Real-world disease characteristics and frontline treatments used in chronic lymphocytic leukaemia in Bulgaria: An observational cohort study (DESCRIBE)

Objective Bruton tyrosine kinase inhibitors and B-cell lymphoma 2 inhibitors are currently the new standard active agents in chronic lymphocytic leukaemia. This observational study describes the real-world use of frontline treatment in Bulgarian patients with active chronic lymphocytic leukaemia and characterises the patient population receiving these treatments. Methods DESCRIBE was a physician-chart review study conducted at eight haematology centres across Bulgaria. Adult patients with confirmed active chronic lymphocytic leukaemia requiring frontline treatment initiation after January 2022 were considered for enrolment. Results A total of 90 patients were included in the study. The mean age (standard deviation) was 62.8 (11.2) years, and 58% were male. The median (range) duration of disease was 6 (0–198) months at the time of frontline treatment initiation and 19.2 (1.2–206.4) months at enrolment. Comorbidities were reported in 58 (64%) patients, with cardiovascular diseases being the most common (57%). Cytogenetic testing rates were lower, particularly for del(11q), tumour protein p53 gene and immunoglobulin heavy chain variable region gene mutation status, which were assessed in only 44%, 21% and 37% of patients, respectively. At the time of frontline treatment initiation, most patients presented with Rai stage II (44%) or Binet stage B (63%). Targeted therapy was used in 77% of cases (46% Bruton tyrosine kinase inhibitors and 31% B-cell lymphoma 2 inhibitors), while chemoimmunotherapy was used in the remaining 23%. Patients with high-risk chronic lymphocytic leukaemia were more likely to receive second-generation Bruton tyrosine kinase inhibitors (odds ratio = 5.59, p < 0.001), and each additional high-risk trait further increased the odds of its use (odds ratio = 2.35, p < 0.01). Conclusions Our findings indicate a shift towards the adoption of novel therapies in Bulgaria, with Bruton tyrosine kinase inhibitors and B-cell lymphoma 2 inhibitors now dominating the contemporary frontline treatment landscape (2022–2023). Improving the rate of testing for specific high-risk molecular and genetic markers is vital to enhancing outcomes in patients with chronic lymphocytic leukaemia. In the era of proven efficacy of targeted agents, chemoimmunotherapy should be discouraged, in line with international guidelines.