Tocilizumab modulates the activity of the classical and alternative complement pathways in rheumatoid arthritis patients

Background

Tocilizumab (TCZ) is a monoclonal antibody that neutralizes interleukin (IL)-6 and is indicated for diseases characterized by markedly elevated inflammatory markers, such as rheumatoid arthritis (RA). The complement system has been implicated in the etiopathogenesis of RA.

Objective

To evaluate the effect of systemic IL-6 inhibition on complement pathways functional activity in RA patients treated with TCZ.

Desing

Prospective non-interventional study.

Methods

Twenty-seven RA patients included in the TOCRIVAR study who received TCZ (8mg/kg IV/q4w) were evaluated at baseline and at weeks 12, 24 and 52 of treatment. Disease activity, as assessed by composite indices, acute phase reactants, and new-generation functional assays of the three complement pathways, was evaluated at baseline and at each follow-up visit. Multivariable linear mixed models were used to determine changes in the complement system cascades over time.

Results

After adjustment for disease activity, basal levels of the classical and alternative pathways decreased significantly after TCZ treatment. The effect on the classical pathway remained significant after 52 weeks. The decrease in the alternative pathway was significant at weeks 12 and 24, but not at week 52 of TCZ treatment. TCZ had no effect on the lectin cascade throughout the follow-up.

Conclusion

TCZ reduces the activity of the classical and alternative pathways of the complement system in RA patients regardless of the improvement in disease activity. This finding may contribute to a better understanding of the mechanisms by which the IL-6 blockade reduces disease activity in RA patients.

Modulation of the K/BxN arthritis mouse model and the effector functions of human fibroblast-like synoviocytes by liver X receptors

The role of liver X receptors (LXR) in rheumatoid arthritis (RA) remains controversial. We studied the effect of LXR agonists on fibroblast-like synoviocytes (FLS) from RA patients and the K/BxN arthritis model in LXRα and β double-deficient (Nr1h2/3-/-) mice. Two synthetic LXR agonists, GW3965 and T0901317, were used to activate LXRs and investigate their effects on cell growth, proliferation and matrix metalloproteinases, and chemokine production in cultured FLS from RA patients. The murine model K/BxN serum transfer of inflammatory arthritis in Nr1h2/3-/- animals was used to investigate the role of LXRs on joint inflammation in vivo. LXR agonists inhibited the FLS proliferative capacity in response to TNF, the chemokine-induced migration, the collagenase activity in FLS supernatant and FLS CXCL12 production. In the K/BxN mouse model, Nr1h2/3-/- animals showed aggravated arthritis, histological inflammation, and joint destruction, as well as an increase in synovial metalloproteases and expression of proinflammatory mediators such as IL-1β and CCL2 in joints compared with wild type animals. Taken together, these data underscore the importance of LXRs in modulating the joint inflammatory response and highlight them as potential therapeutic targets in RA.

POS0616 EFFECT OF TOCILIZUMAB ON THE TRIGLYCERIDES METABOLISM PATHWAYS CONSTITUTED BY ANGIOPOIETIN LIKE-PROTEIN 4, APOLIPOPROTEIN CIII AND LIPOPROTEIN LIPASE IN PATIENTS WITH RHEUMATOID ARTHRITIS

Background

Tocilizumab is a humanized immunoglobulin G antibody to the interleukin 6 (IL-6) receptor that is used in the treatment of patients with rheumatoid arthritis (RA). Patients receiving TCZ are more likely to experience an elevation in total cholesterol, triglycerides and the ratio of low-density lipoprotein to high-density lipoprotein cholesterol. Elevated triglycerides or triglyceride-rich lipoproteins are cause of cardiovascular disease. Although the pathways for the synthesis and metabolism of triglycerides are complex and diverse, three molecules play a central role in their metabolism: apolipoprotein C-III (ApoC3), angiopoietin-like protein 4 (ANGPLT4), and lipoprotein lipase (LPL). LPL hydrolyzes the triglycerides core of chylomicrons

and has a crucial role in regulating plasma triglycerides levels. Besides, ApoC3 and ANGPLT4 participates in the regulation of triglycerides metabolism by the inhibition of LPL, thereby also decreasing the lipolysis of circulating triglycerides.

Objectives

The objective of this study was to evaluate the influence that TCZ has on the TG metabolism axis constituted by ANGPTL4, ApoC3 and LPL. In a second step we have assessed whether the changes that TCZ exerts on the lipid profile can be justified by a modification of this axis.

Methods

TOCRIVAR (ClinicalTrials.gov:NCT01752335) is a one-year prospective clinical trial that analyzes the influence of TCZ on different cardiovascular risk factors including lipid pattern. Twenty-seven RA patients receiving TCZ (8 mg/kg IV/q4w) were assessed at baseline and weeks 12, 24, and 52. Disease activity indexes, serum levels of ApoC3, ANGPLT4 and LPL, and lipoproteins serum concentrations were assessed at every visit.

Results

Acute phase reactants and disease activity were significantly reduced during study visits and at the end of treatment after one year with TCZ. While total and LDL cholesterol initially increased in plasma concentration, then decreased to baseline, lipoprotein (a) was significantly lower, and HDL higher, than baseline at all study visits. TG showed a trend to be significantly higher at 6 months (net increase 29 (95%CI -45-68) mg/dl, percentage increase 36 (95%CI -27-52) %, p=0.079). However, TG did not show significant differences at any visit compared to baseline levels. ANGPLT4 (baseline 387 ± 203 vs final 257 ± 32 wk52 ng/ml, p=0.016) and ApoC3 (baseline 10.1 ± 6.7 vs final 6.3 ± 3.7 mg/dl, p=0.023) were significantly lower at the end of the study (week 52) compared to their initial concentrations. LPL also showed a gradual decrease at each visit (baseline 345 ± 289 vs. final 291 ± 197 ng/ml, p=0.57), although statistical significance was not reached (trend test p=0.56). The decrease in DAS28-ESR at each visit was not associated with the changes produced in the three molecules, thus showing that the decrease in the TG metabolism axis does not depend on the lower activity of the disease produced by TCZ. In contrast, the decline in ApoC3 was significantly correlated with the increase in TG at month 3 (Pearson r -0.494, p=0.037) but not at 6 and 12 months.

Conclusion

TCZ decreases serum levels of ANGPTL4, ApoC3 and LPL. At 3 months, the increase that occurs in TG seems to depend on the inhibition that TCZ exerts over ApoC3. Our findings suggest that the effect of TCZ on the lipid profile in patients with RA could be mediated by the modification that this drug exerts on the ANGPTL4-ApoC3-LPL axis.

References

[1]Iván Ferraz-Amaro, María Vanesa Hernández-Hernández, Beatriz Tejera-Segura Esmeralda Delgado-Frías, María Macía-Díaz, Jose David Machado, Federico Diaz-González. Effect of IL-6 Receptor Blockade on Proprotein Convertase Subtilisin/Kexin Type-9 and Cholesterol Efflux Capacity in Rheumatoid Arthritis Patients. Horm Metab Res 2019;51(3):200-209.

Disclosure of Interests

Sergio Santos-Concepción: None declared, Javier Castro-Hernández: None declared, Vanessa Hernández-Hernández: None declared, Cristina Luna-Gomez: None declared, Iván Ferraz-Amaro Speakers bureau: Dr. Iván Ferraz-Amaro and Dr. Diaz-González would like to acknowledge that he has received grants/research supports from Abbott, MSD, Jansen and Roche, as well as consultation fees from company sponsored speakers’ bureaus associated with Abbott, Pfizer, Roche, Sanofi, Celgene, Grant/research support from: Dr. Iván Ferraz-Amaro and Dr. Diaz-González would like to acknowledge that he has received grants/research supports from Abbott, MSD, Jansen and Roche, as well as consultation fees from company sponsored speakers’ bureaus associated with Abbott, Pfizer, Roche, Sanofi, Celgene, Federico Diaz-Gonzalez Speakers bureau: Dr. Iván Ferraz-Amaro and Dr. Diaz-González would like to acknowledge that he has received grants/research supports from Abbott, MSD, Jansen and Roche, as well as consultation fees from company sponsored speakers’ bureaus associated with Abbott, Pfizer, Roche, Sanofi, Celgene, Consultant of: Dr. Iván Ferraz-Amaro and Dr. Diaz-González would like to acknowledge that he has received grants/research supports from Abbott, MSD, Jansen and Roche, as well as consultation fees from company sponsored speakers’ bureaus associated with Abbott, Pfizer, Roche, Sanofi, Celgene

Tocilizumab-related hypertriglyceridemia is independent of key molecules regulating lipid metabolism

INTRODUCTION

Tocilizumab (TCZ) treatment is associated with dyslipidaemia, including a rise in triglycerides through a mechanism poorly understood. Three molecules play key roles in the regulation of triglyceride metabolism: apolipoprotein C-III (ApoC-III), angiopoietin-like protein 4(ANGPLT4) and lipoprotein lipase (LPL). The aim of this work was to analyse whether the changes in triglycerides shown by TCZ-treated RA patients could stem from the dysregulation that can occur in these regulatory molecules.

METHODS

Twenty-seven RA patients included in the TOCRIVAR study who received TCZ (8 mg/kg IV/q4w) were evaluated at baseline and at Weeks 12, 24 and 52 of treatment. ANGPTL4, ApoC-III and LPL, a complete lipid profile and RA disease activity, were analysed at baseline and at each visit. Multivariable linear mixed models were performed to study changes over time in lipids and regulatory molecules.

RESULTS

After 24 weeks of TCZ treatment, HDL cholesterol, apolipoprotein A1 and triglycerides increased, whereas lipoprotein (a) decreased significantly from baseline values. However, 1 year after TCZ, no significant differences in lipid pattern were observed with respect to baseline. Serum ANGPTL4 and Apo-CIII levels decreased gradually over time, both being significantly lower than baseline values at Week 52. LPL concentration did not change significantly during TCZ treatment. Remarkably, the elevation of triglycerides at Week 24 maintained its statistical significance after adjusting for the changes in ApoC-III, ANGPTL4 and LPL.

CONCLUSION

In TCZ-treated RA patients basal serum levels of ANGPLT4 and ApoC-III, but not LPL, decreased significantly. However, the elevation of triglycerides after TCZ was not related to changes in these regulatory molecules.