Liposomal daunorubicin,fludarabine, and cytarabine (FLAD) as bridge therapy to stem cell transplant in relapsed and refractory acute leukemia

Therapeutic options for patients with relapsed or refractory acute leukemia are still undefined and often unsatisfactory. We report the outcome of 79 patients with relapsed-refractory acute leukemia treated with fludarabine, cytarabine, and liposomal daunorubicin (FLAD regimen) followed by hematopoietic stem cell transplantation (HSCT), when clinically indicated, between May 2000 and January 2013. Forty-one patients had acute myeloid leukemia (AML), and 38 had acute lymphoblastic leukemia (ALL). Two patients with myeloid blast crises of CML and three with lymphoid blast crises were included in the AML and ALL subgroups, respectively. Median age was 48 years (range 13–77). FLAD was well tolerated with negligible, nonhematological toxicity. Six patients (7.5 %) died before response evaluation. Forty-seven patients achieved hematologic complete response (CR). Complete remission rate was 53 and 65 % among AML and ALL patients, respectively. No CR was recorded among 11 refractory AML patients. Twenty-four patients (30 %) underwent HSCT. Nine patients received stem cells from an HLA identical sibling, and 15 from an alternative donor (3 unrelated matched, 12 haploidentical sibling). Median overall survival in AML and ALL patients receiving FLAD therapy was 9 and 8 months, respectively. A 5-year projected OS for patients receiving the whole program (FLAD + HSCT) was 24 % for AML patients (median survival 43 months), 28 % for ALL patients treated in relapse (median survival 15 months), and 0 % for ALL patients treated for refractory disease. In this paper, we show that FLAD seems to be an effective bridge therapy to HSCT for a part of poor prognosis acute leukemia patients. However, prospective studies are needed to confirm our results.     

The Efficacy of Fludarabine,High Dose Cytosine Arabinoside with Granulocyte Colony Stimulating Factor (FLAG) Protocol as Salvage Therapy for Refractory/Relapsed Acute Leukemias in Adult Iraqi Patients

Refractory/relapsed acute leukemia has always been a challenging problem for hematologist. Over the past decade emphasis has been made in the development of regimens containing fludarabine, combined with cytosine arabinoside for the treatment of refractory/relapsed acute leukemias. The aim of this study is to evaluate the efficacy and toxicity of the combination of fludarabine, high dose cytarabine, and granulocyte colony stimulating factor in refractory relapsed cases of acute leukaemia, a prospective study is being conducted at the National Center of Hematology and hematology unit/Baghdad teaching hospital from July 2008 to July 2010. Twenty Patients with refractory/relapsed acute leukemia were treated with fludarabine 30 mg/m² and cytosine arabinoside (Ara-C) 2 g/m² for 5 days, and granulocyte colony stimulating factor G-CSF 300 µg/day from day 0 till neutrophil recovery (ANC > 1.0 × 10⁹/L). Response was evaluated by bone marrow examination on day 30 post chemotherapy. Patients included were refractory acute lymphoblastic leukemia (ALL) (five patients), relapsed ALL (four patients), refractory acute myeloid leukemia (AML) (eight patients), relapsed AML (three patients). Complete remission (CR) was achieved in nine (45 %) patients, while three (15 %) patients got partial remission. Three (15 %) patients died because of post chemotherapy complications and five (25 %) patient failed to achieve remission. Major complications encountered were: anemia, fever, bleeding, mucositis and bacterial infections. FLAG protocol is well tolerated and effective regimen in relapsed/refractory acute leukemias. The toxicity is acceptable, enabling most patients to receive further treatment, including transplantation procedures.     

Sequential continuous infusion of fludarabine and cytarabine associated with liposomal daunorubicin (DaunoXome) (FLAD) in primary refractory or relapsed adult acute myeloid leukemia patients

A large proportion of adult patients with acute myeloid leukemia (AML) relapse after treatment, and some of them are resistant to primary induction chemotherapy. Sixty-one patients from seven hematological centers with poor-risk AML, primary refractory (n = 16), or relapsed (n = 45) were treated with a salvage regimen, including fludarabine (2 days) and cytarabine (3 days) in a sequential continuous infusion, associated with liposomal daunorubicin (3 days) (FLAD). Complete response rate was 44% and 56% for refractory and relapsed patients, respectively, with an overall response rate of 52% (32 of 61). Twenty-two patients (36%) were resistant to the salvage therapy. Seven patients (12%) died early during chemotherapy, four of them because of sepsis. Nineteen patients in complete remission (CR) underwent a stem-cell transplant (SCT) procedure: five autologous, nine from a HL-A identical sibling, and five from HL-A matched unrelated donors. Post-treatment aplasia and mucositis were major toxicities. Twenty patients (62.5%) relapsed after this treatment in a median of 7.3 months; ten patients relapsed after a SCT procedure. Nine patients are alive and disease free; three of them were rescued after a further cytotoxic treatment. The FLAD regimen proved to be an effective and well-tolerated treatment, with acceptable toxicity in this group of high-risk patients. A better response rate was obtained in the subgroup of relapsed patients, compared to patients treated for refractory disease. More then half (five of nine) of long-surviving patients are those who were submitted to a transplant procedure; thus, the main indication for FLAD seems to be to try to induce a rapid CR with minimum toxicity in order to perform a transplant as soon as possible.     

Secondary leukemia after first-line high-dose chemotherapy for patients with advanced germ cell cancer

Purpose We investigated the incidence of secondary leukemia in patients treated with first-line high-dose chemotherapy (HDCT) plus autologous stem cell transplantation (PBSCT) for advanced testicular cancer.Methods Three hundred and twenty-three patients who were entered into two consecutive prospective Phase-II studies of the German Testicular Cancer Study Group were analyzed. A total of 221 patients had received HD-VIP containing cisplatin, ifosfamide, and etoposide and 102 patients were treated with Tax-HD-VIP containing cisplatin, ifosfamide, etoposide, and paclitaxel, each cycle supported by autologous PBSCT.Results Patients had received a median cumulative etoposide dose of 4.9 g/m² (range, 2.2–9.4 g/m²). The median follow-up duration for all patients was 36 months (range, 0–128) with a median follow up time of 50 months (range, 0–128) for patients surviving at least 1 year after therapy. One patient developed a secondary acute myeloid leukemia (s-AML) involving a chromosomal translocation t(11;19)(q23;p13.3) 24 months after the start of chemotherapy resulting in a cumulative incidence of 0.48% [95% confidence interval (CI) 0–1.42]. Additionally, two patients with primary mediastinal germ cell cancer developed a myelodysplastic syndrome. No solid tumors had occurred.Conclusions HDCT including high-dose etoposide with autologous PBSCT as first-line therapy for advanced testicular cancer was associated with an acceptably low risk of developing secondary leukemia.     

Idarubicin in combination with intermediate-dose cytarabine in the treatment of refractory or relapsed acute leukemias

13 patients with refractory or relapsed acute lymphoblastic leukemia (ALL) and 7 patients with acute myeloid leukemia (AML) were treated with a regimen that included idarubicin 12 mg/m2 intravenously daily for 3 d plus cytarabine 2 g/m2 by infusion over 3 hours daily for 3 d. There were 10 remissions (ALL:7; AML:3) in the 15 relapsed patients and 4 (ALL:3) in the 5 patients with primary refractory disease. Severe myelosuppression was observed in all patients. Toxicity of this regimen caused nausea and vomiting, stomatitis, infections and/or liver enzymes increase. Cardiac toxicity was not observed. 2 patients died in aplasia of Gram-negative septicemia and brain hemorrhage. In conclusion, the combination of idarubicin and intermediate-dose cytarabine (IDARA-C) seems to be highly effective and sufficiently well-tolerated for the treatment of refractory and relapsed acute leukemias.     

Five-day 4′-(9-acridinylamino)methanesulphon-m-anisidide and intermediate-dose cytosine arabinoside in high-risk relapsing or refractory acute myeloid leukemia

Summary Twenty-two patients with acute myeloid leukemia (AML), having a median age of 48.3 years (range 26–70; 10 male, 12 female), were treated with 4-(9-acridinylamino)methanesulphon-m-anisidide (m-AMSA) 100 mg/m² and cytosine arabinoside (AraC) 2×1000 mg/m² i.v. on days 1–5. There were 2 M1, 8 M2, 9 M4, 2 M4 Eo, and 1 M5a. Of these, 12 achieved a complete remission, 3 a partial remission and 6 did not respond. The median remission duration was 9.0 months and the median overall survival 8.1 months. Side-effects of induction consisted mainly of haematological toxicity and infections with a median duration of WHO-grade-4 granulopenia and thrombopenia of 20 and 28 days respectively. Organ toxicity was mild with mucositis and cutaneous and liver toxicity being experienced by only a few patients. There was one treatment-related death. Five-day m-AMSA and intermediate-dose AraC is an easy-to-handle condensed treatment schedule with tolerable toxicity. Its effectiveness in relapsed and refractory AML is comparable to combinations of high-dose AraC with m-AMSA, anthracyclines or etoposide.Abbreviations AraC cytosine arabinoside - m-AMSA 4-(9-acridinylamino)methanesulphon-m-anisidide     

High-dose cytosine arabinoside and mitoxantrone in previously-treated acute leukemia patients

35 patients with refractory or relapsed acute leukemia received salvage chemotherapy using high-dose cytosine arabinoside 2 g/m2 intravenously for 3 hours every 12 h, in 8 doses, followed by continuous infusion of mitoxantrone 12 mg/m2/day for 2 d. 9 patients had acute myeloblastic leukemia (AML), (4 relapsed, 5 refractory), 20 had acute lymphoblastic leukemia (ALL) (11 relapsed, 9 refractory) and 6 had chronic myelogenous leukemia (CML) in the blastic phase (BP). 4 out of 9 AML and 16 out of 20 ALL achieved complete remission. Median survival was 6 months for all patients and 10 months for responders. A short (1.5 months) chronic phase was achieved in 3 patients with CML. The main toxic effect was hematologic. A pharmacokinetic study was performed on mitoxantrone. No correlation was found with clinical response. The combination of mitoxantrone and ara-C is an effective antileukemic regimen, especially in ALL.     

A phase I/II study of oral etoposide and idarubicin in elderly patients with high-risk acute myeloid leukemia unable to undergo intensive chemotherapy

Acute myeloid leukemia (AML) is a disease of mostly elderly patients who are often unable to undergo intensive intravenous chemotherapy. In an attempt to provide an all-oral regimen suitable for palliative treatment, we assessed the antileukemic efficacy of combination therapy of idarubicin 20 mg/m² (days 1, 3, and 5) and etoposide (EI) in increasing doses (75–125 mg/m²) on days 1–5. Eleven patients were included (median age 69 years, range: 56–77) with prognostically unfavorable characteristics (myelodysplastic syndrome, relapse, or unfavorable karyotypes). No complete remission and five partial remissions were observed whereas four patients had persistent leukemia. There were two patients who succumbed to early death. Median overall survival was 100 days (range: 8–493 days). Nonhematological toxicities were acceptable with nausea/vomiting being the predominant side effect. Hematological toxicity with grade III/IV aplasia was seen in all patients. In this study EI did not show convincing antileukemic efficacy and was unable to induce clinically useful complete remissions, with a substantial risk profile. In contrast to the situation of elderly patients with standard-risk AML in which similar oral treatment has shown promising activity, EI cannot be recommended for elderly patients with high-risk AML.     

Increasing the dose of aclarubicin in low-dose cytarabine and aclarubicin in combination with granulocyte colony-stimulating factor (CAG regimen) can safely and effectively treat relapsed or refractory acute myeloid leukemia

It is difficult for relapsed and refractory acute myeloid leukemia (AML) patients to achieve complete remission (CR). The CAG regimen [low-dose cytarabine and aclarubicin in combination with granulocyte colony-stimulating factor (G-CSF)] has been used to treat relapsed and refractory AML patients, and showed good therapeutic efficacy. It is unknown, however, whether increasing the dose of aclarubicin in CAG regimen could treat relapsed or refractory AML safely and effectively. We evaluate the efficacy and tolerability of increasing the dose of aclarubicin in CAG regimen, in 37 relapsed or refractory AML patients. All patients were treated with CAG regimen including low-dose cytarabine (10 mg/m² every 12 h, days 1–14), aclarubicin (5–7 mg/m² every day, days 1–14), and G-CSF (200 μg/m² every day, days 1–14) priming. After a single course of therapy, the overall response [CR + partial remission (PR)] rate of all patients was 78.4 % (29/37), in which the CR rate was 62.2 % (23/37). There was no early death. The median overall survival was 6 months (range 2–36 months). Myelosuppression was ubiquitous, but tolerated. No severe non-hematologic toxicity was observed. Thus, increasing the dose of aclarubicin in CAG regimen can be used safely and effectively in the treatment of relapsed or refractory AML.     

Phase I study of evofosfamide,an investigational hypoxia‐activated prodrug,in patients with advanced leukemia

Tumor hypoxia causes resistance to radiation and chemotherapy. Evofosfamide (TH‐302) has exhibited specific hypoxia‐dependent cytotoxicity against primary acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) samples in vitro. Based on these findings, a Phase I study of evofosfamide was designed for patients with relapsed/refractory leukemia (NCT01149915). In this open‐label study, patients were treated with evofosfamide as a 30–60 min/day infusion on Days 1–5 of a 21–day cycle (Arm A, n = 38) or as a continuous infusion over 120 hr over Days 1–5 of a 21‐day cycle (Arm B, n = 11). Forty‐nine patients were treated including 39 (80%) with AML and 9 (18%) with ALL. Patients had received a median of five prior therapies. In Arm A, the dose‐limiting toxicities (DLTs) were grade 3 esophagitis, observed at a dose of 550 mg/m². The maximum tolerated dose (MTD) was a daily dose of 460 mg/m². In Arm B, the DLTs were grade 3 stomatitis and hyperbilirubinemia, observed at a daily dose of 460 mg/m². The continuous infusion MTD was a daily dose of 330 mg/m². Hypoxia markers HIF‐1α and CAIX were highly expressed in leukemic bone marrow and were significantly reduced after evofosfamide therapy. The combined overall response rate in Arms A and B was 6% (2 CR/CRi and 1 PR), with all responses seen in Arm A. Evofosfamide has shown limited activity in heavily pretreated leukemia patients. Further evaluation investigating evofosfamide in combination with cytotoxic or demethylating agents is warranted. Am. J. Hematol. 91:800–805, 2016. © 2016 Wiley Periodicals, Inc.     

Salvage by timed sequential chemotherapy in primary resistant acute myeloid leukemia: analysis of prognostic factors

Primary resistant acute myeloid leukemia (AML) has a very poor prognosis. Etoposide-mitoxantrone-cytarabine (EMA) timed sequential chemotherapy including a first sequence combining mitoxantrone (12 mg/m² per day over 3 days) with cytarabine (500 mg/m² per day over the same period), and a second sequence consisting in etoposide (200 mg/m² per day for 3 days) and cytarabine as in the first sequence, has been proposed as a salvage regimen. Over a 10-year period, 66 primary resistant AML patients have been treated by EMA salvage chemotherapy. All patients displayed intermediate- or high-risk karyotypic abnormalities. Of the 66 patients, 24 [36%, 95% confidence interval (CI): 25–49%] achieved complete remission (CR). Thirty-eight patients were resistant to EMA chemotherapy and four patients died from toxicity during aplasia. After CR achievement, 18 patients received consolidation therapy. Five patients with an HLA-identical sibling donor underwent allogeneic stem cell transplantation (SCT), one patient received autologous SCT, two patients received a second course of EMA chemotherapy, and ten were scheduled for 6-monthly maintenance courses (mini-EMA). Median follow-up was 7.3 years. At the time of analysis, 21 of the 24 patients (87%) who achieved CR have relapsed. Median disease-free survival (DFS) was 5 months (95% CI: 4.3–7.7 months). Median overall survival (OS) was 5 months (95% CI: 3.8–6.7 months). There were only two long-term remitters (3%). In the univariate analysis, CR achievement was mainly related to white blood cell (WBC) count at the time of starting salvage therapy with poorer outcome for patients with more aggressive leukemia (WBC count 10×10⁹/l) (CR rates: 50% vs 10%, p<0.001). Overall survival was also influence by WBC count (median OS: 7.2 months vs 2.8 months, respectively, for WBC <and 10×10⁹/l, p<0.0001). Initial karyotype was not a significant prognostic factor either for CR achievement or for DFS or OS when comparing patients with normal karyotype and those with chromosomal abnormality. In multivariate analysis, WBC count less than 10×10⁹/l with the absence of circulating blasts at the time of starting salvage therapy appeared to be of favorable prognostic value for CR achievement (p=0.002), while WBC count less than 10×10⁹/l appeared to be of favorable prognostic value for survival (p<0.0001). Using these two objective parameters of proven significance, we devised a prognostic system of immediate clinical utility for prognostic stratification and risk-adapted therapeutic choices. Patients with both factors (WBC count <10×10⁹/l and no circulating blasts) or with at least one at the time of starting salvage therapy had a CR rate of 50% and were therefore candidates for intensified post-remission therapy. All other patients displayed a very poor outcome and must be oriented after failure of first-line therapy to alternate therapeutic programs based on investigational drugs.     

Salvage treatment for primary resistant acute myelogenous leukemia consisting of intermediate-dose cytosine arabinoside and interspaced continuous infusions of idarubicin: A phase-II study (no. 06901) of the EORTC Leukemia Cooperative Group

 Twenty-one patients with acute myeloid leukemia (AML) who failed to enter complete remission (CR) after first-line standard-dose remission-induction therapy with 7 days of cytarabine and 3 days of daunorubicin were treated with a salvage regimen containing intermediate-dose cytosine arabinoside (Ara-C) 2×500 mg/m²/day during 7 days in combination with continuous infusions of idarubicin 12 mg/m²/day on days 1, 3, and 5. Twenty patients were considered primary resistant, and one patient had a partial remission after two remission-induction courses. Overall, 11 patients (52%, 95% confidence interval: 30–74%) entered CR. Three patients died during hypoplasia and seven patients had resistant disease or a partial remission. The remission rate in this study compares favorably with the results obtained in similar patient categories. The toxicity of this salvage regimen was remarkably mild. No extramedullary toxicity was observed except for hepatic dysfunction in seven patients. The median duration of remission was 8.5 months, and ultimately, all complete remitters have relapsed except the patient who died from infectious complications after allogeneic bone marrow transplantation (BMT). This study shows that new intensive chemotherapy regimens may be effective after failure of primary treatment. Salvage regimens containing intermediate/high-dose Ara-C and/or alternative anthracyclines or anthracenes should be induced in the treatment of young patients with de novo AML. Received: 12 September 1995 / Accepted: 24 November 1995     

Mitoxantrone and etoposide: an effective regimen for refractory or relapsed acute myelogenous leukemia

23 adult patients with refractory or relapsed acute myelogenous leukemia (AML) received salvage chemotherapy with mitoxantrone and etoposide. The regimen consisted of mitoxantrone, 10 mg/m2/d by 30-min infusion, and etoposide 100 mg/m2/d by 30-min infusion, given 12 h apart for 5 consecutive d. Of 23 patients treated, 13 met the criteria for highly refractory disease (6 primary resistant; 4 with early relapse during maintenance; 3 relapsed and refractory to reinduction). 10 patients had relapsed off-therapy more than 6 months after achieving first CR. Overall, 14 patients (61%) achieved a complete remission (CR): 6/13 (46%) with refractory AML, and 8/10 (80%) with relapsed AML. 2 patients had a partial remission, 2 died in aplasia, and 5 were nonresponders. In responding patients, the median time for recovery of granulocyte count was 27 d. The most important nonhematologic side effect was oral mucositis, which was severe in 35% of cases. No signs of cardiac toxicity were observed. The median CR duration was 5 months (range, 2 to 12+ months). The combination of mitoxantrone and etoposide appears a highly effective and relatively well tolerated salvage regimen for refractory and relapsed AML. Its incorporation into first-line induction and consolidation programs for newly diagnosed AML patients should be considered.     

P-glycoprotein (P-170) expression in acute leukemias

Multidrug resistance (MDR) is still a major obstacle to chemotherapy success in acute myeloid leukemia (AML) and to a less extent acute lymphoblastic leukemia (ALL). Recent studies have shown that the expression of certain gene products mediate the development of resistance to chemotherapeutic agents. The most well characterized of these genes is the multidrug resistance gene MDR-1. This study was planned to study the expression of P-glycoprotein/170 in patients with acute leukemia and the effect of Cyclosporin A (CSA) as a modulator of P-glycoprotein functional activity. The study was carried out on 20 patients with acute leukemia (14 AML cases and 6 ALL cases). In addition, 6 normal individuals served as a reference group. Flow cytometric analysis of P-gp/170 surface expression was performed using UIC-2 MoAb together with the functional assay using Rhodamine 123 (Rh 123) and Cyclosporin A as a modulator.P-gp/170 was expressed on the leukemic cells of 37.5% of relapsed patients (40.0% of AML and 33.3% of ALL cases), whereas 27.2% of de novo patients expressed P-gp/170 (33.3% of AML cases and 0% of ALL cases). The functional activity of MDR-1 gp was 71.4% in AML and 33.3% in ALL patients compared with16.6% in normal lymphocytes. From this study, it is clear that P-gp/170 is expressed to a higher degree in leukemic cells and this is greater in relapsed compared to de novo cases and more in AML than ALL blasts. Functional activity is a more sensitive predictor of chemoresistance than P-gp/170 surface expression.     

Clofarabine,idarubicin, and cytarabine (CIA) as frontline therapy for patients ≤60 years with newly diagnosed acute myeloid leukemia

Clofarabine is a second generation nucleoside analogue with activity in adults with acute myeloid leukemia (AML). A phase I trial of clofarabine, idarubicin, and cytarabine (CIA) in relapsed and refractory AML had shown an overall response rate (ORR) of 48%. To explore this combination further, we conducted a phase II study of (CIA) in patients with newly diagnosed AML ≤60 years. Patients ≥18–60 years with AML and adequate organ function were enrolled. Induction therapy consisted of clofarabine (C) 20 mg m^?2 IV daily (days 1–5), idarubicin (I) 10 mg m^?2 IV daily (days 1–3), and cytarabine (A) 1 g m^?2 IV daily (days 1–5). Patients in remission received up to six consolidation cycles (C 15 mg m^?2 × 3, I 8 mg m^?2 × 2, and A 0.75 g m^?2 × 3). Fifty‐seven patients were evaluable. ORR was 79%. With a median follow up of 10.9 months, the median overall survival (OS) was not reached, the median event‐free survival (EFS) was 13.5 months. Most toxicities were ≤grade 2. Four week mortality was 2%. In subgroup analysis, patients ≤40 years had better OS (P = 0.04) and EFS (P = 0.04) compared to patients >40 years. Compared to historical patients treated with idarubicin and cyarabine (IA), the OS and EFS were significantly longer for CIA treated patients. In multivariate analysis, CIA retained its favorable impact on OS compared to IA. Thus, CIA is an effective and safe therapy for patients ≤60 years with newly diagnosed AML. Am. J. Heamtol. 88:961–966, 2013. © 2013 Wiley Periodicals, Inc.     

All-trans retinoic acid plus low doses of cytarabine for the treatment of “poor-risk” acute myeloid leukemias

Summary Thirteen refractory/resistant AML patients no suitable for additional aggressive chemotherapy, were treated with a combination including all -trans retinoic acid (45 mg/m² sine die) and low doses of Ara-C (20 mg/m² subcutaneously, twice in a day, days 1–10, every 28 days). Ten patients were évaluable; 8 of them achieved a complete remission, two patients with an important tumor burden, failed to achieve a response. One complete remission patient relapsed after 7 months but is still receiving the same therapy and is now in partial remission. We believe this combination effective as inducer of complete remission in those AML patients which cannot tolerate additional heavy treatments. The role of tumor burden in affecting response to therapy remains to be still evaluated.     

Idarubicin monotherapy in multiply pretreated leukemia patients: response in relation to P-glycoprotein expression

 The aim of the study was to test whether fractionated (weekly) idarubicin administration to multiply pretreated leukemia patients is effective and tolerable for outpatient treatment, and whether idarubicin alone can overcome P-glycoprotein (P-gp)-related resistance. P-gp was assessed with an immunocytological technique using the monoclonal antibody 4E3.16. P-gp expression was characterized as a percentage of P-gp-positive blasts. Additionally, the function of P-gp was determined with the rhodamine-123 (R-123) accumulation test in combination with or without verapamil and expressed as the R123 accumulation ratio. Fractionated idarubicin (12 mg/m²/week) was given to 36 acute myelogenous leukemia (AML) patients, 12 acute lymphoblastic leukemia (ALL) patients, and eight chronic myelogenous leukemia (CML) patients in blast crisis. Furthermore, 11 AML and four ALL patients were treated with fractionated daunorubicin at a dose of 50 mg/m²/week. All patients had been pretreated with drugs inducing P-gp-related resistance including daunorubicin and/or doxorubicin or vindesine (CML patients). Of 71 pretreated patients, 51 (72%) had a P-gp value between 25 and 98%. Six of these patients with increased P-gp expression had a nonpumping P-gp; four of them were CD34 positive. Of 51 patients with increased P-gp expression, 30 (59%) were CD34 positive. With regard to idarubicin monotherapy, overall response was 33/56 (59%) patients, and 23/33 (70%) responding patients showed a P-gp expression between 25 and 95%. All idarubicin-responding patients with high P-gp expression before treatment showed a clear reduction of P-gp-positive blasts. No patients with P-gp expression between 34 and 85% treated with fractionated daunorubicin showed response or reduction of P-gp-positive blasts in bone marrow. This study demonstrates that P-gp-related resistance can be overcome in multiply pretreated leukemia patients with idarubicin alone, and that the protocol used here is tolerable for outpatient treatment. Received: 1 October 1996 / Accepted: 27 November 1996     

Prospective Trial of High-Dose Chemotherapy Followed by Infusions of Peripheral Blood Stem Cells and Dose-Escalated Donor Lymphocytes for Relapsed Leukemia after Allogeneic Stem Cell Transplantation

To determine whether induction of graft-versus-host disease (GVHD) improves the outcome of acute relapsed leukemia after stem cell transplantation (SCT), we used high-dose cytarabine (ara-C) followed by infusions of donor-derived buffy coats containing peripheral blood stem cells to treat 12 patients with relapsed leukemia. Donor lymphocyte infusion (DLI) was repeated at least twice over a 5-week interval for patients in whom grade II to IV acute GVHD did not develop after the first DLI. Grade II to IV acute GVHD developed in 4 (33%) of the patients. Chronic GVHD developed in 3 patients, 2 of whom had not experienced acute GVHD. Four (67%) of the 6 patients who developed grade II to IV acute and/or chronic GVHD after DLI responded, but none of the other 6 patients responded. Four (33%) of the patients (2 with acute myelogenous leukemia [AML] and 2 with acute lymphoblastic leukemia [ALL]) achieved complete remission lasting longer than 4 months after the first DLI, but 3 of them had relapses in bone sites. Of these 4 patients, 1 patient with AML and 2 with ALL were alive 8 to 27 months after DLI. These findings indicate that high-dose ara-C combined with megadose DLI may produce durable remission of acute leukemia that has relapsed after SCT when GVHD is induced. The low induction rate of GVHD and extramedullary relapse after remission is achieved with DLI are problems yet to be solved.     

Expression of multidrug resistance (MDR) proteins and in vitro drug resistance in acute leukemias

The expression of the multidrug resistance (MDR) proteins may influence the outcome of treatment in patients with acute leukemia. The aim of this study was to determine the IC50 of cytotoxic drugs (cytosine arabinoside, ara-C and daunorubicin, dnr) using the in vitro 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)2H-tetrazolium, inner salt (MTS) assay method. A total of 82 newly diagnosed acute leukemia cases (43 adult myeloid leukaemia, AML cases and 39 acute lymphoblastic leukaemia, ALL cases) and 16 relapsed cases (8 AML cases and 8 ALL cases) were studied. The MTS assay was performed using two cytotoxic drugs, dnr and ara-C. Cells were incubated with different concentrations of drugs for 4 days and the IC50 was extrapolated from the viability curve. In newly diagnosed cases, we found that childhood ALL samples showed higher IC50 values of dnr (0.040 +/- 2.320) compared to adult AML samples (0.021 +/- 0.158). In contrast, newly diagnosed adult AML samples showed higher IC50 values of ara-C (0.157 +/- 0.529) compared to childhood ALL samples (0.100 +/- 2.350). In relapsed cases, two samples of childhood ALL showed IC50 values of dnr (0.910 +/- 1.760) and ara-C (1.310 +/- 2.390), which was higher compared to childhood AML samples (0.129 +/- 0.214 and 0.210 +/- 0.003, respectively). However, there was no correlation between IC50 values of these drugs tested with clinical outcome. In conclusion, we found that MTS assay is an easy, rapid and non laborious method to study in vitro drug resistance in acute leukaemia cases.     

A phase 1b/2 study of vosaroxin in combination with cytarabine in patients with relapsed or refractory acute myeloid leukemia

Vosaroxin is a first-in-class anticancer quinolone derivative that intercalates DNA and inhibits topoisomerase II. This study assessed the safety and tolerability of vosaroxin plus cytarabine in patients with relapsed/refractory acute myeloid leukemia. Escalating vosaroxin doses (10-minute infusion; 10–90 mg/m²; days 1, 4) were given in combination with cytarabine on one of two schedules: schedule A (24-hour continuous intravenous infusion, 400 mg/m²/day, days 1–5) or schedule B (2-hour intravenous infusion, 1 g/m²/day, days 1–5). Following dose escalation, enrollment was expanded at the maximum tolerated dose. Of 110 patients enrolled, 108 received treatment. The maximum tolerated dose of vosaroxin was 80 mg/m² for schedule A (dose-limiting toxicities: grade 3 bowel obstruction and stomatitis) and was not reached for schedule B (recommended phase 2 dose: 90 mg/m²). In the efficacy population (all patients in first relapse or with primary refractory disease treated with vosaroxin 80–90 mg/m²; n=69), the complete remission rate was 25% and the complete remission/complete remission with incomplete blood count recovery rate was 28%. The 30-day all-cause mortality rate was 2.5% among all patients treated at a dose of 80–90 mg/m². Based upon these results, a phase 3 trial of vosaroxin plus cytarabine was initiated in patients with relapsed/refractory acute myeloid leukemia.