Cereblon modulator iberdomide induces degradation of the transcription factors Ikaros and Aiolos: immunomodulation in healthy volunteers and relevance to systemic lupus erythematosus

Abstract

Objectives: IKZF1 and IKZF3 (encoding transcription factors Ikaros and Aiolos) are susceptibility loci for systemic lupus erythematosus (SLE). The pharmacology of iberdomide (CC-220), a cereblon (CRBN) modulator targeting Ikaros and Aiolos, was studied in SLE patient cells and in a phase 1 healthy volunteer study.

Methods: CRBN, IKZF1 and IKZF3 gene expression was measured in peripheral blood mononuclear cells (PBMC) from patients with SLE and healthy volunteers. Ikaros and Aiolos protein levels were measured by Western blot and flow cytometry. Anti-dsDNA and anti-phospholipid autoantibodies were measured in SLE PBMC cultures treated for 7 days with iberdomide. Fifty-six healthy volunteers were randomised to a single dose of iberdomide (0.03-6 mg, n=6 across seven cohorts) or placebo (n=2/cohort). CD19+ B cells, CD3+ T cells and intracellular Aiolos were measured by flow cytometry. Interleukin (IL)-2 and IL-1β production was stimulated with anti-CD3 and lipopolysaccharide, respectively, in an ex vivo whole blood assay.

Results: SLE patient PBMCs expressed significantly higher CRBN (1.5-fold), IKZF1 (2.1-fold) and IKZF3 (4.1-fold) mRNA levels compared with healthy volunteers. Iberdomide significantly reduced Ikaros and Aiolos protein levels in B cells, T cells and monocytes. In SLE PBMC cultures, iberdomide inhibited anti-dsDNA and anti-phospholipid autoantibody production (IC₅₀ ≈10 nM). Single doses of iberdomide (0.3-6 mg) in healthy volunteers decreased intracellular Aiolos (minimum mean per cent of baseline: ≈12%-28% (B cells); ≈0%-33% (T cells)), decreased absolute CD19+ B cells, increased IL-2 and decreased IL-1β production ex vivo.

Conclusions: These findings demonstrate pharmacodynamic activity of iberdomide and support its further clinical development for the treatment of SLE.

Trial registration number: NCT01733875; Results.

Keywords: B cells; autoantibodies; autoimmunity; systemic lupus erythematosus.

Figure 1

Overexpression of mRNA for cereblon (CRBN), Ikaros (IKZF1) and Aiolos (IKZF3) mRNA in systemic lupus erythematosus (SLE) peripheral blood mononuclear cells (PBMC). Shown are relative mRNA levels of (A) CRBN, (B) IKZF1 and (C) IKZF3 in the PBMCs of normal donors (n=10) and of patients with SLE (n=11). The p values were generated using an unpaired t-test.

Figure 2

Iberdomide (CC-220) reduces Ikaros and Aiolos protein levels in whole blood leucocyte subsets: (A) CD19+ B cells, (B) CD14+ monocytes, (C) CD3+ T cells and (D) granulocytes. Whole blood from healthy donors was treated with CC-220 for 18 hours, lysed, fixed, permeabilised, stained with antibodies and analysed by flow cytometry. *P≤0.05; §P≤0.01; ‡P≤0.001 versus dimethyl sulfoxide (DMSO) control (n=3), by one-way analysis of variance/Dunnett’s multiple comparison test. For representative flow cytometric data, see online supplementary figures S1 and S2. IC₅₀, half maximal inhibitory concentration; MFI, mean fluorescence intensity.

Figure 3

Effect of B cell stimulation and iberdomide (CC-220) on Ikaros and Aiolos protein levels over time. (A) CD19+ B cells were isolated from the peripheral blood mononuclear cells of normal donors and stimulated in the presence of CC-220 or a Syk inhibitor. (B, C) Ikaros and Aiolos were measured by Western blot analysis. Representative blots are shown; graphs represent the mean and SE of the mean (n=3).

Figure 4

Iberdomide (CC-220) inhibits (A) anti-dsDNA and (B) anti-phospholipid IgM (systemic lupus erythematosus) autoantibody production in vitro. In cultures of peripheral blood mononuclear cells from patients with systemic lupus erythematosus, CC-220 inhibited production of anti-dsDNA autoantibodies (n=9) and anti-phospholipid autoantibodies (n=8) with a half maximal inhibitory concentration of approximately 10 nM.

Figure 5

Effect of a single dose of iberdomide (CC-220) on Aiolos expression in (A) CD19+ B cells and (B) CD3+ T cells, and effect on (C) peripheral blood CD19+ B cell counts and (D) CD3+ T cell counts in healthy volunteers. Subjects were randomised to single doses of placebo (0) or CC-220 0.03 mg (cohort A), 0.1 mg (cohort B), 0.3 mg (cohort C), 1 mg (cohort D) or 2 mg (cohort E). Aiolos expression was measured as per cent of baseline at 3, 12 and 24 hours postdose. Peripheral blood B cell and T cell counts were measured as per cent of baseline at day 2, day 3 and day 5 postdose. n=6 per CC-220 treatment group, n=14 for pooled placebo groups. *Data not available. (Due to inclement weather at the clinical site during the dosing of the 0.1 mg cohort, some flow cytometric samples were not received for analysis within the stability window.) MEFL, molecules equivalent fluorescence.

Figure 6

A single dose of iberdomide (CC-220) increased interleukin (IL)-2 production in (A) anti-CD3-stimulated whole blood and (B) decreases IL-1β production by lipopolysaccharide (LPS)-stimulated whole blood ex vivo in healthy volunteers. Subjects were randomised to single doses of placebo (0) or CC-220 0.03 mg (cohort A), 0.1 mg (cohort B), 0.3 mg (cohort C), 1 mg (cohort D) or 2 mg (cohort E). IL-2 (pg/mL) and IL-1β production by ex vivo anti-CD3 or LPS-stimulated whole blood, respectively, was measured as per cent of baseline at 3, 12 and 24 hours postdose. n=6 per CC-220 treatment group, n=10 for pooled placebo groups. *Data not available.