Results of therapy with interferon alpha and cyclic combination chemotherapy in patients with philadelphia chromosome positive chronic myelogenous leukemia in early chronic phase

Response dynamics in chronic-phase chronic myeloid leukemia

Cytogenetic response (CyR), especially complete CyR (CCyR), has historically and is currently associated with a significant survival advantage in patients with chronic-phase chronic myeloid leukemia (CP-CML). CCyR represents a critical level of disease reduction irrespective of treatment type, and timely achievement demonstrates treatment-sensitive disease. Guidelines from European LeukemiaNet and the National Comprehensive Cancer Network therefore state that alternative therapies should be considered for patients not achieving CCyR by 6 or 12 months. Data from clinical trials indicate that early CCyR affords the best benefit:risk ratio by minimizing the mounting risk of disease progression, and the duration of CCyR when achieved affects disease progression. Treatment options for patients who fail to achieve CCyR on standard-dose imatinib (400 mg/day) include imatinib dose escalation, dasatinib, nilotinib, stem-cell transplantation, or a clinical trial. While molecular testing gauges further risk reduction, disease stability, and often elimination of BCR-ABL transcripts below detection threshold, CCyR remains the most important surrogate for long-term survival and cytogenetic testing remains a key part of patient care in the management of CML, particularly early in response. Longerterm follow-up data will be required to confirm CCyR as a surrogate marker for survival in imatinib-resistant patients treated with the secondgeneration tyrosine kinase inhibitors, dasatinib and nilotinib.

High-vs low-dose cytarabine combined with interferon alfa in patients with first chronic phase chronic myeloid leukemia. A prospective randomized phase III study

A prospective randomized phase III study was performed to evaluate whether intensified cytarabine would induce a higher response rate and longer event-free interval as compared to low-dose cytarabine in chronic myeloid leukemia (CML). One hundred and eighteen patients with CML in early chronic phase entered the study. Twenty-eight out of 32 patients assigned to group A received two cycles of a combination of intensified cytarabine and idarubicin followed by interferon alfa (IFN-α) maintenance, 28 patients in group B received standard treatment by a combination of low-dose cytarabine and IFN-α. Forty-nine patients with a human leukocyte antigen-identical sibling donor proceeded to allogeneic stem cell transplantation (allo-SCT) and nine patients were excluded from the analysis. Hematological response was observed in 97% of the patients in group A vs 86% of the patients in group B during the first year of treatment. In group A, 16 patients (50%) achieved a major cytogenetic response, which compared to seven patients (25%) with a major cytogenetic response in group B. With a median follow-up of 58 months (range 34–76), event-free survival was not significantly different between arms A and B. The estimated 5-year survival rate was 56% in the intensified arm and 77% in the low-dose arm (P = 0.05). Recipients of allo-SCT showed a 5-year estimated survival rate of 55%. Although intensified cytarabine induced a higher initial percentage of major and complete cytogenetic responses, responses were not sustained by IFN-α maintenance therapy.

Treatment of CML in pediatric patients: should imatinib mesylate (STI-571, Gleevec) or allogeneic hematopoietic cell transplant be front-line therapy?

BACKGROUND

Long-term survival of pediatric patients with chronic myelogenous leukemia (CML) receiving myeloablative hematopoietic stem cell transplantation from fully-matched related and unrelated donors has been reported between 60 and 75%, but is associated with significant morbidity. Imatinib mesylate (STI-571, Gleevec) and reduced intensity conditioning stem cell transplantation (RIC) are two promising new tools that offer potential for decreasing therapy associated morbidity for patients with CML.

RESULTS

Large trials have shown significant responses in chronic phase patients treated with imatinib and reasonable but short-lived responses in advanced phase CML. Data from adult studies is beginning to define populations likely to progress or have prolonged responses to imatinib, and some adult treatment paradigms are moving toward reserving transplantation until patients are at risk of failure with imatinib. Early trials of RIC transplantation in CML show decreased transplant related morbidity with efficacy similar to conventional transplantation, but the approach has yet to be verified in phase III studies. Data in pediatric patients with imatinib and RIC transplantation is limited.

CONCLUSIONS

Studies with imatinib are underway in pediatrics, but whether pediatric dosing schemes will lead to outcomes similar to adults is unknown. Because HLA-matched myeloablative transplantation offers a high rate of cure in the pediatric population, clinical studies assessing the role of imatinib mesylate and RIC transplantation should be planned carefully in order to avoid sub-optimal outcomes.

Survival Advantage with Imatinib Mesylate Therapy in Chronic-Phase Chronic Myelogenous Leukemia (CML-CP) after IFN-α Failure and in Late CML-CP, Comparison with Historical Controls

PURPOSE

The purpose of this research was to compare the survival of patients with Philadelphia chromosome (Ph) -positive chronic myelogenous leukemia (CML) post-IFN-alpha failure treated with imatinib to historical experiences with standards of care or other therapies.

EXPERIMENTAL DESIGN

The outcome of 261 patients with Ph-positive chronic phase CML post-IFN failure treated with imatinib was compared with 204 historical control patients treated for a similar disease status with existing therapies. A subset of 147 patients in late chronic phase CML and 100% Ph-positive status treated with imatinib was compared with 95 patients in a similar disease status treated with IFN. Multivariate analyses were conducted to assess the independent prognostic effect of therapy (imatinib versus other) on survival.

RESULTS

In the first analysis involving 261 patients on imatinib plus 204 historical patients, the complete cytogenetic response rates were 62% and 19%, respectively (P < 0.001). A multivariate analysis identified pretreatment peripheral blasts and thrombocytosis to be independent poor prognostic factors for survival. Imatinib therapy (versus others) was a significant independent favorable prognostic factor for survival (hazard ratio, 0.17; P < 0.0001). In the second analysis involving the subset of 147 patients receiving imatinib plus 95 historical patients treated with IFN regimens, the complete cytogenetic response rates were 41% and 7%, respectively (P < 0.001). A multivariate analysis selected pretreatment anemia and peripheral blasts to be significant independent poor prognostic factors for survival. Imatinib therapy (versus IFN) was an independent favorable prognostic factor for survival (hazard ratio, 0.20; P < 0.0001). Three-month and 6-month landmark analyses showed that patients in all cytogenetic response categories (major, minor, and none) after imatinib therapy had survival outcomes better than the historical control population. Within each cytogenetic response category, survival was also better with imatinib than with other therapies.

CONCLUSIONS

This analysis provides evidence for a survival advantage with imatinib versus other therapies in chronic-phase CML post-IFN failure, and for a survival advantage with imatinib versus IFN in late chronic-phase CML.

Imatinib mesylate therapy improves survival in patients with newly diagnosed Philadelphia chromosome-positive chronic myelogenous leukemia in the chronic phase: comparison with historic data

BACKGROUND

The International Randomized study of Interferon-alpha plus cytarabine (IFN-alpha plus ara-C) versus STI571 (imatinib mesylate) [IRIS trial] in patients with newly diagnosed Philadelphia chromosome (Ph)-positive, chronic-phase chronic myelogenous leukemia (CML) has not shown (to date) a survival advantage for imatinib. This was most likely because approximately 90% of patients receiving IFN-alpha plus ara-C changed to imatinib therapy after a median of 8 months into therapy.

METHODS

The authors analyzed the results with imatinib therapy in patients with newly diagnosed Ph-positive CML in chronic phase and compared their outcome with patients who received IFN-alpha regimens. A total of 187 patients with Ph-positive CML in early chronic phase treated with imatinib were compared with a historic group of 650 similar patients treated with IFN-alpha regimens from 1982 until 1997.

RESULTS

Patients who received imatinib were significantly older and had significantly more bone marrow basophilia and less leukocytosis. The complete cytogenetic response (Ph 0%) rates were better with imatinib (81% vs. 32%; P < 0.001), as were the survival rates (30-month estimated survival rates 98% vs. 88%; P = 0.01). A multivariate analysis of the total study group of 837 patients identified imatinib therapy to be a significant independent favorable prognostic factor for survival (P = 0.01).

CONCLUSIONS

The current study is the first to indicate the survival advantage of imatinib compared with IFN-alpha, the previous standard of care, in patients with early chronic-phase CML.

Prediction of initial cytogenetic response for subsequent major and complete cytogenetic response to imatinib mesylate therapy in patients with Philadelphia chromosome-positive chronic myelogenous leukemia

BACKGROUND

Obtaining a major (Philadelphia chromosome [Ph] of < 35%) or a complete cytogenetic response (Ph of 0%) has been associated with excellent long-term survival. Cytogenetic response may continue to improve with therapy. Because early allogeneic stem cell transplantation (SCT) may be associated with a better outcome, early parameters predicting for subsequent cytogenetic responses would optimize the treatment decision-making.

METHODS

The current study was performed to analyze whether early cytogenetic responses may be predictive of later major or complete cytogenetic responses to imatinib mesylate therapy in patients with Ph-positive chronic myelogenous leukemia (CML).

RESULTS

Two hundred sixty-one patients with Ph-positive, chronic-phase CML after failure with interferon therapy who were treated with imatinib mesylate therapy were analyzed. A persistence of 100% Ph-positive cells after > or = 6 months of imatinib mesylate therapy was associated with a major cytogenetic response rate of 9-13% and a complete cytogenetic response rate of 0-4%. However, a minor cytogenetic response after 3-12 months of therapy still was associated with high rates of major (68-83%) or complete (35-54%) cytogenetic response rates.

CONCLUSIONS

Patients with Ph-positive, chronic-phase CML who have persistent 100% Ph-positive disease after > or = 6 months of imatinib mesylate therapy may be offered allogeneic SCT or considered for alternative investigational therapies.

Complete cytogenetic and molecular responses to interferon-alpha-based therapy for chronic myelogenous leukemia are associated with excellent long-term prognosis

BACKGROUND

Little is known regarding long-term prognosis among patients with Philadelphia chromosome (Ph)-positive chronic myelogenous leukemia (CML) who achieve a complete cytogenetic response (0% Ph-positive cells) after treatment with interferon-alpha.

METHODS

The authors analyzed 512 patients with Ph-positive, early chronic-phase CML who were treated with interferon-based therapies between 1981-1995 for the incidence and durability of complete cytogenetic response, and in relation to long-term prognosis.

RESULTS

One hundred forty patients (27%) achieved a complete cytogenetic response. Their 10-year survival rate was 78%. At the time of last follow-up, 44 patients (31%, 9% of the total) were alive, 21 in first and 23 in second durable complete cytogenetic response (median, 127 months; range, 88-191 months); 39 patients had not received any therapy for a median of 50 months (range, 11-139 months). Analysis by reverse transcriptase-polymerase chain reaction in 78 patients during complete cytogenetic response showed 46 who had achieved at least 1 complete molecular response. Five of these 78 patients had died by the time of last follow-up, but only 2 had died of disease-specific causes. Recurrence rates were significantly lower and cytogenetic response durations were significantly longer among patients who achieved at least one complete molecular response.

CONCLUSIONS

Achieving a complete cytogenetic or molecular response after therapy with interferon-alpha appears to be associated with excellent long-term prognosis. Approximately 10% of patients reportedly can achieve durable complete cytogenetic response, with or without continuation of interferon. This finding emphasizes the potential of long-term event-free survival in CML patients outside the context of allogeneic stem cell transplantation, which may be improved with new therapies such as imatinib mesylate.

Imatinib mesylate therapy for relapse after allogeneic stem cell transplantation for chronic myelogenous leukemia

Twenty-eight adults with chronic myelogenous leukemia (CML) that had relapsed after allogeneic stem cell transplantation (SCT) received imatinib mesylate (400-1000 mg/d). Disease was in chronic phase in 5 patients, accelerated in 15, and blastic in 8 (7 medullary, 1 extramedullary); median time from transplantation to relapse was 9 months (range, 1-137 months). Thirteen patients had undergone salvage donor lymphocyte infusion (DLI) (median time from DLI to imatinib mesylate therapy, 4 months [range, 2-39 months]). The overall response rate was 79% (22 of 28 patients); the complete hematologic response (CHR) rate was 74% (17 of 23 patients), and the cytogenetic response rate was 58% (15 of 26 patients; complete response in 9 [35%] patients). CHR rates were 100% for chronic phase, 83% for accelerated phase, and 43% for blastic phase. The patient with extramedullary blastic disease achieved complete response. Cytogenetic response rates were 63% (12 of 19 patients) for chronic or accelerated phases (complete cytogenetic response in 8) and 43% for blastic phase (3 of 7 patients). At median follow-up of 15 months, 19 patients were alive, 9 with no evidence of disease. The 1-year estimated survival rate was 74%. Five patients had recurrence of grade 3 (3 patients) or grades 1 to 2 (2 patients) graft-versus-host disease (GVHD). Severe granulocytopenia developed in 43% of patients and thrombocytopenia in 27%; both conditions reversed with dose adjustments of imatinib mesylate. We conclude that imatinib mesylate effectively controlled CML that recurred after allogeneic SCT, but it was associated with side effects including myelosuppression and recurrence of severe GVHD.