Phase 1 double-blind randomized safety trial of the Janus kinase inhibitor tofacitinib in systemic lupus erythematosus

Abstract

Increased risk of premature cardiovascular disease (CVD) is well recognized in systemic lupus erythematosus (SLE). Aberrant type I-Interferon (IFN)-neutrophil interactions contribute to this enhanced CVD risk. In lupus animal models, the Janus kinase (JAK) inhibitor tofacitinib improves clinical features, immune dysregulation and vascular dysfunction. We conducted a randomized, double-blind, placebo-controlled clinical trial of tofacitinib in SLE subjects (ClinicalTrials.gov NCT02535689). In this study, 30 subjects are randomized to tofacitinib (5 mg twice daily) or placebo in 2:1 block. The primary outcome of this study is safety and tolerability of tofacitinib. The secondary outcomes include clinical response and mechanistic studies. The tofacitinib is found to be safe in SLE meeting study's primary endpoint. We also show that tofacitinib improves cardiometabolic and immunologic parameters associated with the premature atherosclerosis in SLE. Tofacitinib improves high-density lipoprotein cholesterol levels (p = 0.0006, CI 95%: 4.12, 13.32) and particle number (p = 0.0008, CI 95%: 1.58, 5.33); lecithin: cholesterol acyltransferase concentration (p = 0.024, CI 95%: 1.1, -26.5), cholesterol efflux capacity (p = 0.08, CI 95%: -0.01, 0.24), improvements in arterial stiffness and endothelium-dependent vasorelaxation and decrease in type I IFN gene signature, low-density granulocytes and circulating NETs. Some of these improvements are more robust in subjects with STAT4 risk allele.

Fig. 1. Tofacitinib inhibits STAT1 phosphorylation in CD4 + T cells.

a Significant inhibition of pSTAT1 in patients on tofacitinib at day 56 (P = 0.023) with the return to baseline at day 84 n = 20 biologically independent samples. Data are presented as mean values + /− SEM. A mixed linear model for repeated measures was used. b No significant change noted in patients on placebo. n = 10 biologically independent samples. Data are presented as mean values + /− SEM. A mixed linear model for repeated measures was used. c Tofacitinib decreases the type I IFN gene signature, gene expression in peripheral blood by Nanostring: Heatmap showing interferon-stimulated gene expression in peripheral blood by nanostring: Log2 mean fold change in expression of interferon-stimulated genes from baseline to day 56 and 84 in subjects on tofacitinib (n = 20 biologically independent samples) and placebo (n = 10 biologically independent samples). Source data are provided as a Source Data file. Results shown as fold change in stimulated vs. unstimulated cell population. A mixed linear model for repeated measures was used. Unpaired two-tailed, t test were used where appropriate. No adjustments were made for multiple comparisons.

Fig. 2. Circulating LDGs and NETs are modulated by tofacitinib.

a Results represent changes in percentage of circulating LDGs: Subjects treated with tofacitinib vs. placebo. Significant decrease in LDGs in tofacitinib group P = 0.048 at day 56 and P = 0.014 at day 84 using unpaired t test. b Changes in absolute neutrophil counts. c Circulating NET levels at baseline: Individuals positive for STAT4 risk allele (each subject represented by closed circles) have enhanced circulating NET levels (assessed by human neutrophil elastase (HNE)-dsDNA complexes) then subjects who are STAT4 risk allele negative (each subject represented by open circles) P = 0.02 using unpaired t test. d Changes in circulating NET levels during the study: Patients who are STAT4 risk allele positive and receive tofacitinib display significant decrease in circulating NET complexes P = 0.037 using unpaired t test. Source data are provided as a Source Data file. All data represent mean ± SEM, *P < 0.05, and are based on tofacitinib n = 20, placebo n = 10. Unpaired two-tailed, t test were used for all results. No adjustments were made for multiple comparisons.

Fig. 3. Tofacitinib modulates HDL levels and function in SLE.

a Percent change in serum HDL-C at day 56 compared to day 1 based on STAT4 risk allele status (each circle and square represent individual subject): Results represent *P = 0.037 for the difference between STAT4 risk allele-positive subjects on tofacitinib vs placebo and **P = 0.002 STAT4 risk allele-negative subjects on tofacitinib vs placebo. Unpaired t test was used. b Percent change in Lecithin–cholesterol acyltransferase (LCAT) concentration at day 56 compared to day 1 based on STAT4 risk allele status (each circle and square represent individual subject): Results represent *P = 0.033 for the difference between STAT4 risk allele-positive subjects on tofacitinib vs placebo and *P = 0.044 for the difference between STAT4 risk allele-positive subjects on tofacitinib vs STAT4 risk allele-negative subjects on tofacitinib. Kruskal–Wallis test (unpaired, nonparametric) was used. Source data are provided as a Source Data file. All results represent mean ± SEM, *P < 0.05 **P < 0.01, and are based on tofacitinib n = 20, placebo n = 10. Two-tailed tests were used where appropriate. No adjustments were made for multiple comparisons.

Fig. 4. Tofacitinib improves arterial stiffness and endothelial dysfunction in association with STAT4 risk allele status.

a Right cardioankle vascular index (CAVI): Results represent changes in CAVI in subjects on tofacitinib vs placebo in STAT4 risk allele-positive and -negative subjects during the trial. b Pulse wave velocity (PWV): Results represent changes in PWV in subjects on tofacitinib vs placebo in STAT4 risk allele-positive and -negative subjects during the trial. c Reactive hyperemia index (RHI): Results represent changes in RHI in subjects on tofacitinib vs placebo in STAT4 risk allele-positive and -negative subjects during the trial. Source data are provided as a Source Data file. All results represent mean ± SEM and are based on tofacitinib n = 20, placebo n = 10. The paired t test, Mann–Whitney U, or ANOVA were used for comparison where appropriate based on normality of distribution. Two-tailed tests were used where appropriate. No adjustments were made for multiple comparisons.