SB1532

SB1532 is a small molecule telomerase inhibitor currently under investigation for the treatment of hematological malignancies, specifically myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Telomerase activation is a primary mechanism used by approximately 85% of human cancer cells to maintain telomere length and achieve cellular immortality. SB1532 works by inhibiting this enzyme, leading to telomere erosion and eventual senescence or apoptosis in malignant cells. Recent research presented at ASH 2025 highlights its potential when used in a sequential treatment regimen; inhibiting telomerase with SB1532 followed by inhibition of the alternative lengthening of telomeres (ALT) pathway (using agents like trabectedin) has demonstrated significant synergistic effects in reducing cell viability in MDS and AML cell lines while sparing normal primary fibroblasts.