Background and importance Baricitinib has recently been used off-label for COVID-19 because of its potential role in reducing systemic inflammation, lung damage, immune response and viral endocytosis based on preclinical data.

Aim and objectives To analyse the effectiveness and safety of baricitinib for severe COVID-19 in hospitalised patients.

Material and methods An observational, retrospective, multidisciplinary, single centre study was conducted in patients diagnosed with COVID-19 and receiving treatment with baricitinib in a tertiary hospital between 15 March and 30 April 2020. All adult patients receiving baricitinib for 3 or more days were included. The variables collected were: sex, age, admission period, days of treatment, medication during admission, analytical parameters, overall survival (OS) and adverse events (AE). Clinical improvement was measured as the difference in values on a 1–8 scale of clinical status during admission (from 1=hospital discharge without limitation of activities to 8=death) between day +1 of starting baricitinib and day +14. Other COVID-19 treatments were allowed. Data were collected from the hospital electronic prescription programme and the electronic medical records. Statistical analysis was performed with SPSS V.25, expressing the variables as frequencies and medians (IQR), and the Wilcoxon test.

Results 43 patients treated with baricitinib were included: 70% men (n=30), aged 70 years (IQR 54–79). Duration of treatment was 6 days (IQR 5–7), with a hospital stay of 12 days (IQR 9–25) from the start of baricitinib. Clinical improvement was 3 points (IQR 1–4) on the clinical scale (6 points (IQR 6–4) on day +1 vs 3 points (IQR 2–4) on day +14) with a statistically significant difference (p<0.01). At the end of the study period, the OS rate was 100% (n=43 discharge due to clinical improvement (100%)). All analytical parameters related to a poor prognosis of COVID-19 improved with statistically significant differences (p<0.05) on day +14: IL-6 −50.7 pg/mL, PCR −86.4 mg/l, ferritin −159.0 ng/mL, lymphocytes +0.41×10³/mm³, platelets +51.0×10³/mm³ and D-dimers −347 ng/mL. No AE of interest associated with baricitinib were found.

Conclusion and relevance Patients treated with baricitinib for COVID-19 in our study presented statistically significant clinical and analytical improvement without relevant AE. The results of ongoing clinical trials will shed more light on its efficacy and safety in treating COVID-19.

Conflict of interest No conflict of interest.