Repeated 4-hour infusions of low-dose decitabine induce hematologic and cytogenetic remissions in older, high-risk MDS patients with complex karyotype including monosomy 7. (A) A 76-year-old woman (patient 4003 of phase 2 study PCH 95-11; see also Lübbert et al² ) diagnosed with MDS RAEB-t (French-American-British [FAB] classification)/AML (World Health Association [WHO] classification) and complex karyotype (8 different structural and numerical abnormalities including monosomy 7) achieved a complete cytogenetic normalization after 3 courses, and a complete hematologic remission after 4 courses of low-dose DAC (nine 4-hour infusions of 15 mg/m² decitabine, 3 times per day, on 3 consecutive days). Note early, isolated platelet response after course 1 (filled arrow). The patient relapsed 6 months after the fifth course of DAC, and a repeated treatment (one course only) was not successful. The patient required 93 days in the hospital from the start of therapy, thus 79% of surviving days were spent at home. (B) A 75-year-old woman (patient 4007 of phase 2 study PCH 95-11) diagnosed with MDS RAEB-t (FAB)/AML (WHO) with complex karyotype (t chromosomal aberrations including monosomy 7) received 4 courses of DAC (same dosing and schedule as the patient in panel A). This patient achieved a complete hematologic and cytogenetic remission after 2 courses. Note early, isolated platelet response also after course 1 (filled arrow). Two months after discontinuation of DAC, the patient suffered a relapse presenting as full-blown acute myeloid leukemia, and she succumbed to refractory disease shortly thereafter. In total, 82% of surviving days from start of therapy were spent at home.