IL-6 Blockade and its Therapeutic Success in Giant Cell Arteritis

Analysis of Development Mechanism of Giant Cell Arteritis in Nude Mouse Model through Color Duplex Sonography and Computerized Tomography Nanocontrast Agent

To explore the application value of color duplex sonography and enhanced computerized tomography (CT) inspection based on a nanocontrast agent in diagnosis and pathogenesis in giant cell arteritis (GCA), the GCA nude mouse model was constructed. In this study, 40 healthy male BalB/c nude mice aged 6-8 weeks were randomly divided into a control group (no model) and an experimental group (model), with 20 mice in each group, and the temporal artery tissue of GCA patients diagnosed as positive by temporal artery biopsy was implanted into nude mice to construct a GCA nude mouse model. Abdominal aortic biopsy and immunohistochemistry were used to verify the success of the GCA nude mouse model. All nude mice were subjected to color duplex sonography and enhanced CT examination based on a nanocontrast agent. At the same time, the basic indicators such as body weight, temperature, white blood cell (WBC), lymphocytes (LYM), hemoglobin (HGB), and platelet (PLT) were measured, and the protein expression levels of interleukin-6 (IL-6) and signal transducer and activator of transcription 3 (STAT3) were detected by immunohistochemistry. The results showed that the temporal artery wall of the nude mice in the experimental group thickened and the lumen was significantly narrowed, indicating that the cell arteritis model of nude mice was successfully constructed; ultrasound examination showed that the right superficial temporal artery vascular cavity narrowed, the blood flow signal changed like a filling defect around the periphery, and there was a low echo halo. CT examination showed that the left superficial temporal artery narrowed, and the inner diameter of the narrow segment of blood vessels changed like a bead. The body weight of nude mice in the experimental group decreased significantly after the modeling was completed (P < 0.05); after modeling, the body temperature of the nude mice in the experimental group increased significantly (P < 0.05); LYM and HGB values of nude mice in the experimental group were significantly lower than those in the control group (P < 0.05); the content of IL-6, STAT3, IL-6, and STAT3 proteins in the arterial tissue of nude mice in the experimental group was lower than that of the control group (P < 0.05), indicating that color duplex sonography and CT contrast agent technology can be used in the diagnosis and development mechanism research of GC.

A Multicentre, Randomised, Double-Blind, Placebo-Controlled, Parallel-Group Study to Evaluate the Efficacy and Safety of Sirukumab in the Treatment of Giant Cell Arteritis

INTRODUCTION

To evaluate the efficacy and safety of sirukumab in giant cell arteritis (GCA).

METHODS

In this multicentre, randomised, double-blind, placebo-controlled, two-part phase 3 trial (NCT02531633; Part A [52-week double-blind treatment]; Part B [104-week follow-up]), patients with GCA were randomised (3:3:2:2:2) to sirukumab 100 mg every 2 weeks plus 6-month or 3-month prednisone taper, sirukumab 50 mg every 4 weeks plus 6-month prednisone taper, or placebo every 2 weeks plus 6-month or 12-month prednisone taper. The primary endpoint was the proportion of patients in sustained remission at week 52. Secondary endpoints included disease flare and safety. The study was terminated early (October 2017; sponsor decision).

RESULTS

Of 161 patients randomised (sirukumab: n = 107; placebo: n = 54), 28 (17.4%) completed week 52 (median treatment duration: 24-30 weeks). In a revised intent-to-treat (ITT) subgroup (completed week 52 or discontinued before study termination [n = 55]); six patients (all receiving sirukumab) achieved the primary endpoint. In the ITT population (n = 161), the proportion of patients with flares (week 2-52) was lower with sirukumab (18.4-30.8%) than placebo (37.0-40.0%). The proportion of patients with flares (week 2-12) was highest with sirukumab 100 mg every 2 weeks plus 3-month prednisone taper (23.1%). In Part A, 94.4% of patients reported ≥ 1 treatment-emergent adverse event (TEAE); 19.3% reported serious TEAEs. The proportions of patients with TEAEs were generally similar across treatment arms. No deaths occurred.

CONCLUSIONS

Although data were limited due to early termination and shortened treatment duration, sirukumab treatment resulted in numerically lower proportions of patients with flare by week 52 versus placebo, with no unexpected safety findings.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT02531633.