A phase I and pharmacodynamic study of sequential topotecan and etoposide in patients with relapsed or refractory acute myelogenous and lymphoblastic leukemia

Timed-sequential chemotherapy as induction and/or consolidation regimen for younger adults with acute myelogenous leukemia

Increasing the intensity of induction chemotherapy has generated considerable recent interest in the treatment of acute myeloid leukemia. Achieving complete remission is a sine qua non condition for prolonged disease-free survival and may affect long-term outcome. In this setting, administering a repeat course of induction shortly after completion of the first course, known as timed-sequential chemotherapy (TSC), has been tested and may lead to an improved long-term outcome. Whether these results are due to the biologic recruitment of cell cycle-specific agents is unknown. However, this strategy to intensify induction may lead to more profound myelosuppression and to potential toxicities. Here we review the results of timed-sequential chemotherapy, used as induction regimen in de novo, relapsed or refractory AML or used as post-remission therapy, and compare them with those from other types of regimens.

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.

Sequential topoisomerase targeting and analysis of mechanisms of resistance to topotecan in patients with acute myelogenous leukemia

Resistance to topoisomerase I (TOP1)-targeting drugs such as topotecan often involves upregulation of topoisomerase II (TOP2), with accompanying increased sensitivity to TOP2-targeting drugs such as etoposide. This trial was designed to investigate sequential topoisomerase targeting in the treatment of patients with high-risk acute myelogenous leukemia. An initial cohort of patients received topotecan and cytosine arabinoside daily for 5 days. Serial samples of circulating mononuclear cells were examined to evaluate peak elevations of TOP2-alpha protein expression. In subsequent cohorts, etoposide was administered daily for 3 days, beginning 6 h after initiation of the topotecan infusion. The etoposide dose was escalated to determine a maximum-tolerated dose. Circulating mononuclear cells were analyzed for TOP1 mutations and ABCG2 protein expression. In addition, systemic and intracellular topotecan concentrations were measured. Thirty-one patients were enrolled. On the basis of TOP1-alpha protein levels in three patients with peripheral blast counts greater than 50%, etoposide administration began 6 h after initiation of the topotecan/cytosine arabinoside infusion. Using this schedule of administration, the maximum-tolerated dose of etoposide was 90 mg/m. No TOP1 mutations were identified, but increases in ABCG2 expression during the infusion were observed in mononuclear cells from two of four evaluable patients. Administration of etoposide 6 h after initiation of a topotecan/cytosine arabinoside infusion is feasible and is associated with clinical activity. Analysis of TOP2-alpha protein levels in this small number of patients indicated that peak increases occurred earlier than expected based on earlier publications. Upregulation of ABCG2 was detected in circulating cells and may represent an inducible form of drug resistance that should be investigated further.

A phase I and pharmacodynamic study of fludarabine, carboplatin, and topotecan in patients with relapsed, refractory, or high-risk acute leukemia

PURPOSE

A novel regimen designed to maximize antileukemia activity of carboplatin through inhibiting repair of platinum-DNA adducts was conducted in poor prognosis, acute leukemia patients.

EXPERIMENTAL DESIGN

Patients received fludarabine (10 to 15 mg/m(2) x 5 days), carboplatin (area under the curve 10 to 12 by continuous infusion over 5 days), followed by escalated doses of topotecan infused over 72 hours (fludarabine, carboplatin, topotecan regimen). Twenty-eight patients had acute myelogenous leukemia (7 untreated secondary acute myelogenous leukemia, 11 in first relapse, and 10 in second relapse or refractory), 1 patient had refractory/relapsed acute lymphoblastic leukemia, and 2 patients had untreated chronic myelogenous leukemia blast crisis. Six patients had failed an autologous stem cell transplant. Patients ranged from 19 to 76 (median 54) years. Measurement of platinum-DNA adducts were done in serial bone marrow specimens.

RESULTS

Fifteen of 31 patients achieved bone marrow aplasia. Clinical responses included 2 complete response, 4 complete response with persistent thrombocytopenia, and 2 partial response. Prolonged myelosuppression was observed with median time to blood neutrophils >/=200/microl of 28 (0 to 43) days and time to platelets >/=20,000/microl (untransfused) of 40 (24 to 120) days. Grade 3 or greater infections occurred in all of the patients, and there were 2 infection-related deaths. The nonhematologic toxicity profile was acceptable. Five patients subsequently received allografts without early transplant-related mortality. Maximum tolerated dose of fludarabine, carboplatin, topotecan regimen was fludarabine 15 mg/m(2) x 5, carboplatin area under the curve 12, and topotecan 2.55 mg/m(2) over 72 hours. An increase in bone marrow, platinum-DNA adduct formation between the end of carboplatin infusion and 48 hours after the infusion correlated with bone marrow response.

CONCLUSIONS

Fludarabine, carboplatin, topotecan regimen is a promising treatment based on potential pharmacodynamic interactions, which merits additional study in poor prognosis, acute leukemia patients.

The therapy of relapsed acute leukaemia in adults

Although the cure of acute leukaemia has improved significantly, many patients will still relapse and die. The unraveling of the molecular pathogenesis of acute leukaemia has lead to the identification of new prognostic factors and improved the detection of minimal residual disease. The treatment of relapsed acute leukaemia with chemotherapy remains unsatisfactory. Allogeneic or autologous blood and marrow transplant (BMT) can cure a subset of patients with relapsed acute leukaemia. The identification of the graft-vs-leukaemia (GVL) effect has lead to the development of donor lymphocyte infusions to re-induce remission in patients with relapsed leukaemia after allogeneic BMT and also stimulated the development of the less toxic nonmyeloablative allogeneic transplant approach. The identification of molecular targets of therapy and the development of monoclonal antibody-directed therapy has generated optimism. It is possible that combinations of chemotherapy, molecularly directed therapy, and immunotherapy may be combined to cure an increasing proportion of patients with acute leukaemia.

A phase II study of timed sequential therapy of acute myelogenous leukemia (AML) for patients over the age of 60: two cycle timed sequential therapy with topotecan, ara-C and mitoxantrone in adults with poor-risk AML

Acute myeloid leukemia (AML) in the elderly is a serious problem characterized by poor response to therapy and short survival. To improve response to therapy, a timed sequential therapy (TST) approach was designed utilizing topotecan, cytosine arabinoside (ara-C) and mitoxantrone based on multiple studies suggesting that topotecan and mitoxantrone are effective in older patients. Thirty-two adults, >or=60-year-old (median age 69) were included. None had favorable cytogenetics and 44% had and antecedent myelodysplastic syndrome (MDS) or 2 degrees AML. Fifty-nine percent achieved a complete response (CR). Median overall survival (OS) was 6.5 months (95% confidence interval (CI): 3.1-12.0 months; range, 15 days to 25.3 months). Disease-free survival (DFS) for the 19 patients achieving a CR was 7.7 months (95% CI: 6.1-13.7 months; range, 2.9-25.3 months). There were no differences in OS or DFS between cytogenetic or disease etiology groups. Although TST was well tolerated, long-term results in this group of patients are not satisfactory and new approaches are needed.