Background and Importance Ibrutinib is a Bruton tyrosine-kinase inhibitor used in first and subsequent lines of treatment of chronic lymphocythic leukaemia (CLL). Ibrutinib has demonstrated its efficacy and safety in many studies published to date. There is also experience available about this topic in real- world practice. However, the safety’s evidence is different between both scenarios. Because the use of ibrutinib may vary among different countries and hospitals in the same country, we question whether safety’s information in our patients is according to real-world evidence.

Aim and Objectives To analyse the safety profile of ibrutinib in CLL all-lines of treatment, and the management of its toxicity.

Secondary endpoints to determine ibrutinib’s type responses.

Material and Methods Observational, descriptive, single-centre, retrospective and longitudinal study. Inclusion criteria: patients CLL diagnosed who started single-agent ibrutinib treatment from January 2016 to December 2022, aged ≥18 years-old. Patients treated in clinical trials and compassionate use contexts, were excluded. Quantitative variables will be described with means or medians (ranges); qualitative variables with absolute and relative frequencies.

Results Sixty patients were included, 35% received ibrutinib in first-line setting. 642 adverse events (AEs) were described, average: 10,7 (2–32) AEs/patient. Most common AEs of any grade were haematological toxicity (18,1%) mainly anaemia and neutropenia, and infections (15.9%). As special interest EAs, it was found arterial hypertension (3.7%), atrial fibrillation (1.2%) and heart failure (0.8%). Most frequent grade ≥3 AEs were: infections (27%) especially respiratory infections, haematological toxicity (16%) and arterial hypertension (13%). Five patients died during ibrutinib treatment. Temporary interruptions occurred in 68% patients, mostly because AEs (69%) and surgical procedures/diagnostics tests. 27% of patients needed dose reductions for toxicity management. Any patient required a second reduction for its management. Main reasons for treatment end were AEs (32%), disease progression (19%) and death (19%). Treatment response was evaluated in 51 patients: complete response (56%), partial response (20%) and stable disease progression (7%).

Conclusion and Relevance Despite the elevated number of AEs detected, none of special of interest. not previously described have been found. Safety profile shown by ibrutinib in our treated population is comparable to that described in previous published studies. Surprisingly, complete response frequency detected is higher than reported in other studies.

Conflict of Interest No conflict of interest.