Prevalence and dynamics of bcr-abl kinase domain mutations during imatinib treatment differ in patients with newly diagnosed and recurrent bcr-abl positive acute lymphoblastic leukemia

Imatinib is highly effective in newly diagnosed, but not in relapsed, Philadelphia chromosome positive acute lymphoblastic leukemia (Ph+ ALL). BCR-ABL tyrosine kinase domain (TKD) mutations are associated with acquired imatinib resistance, but their role in primary resistance is uncertain. Using highly sensitive ligation-PCR and denaturing high-performance liquid chromatography (DHPLC), we identified baseline TKD mutations in 21% and 42% of imatinib-naïve patients with newly diagnosed (n=26) or recurrent (n=65) Ph+ ALL, respectively (P=ns). Within 4 weeks of starting the imatinib treatment, absolute levels of mutant bcr-abl transcripts increased significantly in patients with advanced, but not with de novo, Ph+ ALL. The net expansion of pre-existing mutant clones during imatinib treatment resulted in the rapid appearance of initially undetectable TKD mutations, which after 4 weeks were detectable in 70% of patients with advanced disease. There was a high degree of concordance between the type of mutations detected at relapse and during initial imatinib treatment. The profoundly different outgrowth dynamics of leukemic clones with bcr-abl mutations in imatinib-treated patients who differ in their disease history, provides clinical-translational evidence for a contributory role of non-mutational resistance mechanisms, possibly induced by prior chemotherapy. Moreover, the prevalence of pre-existing, clinically relevant TKD may have been underestimated in tyrosine kinase inhibitor-naïve patients with Ph+ ALL.

First case of successful allogeneic stem cell transplantation in an HIV-patient who acquired severe Aplastic Anemia

We report on the first successful allogeneic stem cell transplantation (SCT) in an HIV-infected patient with severe aplastic anemia (SAA) per- formed at a tertiary care institution. Highly active antiretroviral therapy (HAART) was administered until transplantation and restarted 34 days later with sustained virological response. The patient did however develop a rapid rise in HIV load during the interruption of HAART associated with an acute febrile illness. Due to the extended period between the onset of SAA until SCT, the posttransplant course was complicated by bacterial infections. Stage two skin GvHD, but no AIDS-defining opportunistic diseases were experienced. Neutrophils recovered to >0.5/nL on day +18 and the CD4 count reached 250/microL on day +71 and >500/microL on day +182. The patient is in good condition with an ECOG score of 0 twelve months after transplantation. This report demonstrates the feasibility of allogeneic stem cell transplantation in the HIV setting.

Efficacy and safety of imatinib mesylate (Glivec™) in combination with interferon-α (IFN-α) in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL)

Imatinib has marked antileukemic activity in advanced Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL), but secondary resistance develops rapidly, reflecting the limitations of single-agent therapy. Experimental data suggest that interferon-alpha (IFN-alpha) enhances the antileukemic activity of imatinib. We therefore examined combined imatinib and low-dose IFN-alpha in six patients with Ph+ALL who were ineligible for stem cell transplantation. All patients had received imatinib for 0.5-4.8 months prior to IFN-alpha, for relapsed (n=3) or refractory (n=1) Ph+ALL or as an alternative to chemotherapy following severe treatment-related toxicity (n=2). Five patients were in hematologic remission (CR) with minimal residual disease (MRD+), one patient was refractory to imatinib. Four of the five MRD+ patients are alive in CR after a median treatment duration of 20 (11-21) months. Two of these patients are in continuous CR 21 months after imatinib was initiated, while the other two patients experienced an isolated meningeal relapse that was successfully treated with additional intrathecal chemotherapy. Sustained molecular remissions were achieved in three patients and are ongoing 13 and 10.5 months after central nervous system (CNS) relapse and 6 months after starting concurrent IFN-alpha and imatinib, respectively. Marrow relapse occurred in one of the five MRD+ patients. Combination treatment was associated with a complete marrow response of 5 months duration in the imatinib-refractory patient. Imatinib combined with low-dose IFN-alpha may achieve prolonged hematologic and molecular remissions in a subset of patients with advanced Ph+ALL, who are not candidates for allogeneic SCT. CNS prophylaxis is necessary and may enhance the antileukemic activity of imatinib and IFN-alpha.

Serial minimal residual disease (MRD) analysis as a predictor of response duration in Philadelphia-positive acute lymphoblastic leukemia (Ph+ALL) during imatinib treatment

Patients with refractory or relapsed Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) rarely have prolonged responses to salvage therapy, including imatinib, resulting in a short opportunity for potentially curative stem cell transplantation. To identify minimal residual disease (MRD) parameters predictive of imminent relapse, we quantitated Bcr-Abl expression by real-time PCR in peripheral blood (PB) and bone marrow (BM) of 24 Ph+ALL patients after achieving a complete response and MRD minimum. The ratio of Bcr-Abl and glyceraldehyde-3-phosphate dehydrogenase copies, magnitude of increase and velocity of increase were evaluated regarding subsequent time intervals to relapse, death or censoring. High Bcr-Abl levels >/=5 x 10(-4) in PB (n=23) and >/=10(-4) in BM (n=18) were significantly associated with short time periods to relapse. Bcr-Abl increases >2 logarithmic units (log) in PB, but not in BM preceded short-term relapse. The velocity of Bcr-Abl increases predicted response duration in PB (cutoff: 1.25 log/30 days) and BM (0.6). Bcr-Abl level and velocity of increase in BM as well as magnitude of increase in PB correlated with remaining periods of survival and predicted relapse within 2 months in nine of 10, 10 of 11 and four of four patients, respectively. Thus, these MRD parameters may guide timing and intensity of therapeutic modifications.

Response to imatinib in patients who relapse after allogeneic stem cell transplantation for chronic myeloid leukemia

We studied 128 patients with chronic myeloid leukemia (CML) relapsing after allogeneic stem cell transplantation (SCT). Disease at the time of treatment with Imatinib was in chronic phase (CP) in 51 patients, accelerated phase (AP) in 31 and blastic crisis (BC) in 46. Of the 51 patients in CP, 14 were in cytogenetic and two in molecular relapses. The median interval between relapse and Imatinib therapy was 5 months (0-65). A total of 50 patients had failed treatment with donor lymphocyte infusions prior to Imatinib. The overall hemato-logical response rate was 84% (98% for patients relapsing in CP). The complete cytogenetic response (CCR) was 58% for patients in CP, 48% for AP and 22% for patients in BC. Complete molecular responses were obtained in 25 patients (26%), of whom 21 were in CP or AP. With a median follow-up of 9 months, the estimated 2-year survival for CP, AP and BC patients was 100, 86 and 12%, respectively. Out of 79 evaluable patients, 45 (57%) achieved full donor and 11 (14%) mixed chimerism after Imatinib. We conclude that Imatinib has significant activity against CML in relapse after allogeneic SCT. Durable cytogenetic and molecular remissions are obtainable in patients in CP.

Stable molecular remission induced by imatinib mesylate (STI571) in a patient with CML lymphoid blast crisis relapsing after allogeneic stem cell transplantation

We report the response to the ABL kinase inhibitor imatinib mesylate (STI571) in a patient with chronic myeloid leukemia (CML) who relapsed twice after dose-reduced allogeneic stem cell transplantation (alloSCT) for B lymphoid blast crisis (BC) and failed to develop an antileukemic response despite grade 3 graft-versus-host disease (GvHD). Complete hematologic, cytogenetic and molecular responses were achieved within 9 weeks of therapy and are maintained after 27 months. Extensive chronic skin GvHD necessitating immunosuppressive therapy developed after 14 months. This case illustrates the ability of imatinib to induce sustained hematologic and molecular remissions in some patients relapsing with advanced stage CML after alloSCT.

Therapy with imatinib mesylate (Glivec) preceding allogeneic stem cell transplantation (SCT) in relapsed or refractory Philadelphia-positive acute lymphoblastic leukemia (Ph+ALL)

Imatinib has pronounced antileukemic activity in Ph+ALL, although responses are usually short. To determine whether imatinib may facilitate allogeneic SCT in relapsed or refractory Ph+ALL, we evaluated 46 consecutive, not previously transplanted patients who were enrolled in phase II studies of imatinib. Of 30 patients eligible for SCT, 22 (73%) were actually transplanted. Ten patients were in complete hematologic remission (CHR) (n = 5) or had a complete marrow response (CMR) (n = 5) at the time of SCT, 12 patients had again relapsed or were refractory. After SCT, 18 patients were in complete remission, one patient was refractory, three patients died prior to response assessment. Seven patients (32%) are in ongoing complete remission with a median follow-up of 9.4 (range 1.7-23.8) months. Seven patients (32%) relapsed a median of 5.2 months after SCT. Transplant-related mortality (TRM) was 36%. Probability of disease-free survival (DFS) is 25.5 +/- 9.8% overall and 51.4 +/- 17.7% when SCT was performed in CHR or CMR, compared with 8.3 +/- 8% for SCT during overt leukemia (P = 0.06). In conclusion, imatinib is a well-tolerated salvage therapy prior to allogeneic SCT in patients with Ph+ALL, but requires that SCT be performed within a few weeks of starting treatment to avoid resistance. Disease status at time of transplantation is an important determinant of DFS and TRM.

Hematologic and cytogenetic remission by STI571 (Glivec) in a patient relapsing with accelerated phase CML after second allogeneic stem cell transplantation

We describe the clinical activity of the ABL kinase inhibitor STI571 in a patient with accelerated phase of chronic myeloid leukemia (CML) relapsing after a second allogeneic BMT and with minimal levels of donor chimerism. STI571 resulted in rapid elimination of leukemic cells with ensuing prolonged severe leukopenia and neutropenia complicated by neutropenic fever and colitis. Subsequent hematopoietic recovery was driven by donor derived cells and was associated with grade 3 graft-versus-host disease (GVHD). STI571 induced sustained hematological and cytogenetic remission combined with controllable GvHD, therapeutic goals not achieved by two preceding allogeneic transplants and repeated donor lymphocyte transfusions (DLT).

Older patients with high-risk fungal infections can be successfully allografted using non-myeloablative conditioning in combination with intensified supportive care regimens

Leukaemic patients with advanced disease and severe fungal infections as well as older patients with substantial co-morbidity are usually excluded from conventional allotransplantation because of increased morbidity and mortality. We approached allogeneic transplantation in four patients with a median age of 62 years (one chronic myeloid leukaemia in blast crisis, one high-risk acute myeloid leukaemia (AML) in first complete remission (CR1), one AML in 2nd relapse, one AML in CR2 with pre-existing fungal lung infections (two aspergillus, two mucor) and additional co-morbidity (diabetes n = 2, aortic aneurysm n = 1, arterial sclerosis n = 2) by combining non-myeloablative conditioning with an intensified supportive care regimen, including amphotericin B and 4-12 (median 9) prophylactic granulocyte transfusions from granulocyte colony-stimulating factor (G-CSF)-stimulated volunteer donors. G-CSF was also given to patients until neutrophil recovery. All four patients recovered to a neutrophil count of 0.5 x 109/l after a median of 11.5 d (range 11-13 d). Prophylactic granulocyte transfusions also reduced the need for platelet transfusions and minimized mucositis. All patients were discharged at a median of 25 d (range 18-59 d) and are alive and well after a median follow-up of > 390 d (range 336-417 d) without evidence of leukaemia. Regression of the fungal lesions was documented in three patients, with a slight progression detected by computerized tomography scan of the chest in one patient. We conclude that pulmonary fungal infections are not a contraindication for allogeneic stem cell transplantation, if non-myeloablative conditioning regimens are used in combination with granulocyte transfusions, intravenous amphotericin B and G-CSF.

Recombinant human granulocyte and granulocyte-macrophage colony-stimulating factor (G-CSF and GM-CSF) administered following cytotoxic chemotherapy have a similar ability to mobilize peripheral blood stem cells

The availability of hematopoietic growth factors has greatly facilitated the mobilization and collection of peripheral blood stem cells (PBSC). It was the aim of this double-blind study to compare the PBSC-mobilizing efficacy of recombinant human G-CSF and GM-CSF when administered post-chemotherapy. Twenty-six patients with relapsed Hodgkin's disease were included in the study. Their median age was 31 years (range, 22-59) and 14 patients were males and 12 were females. Patients were pretreated with a median of eight cycles of cytotoxic chemotherapy, while 18 patients had undergone extended field irradiation. The patients received dexamethasone 24 mg days 1-7, melphalan 30 mg/m2 day 3, BCNU 60 mg/m2 day 3, etoposide 75 mg/m2 days 4-7, Ara-C 100 mg/m2 twice daily days 4-7 (Dexa-BEAM). Twelve patients were randomized to receive 5/microg/kg/day G-CSF and 14 patients to receive 5 microg/kg/day GM-CSF, both administered subcutaneously starting on day 1 after the end of Dexa-BEAM. Primary endpoints of the study were the number of CD34+ cells harvested per kg body weight on the occasion of six consecutive leukaphereses and the time needed for hematological reconstitution following autografting. Twenty-one patients completed PBSC collection, and six patients of the G-CSF group and nine of the GM-CSF group were autografted. No difference was observed with respect to the median yield of CFU-GM and CD34+ cells: 32.5 x 10(4)/kg vs 31.3 x 10(4)/kg CFU-GM, and 7.6 x 10(6)/kg vs 5.6 x 10(6)/kg CD34+ cells, for G-CSF and GM-CSF, respectively (U test, P= 0.837 and 0.696). High-dose chemotherapy consisted of cyclophosphamide 1.7 g/m2 days 1-4, BCNU 150 mg/m2 days 1-4, etoposide 400 mg/m2 days 1-4. All patients transplanted with more than 5 x 10(6) CD34+ cells/kg had a rapid platelet recovery (20 x 10(9)/l) between 6 and 11 days and neutrophil recovery (0.5 x 10(9)/1) between 9 and 16 days, while patients transplanted with less than 5 x 10(6)/kg had a delayed reconstitution, regardless of the kind of growth factor used for PBSC mobilization. In conclusion, our data indicate that in patients with Hodgkin's disease G-CSF and GM-CSF given after salvage chemotherapy appear to be not different in their ability to mobilize PBSC resulting in a similar time needed for hematological reconstitution when autografted following high-dose therapy.

Comparison of toxicity and outcome in patients with acute myeloid leukemia treated with high-dose cytosine arabinoside consolidation after induction with a regimen containing idarubicin or daunorubicin

The toxicity and outcome after high-dose ara-C/daunorubicin (HDara-C/DNR) consolidation therapy in de novo AML was compared in 11 patients who received an idarubicin-containing induction therapy (IDA; from June 1995 to March 1997) and 16 patients pretreated with daunorubicin (DNR; from July 1990 to May 1995) for induction. The DNR group consisted of two cohorts, one (n = 6) of patients who had received, as had the IDA group, two induction and one intermediate-dose ara-C consolidation courses, and another (n = 10) of patients who had been pretreated with one induction and one consolidation course prior to HDara-C/DNR. There was no difference in the relative dose between the three cohorts. Following HDara-C/DNR, the IDA-pretreated patients experienced a more prolonged myelosuppression during consolidation therapy compared with the DNR group. Duration of neutropenia (< 500 neutrophils/microl) following HDara-C/DNR was 31.2 +/- 16 days (mean +/- SEM) in the IDA group compared with 18.7 +/- 5 days in the DNR group (p < .001 Mann-Whitney U-test). The duration 'of thrombocytopenia (platelets < 25000/microl) was 34.8 +/- 20 days in the IDA group vs. 18.5 +/- 6 days in the DNR group (p < .005). The more prolonged myelosupression was associated with a longer duration of fever (18.9 +/- 24 vs. 6.9 +/- 5.2 days). A greater incidence, length (11 +/- 8 vs. 1.2 +/- 2 days), and severity of diarrhea were observed in the IDA-pretreated group. Three of 11 IDA patients experienced WHO grade III-IV diarrhea. In the IDA group two patients developed severe enterocolitis with Candida septicemia, and one of these patients died. One patient in the IDA group died during prolonged aplasia. In the DNR group 6/16 patients experienced grade I-II diarrhea. Two patients in each group died during consolidation therapy. The CR rate was 87% in the IDA group and 79% in the DNR group. Relapse-free survival after HDara-C is 50% at a median follow-up of 60 months in the DNR group and 45% after a median follow-up of 17 months in the IDA group. Whether the advantage of the superior response rate in the IDA-treated patients may be lost during HDara-C consolidation treatment due to increased toxicity remains to be proven in larger trials.

Cytomegalovirus monitoring by polymerase chain reaction of whole blood samples from patients undergoing autologous bone marrow or peripheral blood progenitor cell transplantation

Sensitive screening for cytomegalovirus (CMV) by polymerase chain reaction (PCR) following autologous bone marrow or peripheral blood progenitor cell transplantation has not been evaluated. In a three-center study, 98 autograft transplant recipients were prospectively screened for CMV infection by PCR and culture techniques. At a median of 20 days (range, 3-28) after transplantation, 21 (39.6%) of 53 CMV-seronegative patients were PCR positive for CMV, and at a median of 17 days (range, 7-84) after transplantation, 19 (42.2%) of 45 CMV-seropositive patients were PCR positive for CMV. Low-level DNAemia (1-10 fg CMV DNA/mL blood) occurred for 1 week in 31 patients but was never associated with CMV disease. Of 9 patients who presented with at least two consecutive positive PCR results, 1 developed CMV pneumonia. No patients died because of CMV disease. Screening for CMV infection by PCR had a negative predictive value of 100% (as also observed after allogeneic transplantation), but its positive predictive value was significantly lower.

Residual leukemia and immunomagnetic bead purging in patients with BCR-ABL-positive acute lymphoblastic leukemia

Residual leukemia was evaluated in autologous bone marrow grafts harvested in first (n = 11) or second (n = 3) complete remission from 14 patients with BCR-ABL-positive acute lymphoblastic leukemia after treatment according to the German multicenter ALL protocols. The intervals from diagnosis to BM harvest were median 159 (range 78-463) and from preceding chemotherapy to BM harvest median 39 (range 26-69) days, respectively. A limiting log(10)-dilution RT-PCR was used to semiquantify BCR-ABL-positive cells. All autografts appeared to be significantly contaminated with residual leukemic cells. The BCR-ABL-specific titers ranged from 1:10(3) to 1:10(6) (median 1:10(4)) above the limit of detection. This was the rationale to purge the grafts using two cycles of IgM anti-CD10, CD19, and AB4 MoAbs-coated immunomagnetic beads (IMB). Purging depleted median 3 (range 2-4) logs of residual leukemia, resulting in a median 1:10(1) (range 1:10(0) to 1:10(3)) postpurge BCR-ABL-specific titer. The second purging cycle accounted for 1 log of depletion. The mean +/- s.e.m. post-purge recoveries of MNC and CFU-GM were 59 +/- 4%, and 61 +/- 9%, respectively. We conclude that all BCR-ABL-positive ALL patients achieving CR by cytological criteria have critically high levels of residual leukemia in their bone marrow, which can be reduced by median 3 log using immunomagnetic bead purging.

Purging of peripheral blood stem cells yields BCR-ABL-negative autografts in patients with BCR-ABL-positive acute lymphoblastic leukemia

Remission marrow from patients with BCR-ABL+ acute lymphoblastic leukemia (ALL) achieving clinical remission (CR) after induction or consolidation chemotherapy according to the German multicenter adult ALL (GMALL) protocol showed high titers of residual BCR-ABL+ cells. Therefore, we initiated a pilot study to monitor circulating BCR-ABL+ cells and to collect, purge, and autograft peripheral blood stem cells (PBSC) in these patients. After GMALL 05/93 high-risk phase II of induction chemotherapy (high-dose AraC 3 g/m2 x 8 does and mitoxantrone 10 mg/m2 x 3 doses), patients received 5-10 micrograms/kg subcutaneous recombinant human granulocyte colony-stimulating factor (rhG-CSF) daily. Mobilized CD34+ cells peaked between 20 and 26 days after starting chemotherapy at 4.8-75.6 (median 10.8) x 10(4)/mL peripheral blood (PB) (n = 5). Patients treated with additional chemotherapy cycles failed to mobilize adequate numbers of CD34+ cells. PB stem cells (PBSC) were purged using a cocktail of CD10, CD19, and AB4 monoclonal antibodies (mAbs) coupled to immunomagnetic beads (IMB). The median recoveries of total nucleated cells (TNC) and CD34+ cells after mAb/IMB purging were 84 and 81%. The peak numbers of CD34+ cells collected in a single leukapheresis were median 8.6 x 10(6)/kg pre- and 5.2 x 10(6)/kg postpurge (n = 4). The absolute prepurge CD19+ cells were as low as median 2.7 (range 1.4-19) x 10(6) per leukapheresis. Residual BCR-ABL+ cells in unpurged leukapheresis products were assessed by limiting-log10-dilution nested reverse-transcriptase polymerase chain reaction (RT-PCR) as one in 10(5) to one in 10(6) normal cells and were consistently undetectable in all purged PBSC autografts. We conclude that sufficient numbers of CD34+ cells for PBSCT can be collected after phase II but not at later stages of the GMALL 05/93 high risk protocol; PBSC grafts are 3 log less contaminated with residual BCR-ABL+ cells compared to an historical series of 13 autologous BM grafts; and purging of PBSC with mAb/IMB is feasible with minor loss of CD34+ cells and abolished BCR-ABL signals in the grafts.

Microangiopathic hemolytic anemia and renal impairment following autologous bone marrow transplantation: a case of hemolytic uremic syndrome?

Thrombotic microangiopathy, which encompasses both thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS), is a severe and life-threatening complication following bone marrow transplantation (BMT). It has been reported after allogeneic BMT but may also occur after autologous BMT. Here we describe a case of microangiopathic hemolytic anemia and progressive renal failure subsequent to autologous BMT.