Results of Therapy for Acute Myeloid Leukemia in First Relapse

A Phase II Study of CLAG Regimen Combined With Imatinib Mesylate for Relapsed or Refractory Acute Myeloid Leukemia

INTRODUCTION

No standard salvage chemotherapy regimen is available for relapsed or refractory (RR) acute myeloid leukemia (AML). Preclinical data have suggested synergy in vitro between cytarabine and imatinib mesylate (IM) on AML cell growth inhibition. After demonstrating the safety and feasibility in a phase I study, we conducted a phase II clinical study of CLAG (cladribine, cytarabine, granulocyte colony-stimulating factor) regimen combined with IM for patients with RR-AML.

PATIENTS AND METHODS

We performed a single-institution 2-stage phase II study. The primary endpoint was the remission rate measured using the standard AML response criteria. The secondary endpoints included overall survival (OS) and progression-free survival (PFS).

RESULTS

From August 2009 to April 2011, 38 patients were treated at the Moffitt Cancer Center. Their median age was 62 years (range, 26-79 years). Of the 38 patients, 7 (18%) had refractory AML, 19 (50%) had early relapse, and 12 (32%) had late relapse. At the original diagnosis, only 2 patients had favorable risk factors, 18 had intermediate risk, and 16 had poor risk; for 2 patients, the karyotype was missing. The overall response rate for all 38 evaluable patients was 37%. The median OS was 11.1 months (95% CI, 4.8-13.4 months), the median PFS was 4.9 months (95% CI, 1.6-11.7 months). Among the responders, 8 of 14 patients subsequently underwent allogeneic hematopoietic cell transplantation.

CONCLUSION

CLAG plus IM was well tolerated, with encouraging signs of activity in patients with poor-risk AML.

Management of Relapsed/Refractory Acute Myeloid Leukemia in the Elderly: Current Strategies and Developments

Elderly patients with acute myeloid leukemia (AML) who are refractory to or relapse following frontline treatment constitute a poor-risk group with a poor long-term outcome. Host-related factors and unfavorable disease-related features contribute to early treatment failures following frontline therapy, thus making attainment of remission and long-term survival with salvage therapy particularly challenging for elderly patients. Currently, no optimal salvage strategy exists for responding patients, and allogeneic hematopoietic stem cell transplant is the only curative option in this setting; however, the vast majority of elderly patients are not candidates for this procedure due to poor functional status secondary to age and age-related comorbidities. Furthermore, the lack of effective salvage programs available for elderly patients with recurrent AML underscores the need for therapies that consistently yield durable remissions or durable control of their disease. The purpose of this review was to highlight the currently available strategies, as well as future strategies under development, for treating older patients with recurrent AML.

Gemtuzumab ozogamicin with cytarabine and mitoxantrone as a third-line treatment in a poor prognosis group of adult acute myeloid leukemia patients: a single-center experience

We analyzed the safety and efficacy of gemtuzumab ozogamicin (GO) combined with cytarabine and mitoxantrone in the treatment of 21 patients with acute myeloid leukemia (11 refractory and 10 in second relapse). Patients' median age was 52 years (range 36-68); all patients had previously been treated with anthracycline-containing regimens (daunorubicin and idarubicin). GO at a dosage of 3 mg/m2 was administered as a 2-h intravenous infusion on days 1 and 14, cytarabine at 100 mg/m2 on days 1-7, and mitoxantrone at 12 mg/m2 on days 1-3. Infusion-related events were observed in 15 of 21 (71.4%) patients. The incidence of grade 1 or 2 elevations of bilirubin and hepatic transaminases was 4 of 21 (19%) and 3 of 21 (14.2%). In response to chemotherapy, 2 of 21 (9.5%) achieved complete remission and 2 of 21 (9.5%) achieved complete remission with incomplete platelet recovery, with an overall remission rate of 4 of 21(19%); median survival of these 4 patients was 7 months. Four of 21 patients (19%) died during aplasia after chemotherapy; no veno-occlusive disease occurred. No treatment-related cardiotoxicity or cerebellar toxicity was observed. In our experience, the addition of GO to mitoxantrone and cytarabine is feasible in refractory or second relapse acute myeloid leukemia patients but yields a low response rate when used as a third-line treatment.

Prognostic Index for Adult Patients With Acute Myeloid Leukemia in First Relapse

Purpose

The treatment of acute myeloid leukemia (AML) in first relapse is associated with unsatisfactory rates of complete responses that usually are short lived. Therefore, a clinically useful prognostic index can facilitate therapeutic decision making and evaluation of investigational treatment strategies at relapse of AML.

Patients and Methods

A prognostic score is presented based on the multivariate analysis of 667 AML patients in first relapse among 1,540 newly diagnosed non-M3 AML patients (age 15 to 60 years) entered onto three successive Dutch-Belgian Hemato-Oncology Cooperative Group and the Swiss Group for Clinical Cancer Research Collaborative Group trials.

Results

Four clinically relevant parameters are included in this index (ie, length of relapse-free interval after first complete remission, cytogenetics at diagnosis, age at relapse, and whether previous stem-cell transplantation was performed). Using this stratification system, three risk groups were defined: a favorable prognostic group A (overall survival [OS] of 70% at 1 year and 46% at 5 years), an intermediate-risk group B (OS of 49% at 1 year and 18% at 5 years), and a poor-risk group C (OS of 16% at 1 year and 4% at 5 years).

Conclusion

The prognostic index estimates the outcome of AML patients in first relapse using four commonly applied clinical parameters and might identify patients who are candidates for salvage and investigational therapy.

Outcome of patients with acute myelogenous leukemia after second salvage therapy

BACKGROUND

Although the prognosis is poor for patients with acute myelogenous leukemia (AML) who have disease recurrence after frontline therapy, this is a general reflection of first salvage therapies. The outcome of patients undergoing second salvage therapy in relation to complete response (CR) rates and survival has not been documented. The authors analyzed the outcome of patients with AML undergoing second salvage therapy, and identified prognostic factors associated with response and survival.

METHODS

The records of 594 patients with AML undergoing second salvage therapy from 1980 until 2004 were reviewed. The patient median age was 50 years. Salvage therapy included allogeneic stem cell transplantation (SCT) in 74 patients, standard-dose cytosine arabinoside (ara-C) combinations in 30 patients, high-dose ara-C combinations in 171 patients, non-ara-C combinations in 73 patients, and Phase I-II single agents in 246 patients.

RESULTS

Overall, 76 patients (13%) achieved CR. The median CR duration was 7 months. The median survival was 1.5 months, and the 1-year survival rate was 8%. A multivariate analysis of prognostic factors for CR identified the following 6 independent adverse factors: first CR duration < 6 months; second CR duration < 6 months; salvage therapy not including allogeneic SCT; non-inversion 16 AML; platelet counts < 50 x 10(9)/L, and leukocytosis > 50 x 10(9)/L. Patients were divided into low-risk (1-2 adverse factors; 8%), intermediate 1 (3 factors; 20%), intermediate 2 (4 factors; 38%), and high-risk groups (5-6 factors; 33%) with respective CR rates of 54%, 26%, 8%, and 0%. The respective 1-year survival rates were 36%, 21%, 6%, and 1%. A multivariate analysis for survival identified the following 7 independent adverse factors: first CR duration < 12 months; second CR duration < 6 months; bilirubin level > or = 1 mg/dL; albumin level < 3 g/dL; age > 60 years; bone marrow blasts > or = 50%; and year of therapy before 1991. Patients were divided into low-risk (0-2 adverse factors; 39%), intermediate (3 factors; 27%), and high-risk groups (> or = 4 factors; 34%) with estimated 1-year survival rates of 22%, 6%, and 0%, respectively. The respective CR rates were 26%, 8%, and 2%.

CONCLUSIONS

The current analysis established the outcome and prognostic factors associated with second salvage therapy in AML. It also proposed risk models and groups that could be used for comparison of results of present and future investigational strategies.

FLAG-IDA in the treatment of refractory/relapsed acute myeloid leukemia: single-center experience

We evaluated the efficacy and toxicity profiles of the combination of fludarabine, high-dose cytosine arabinoside (AraC), idarubicin, and granulocyte colony-stimulating factor (G-CSF) in refractory/relapsed acute myeloblastic leukemia (AML) patients. Between October 1998 and February 2002, 46 AML patients were treated with FLAG-IDA (fludarabine 30 mg/m(2), AraC 2 g/m(2) for 5 days, idarubicin 10 mg/m(2) for 3 days, and G-CSF 5 micro g/kg from day +6 until neutrophil recovery). Thirty patients were in relapse after conventional chemotherapy including cytarabine, etoposide, and daunorubicin or mitoxantrone according to the GIMEMA protocols. Four were in relapse after autologous peripheral stem cell transplantation and two after allogeneic bone marrow transplantation. Ten patients had refractory disease (after 10 days of standard doses of cytarabine, 3 days of mitoxantrone or daunorubicin, and 5 days of etoposide). Recovery of neutrophils and platelets required a median of 19 and 22 days from the start of therapy. Complete remission (CR) was obtained in 24 of 46 patients (52.1%) and 3 of 46 (6.6%) died during reinduction therapy: 2 due to cerebral hemorrhage and 1 due to fungemia ( Candida tropicalis). Fever >38.5 degrees C was observed in 40 of 46 patients (86.9%), 27 had fever of unknown origin (FUO) and 13 documented infections; 31 of 46 (67.3%) developed mucositis and 14 of 46 (30.4%) had grade 2 WHO transient liver toxicity. After achieving CR, 11 patients received allogeneic stem cell transplantation, 4 patients received autologous stem cell transplantation, 4 were judged unable to receive any further therapy, and 5 refused other therapy. Ten patients are at present in continuous CR after a median follow-up of 13 months (range: 4-24). In our experience, FLAG-IDA is a well-tolerated and effective regimen in relapsed/refractory AML. The toxicity is acceptable, enabling most patients to receive further treatment, including transplantation procedures.

Licensure of gemtuzumab ozogamicin for the treatment of selected patients 60 years of age or older with acute myeloid leukemia in first relapse

This paper discusses background information and the body of clinical data that has been accumulated to demonstrate the efficacy and safety of gemtuzumab ozogamicin (Mylotarg, Wyeth Pharmaceuticals, Philadelphia, PA). Based on these data, gemtuzumab ozogamicin was approved by the United States Food and Drug Administration for the treatment of patients with CD33-positive acute myeloid leukemia in first relapse who are 60 years of age or older and who are not considered candidates for other cytotoxic chemotherapy. The recommended dosage of gemtuzumab ozogamicin is 9 mg/m2, administered as a 2-hour intravenous infusion for a total of 2 doses with 14 days between doses.

The treatment of acute myeloid leukemia in first relapse: a comprehensive review of the literature

Twenty years of published literature was reviewed for chemotherapy regimens used to treat patients with acute myeloid leukemia (AML) in first relapse. Thirty-one trials containing at least 20 patients in first relapse and information on patient age, duration of first complete remission (CR1), and rate of second complete remission (CR2) were analyzed. These trials included 10 retrospective studies with CR2 rates ranging from 30 to 64%, two phase II single-agent studies with CR2 rates of 8 and 25%, 15 phase II combination-agent studies with CR2 rates ranging from 14 to 87%, and four phase III randomized studies with CR2 rates ranging from 40 to 89%. When reported, median duration of CR2 was < or = 14 months and overall median survival was < or = 12 months. The probability of 3-year survival ranged from 8 to 29%. Combination therapies resulted in higher CR2 rates but were associated with longer duration of myelosuppression and greater incidence of mucositis. None of the reviewed regimens provided durable remissions for the majority of AML patients in first relapse. The CR2 rates were closely associated with age and duration of CR1. Therefore, considering the poor clinical outcomes of patients with AML in first relapse, improved therapies need to be developed.

Antibody-targeted chemotherapy of older patients with acute myeloid leukemia in first relapse using Mylotarg (gemtuzumab ozogamicin)

We analyzed the safety and efficacy of Mylotarg (gemtuzumab ozogamicin, an antibody-targeted chemotherapy consisting of a humanized anti-CD33 antibody linked to calicheamicin, a potent antitumor antibiotic) in the treatment of 101 patients > or =60 years of age with acute myeloid leukemia (AML) in untreated first relapse in three open-label trials. Mylotarg is administered as a 2-h intravenous infusion at 9 mg/m(2) for two doses with 14 days between doses. The overall remission rate was 28%, with complete remission (CR) in 13% of patients and complete remission with incomplete platelet recovery (CRp) in 15%. Median survival was 5.4 months for all patients and 14.5 months and 11.8 months for patients achieving CR and CRp, respectively. CD33 antigen is present on normal hematopoietic progenitor cells; thus, an expected high incidence of grade 3 or 4 neutropenia (99%) and thrombocytopenia (99%) was observed. The incidences of grade 3 or 4 elevations of bilirubin and hepatic transaminases were 24% and 15%, respectively. There was a low incidence of grade 3 or 4 mucositis (4%) and infections (27%) and no treatment-related cardiotoxicity, cerebellar toxicity, or alopecia. Mylotarg is an effective treatment for older patients with CD33-positive AML in first relapse and has acceptable toxicity.

Efficacy and safety of gemtuzumab ozogamicin in patients with CD33-positive acute myeloid leukaemia in first relapse

Gemtuzumab ozogamicin (CMA-676, Mylotarg, an antibody-targeted chemotherapy agent, was recently approved by the FDA for the treatment of patients with CD33+ acute myeloid leukaemia (AML) in first relapse who are 60 years of age or older and who are not considered candidates for other types of cytotoxic chemotherapy. In combined Phase II studies of 142 patients with CD33+ AML in first relapse, gemtuzumab ozogamicin monotherapy was associated with a 30% overall response rate. While treated patients had relatively high incidences of myelosuppression, grade 3 or grade 4 hyperbilirubinaemia (23%) and elevated hepatic transaminases (17%), the incidences of grade 3 or grade 4 mucositis (4%) and infections (28%) were low compared with what might be expected in association with conventional chemotherapeutic treatment. In contrast with the usual in-patient administration of cytarabine and anthracycline-containing induction regimens, a large number of patients were treated with gemtuzumab ozogamicin as outpatients (38% and 41% for the first and second doses, respectively). Two prognostic factors for patients with AML in first relapse, age and duration of complete remission, had relatively little effect on response rates to gemtuzumab ozogamicin. Preliminary data in pediatric patients also suggest the immunoconjugate to be reasonably well tolerated. Studies of gemtuzumab ozogamicin in combination with anthracycline and cytarabine are underway. Gemtuzumab ozogamicin, administered to patients with CD33+ AML in first relapse, has shown overall response rates comparable to conventional agents and a safety profile that appears to be favourable.

Efficacy and safety of gemtuzumab ozogamicin in patients with CD33-positive acute myeloid leukemia in first relapse

PURPOSE

Three open-label, multicenter trials were conducted to evaluate the efficacy and safety of single-agent Mylotarg (gemtuzumab ozogamicin; CMA-676; Wyeth Laboratories, Philadelphia, PA), an antibody-targeted chemotherapy agent, in patients with CD33-positive acute myeloid leukemia (AML) in untreated first relapse.

PATIENTS AND METHODS

The study population comprised 142 patients with AML in first relapse with no history of an antecedent hematologic disorder and a median age of 61 years. All patients received Mylotarg as a 2-hour intravenous infusion, at a dose of 9 mg/m(2), at 2-week intervals for two doses. Patients were evaluated for remission, survival, and treatment-emergent adverse events.

RESULTS

Thirty percent of patients treated with Mylotarg obtained remission as characterized by 5% or less blasts in the marrow, recovery of neutrophils to at least 1,500/microL, and RBC and platelet transfusion independence. Although patients treated with Mylotarg had relatively high incidences of myelosuppression, grade 3 or 4 hyperbilirubinemia (23%), and elevated hepatic transaminase levels (17%), the incidences of grade 3 or 4 mucositis (4%) and infections (28%) were relatively low. There was a low incidence of severe nausea and vomiting (11%) and no treatment-related cardiotoxicity, cerebellar toxicity, or alopecia. Many patients received Mylotarg on an outpatient basis (38% and 41% of patients for the first and second doses, respectively). Among the 142 patients, the median total duration of hospitalization was 24 days; 16% of patients required 7 days of hospitalization or less.

CONCLUSION

Administration of the antibody-targeted chemotherapy agent Mylotarg to patients with CD33-positive AML in first relapse induces complete remissions with what appears to be a favorable safety profile.

A multicentre, open, non-comparative phase II study of a combination of fludarabine phosphate, cytarabine and granulocyte colony-stimulating factor in relapsed and refractory acute myeloid leukaemia and de novo refractory anaemia with excess of blasts in transformation

The primary objective of this study was to determine the complete remission (CR) rate achieved with the FLAG (fludarabine phosphate, cytarabine and granulocyte colony-stimulating factor) regimen in patients with relapsed or refractory acute myeloid leukaemia (AML) or de novo refractory anaemia with excess of blasts in transformation (RAEB-t). Secondary objectives were to evaluate survival and toxicity. Induction treatment consisted of between one and two courses of FLAG. Patients achieving CR received between one and two courses of consolidation treatment. Eighty-three of the 89 patients entering the study were eligible for assessment. CR rates were: 17 out of 21 (81%) in late relapse AML (Group 1), 13 out of 44 (30%) in early relapse/refractory AML (Group 2), and 10 out of 18 (56%) in de novo RAEB-t (Group 3). Thirty-four of the 40 responders (85%) achieved CR after one induction course. Median survival times were 1.4 years, 3 months and 1.6 years in Groups 1, 2 and 3 respectively. Other than myelosuppression, the FLAG regimen was not generally associated with clinically significant toxicity and was well tolerated by most patients including the elderly. The FLAG regimen offers a very effective alternative treatment for CR induction in poor prognosis adult patients with either relapsed or refractory AML or de novo RAEB-t. FLAG delivers high-dose treatment without increasing overall toxicity, an approach which is of particular value in older patients, who constitute the majority in these diseases. It is therefore an important advance in developing new treatment options for these patients.

Mitoxantrone and intermediate-dose cytosine arabinoside for poor-risk acute leukemias: response to treatment and factors influencing outcome

Mitoxantrone (MIT, 12 mg/m2, i.v. 5 days) and intermediate-dose cytosine arabinoside (IDAC 1 g/m2/12 h, i.v. 3 days) was given to 43 patients with poor-risk acute leukemias (AL). Moderate or severe toxicity was infrequent. The proportion of complete remissions (CR) in the main patient categories was as follows: 15/18 (85 per cent) in acute myeloid leukemia (AML) in the first relapse, 2/6 in ALL in the first relapse, 0/2 in AML in relapse after bone marrow transplantation (BMT), 2/7 in AML refractory to first-line treatment (REF-AL), and 1/6 in postmyelodysplastic (PMD-AL) plus secondary AL (S-AL). The mortality rate during induction was 23 per cent. Median duration of CR was 24 weeks. The multivariate prognostic factor analysis on CR obtention showed that data concerning treatment for the first relapse and platelet count higher than the median of the series were favourable. On the contrary, PMD-AL, S-AL and REF-AL were unfavourable situations. A percentage of marrow erythroblasts superior to the median was a favourable prognostic factor for survival. Finally, the duration of CR after MIT-IDAC was directly related to the duration of previous CR. In conclusion, MIT-IDAC was highly effective to attain CR in AML in the first relapse. However, due to the poor long-term results in these patients, additional measures are recommended after CR.