Influence of safety warnings on the prescribing attitude of JAK 2inhibitors for rheumatoid arthritis in Italy

The Janus kinase inhibitors (JAKi) tofacitinib (TOFA), baricitinib (BARI), upadacitinib (UPA) and 74 filgotinib (FILGO) are effective drugs for the treatment of rheumatoid arthritis. However, the US 75 Food & Administration (FDA) raised concerns on the safety of TOFA after its approval. This 76 prompted the European Medicines Agency (EMA) to issue two safety warnings for limiting TOFA 77 use then extended in a third warning to all Jaki in patients at high risk of developing serious adverse 78 events (SAE). These included thrombosis, major adverse cardiac events (MACE) and cancer. Thepurpose of this work was to analyze how the first two safety warnings from EMA affected the pre- 80 scribing of Jaki by rheumatologists in Italy. All patients with rheumatoid arthritis who had been 81 prescribed JAKi for the first time in a 36-month period from July 1, 2019, to June 30, 2022 were con- 82 sidered. Data were obtained from the medical records of 29 Italian tertiary referral rheumatology 83 centers. Patients were divided into three groups of 4 months each, depending on whether the JAKi 84 prescription had occurred before the EMA's first safety alert (July 1-October 31, 2019, Group 1), 85 between the first and second alerts (November 1, 2019-February 29, 2020, Group 2), or between the 86 second and third alerts (March 1, 2021-June 30, 2021, Group 3). Percentage and absolute changes in 87 patients prescribed the individual JAKi were analyzed. Differences among the three Groups of pa- 88 tients in demographic and clinical characteristics were also assessed. A total of 864 patients were 89 prescribed a JAKi during the entire period considered. Of these, 343 were identified in Group 1, 233 90 in Group 2 and 288 in Group 3. An absolute reduction of 32% was observed in the number of patients 91 prescribed a JAKi between Group 1 and Group 2 and 16% between Group 1 and Group 3. In contrast, 92 there was a 19% increase in the prescription of a JAKi in patients between Group 2 and Group 3. In 93 the first Group, BARI was the most prescribed drug (227 prescriptions, 66.2% of the total), followed 94 by TOFA (115, 33.5%) and UPA (1, 0.3%). In the second Group, the most prescribed JAKi was BARI 95 (147, 63.1%), followed by TOFA (65, 27.9%) and UPA (33, 11.5%). In the third Group, BARI was still 96 the most prescribed JAKi (104 prescriptions, 36.1%), followed by UPA (89, 30.9%), FILGO (89, 21.5%) 97 and TOFA (33, 11.5%). The number of patients prescribed TOFA decreased significantly between 98 Group 1 and Group 2 and between Group 2 and Group 3 (p ˂ 0.01). Patients who were prescribed 99 BARI decreased significantly between Group 1 and Group 2 and between Group 2 and Group 3 (p 100 ˂ 0.01). In contrast, patients prescribed UPA increased between Group 2 and Group 3 (p ˂ 0.01). 101 These data suggest that the warnings issued for TOFA were followed by a reduction in total JAKi 102 prescriptions. However, the more selective JAKi (UPA and FILGO) were perceived by prescribers 103 as favorable in terms of risk/benefit ratio and their use gradually increased at the expense of the 104 other molecules.