Early haematologic response to anifrolumab in SLE: results from the European multicentre EFFORT-SLE study

To evaluate the efficacy and safety of anifrolumab (ANI) for the haematologic manifestations of SLE in routine clinical practice.

In this retrospective multicentre European study, adult patients with SLE presenting with ≥1 disease-related haematologic abnormality at ANI initiation were included. Clinical and laboratory data were collected at baseline and at 3, 6, 12, 18 and 24 months. Complete haematologic response (CHR) was defined as normalization of all baseline abnormalities, whereas partial haematologic response (PHR) was defined as normalization of at least one affected lineage.

Forty-seven patients from seven European countries were included (91.5% female). ANI was specifically initiated for haematologic involvement in 21/47 (44.7%), whereas 26/47 (55.3%) started treatment for other SLE manifestations but had ≥1 haematologic abnormality at baseline. CHR was achieved in 8/43 (18.6%) patients at 3 months and cumulatively in 14/46 (30.4%) within 6 months (overall 17/47, 36.2%), with comparable rates regardless of treatment indication. PHR occurred in 17/43 (39.5%) at 3 months and in 11/37 (29.7%) at 6 months. Haemoglobin, leucocyte and lymphocyte counts significantly improved by month 3, whereas platelet counts showed a non-significant increase. Higher baseline CRP, ESR and SLE-DAS were associated with the lack of CHR. Twelve patients (25.5%) discontinued ANI, and 17 (36.2%) experienced adverse events without discontinuation.

ANI was associated with early haematologic improvement, with one-third of patients achieving complete normalization under a stringent definition of remission. Responses involved multiple haematologic lineages and were less frequent in patients with higher inflammatory activity, although confirmation in broader populations is warranted.