at multiple timepoints in both ixekizumab treatment arms. Female patients also had smaller numeric changes from baseline in the composite measures' individual components. CONCLUSION: Compared to female patients, male patients had greater response rates in ACR20/50/70, MDA/VLDA, and DAPSA LDA/remission and numerically larger improvements in these measures' individual components, although clinical significance is unclear. Continued efforts to understand sex differences in treatment response may provide insights that can help optimize clinical decision making. TRIAL REGISTRATION: ClinicalTrials.gov identifiers, NCT01695239 and NCT02349295.

Efficacy and Safety of Ixekizumab in Patients with Psoriatic Arthritis and Inadequate Response to TNF Inhibitors: 3-Year Follow-Up (SPIRIT-P2).

PURPOSE: Ixekizumab is a high-affinity monoclonal antibody that selectively targets interleukin-17A. The objective of this study was to assess the long-term efficacy and safety (to week 156) of ixekizumab in patients with active psoriatic arthritis and inadequate response or intolerance to one or two tumor necrosis factor inhibitors. METHODS: In the SPIRIT-P2 study (ClinicalTrials.gov ID: NCT02349295), patients were randomized to placebo or ixekizumab 80 mg every 4 weeks (IXE Q4W) or every 2 weeks (IXE Q2W) following a 160-mg starting dose. During the extension period (weeks 24-156), patients maintained their original ixekizumab dose, and placebo patients received IXE Q4W or IXE Q2W (1:1). Exposure-adjusted incidence rates (IRs) per 100 patient-years (PY) are presented. RESULTS: Of 363 patients enrolled in the study, 310 entered the extension period. In all patients treated with IXE Q4W and IXE Q2W at week 0, responses persisted to week 156. At week 156, clinical responses (observed) in patients treated with IXE Q4W and IXE Q2W were assessed [American College of Rheumatology (ACR) response criteria and minimal disease activity (MDA) criteria]: 84 and 85% showed 20% improvement (ACR20); 60 and 58% showed 50% improvement (ACR50); 35 and 47% showed 70% improvement (ACR70), respectively; and 48 and 54% showed MDA. Placebo patients re-randomized to ixekizumab also demonstrated sustained efficacy, as measured by ACR and MDA responses. In the All Ixekizumab Exposure Safety Population (n = 337), with 644 PY of ixekizumab exposure, treatment-emergent adverse events (TEAEs) were reported by 286 patients (44.4 IR). The most common TEAEs were upper respiratory tract infection (9.80 IR), nasopharyngitis (8.2 IR), sinusitis (6.2 IR), and bronchitis (4.5 IR). Serious adverse events were reported by 42 (6.5 IR) patients (included 3 deaths and 10 infections). CONCLUSION: In this 156-week study of ixekizumab, improvements in signs and symptoms of psoriatic arthritis and the safety profile remained consistent with those in previous reports. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02349295.

Efficacy and Safety of Ixekizumab with or Without Methotrexate in Biologic-Naïve Patients with Psoriatic Arthritis: 52-Week Results from SPIRIT-H2H Study.

INTRODUCTION: In the SPIRIT-H2H (ClinicalTrials.gov: NCT03151551) trial in biologic-naïve patients with active psoriatic arthritis (PsA), ixekizumab (IXE) was superior to adalimumab (ADA) at week 24 in terms of achieving a combined endpoint of ≥ 50% improved response in the American College of Rheumatology scale score (ACR50) and 100% improvement in the Psoriasis Areas and Severity Index (PASI100), and was non-inferior in terms of achieving ACR50. IXE resulted in similar improvements of PsA manifestations irrespective of the use of concomitant conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs), while ADA response was higher with concomitant csDMARD use. The aim of this study was to determine the efficacy and safety of treatment with IXE and ADA with or without methotrexate (MTX), the most commonly use csDMARD, through week 52 in patients with PsA. METHODS: In the open-label, rater-blinded, head-to-head SPIRIT-H2H trial, randomization of patients was stratified by concomitant use of csDMARD and moderate-to-severe plaque psoriasis involvement. In the post-hoc subgroup analysis presented here, subgroups were defined as with/without concomitant MTX use at baseline. Treatment group effects within subgroups were tested using Fisher's exact test. Missing data were imputed using non-responder imputation. RESULTS: By week 52, IXE provided similar improvements in the combined ACR50 and PASI100 endpoint, ACR50, and other PsA-related domains regardless of whether IXE was used with or without MTX, while ADA efficacy appeared to be improved with concomitant MTX use. When used without concomitant MTX, IXE resulted in significantly higher response versus ADA in terms of the combined ACR50 and PASI100 (p = 0.002) endpoint, minimal disease activity (p = 0.016), and very low disease activity (p = 0.037). The safety of both agents was consistent with their known safety profiles regardless of concomitant MTX use. CONCLUSION: In PsA patients with inadequate control of the disease, IXE delivers consistent efficacy in several clinical domains of the disease regardless of concomitant MTX use. The efficacy of ADA is increased by the concomitant use of MTX. These findings can inform treatment decisions when considering the need for concomitant MTX use with IXE or ADA at initiation or for long-term maintenance.

Enhancement of DNA cleavage activity of an unnatural ferrocene-amino acid conjugate.

The nucleolytic activity of an unnatural ferrocenyl amino acid can be significantly enhanced under reducing or Fenton conditions while exploiting different mechanisms of DNA cleavage. In addition, results from high resolution electrophoresis indicate that the ferrocenyl amino acid exhibits non-sequence specific cleavage of the DNA backbone.