Topoisomerase I inhibitors, like topotecan, have activity in myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML). 9-Nitro-camptothecin (9-NC) is a new oral topoisomerase inhibitor with a good safety profile. The aims of the current study were to evaluate the activity and safety of 9-NC in MDS and CMML.
Adults with a diagnosis of MDS (n = 12) and CMML (n = 32) received 9-NC 2 mg/m2 orally daily 5 days a week, every 4 to 6 weeks.
Overall, 5 (11%) patients achieved complete response (CR), 7 (16%) had a partial response (PR), and 6 (14%) had hematologic improvement (HI), for an overall response rate of 41%. The response rate was similar in MDS and CMML. Severe (Grade 3–4) side effects included nausea and vomiting (7%), diarrhea (18%), other gastrointestinal toxicities (5%), and genitourinary toxicities (12%).
9-NC is active in MDS and CMML. The paucity of available therapies in CMML makes 9-NC a good candidate for further studies as a single agent, or in combination with decitabine, 5-azacitidine or cytarabine. Cancer 2006. © 2006 American Cancer Society.