[Treatment of myelodysplastic syndromes (MDS) with oral administration of N4-palmitoyl-1-beta-D-arabinofuranosyl cytosine (PLAC)].

A phase II clinical trial on MDS was conducted in a cooperative study with orally administrable ara-C analogue, PLAC, which is resistant to cytidine deaminase and had shown an anti-tumor activity on various experimental tumors by oral route. Fifty MDS (3 RA, 18 RAEB, 11 RAEB-T, 18 RAEB-blast crisis (BC) were treated orally with 100 to 400mg/body of daily PLAC. One good response (GR) and 3 partial responses (PR) were obtained in 18 RAEB, and 2 complete remissions, 1 GR and 1 PR were noted in 11 RAEB-T, while 3 PR were seen in 18 RAEB-BC. Overall CR rates were 4%, GR rates 4% and PR rates 14%. Thus, 22% of MDS responded to oral PLAC. No clear daily dose-response was noted. Response, however, was dependent on the treatment period and was obtained in cases which had been treated for more than 20 days. Besides myelosuppression, side effects were mainly gastrointestinal, and anorexia (32%), nausea/vomiting (30%) and diarrhea (8%) were observed. Oral PLAC seems to be active on MDS which does not necessarily require admission to hospital.