Edward M Vital

Background Observations with rituximab suggest B-cell independent mechanisms of cutaneous lupus erythematosus (CLE) in systemic lupus erythematosus (SLE), especially discoid lupus erythematosus (DLE). Type-I interferon receptor blockade with anifrolumab shows efficacy in SLE, but efficacy for cutaneous disease of specific morphologies has not been studied. Interferon has pleotropic immune effects and it is unknown which of these are critical to therapeutic response. Objectives We evaluated clinical efficacy and quality-of-life impact of type-I interferon-blockade in: (i) rituximab-refractory CLE; (ii) DLE and other morphologies and (iii) transcriptomic and flow cytometric biomarkers. Methods We conducted a prospective single-centre study of anifrolumab in refractory mucocutaneous SLE. CLE Disease Area and Severity Index (CLASI) activity score, health-related quality of life, 96-probe TaqMan® gene expression analysis capturing key SLE blood transcriptome signatures, and eight-colour flow cytometry were undertaken at baseline, 1, 3 and 6 months. Results Seven patients [DLE (n = 5), chilblain lupus erythematosus (n = 1), subacute CLE (n = 1)] were evaluated. The median number of prior therapies was six (range 3–15), including rituximab in six of seven patients. Median CLASI-A showed rapid and sustained improvement from 17 at baseline to 6 (P = 0.016) at 1 month and 0 (P < 0.001) by 3 months. The median percentage reduction in CLASI-A at 3 months was 60%. Significant improvements were observed in Dermatology Life Quality Index scores (P < 0.001), EuroQol 5D visual analogue scale (P = 0.002) and LupusQoL fatigue, image and planning domains (P ≤ 0.05). One patient discontinued treatment owing to severe herpes zoster. Clinical responses paralleled discrete suppression of interferon-stimulated genes (ISGs) from SLE blood transcriptome module M1.2 with more varied downregulation in other interferon modules. Myeloid and inflammation-annotated genes remained upregulated throughout treatment. Intermediate monocytes (CD14++CD16+) reduced to normal levels during therapy (P = 0.014), while other flow subsets showed no substantive changes. Conclusions These data indicate rapid efficacy of anifrolumab in DLE and rituximab-resistant CLE. Response is associated with suppression of a subset of ISGs and decline in intermediate monocytes. Suppression of all ISGs or the wider SLE blood transcriptome is not required for response.