Assessment of radiographic progression in patients with rheumatoid arthritis treated with tofacitinib in long-term studies

JAK inhibition ameliorates bone destruction by simultaneously targeting mature osteoclasts and their precursors

BACKGROUND

Rheumatoid arthritis (RA) is characterized by chronic inflammation and resultant cartilage/bone destruction because of aberrantly activated osteoclasts. Recently, novel treatments with several Janus kinase (JAK) inhibitors have been shown to successfully ameliorate arthritis-related inflammation and bone erosion, although their mechanisms of action for limiting bone destruction remain unclear. Here, we examined the effects of a JAK inhibitor on mature osteoclasts and their precursors by intravital multiphoton imaging.

METHODS

Inflammatory bone destruction was induced by local injection of lipopolysaccharides into transgenic mice carrying reporters for mature osteoclasts or their precursors. Mice were treated with the JAK inhibitor, ABT-317, which selectively inhibits the activation of JAK1, and then subjected to intravital imaging with multiphoton microscopy. We also used RNA sequencing (RNA-Seq) analysis to investigate the molecular mechanism underlying the effects of the JAK inhibitor on osteoclasts.

RESULTS

The JAK inhibitor, ABT-317, suppressed bone resorption by blocking the function of mature osteoclasts and by targeting the migratory behaviors of osteoclast precursors to the bone surface. Further exhaustive RNA-Seq analysis demonstrated that Ccr1 expression on osteoclast precursors was suppressed in the JAK inhibitor-treated mice; the CCR1 antagonist, J-113863, altered the migratory behaviors of osteoclast precursors, which led to the inhibition of bone destruction under inflammatory conditions.

CONCLUSIONS

This is the first study to determine the pharmacological actions by which a JAK inhibitor blocks bone destruction under inflammatory conditions; this inhibition is beneficial because of its dual effects on both mature osteoclasts and immature osteoclast precursors.

LY294002 attenuates inflammatory response in endotoxin-induced uveitis by downregulating JAK3 and inactivating the PI3K/Akt signaling

CONTEXT

Uveitis is a prevalent inflammatory eye disease that damages the vision of patients and even leads to blindness. LY294002, an inhibitor of PI3K, was reported to suppress the inflammation and alleviate the progression of many diseases. However, the function of LY294002 in uveitis is unclear.

OBJECTIVE

This study aimed to explore the function of LY294002 in endotoxin-induced uveitis (EIU).

MATERIALS AND METHODS

EIU rat models were established via a single intravitreal injection of LPS. At 24 h after LPS injection, the rats received LY294002 treatment for 14 days. The histopathology was observed by H&E staining. The concentration of proinflammatory cytokines in aqueous humor was tested by ELISA. The expression of proinflammatory cytokines in the iris ciliary body (ICB) and retina of EIU rats were detected by RT-qPCR. JAK3, PI3K, and Akt expression were assessed by RT-qPCR and western blotting. Translocation of Akt in rat retinal Müller cells (rMC-1) was evaluated by immunofluorescence staining.

RESULTS

LY294002 alleviated ocular inflammation and decreased inflammatory cell infiltration in the anterior chamber, iris, ciliary body, vitreous cavity, and retina of EIU rats. LY294002 decreased the concentration of proinflammatory cytokines INF-γ, IL-17, IL-6, TNF-α, and IL-1β in aqueous humor and their expression in the ICB and retina of EIU rats. LY294002 downregulated JAK3 expression in EIU rats. LY294002 inhibited p-PI3K and p-Akt expression in EIU rats and restrained Akt translocation from cytoplasm to cell membrane in LPS-treated rMC-1 cells.

CONCLUSION

LY294002 ameliorates inflammation in EIU by downregulating JAK3 and inactivating the PI3K/Akt signaling.

Radiographic Progression of Structural Joint Damage Over 5 Years of Baricitinib Treatment in Patients With Rheumatoid Arthritis: Results From RA-BEYOND

OBJECTIVE

To evaluate the effect of baricitinib on inhibiting radiographic progression of structural joint damage over 5 years in patients with active rheumatoid arthritis (RA).

METHODS

Patients completed 1 of 3 phase III baricitinib trials (ClinicalTrials.gov: NCT01711359, NCT01710358, or NCT01721057) and entered the long-term extension RA-BEYOND (NCT01885078), in which patients received once-daily 4 mg or 2 mg baricitinib. Across these trials, patients initially receiving methotrexate (MTX) or adalimumab (ADA) switched to baricitinib 4 mg at Week 52. Patients initially receiving placebo (PBO) switched to baricitinib 4 mg at Week 24. Radiographs were scored at baseline and Years 2, 3, 4, and 5. Change from baseline in van der Heijde modified total Sharp score (ΔmTSS) was computed.

RESULTS

Overall, 2125 of 2573 (82.6%) randomized patients entered RA-BEYOND; 1837 of 2125 (86.4%) entered this analysis. From Years 3 to 5, higher proportions of disease-modifying antirheumatic drug (DMARD)-naïve patients on initial baricitinib (monotherapy or with MTX) had no progression vs initial MTX (ΔmTSS ≤ 0 at Year 5: 59.6% baricitinib 4 mg; 66.2% baricitinib 4 mg + MTX; 40.7% MTX). Higher proportions of patients with inadequate response (IR) to MTX on initial baricitinib or ADA vs PBO had no progression (ΔmTSS ≤ 0 at Year 5: 54.8% baricitinib 4 mg; 55.0% ADA; 50.3% PBO). Higher proportions of patients with conventional synthetic DMARD-IR on initial baricitinib 4 mg had less progression vs initial PBO or baricitinib 2 mg (ΔmTSS ≤ 0 at Year 5: 66.7% baricitinib 4 mg; 58.2% baricitinib 2 mg; 60.0% PBO).

CONCLUSION

Oral baricitinib maintained lower levels of radiographic progression than initial conventional synthetic DMARD or PBO through 5 years in patients with active RA.

Efficacy of Long-Term Treatment with Once-Daily Baricitinib 2 mg in Patients with Active Rheumatoid Arthritis: Post Hoc Analysis of Two 24-Week, Phase III, Randomized, Controlled Studies and One Long-Term Extension Study

INTRODUCTION

To evaluate long-term efficacy of once-daily baricitinib 2 mg in patients with active rheumatoid arthritis who had an inadequate response (IR) to conventional synthetic disease-modifying antirheumatic drugs (csDMARD) or biologic DMARDs (bDMARD).

METHODS

Data from patients treated with baricitinib 2 mg daily in two 24-week, phase III studies, RA-BUILD (csDMARD-IR; NCT01721057) and RA-BEACON (bDMARD-IR; NCT01721044), and one long-term extension study (RA-BEYOND; NCT01885078), were analyzed (120 weeks). The main outcomes were achievement of low-disease activity (LDA; Simple Disease Activity Index [SDAI] ≤ 11), clinical remission (SDAI ≤ 3.3), Health Assessment Questionnaire Disability Index (HAQ-DI) ≤ 0.5 and improvement from baseline of ≥ 0.22, and safety. Analysis populations included (1) all patients and (2) never-rescued patients. Completer and non-responder imputation (NRI) analyses were conducted on each population.

RESULTS

In RA-BUILD, 684 were randomized (229 to baricitinib 2 mg, 180 of whom completed RA-BUILD and entered RA-BEYOND). In RA-BEACON, 527 were randomized (174 to baricitinib 2 mg, 117 of whom completed RA-BEACON and entered RA-BEYOND). In RA-BUILD-BEYOND, 85.1% (63/74, completer) and 27.5% (63/229, NRI) of csDMARD-IR patients treated with baricitinib 2 mg achieved SDAI LDA; 40.5% (30/74, completer) and 13.1% (30/229, NRI) were in SDAI remission; 62.2% (46/74, completer) and 20.1% (46/229, NRI) had HAQ-DI ≤ 0.5 and 81.1% (60/74, completer); and 26.2% (60/229, NRI) achieved ≥ 0.22 change from baseline at week 120. In RA-BEACON-BEYOND, 86.5% (32/37, completer) and 18.4% (32/174, NRI) of bDMARD-IR patients treated with baricitinib 2 mg achieved SDAI LDA; 24.3% (9/37, completer) and 5.2% (9/174, NRI) were in SDAI remission; 50.0% (19/38, completer) and 10.9% (19/174, NRI) had HAQ-DI ≤ 0.5; and 73.7% (28/38, completer) and 16.1% (28/174, NRI) achieved ≥ 0.22 change from baseline at week 120. Rates of adverse events of special interest were consistent with previous reports.

CONCLUSIONS

Long-term treatment with baricitinib 2 mg demonstrated efficacy for up to 120 weeks and was well tolerated.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT01721057, NCT01721044, and NCT01885078.