Challenges in Chronic Myeloid Leukemia Management in South America

Real World Evidence From 2 Decades of First-Line TKI Therapy in Chronic Myeloid Leukemia (CML): Insights From ACHO's RENEHOC Registry

BACKGROUND

Chronic myeloid leukemia (CML) treatment has significantly evolved with the introduction of tyrosine kinase inhibitors. However, access to these treatments and outcomes vary globally. This study examines 2 decades of CML management in Colombia using the RENEHOC registry, focusing on TKI efficacy, safety, and healthcare system challenges.

METHODS

We performed a descriptive analysis of the sociodemographic and clinical characteristics of 994 CML patients from the RENEHOC cohort in Colombia, who were treated over the past 20 years. Trends in first-line TKI use were assessed, and Kaplan-Meier survival curves were used to estimate EFS and OS. The log-rank test was used to compare survival curves between different first-line TKIs.

RESULTS

The analysis shows trends in the use of first-line TKIs over a 20-year period in Colombia, where, as in other countries, the use of second-generation TKIs in the first-line setting is gradually increasing. Despite the difficulties of the Colombian healthcare system, the results in terms of OS are excellent regardless of the first-line TKI; however, patients treated with imatinib switched lines significantly more often than those treated with second-generation TKIs (imatinib 58.7%, nilotinib 19.5%, dasatinib 29.3%). The median duration of treatment was significantly shorter with imatinib compared to dasatinib and nilotinib (4.08, 12.75 and not reached, respectively). Intolerance was the most common reason for switching in this cohort of patients. The median observation time for OS was 64.89 months (SD 60.15), with survival rates of 99.4% at 1 year, 97.7% at 3 years and 96.6% at 5 years.

CONCLUSIONS

The results of this analysis show excellent results in terms of OS for patients with CML treated in Colombia over the last 20 years, despite the difficulties inherent in the health system. Patients treated with first-line imatinib had more frequent line changes. In general, intolerance was the most common reason for switching lines. Despite its retrospective nature, this study allows us to outline how treatment patterns in the country have changed over time. Continued efforts to include more centers and patients in prospective studies are essential to better understand the long-term effects of treatment and to improve adherence to guideline recommendations in clinical practice.

The Role of Molecular or Cytogenetic Response as a Favorable Prognostic Factor Before Hematopoietic Stem Cell Transplantation for Chronic Myeloid Leukemia

Tyrosine kinase inhibitors (TKIs) have revolutionized therapy for patients with chronic myeloid leukemia (CML) over the last two decades. However, some patients still do not achieve an adequate response to these drugs, and hematopoietic stem cell transplantation (HSCT) is indicated in this scenario. We present the results of a 20-year follow-up study of 70 patients who underwent transplantation after TKI failure. The primary objective of this study was to evaluate overall survival (OS) and the secondary objective was to evaluate the outcomes of relapse-free survival (RFS), GVHD-free, relapse-free survival (GFRS) and the incidences of relapse (RI), non-relapse mortality (NRM), acute and chronic GVHD. Median survival was 11 years, with a 1-year OS of 70% (57.8 to 79.3) and a 5-year OS of 57.7% (45.1 to 68.5). The estimated 5-year OS was not different for CP1 (60%) versus advanced stages (45%); P = .60. The degree of response immediately before transplantation was directly associated with worse outcomes [HR 5.89 (1.19-29.16); P = .03] for patients with only a hematological response compared with patients with a cytogenetic or molecular response. This study corroborates the potential of HSCT in the scenario of therapeutic failure and highlights the role of molecular or cytogenetic response as a potential target to be achieved before transplantation.