The European LeukemiaNet’s new scoring system, known as ELTS, is based on chronic myeloid leukemia (CML) patients who were initially treated with imatinib. Relevant variables include age, peripheral blasts, spleen size, and platelet count.
Nilotinib (NIL) is a viable alternative in the treatment of CML. To learn the prognostic value of the ELTS score in a cohort of CML patients in early chronic phase treated with NIL-based regimens as first-line therapy, researchers evaluated data from 345 adult patients.1 These patients were enrolled in multicenter studies conducted by the GIMEMA CML WP or were treated at the University Hospital of Bologna, Italy. Initial treatment was NIL 300 mg twice daily or NIL 400 mg twice daily. The intention-to-treat population of each study was analyzed.
The median age of these patients was 53 years (range, 18-86 years). Distribution according to the different scoring systems was as follows: 41% low, 40% intermediate, and 19% high Sokal score; 94% low and 6% high EUTOS score; and 59% low, 30% intermediate, and 10% high ELTS score. The median follow-up was 59 months (range, 24-82 months).
Cumulative incidence of major molecular response (MMR) and BCR-ABL1IS ratio <0.1% (MR4.0) was 83% and 69%, respectively. Six-year progression-free survival (PFS), overall survival (OS), and cumulative incidence of leukemia-related death (LRD) were 91%, 92%, and 4%, respectively.
All 3 scores were associated with significantly different probabilities of MMR (cumulative incidence of MMR according to ELTS score: 90%, 77%, and 61% in low-, intermediate-, and high-risk patients, respectively; P <0.001), but only the ELTS score was able to predict achievement of MR4.0 (cumulative incidence of MR4.0: 75%, 63%, and 53% in low, intermediate, and high ELTS score patients, respectively; P = 0.013).
Interestingly, both the Sokal score and the ELTS score, but not the EUTOS score, predicted OS (P = 0.021 and P = 0.037, respectively). The ELTS score predicted a significantly different PFS (P = 0.038); 6-year cumulative incidence of progression was 2%, 7%, and 6% in patients with low, intermediate, and high ELTS scores, respectively. Potentially due to the low number of deaths related to CML, all 3 scores failed to predict LRD. However, when comparing patients with low ELTS score and patients with intermediate and high ELTS risk, the difference became significant.
Researchers concluded that in a cohort of CML patients initially treated with NIL-based regimens, the prognostic predictive ability of the new ELTS score was superior to the Sokal and EUTOS scores. 1. Castagnetti F, et al. EHA 2016. Abstract S434.