In vivo selection of a complex mutant TEM (CMT) from an inhibitor-resistant TEM (IRT) during ceftazidime therapy.

OBJECTIVES: A relapse from Escherichia coli bloodstream infection was observed in a patient with acute leukaemia treated with ceftazidime for 7 days for febrile neutropenia. Whereas the original E. coli isolate was resistant to ß-lactam/ß-lactamase inhibitor combinations (EC1), the relapse E. coli isolate showed a similar phenotype but with resistance extended to ceftazidime (EC2). We investigated the molecular mechanisms of ß-lactam resistance and sought if EC2 could have been selected in vivo from EC1. METHODS: EC1 and EC2 isolates were compared for antibiotic MICs, plasmid content, genotyping, ß-lactamase genes and their environment. Both isolates were conjugated with E. coli JW4111ΔampC and MICs determined for transconjugants. In addition, ceftazidime-resistant mutants were selected in vitro from EC1. RESULTS: EC1 and EC2 showed identical patterns for genotyping and resistance plasmids. PCR sequencing of blaTEM in EC1 showed the mutations M69L and N276D corresponding to TEM-35, also called inhibitor-resistant TEM (IRT)-4. In EC2, the TEM allele showed an additional mutation, R164S, known to confer resistance to ceftazidime. The combination of these three mutations was previously reported in TEM-158, described as the complex mutant TEM (CMT)-9, associated with resistance to ß-lactamase inhibitors and third-generation cephalosporins. In vitro selection of ceftazidime-resistant mutants from EC1 yielded six different CMT alleles, including TEM-158 containing the R164S mutation. CONCLUSIONS: This first known report of in vivo selection of CMT from IRT, reproduced in vitro, shows how the evolution of ß-lactamase enzymes is easily driven by antibiotic pressure, even during a short antibiotic therapy.

Allogeneic stem cell transplantation improves the outcome of adults with t(1;19)/E2A-PBX1 and t(4;11)/MLL-AF4 positive B-cell acute lymphoblastic leukemia: results of the prospective multicenter LALA-94 study.

Adult patients with acute lymphoblastic leukemia (ALL) and t(1;19)/E2A-PBX1 or t(4;11)/MLL-AF4 have a poor outcome. We have evaluated the impact of an intensified post-remission therapy using a high-dose chemotherapy course followed by allogeneic or autologous SCT on the outcome of 58 patients with t(1;19)/E2A-PBX1 (E2A group, n=24) or t(4;11)/MLL-AF4 (MLL group, n=34) treated in the LALA-94 multicenter prospective study. Patients in the MLL group had higher WBC counts and more frequent DIC. CR rates achieved by MLL and E2A groups were similar to other B-cell ALL (87, 82 and 86% respectively). While in CR, patients with a donor were assigned to alloSCT (n=22), the remaining patients with were randomized between autoSCT (n=15) or chemotherapy (n=8). Five-year overall survival was 31 and 45% for E2A and MLL groups, respectively. In both groups, DFS was higher in the alloSCT arm as compared to autoSCT and chemotherapy arms. The results of this study show that chemotherapy intensification did not overcome the poor prognosis of adults with t(1;19)/E2A-PBX1. Allogeneic SCT should thus be offered in first CR to patients with t(1;19)/E2A-PBX1 or t(4;11)/MLL-AF4. New therapeutic approaches are needed for patients without donor.

Incidence, clinical features, and outcome of all trans-retinoic acid syndrome in 413 cases of newly diagnosed acute promyelocytic leukemia. The European APL Group.

All trans-retinoic acid (ATRA) syndrome is a life-threatening complication of uncertain pathogenesis that can occur during the treatment of acute promyelocytic leukemia (APL) by ATRA. Since its initial description, however, no large series of ATRA syndrome has been reported in detail. We analyzed cases of ATRA syndrome observed in an ongoing European trial of treatment of newly diagnosed APL. In this trial, patients 65 years of age or less with an initial white blood cell count (WBC) less than 5,000/microL were initially randomized between ATRA followed by chemotherapy (CT) (ATRA-->CT group) or ATRA with CT started on day 3; patients with WBC greater than 5,000/microL received ATRA and CT from day 1; patients aged 66 to 75 received ATRA-->CT. In patients with initial WBC less than 5, 000/microL and allocated to ATRA-->CT, CT was rapidly added if WBC was greater than 6,000, 10,000, 15,000/microL by days 5, 10, and 15 of ATRA treatment. A total of 64 (15%) of the 413 patients included in this trial experienced ATRA syndrome during induction treatment. Clinical signs developed after a median of 7 days (range, 0 to 35 days). In two of them, they were in fact present before the onset of ATRA. In 11 patients, they occurred upon recovery from the phase of aplasia due to the addition of CT. Respiratory distress (89% of the patients), fever (81%), pulmonary infiltrates (81%), weight gain (50%), pleural effusion (47%), renal failure (39%), pericardial effusion (19%), cardiac failure (17%), and hypotension (12%) were the main clinical signs, and 63 of the 64 patients had at least three of them. Thirteen patients required mechanical ventilation and two dialysis. A total of 60 patients received CT in addition to ATRA as per protocol or based on increasing WBC; 58 also received high dose dexamethasone (DXM); ATRA was stopped when clinical signs developed in 30 patients. A total of 55 patients (86%) who experienced ATRA syndrome achieved complete remission (CR), as compared with 94% of patients who had no ATRA syndrome (P = .07) and nine (14%) died of ATRA syndrome (5 cases), sepsis (2 cases), leukemic resistance (1 patient), and central nervous system (CNS) bleeding (1 patient). None of the patients who achieved CR and received ATRA for maintenance had ATRA syndrome recurrence. No significant predictive factors of ATRA syndrome, including pretreatment WBC, could be found. Kaplan Meier estimates of relapse, event-free survival (EFS), and survival at 2 years were 32% +/- 10%, 63% +/- 8%, and 68% +/- 7% in patients who had ATRA syndrome as compared with 15% +/- 3%, 77% +/- 2%, and 80% +/- 2% in patients who had no ATRA syndrome (P = .05, P = .003, and P = .03), respectively. In a stepwise Cox model that also included pretreatment prognostic variables, ATRA syndrome remained predictive for EFS and survival. In conclusion, in this multicenter trial where CT was rapidly added to ATRA in case of high or increasing WBC counts and DXM generally also used at the earliest clinical sign, the incidence of ATRA syndrome was 15%, but ATRA syndrome was responsible for death in only 1.2% of the total number of patients treated. However, occurrence of ATRA syndrome was associated with lower EFS and survival.

Combined therapy with all-trans-retinoic acid and high-dose chemotherapy in patients with hyperleukocytic acute promyelocytic leukemia and severe visceral hemorrhage.

Acute promyelocytic leukemia (APL) is associated with a high incidence of disseminated intravascular coagulation (DIC) and early hemorrhagic death. The risk of early fatal hemorrhage is increased when high peripheral-blood blast count and severe DIC accompanied by visceral hemorrhage are present at diagnosis. Progressive cytolysis induced by daily increased doses of chemotherapy, or differentiation all-trans-retinoic acid (ATRA) therapy have been proposed for initial control of DIC, but both are dangerous in hyperleukocytic APL patients. We report our results obtained in three high-risk APL patients treated with a combination of conventional chemotherapy and ATRA. All patients had documented hyperleukocytic APL [M3 or M3-variant subtype, (15, 17) translocation] with DIC, and all had critical clinical course before treatment. Patient 1 presented with cerebral hemorrhage, patients 2 and 3 had acute respiratory failure probably due to pulmonary leukemic infiltration and pulmonary hemorrhage. In order to minimize the severity of DIC during chemotherapy-induced acute cytolysis, ATRA (45 mg/m2 per day) was started on the first or second day of chemotherapy and withdrawn when complete remission (CR) was achieved. Despite adverse clinical features, CR was obtained in these three high-risk patients. Patient 1 showed no increase of cerebral bleeding during therapy. Patients 2 and 3 required transient intensive care, with mechanical ventilation from day 4 to day 11 for one of them. Differentiating granular cells were present in peripheral blood of all patients from the day 5, 12 and 8 of cytotoxic therapy. For the three patients, the number of days with white blood cell count < 1 x 10(9)/l was only 2, 7 and 11 days respectively. These results suggest that differentiation therapy with ATRA may be useful even in hyperleukocytic APL patients, when ATRA is used in combination with chemotherapy. The mechanisms of this putative beneficial effect are discussed.

Autologous peripheral blood stem cell transplantation after high dose therapy in patients with advanced lymphomas.

Thirty-eight patients with refractory or relapsed non-Hodgkin's lymphoma (19 patients) or Hodgkin's disease (19 patients) were treated with salvage therapy. The peripheral stem cell collection was performed during hematologic recovery after myeloablative chemotherapy. In eight patients with Hodgkin's disease the number of CFU-GM collected was less than 0.5 x 10(4)/kg and these patients were excluded for stem cell transplantation. In the remaining 30 patients, a median of 4 x 10(4) CFU-GM/kg was collected (range 0.8-100 x 10(4)/kg) by three leukaphereses in 25 patients and six to 11 leukaphereses in five patients. Conditioning regimens were CBV (eight), BEAM (six), BEAC (10) and cyclophosphamide + total body irradiation (TBI) (six). Without TBI, the mean time for reaching a granulocyte count greater than 0.5 x 10(9)/l was 18 days and for a platelet count greater than 50 x 10(9)/l was 19 days in 23 out of 24 patients. With TBI, in five patients the mean time for reaching a granulocyte count greater tahn 0.5 x 10(9)/l was 37 days and for a platelet count greater than 50 x 10(9)/l was greater than 100 days. Complications were minor. There was only one toxic death. The outcome in these patients was similar to that observed in patients who received autologous bone marrow transplantation for advanced lymphomas. In conclusion, we observed good hematologic recovery except when TBI was used in the conditioning regimen.