Background and Importance The treatment of chronic myeloid leukaemia (CML) with tyrosine kinase inhibitors (TKI) results in optimal cytogenetic and molecular reponses, improving life expectancy. Nevertheless as a lifelong pharmacological treatment, can lead to adverse events (AEs) that can substantially impact the quality of life, adherence and therefore the succes of treatment. Nowadays, discontinuing treatment in patients who achieved a sustained deep molecular response (DMR) is the main goal in CML therapy, in order to achieve a Treatement-Free Remision (TFR), leading to lower occurrence of drug-related AEs, cost reduction and feeling of cure.

Aim and Objectives To describe the clinical experience of discontinuing the therapy with TKI in patients diagnosed with CML.

Material and Methods Retrospective, descriptive, single centre (350-bed university hospital) study of patients with Philadelphia chromosome (Ph) positive CML in chronical phase, treated with TKI till august 2022. Criteria for discontinuing the treatment: ≥5 years with TKI treatment and DMR achieved (molecular response (MR) ≥4.0 during ≥36 months). Outcomes were collected from medical records: gender, age, TKI treatment, follow-up time, candidates to discontinuation, time elapsed to reach MR, time between treatment start and discontinuation, TFR duration, percentage of patients who lost reponse and were reintroducted to therapy, time to lost of response, withdrawal symptoms and disease progression.

Results There were 48 patients, 70,83% male. Population presented a mean age of 61 (25-81) years. All received first-line imatinib, except one patient who received dasatinib. Follow-up time median was 60 months (3-243). 25% were candidates to discontinuation, median time to reach MR was 15 months (3-50). Time between treatment start and discontinuation showed a median of 9 years (3-16). TFR median was 10 months (3-108). Percentage of patients who lost response and were reintroducted to therapy was 25%. Median time to lost of response was three months since discontinuation. Just one patient shows a withdrawal symptom (severe anemic) and none of them shows a progression to advanced disease stages.

Conclusion and Relevance High percentage of candidates were safely discontinued and currently remain untreated. Reduction of toxicities associated with TKI therapy could drive to a clinical benefit for CML patients, improving living conditions.

Conflict of Interest No conflict of interest