OBJECTIVES : To describe clinical characteristics and MRD testing patterns in Italian patients receiving front-line treatment for B-cell precursor ALL.

METHODS : This retrospective, observational, medical chart review included adults (≥18 years) newly diagnosed with B-cell precursor ALL in four Italian hospitals between January 2011 and December 2016. Patients were followed until last chart entry (at time of data abstraction [August 2018–January 2019]) or death. Details of the patients’ clinical characteristics, MRD testing patterns and treatments were collected. Patients achieving a complete response (CR) were stratified by MRD status as assessed after first induction cycle (MRD1).

RESULTS : Overall, 77 patients were included (mean age 47.7 years; 51% male; 12% ECOG status of ≥3). Mean leucocyte count was 48.6 x10⁹/L and 40% had received stem cell transplantation (SCT). Median follow-up was 46.7 months (adjusted; interquartile range [Q1, Q3]: 38.4, 66.4). Overall, 44 (57%) patients had a CR; 35/44 (80%) CRs were per the Northern Italy Leukemia Group (NILG) protocol. At MRD1 timepoint, 14/44 (32%) patients were MRD+, 27/44 (61%) were MRD- and 3/44 (7%) were MRD unknown. Thirty-six percent of MRD+ patients were male. Mean leukocyte count was 66.9 vs. 32.2 ×10⁹/L in MRD+ vs. MRD- patients. In total, 292 MRD tests were performed; 67% of tests used PCR. Patients received a mean total of 3.48 MRD tests during front-line treatment, with an average of 1.11, 1.85 and 0.84 tests performed during induction, consolidation and SCT, respectively. MRD testing rates across these phases were 95%, 93% and 84%, respectively. Overall, there were 98 positive MRD tests: 37% used 1×10^-3 and 31% used 1×10^-4 as positivity cut-offs; 22% used an intermediate value and the cut-off was unknown in 10% of tests.

CONCLUSIONS : MRD testing in patients with B-cell precursor ALL was generally consistent with Italian guideline/protocol recommendations. MRD was most commonly tested using PCR.