Hypomethylating agents in vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic syndrome (VEXAS): A systematic review.

VEXAS syndrome (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) is an X-linked, systemic, haemato-inflammatory syndrome caused by somatic mutations in the UBA1 gene. No standardized treatment guidelines exist, but evidence is emerging that treatment with hypomethylating agents (HMAs) can induce improvement of the inflammatory symptoms, reverse cytopenia, enable weaning of the corticosteroids and, in some cases, induce molecular remission. We systematically reviewed the literature to evaluate the experience with HMA in the management of VEXAS, following 2020 PRISMA guidelines across three databases. A total of 30 citations reporting 166 patients with genetically confirmed VEXAS syndrome treated with HMA were included. All but three patients were males (98%), and the median age was 71 years (range, 29-86). Inflammatory symptoms (96% of patients), constitutional symptoms (84%) and cytopenia (89%) were most frequently reported, and 81% had a concomitant diagnosis of myelodysplastic syndromes (MDS). Most mutations were substitutions of p.Met41 (81%). Overall inflammatory response was achieved in 59% of treated patients with most complete response (52%). Responses were documented in patients with and without concomitant MDS. Any haematological response was achieved in 74% of the patients, and eradication of the UBA1 clone (to a variant allele fraction of <2%) was detected in 51% of cases in whom mutation testing was performed (n = 32/63). Toxicity was the most frequent reason for discontinuation of therapy. This review highlights HMAs as a feasible option in the management of VEXAS syndrome. Prospective studies are needed to identify predictors for response or resistance and optimal regimens.