Intravenous bolus topotecan in patients with myelodysplastic syndrome

Activity of 9-nitro-camptothecin, an oral topoisomerase I inhibitor, in myelodysplastic syndrome and chronic myelomonocytic leukemia

BACKGROUND

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.

METHODS

Adults with a diagnosis of MDS (n = 12) and CMML (n = 32) received 9-NC 2 mg/m(2) orally daily 5 days a week, every 4 to 6 weeks.

RESULTS

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%).

CONCLUSIONS

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.

Phase II study of low-dose topotecan in myelodysplastic syndromes: a Hoosier Oncology Group (HOG) study

Topotecan has demonstrable activity in high-risk MDS and CMMoL. However, the significant toxicity of topotecan administered at a dose of 2mg/m2 i.v. daily for 5 days as a continuous infusion limits its use in older patients. Therefore, we studied topotecan 1.5mg/m2 per day i.v. over 2 h for three consecutive days in 20 patients with high-risk MDS (12 RAEB; 4 RAEB-T; 4 CMMoL). Cycles were given every 4-6 weeks. Fifteen patients were evaluable for response. Only one patient achieved a durable complete remission (CR). There were three deaths within the first cycle of therapy. Severe myelosuppression was the most common toxicity. Grades 3-4 infections were documented in four patients. We conclude that topotecan administered at this dose and schedule has no clinically significant activity.