Intracellular JAK inhibitors (JAKi) are a new group of drugs, effective orally, for the treatment of rheumatoid arthritis (RA). They work at the intracellular level by inhibiting several group I and II cytokines.1 Although, in general, the increase in infections is similar to that of other biological drugs, there appears to be a higher incidence of herpes zoster infection, in particular related to age and steroid treatment.2

Baricitinib (BARI) is a selective JAK1-JAK2 inhibitor that, when administered as a single daily dose, has been shown to be effective and safe in clinical trials in patients with RA who have not responded to conventional synthetic disease modifying drugs (csDMARDs) or biological drugs (bDMARDs).3–7 However, there is little information in patients from clinical practice.8–11

The aim of this study, conducted in a real-life situation, was to determine the response to BARI in patients with inadequate response to csDMARDs or bDMARDs.

From October 2017 to June 2019 we collected patient characteristics (age, gender, comorbidity, BMI), characteristics of RA and of treatment when starting BARI and at the last recorded visit (disease duration, RF and ACPA, DAS28-ESR and CDAI, previous or concomitant treatment with FAMEcs or FAMEb, time on BARI, reason for discontinuation of treatment, severe adverse effects).

Of 230 RA patients in our centre who received a bDMARD or JAKi, 50 (22%) were treated with BARI. Eighty-four percent were female, with a mean age of 59 ± 10.5 years, the mean BMI was 28.3 ± 7 and mean duration of RA was 10.5 ± 8.5 years (range: 1–39 years). The RF and ACPA were positive at 80% and 82% respectively. Forty-seven (94%) patients received a concomitant csDMARD: methotrexate: 28 (56%), leflunomide: 15 (30%), hydroxychloroquine: 3 (6%), and salazopyrin: one (2%). At the start of treatment with BARI 23 (57%) patients were treated with prednisone daily (mean: 7.2 ± 4.7 mg; median: 5 mg; range: 2.5–20 mg).

BARI was the first drug after failure of a csDMARD (F1) in 27 (54%) patients, and after failure of a bDMARD in 23 (46%): the second drug (D2) in 4 (8%), third (D3) in 6 (12%), fourth (D4) in 8 (16%) and fifth (D5) in 5 (10%) patients.

For the analysis, during time under treatment with BARI, 10 patients were discarded: 8 because they came from clinical trials and 2 because they had been under treatment for less than a month, leaving 20 patients in the D1 group and 20 patients in the D2-D5 group. The overall average time on BARI was 9.6 ± 3.2 months, and D1, D2, D3, D4, D5, at 7.5, 7, 7.4, 7.7 and 11 months, respectively. The average time on BARI was 5.4 months. It was discontinued in 10/40 (25%) patients: in 5 (12.5%) patients due to loss of effectiveness, in 4 (10%) due to complications and in one (2.5%) patient due to transfer home.

When comparing patients treated with BARI as D1 versus group D2-D5, significant differences were detected in the mean duration of RA (7.1 ± 6.8 vs. 14.3 ± 8.5, P = .003). Of the D2-D5 patients, prior to starting on BARI, 9 (45%) D2 patients had failed to achieve one therapeutic target (TT), 8 (40%) D3 patients had failed to achieve 2 TT, and 3 (15%) D4-D5 patients had failed to achieve 3 TT. When comparing the results of DAS-ESR and CDAI from the baseline visit and the last visit, significant differences were obtained in all groups (Table 1).

BARI treatment was discontinued in 4 (20%) patients: 2 due to herpes zoster (one 58-year-old patient, on treatment with 2.5 mg of prednisone daily; one 71-year-old patient without corticoid treatment; both on methotrexate treatment at a dose of 15 mg weekly), one patient due to anaemia with haemoglobin less than 8 g/dL and the remaining patient due to increased transaminases, not controlled by reducing the BARI dose to 2 mg. During the time of the study, none of the patients presented a thrombotic event.

In this real-life study BARI was effective and safe. It can achieve clinical remission or low disease activity even in patients who have previously failed with various bDMARDs or several therapeutic targets. BARI losses of 20% in the first year of treatment usually occur in the first six months of treatment.