Phase II study of topotecan and thalidomide in patients with high-risk myelodysplastic syndromes.

This phase II trial investigated the safety and preliminary efficacy of a topotecan/thalidomide combination therapy in patients with myelodysplastic syndrome who had refractory anemia with excess blasts (RAEB), RAEB with transformation, or chronic myelomonocytic anemia. Patients received three 21-day cycles of topotecan 1.25 mg/m(2) on days 1-5, which was repeated for two additional cycles in patients whose bone marrow blast percentages did not decrease. Oral thalidomide was then started at 100 mg/day (with the dose escalated up to 300 mg/day if well tolerated) for up to 1 year. Patients were monitored throughout the trial for hematologic and clinical adverse events, and efficacy was assessed using International Working Group (IWG) criteria. Forty-five patients, mostly elderly (median age 68 years; range 52-79 years), were enrolled. Therapy was generally well tolerated compared to high-dose chemotherapy. Three patients died from disease progression/infections during topotecan therapy, and four patients discontinued topotecan because of high-grade neutropenia (two patients), syncope (one patient), or hip surgery (one patient). Of 24 patients who received thalidomide, three discontinued because of treatment-related toxicity. Thirty-eight patients were evaluable for response: nine (24%) had hematologic improvement and 13 (34%) had stable disease. Responses occurred in patients with all disease subtypes. Six patients achieved transfusion independence, and one patient had a trilineage response. Approximately one-third of the patients had decreases in bone marrow blasts of 50%. Therefore, a topotecan and thalidomide combination therapy is promising, although further studies are needed to determine the optimum doses and schedule.

Arsenic trioxide and thalidomide combination produces multi-lineage hematological responses in myelodysplastic syndromes patients, particularly in those with high pre-therapy EVI1 expression.

Twenty-eight myelodysplastic syndromes (MDS) patients were treated with arsenic trioxide (ATO) and thalidomide. Seven patients responded including one complete hematologic and cytogenetic response and one with regression in spleen size. Two trilineage responses were seen in patients with inv(3)(q21q26.2). Three of five patients who had high pre-therapy EVI1 levels showed unexpectedly good responses while two died early in the first cycle. In vitro studies using 32Dcl3 cells forced to express EVI1 confirmed increased sensitivity of these cells to ATO. Both low/high risk MDS may benefit significantly from therapy with ATO/thalidomide, and those with high pre-therapy EVI1 expression may be uniquely sensitive.

Involvement of cyclin D1 and E2F1 in intramedullary apoptosis in myelodysplastic syndromes.

An unusually high incidence of apoptosis in S-phase cells is characteristically found in the bone marrow (BM) of patients with myelodysplastic syndromes (MDS). Previously, E2F1, c-myc, and Cyclin D1 have been shown to bring about both S-phase changes and/or apoptotic changes. We have already found a stoichiometric imbalance between pRb and E2F1 causing deregulated E2F1 activity in these disorders. In the present study, we investigated the status of Cyclin D1 in relation to E2F1 and apoptosis in 19 patients with a confirmed diagnosis of MDS in comparison with 6 healthy donors. Cyclin D1 was localized immunohistochemically using a specific monoclonal antibody (1:150 dilution) in plastic-embedded BM sections. The nuclear localization of Cyclin D1 graded on a subjective rating scale of 0 (negligible staining) to 8+ (highest), demonstrated negligible levels in normal marrows (median 1+), and in 11/19 evaluable MDS marrows. In contrast, 8/19 MDS biopsies showed an almost four-fold increase in Cyclin D1 localization (p< or =0.001). A western blot analysis of E2F1 in corresponding bone marrow (BM) aspirate mononuclear cells (MNC) demonstrated that the MDS patients with elevated Cyclin D1 expression also had a significant increase in E2F1 protein (p< or =0.03). Additionally, these patients revealed higher levels of mRNA of one of the E2F1 transcriptional target genes, dihydrofolate reductase (DHFR, p=0.01). Subsequently, the relationship of Cyclin D1 with apoptosis was elucidated in a colocalization experiment in BM biopsy sections using immunohistochemistry for Cyclin D1 and in situ end labeling of DNA (ISEL) for apoptosis. The percentage of ISEL-positive apoptotic cells was several fold higher in MDS as compared to normal BMs (p=0.009). Interestingly, 7-41% (median 20%) of the apoptotic cells in different MDS BMs revealed co-localization of Cyclin D1 in their nucleus, whereas in normal BMs co-localization was virtually absent (p=0.008). Thus, it is possible that in a subset of MDS patients, apoptotic death of bone marrow cells may involve Cyclin D1/E2F1 pathway.

Pentoxifylline, Ciprofloxacin and Dexamethasone Improve the Ineffective Hematopoiesis in Myelodysplastic Syndrome Patients; Malignancy.

Twenty-five patients with a diagnosis of myelodysplastic syndromes (MDS) were randomized to either begin therapy with pentoxifylline, ciprofloxacin and dexamethasone (PCD) immediately (10 patients) or after a 12 week observation period (control arm, 15 patients). PCD was administered with the goal of suppressing cytokine-induced excessive intramedullary apoptosis of hematopoietic cells. No marked fluctuations of blood counts were noted during the period of observation. Twenty-two patients completed at least 12 weeks of therapy: 18/22 showed some type of hematologic response, 9/18 showing an improvement in absolute neutrophil count only (p = < 0.001) and 9/18 showing multi-lineage responses. No unique category of MDS responded better, however 19/25 patients had refractory anemia (RA)/RA with ringed sideroblasts. The median time to response was 6 weeks and 3/18 responding patients maintained their responses beyond a year. We conclude that hematologic improvement in response to PCD therapy supports the validity of this unique anti-cytokine approach. Future trials should combine PCD therapy with established approaches (growth factors/chemotherapy) and also should focus on identifying more effective ways of suppressing the pro-apoptotic cytokines in MDS.