Long-term outcome of autologous transplantation of peripheral blood progenitor cells as postremission management of adult acute myelogenous leukemia in first complete remission

Long-Term Outcome of Autologous Hematopoietic Stem Cell Transplantation (AHSCT) for Acute Myeloid Leukemia (AML)- Single Center Retrospective Analysis

For patients with acute myeloid leukemia (AML) in complete remission without an acceptable HLA donor, the autologous hematopoietic stem cell transplantation (AHSCT) may remain a therapeutic option as remission consolidation, however its role is still a subject of continued debate. One hundred and twenty patients who underwent AHSCT for AML were included in this retrospective single center analysis. The procedure was performed over a 19 years period and transplanted patients were in first complete remission (CR1; n = 109) or in second CR (CR2; n = 11). The median age at transplant was 37 years (range 18–64). The source of stem cells was bone marrow (n = 61; 50.8%), peripheral blood (n = 36; 30%) and bone marrow with peripheral blood (n = 23; 19.2%). The median time from AML diagnosis to AHSCT was 0.8 year (range 0.3–4.4) and the median follow-up after AHSCT for surviving patients was 12.8 years (range 3.1–20.5). The median LFS was 1.1 year. The probability of LFS calculated at 5 years and 10 years after transplantation was 28% (95%CI, 22%–32%) and 21% (95%CI, 18%–24%), respectively. The last relapse occurred 14.8 years after AHSCT and among patients who survived >2 years, 28.4% (27/95) had leukemia recurrence. The median OS was 1.7 years. The probability of OS after 5 years and 10 years was 29% and 22%, respectively. There was a tendency for increased LFS for patients younger than 50 years at transplant if compared to older population. AHSCT for AML was safe with acceptable toxicity profile. Leukemia recurrence remained the leading cause of death.

A phase I study of targeted, dose-escalated intravenous busulfan in combination with etoposide as myeloablative therapy for autologous stem cell transplantation in acute myeloid leukemia

BACKGROUND

Busulfan and etoposide have been used as myeloablative therapy for autologous hematopoietic stem cell transplantation (HSCT) in adults with acute myeloid leukemia (AML) for > 20 years. The use of targeted intravenous (I.V.) busulfan has significantly improved the tolerability and efficacy of this regimen. We designed a dose-escalation study to examine the maximum tolerated dose (MTD) of targeted I.V. busulfan with bolus etoposide as preparative therapy for autologous HSCT in AML.

PATIENTS AND METHODS

In this single-center, phase I study, adult AML patients received I.V. busulfan targeted to either an area under the curve (AUC) of 1250 (cohort 1) or 1400 (cohort 2) μmol/min over 16 doses. Dose adjustments based on plasma pharmacokinetics occurred before doses 2 and 11. Etoposide 60 mg/kg I.V. was administered 24 hours after the last busulfan dose and 3 days before stem cell infusion.

RESULTS

Twelve patients with intermediate-risk AML in first complete remission were treated. All patients in cohort 1 and 5 patients (83%) in cohort 2 were within 10% of the target AUC. The MTD was not reached, although Grade ≥ 3 mucositis occurred in 3 patients (50%) in cohort 1 and in 4 patients (66%) in cohort 2, limiting further dose escalation. Two-year relapse-free survival was 33% in cohort 1 versus 67% in cohort 2 (P = .08).

CONCLUSION

Etoposide and targeted, dose-escalated I.V. busulfan as myeloablative therapy for autologous HSCT in AML is safe, with mucositis being the most significant toxicity. A phase II study is warranted to further evaluate the activity and safety of busulfan targeted to AUC 1400 μmol/min.

Wilms' tumor gene 1 transcript levels in leukapheresis of peripheral blood hematopoietic cells predict relapse risk in patients autografted for acute myeloid leukemia

Autologous hematopoietic stem cell transplantation (ASCT) is a curative option alternative to allogeneic transplantation for patients with acute myeloid leukemia (AML). Relapse after ASCT can be due to contamination with leukemic blasts of autologous peripheral blood stem cells (PBSCs) collected by leukapheresis (LK). Identification and quantification of a minimal residual disease (MRD) marker in PBSCs could be relevant in determining the relapse risk after ASCT. High levels of the WT1 gene transcript in bone marrow of AML patients after treatment completion predict disease relapse. We evaluated WT1 transcript levels in autologous PBSC from LK used for ASCT in 30 consecutive AML patients in complete remission (CR) and established a correlation with clinical outcome. At diagnosis, all patients had WT1 overexpression. All patients were in morphological and genetic CR at the time of PBSC collection and before ASCT. Real-time quantitative PCR of WT1 was performed in samples of each LK, using TaqMan technology on RNA from mononucleated cells. The median WT1 transcript level in the PBSC graft (WT1-LK) of patients who relapsed was significantly higher than of those who did not relapse after transplantation (P <.0001). We defined a cut-off level of 80 WT1-LK copies/ABL 10e4 copies to discriminate between positive and negative PBSC grafts. The cut-off level was strongly associated with disease recurrence, DFS and OS. Our study represents the largest series of patients evaluating WT1 as a marker of MRD in PBSC LK products using a completely standardized real-time WT1-reverse transcriptase-PCR based assay. These data, if confirmed by prospective study, will help to determine an individual patient's adapted postremission allocation strategy.

Chemotherapy for patients with acute myeloid leukemia in first remission

Although the majority of patients with acute myeloid leukemia (AML) achieve a complete remission with induction chemotherapy, most will ultimately relapse. Therefore, the optimal postremission therapy for AML remains to be defined, and further improvements in treatment strategies are required. Clinical trials have demonstrated that early intensive consolidation therapy with high-dose cytarabine can produce prolonged responses in up to 40% of patients in remission after standard induction therapy. Equally, however, it has been shown that high-dose cytarabine used in induction therapy can deliver equivalent long-term results. Autologous and allogeneic stem cell transplantation in first remission are also valid alternatives, but the value of low-dose maintenance treatment seems confined to acute promyelocytic leukemia. Further improvement in the treatment of AML is likely to depend on the development of new strategies, such as molecularly targeted or immune therapies.

A Long-term Follow-up Analysis in Adult Acute Myeloid Leukemia Patients after Hematopoietic Stem Cell Transplantation

Aims and Background

Over the last 17 years, 119 adult acute myeloid leukemia patients have undergone hematopoietic stem cell transplantation at our Center.

Study Design

Seventy patients in first complete remission received hematopoietic stem cell transplantation (28 allogeneic and 42 autologous HSCT) as late intensification after conventional chemotherapy; 38 patients received allogeneic hematopoietic stem cell transplantation in a more advanced phase. A reference group was built up by collecting 40 acute myeloid leukemia patients who received high-dose cytosine arabinoside as late intensification and whose complete remission lasted more than 10 months.

Results

Results of the study led to conclude that an earlier timing of allogeneic hematopoietic stem cell transplantation can be recommended in order to treat patients who would otherwise suffer an early relapse.

Conclusions

The outcome of autologous hematopoietic stem cell transplantation in patients not in first complete remission supports the possibility of achieving good quality second complete remissions and suggests that autografting may be a life-saving strategy in selected acute myeloid leukemia patients with advanced disease.

Autologous stem cell transplantation using modified TAM or combination of triple-alkylating agents conditioning regimens as one of the post-remission treatments in patients with adult acute myeloid leukemia in first complete remission

A total of 174 newly diagnosed adult acute myeloid leukaemia (AML) patients were treated in first complete remission (CR1) using modified TAM or a combination of triple-alkylating agents followed by autologous transplantation (AT). Cytogenetic risk groups were classified and most patients received mobilized peripheral blood stem/progenitor cells (PBSCs). The infused cell dose consisted of a median of 4.1+/-2 (range, 1.2-17.1)x 10(6)/kg CD34+ cells. With a median follow-up of 51 months (range, 5-131 months) after CR1, the estimated 5-year disease-free survival (DFS) rate was 68 (95% confidence interval (CI), 63-73%) and the event-free survival rate at 5 years was 59 (95% CI, 54-64%). AML patients other than M3 subtype, the long-term DFS rate was 76, 33% for favourable and unfavourable risk groups, respectively. In all, 40 patients had relapses (40/174, 23%) at the median 15 months after CR1 (range, 8-66 months). Overall, seven patients (4%) died in connection with AT. The infused CD34+ cell dose (P=0.0389) was associated with survival by multivariate analysis. In conclusion, two novel conditioning regimens in AT are feasible for adults with variable risk AML followed for over a 10-year period.