Efficacy of low-dose dasatinib (50mg) in chronic myeloid leukemia: Chronic phase (CML-CP) in LMIC—Are we there yet?

e18571 Background: Worldwide, the literature on low-dose Dasatinib (50 mg) in CML-CP shows comparable efficacy with enhanced tolerance and fewer treatment interruptions due to reduced toxicity compared to the standard dose (100 mg). In India, CML onset occurs at a younger age than in Western countries, with many patients discontinuing treatment early due to financial constraints or respiratory toxicity, primarily pleural effusion. Our study aimed to evaluate the efficacy, tolerability, and toxicity profile of low-dose Dasatinib in CML-CP patients in India. Methods: This study is a hospital-based, single-arm, prospective interventional trial conducted in the Department of Hematology at AIIMS, Bhubaneswar, Odisha, India. A total of 39 patients, all newly diagnosed, treatment naïve CML-CP, over 18 years of age with adequate organ function & who consented to the study were recruited between May 2021 and April 2023. Patients with underlying cardiac or pulmonary illnesses, or those presenting in advanced phase, were excluded. Quantitative BCR-ABL1 PCR assessments were conducted at 3, 6, and 12 months following the initiation of dasatinib treatment. Results: Table 1 shows the baseline characteristics of all 39 patients. At 3 months, 30 (76.9%) out of 39 patients achieved EMR. Out of the 39 patients recruited, only 31 were evaluable for response at 12 months. MMR at the end of 1 year was achieved in 20 (64.5%) out of 31 patients on Dasatinib 50mg OD. Dose escalation was required in 13 (33.3%) patients. Grade 3 /4 hematological toxicities were observed in 25.7% of patients, however, no patient in the study developed respiratory or cardiac toxicities. Conclusions: Although limited by its small sample size, our study contributes to the existing body of evidence of low-dose Dasatinib( 50mg OD). Notably, no cases of cardiac or pulmonary toxicity were observed in our study. These findings suggest the potential for dose individualization, optimizing therapeutic outcomes while minimizing toxicity. Baseline characteristics. Characteristic Total number of patients n=39 Median age, yr (range) 40 (33-47) Male, n (%) 21 (53.8) Median WBCs, x 10 9 /L (range) 213.8 (107.6-303.4) Median hemoglobin, g/dL (range) 9.1 (8.3-10.5) Median platelets, x 10 9 /L (range) 426 (290-584) Peripheral blood basophils, % (range) 6 (3-8.4) Peripheral blood blasts, % (range) 5 (2-6) Median spleen size, cm (range) 12 (11-16) Additional cytogenetic abnormalities, n (%) 0 (0) Sokal risk group, n (%) Low 23 (59) Intermediate 9 (23.1) High 7 (17.9)