Data from a phase II clinical study demonstrated that the investigational oral agent rubitecan (9-nitrocamptothecin, or 9NC) is active in both chronic myelomonocytic leukemia (CMML) and myelodysplastic syndromes (MDS). These data were presented at the 43rd annual meeting of the American Society of Hematology (ASH) in Orlando.
The trial was conducted in 35 evaluable patients who had previously received a minimum of one prior therapy, and who had been diagnosed with either CMML (n = 23) or MDS (n = 12). The median age of the study population was 69 years (range: 29 to 81 years). The objective response rate was 28%four complete responses and six partial responses. In addition, hematologic improvement was observed in 14%, leading to an overall response rate of 42%.
The most common side effects were diarrhea (in 20% of patients) and nausea/vomiting (in 9% of patients). These toxicities usually improved during periods when chemotherapy was suspended.
"We conclude that 9-NC has activity in CMML and MDS," said Dr. Hagop Kantarjian, an oncologist at the M. D. Anderson Cancer Center in Houston and lead investigator of the study. "A lower dose and a hiatus between cycles may improve tolerance. Further studies in these diseases are ongoing."