Beyond TKIs: Advancing Therapeutic Frontiers with Immunotherapy, Targeted Agents, and Combination Strategies in Resistant Chronic Myeloid Leukemia

Background: Chronic myeloid leukemia (CML) relates to the abnormal presence of the Philadelphia chromosome, which originates the production of the BCR-ABL1 fusion protein and therefore leads to neoplastic transformation and unregulated cell growth. The advent of tyrosine kinase inhibitors (TKIs) has resulted in tremendous improvements in CML scenarios; however, there are practical difficulties, especially considering the late stages of the disease. This review examines recently developed strategies that are intended to increase the efficiency of treatment by overcoming TKI resistance. Methods: We performed a literature review of such databases as PubMed, Scopus, Web of Science, and Embase for the last ten years. The following keywords were used in the studies: ‘CML’, ‘TKI resistance’, ‘novel therapies’, ‘immunotherapy’, ‘targeted agents’, and ‘combination therapies’. Only those studies were included that were clinical trials and preclinical across-the-board developmental programs that attempt to target the tumor at multiple levels and not just focus on basic first-line TKIs. Results: In CML patients who do not respond to TKIs, novel therapeutics encompass ponatinib, asciminib, CAR-T immunotherapy, and BCL-2 and mTOR inhibition in conjunction with TKI therapy. This addresses both BCR-ABL1-dependent and independent resistance mechanisms, increasing the chance of achieving deeper molecular response and reduced toxicity. Nonetheless, they exhibit diverse characteristics regarding efficacy, safety, cost, and quality of life effects. Discussion: Nonetheless, numerous challenges remain regarding the understanding of the mechanisms of resistance, the long-term efficacy of novel medicines, and the ideal combinations to attain optimal outcomes. Areas of future research include the search for other patterns of molecular resistance, tailoring specific treatments to patients, and incorporating AI to improve diagnosis and monitoring. Conclusion: The introduction of novel therapeutic techniques into clinical practice needs a collaborative approach and persistent dynamism to new findings from research. Our analysis indicates that the challenges posed by resistant CML disease are complex and require further improvements in therapeutic and clinical protocol development.