Arsenic-induced neurotoxicity in patients with acute promyelocytic leukaemia

Arsenic trioxide is an essential component of therapy for acute promyelocytic leukaemia (APL) and is currently dosed on actual body weight with no upper limit. Arsenic-induced neurotoxicity is a well-recognised complication; however, there is uncertainty about its relationship to arsenic dose and obesity. We conducted a large multicentre retrospective study of 487 patients with APL treated with arsenic-based therapy across 23 sites in Australia from 2008 to 2023. The primary outcome was incidence of neurotoxicity, and secondary outcomes included relationship of neurotoxicity to obesity and cumulative arsenic dose. Any-grade neurotoxicity occurred in 113 (23%) patients, predominantly peripheral neuropathy (91%). Most events were grade 1-2 severity (85%), with grade 3 events in 12% and grade 4-5 in 3%. The incidence of neurotoxicity increased with BMI (non-obese: 16%, obesity class I: 25%, obesity class II-III: 41%; p < 0.001). On univariable analysis, obesity class I (OR 1.81, p = 0.036), obesity class II-III (OR 3.93, p < 0.001), weight >100 kg (OR 2.72, p < 0.001), daily arsenic trioxide dose >15 mg (OR 5.05, p < 0.001) and cumulative induction dose >500 mg (OR 3.95, p < 0.001) were all significantly associated with neurotoxicity. Obesity class II-III and induction dose >500 mg remained significant on multivariable analysis. Our study highlights the strong association between BMI, arsenic trioxide dose and neurotoxicity. Pre-emptive dose reductions should be considered for obese patients receiving high doses of arsenic.

Management of acute promyelocytic leukemia: updated recommendations from an expert panel of the European LeukemiaNet

Since the comprehensive recommendations for the management of acute promyelocytic leukemia (APL) reported in 2009, several studies have provided important insights, particularly regarding the role of arsenic trioxide (ATO) in frontline therapy. Ten years later, a European LeukemiaNet expert panel has reviewed the recent advances in the management of APL in both frontline and relapse settings in order to develop updated evidence- and expert opinion-based recommendations on the management of this disease. Together with providing current indications on genetic diagnosis, modern risk-adapted frontline therapy, and salvage treatment, the review contains specific recommendations for the identification and management of the most important complications such as the bleeding disorder APL differentiation syndrome, QT prolongation, and other all-trans retinoic acid- and ATO-related toxicities, as well as recommendations for molecular assessment of the response to treatment. Finally, the approach to special situations is also discussed, including management of APL in children, elderly patients, and pregnant women. The most important challenges remaining in APL include early death, which still occurs before and during induction therapy, and optimizing treatment in patients with high-risk disease.

Retinoic acid and arsenic trioxide in the treatment of acute promyelocytic leukemia: current perspectives

Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia (AML) with a unique morphological appearance, associated coagulopathy and canonical balanced translocation of genetic material between chromosomes 15 and 17. APL was first described as a distinct subtype of AML in 1957 by Dr Leif Hillestad who recognized the pattern of an acute leukemia associated with fibrinolysis, hypofibrinogenemia and catastrophic hemorrhage. In the intervening years, the characteristic morphology of APL has been described fully with both classical hypergranular and variant microgranular forms. Both are characterized by a balanced translocation between the long arms of chromosomes 15 and 17, [t(15;17)(q24;q21)], giving rise to a unique fusion gene PML-RARA and an abnormal chimeric transcription factor (PML-RARA), which disrupts normal myeloid differentiation programs. The success of current treatments for APL is in marked contrast to the vast majority of patients with non-promyelocytic AML. The overall prognosis in non-promyelocytic AML is poor, and although there has been an improvement in overall survival in patients aged <60 years, only 30%-40% of younger patients are still alive 5 years after diagnosis. APL therapy has diverged from standard AML therapy through the empirical discovery of two agents that directly target the molecular basis of the disease. The evolution of treatment over the last 4 decades to include all-trans retinoic acid and arsenic trioxide, with chemotherapy limited to patients with high-risk disease, has led to complete remission in 90%-100% of patients in trials and rates of overall survival between 86% and 97%.

Excellent outcomes for adolescents and adults with acute lymphoblastic leukemia and lymphoma without allogeneic stem cell transplant: the FRALLE-93 pediatric protocol

Adolescents and adults with acute lymphoblastic leukemia/lymphoma (ALL) have better outcomes when treated using pediatric protocols compared with treatment using adult protocols. We reviewed the progress and outcomes of 40 adolescents and adults up to 45 years of age, from three Australian centers, treated on the intensive French group for childhood ALL (FRALLE)-93 pediatric protocol. All except one patient achieved a morphologic complete remission following induction chemotherapy. Three-year overall survival for all-risk and standard-risk disease was 70% and 75%, respectively. The treatment protocol was generally well tolerated with no treatment related mortality. The FRALLE-93 pediatric protocol showed excellent overall survival for patients with standard-risk disease, without the need for allogeneic hematopoietic stem cell transplant in first remission.

Long-term survival in multiple myeloma is associated with a distinct immunological profile, which includes proliferative cytotoxic T-cell clones and a favourable Treg/Th17 balance

Despite improved outcomes in multiple myeloma (MM), a cure remains elusive. However, even before the current therapeutic era, 5% of patients survived >10 years and we propose that immune factors contribute to this longer survival. We identified patients attending our clinic, who had survived >10 years (n=20) and analysed their blood for the presence of T-cell clones, T-regulatory cells (Tregs) and T helper 17 (Th17) cells. These results were compared with MM patients with shorter follow-up and age-matched healthy control donors. The frequency of cytotoxic T-cell clonal expansions in patients with <10 years follow-up (MM patients) was 54% (n=144), whereas it was 100% (n=19/19) in the long-survivors (LTS-MM). T-cell clones from MM patients proliferated poorly in vitro, whereas those from LTS-MM patients proliferated readily (median proliferations 6.1% and 61.5%, respectively (P<0.0001)). In addition, we found significantly higher Th17 cells and lower Tregs in the LTS-MM group when compared with the MM group. These results indicate that long-term survival in MM is associated with a distinct immunological profile, which is consistent with decreased immune suppression.

Results of the APML3 trial incorporating all-trans-retinoic acid and idarubicin in both induction and consolidation as initial therapy for patients with acute promyelocytic leukemia

BACKGROUND

Initial therapy for patients with acute promyelocytic leukemia most often involves the combination of all-trans-retinoic acid with anthracycline-based chemotherapy. The role of non-anthracycline drugs in induction and consolidation is less well-established and varies widely between different cooperative group protocols.

DESIGN AND METHODS

In an attempt to minimize relapse and maximize survival for patients with newly diagnosed acute promyelocytic leukemia, the Australasian Leukaemia and Lymphoma Group utilized all-trans-retinoic acid and idarubicin as anti-leukemic therapy for both induction and consolidation. The protocol (known as APML3) was subsequently amended to incorporate maintenance with all-trans-retinoic acid, methotrexate and 6-mercaptopurine.

RESULTS

Eight (8%) of 101 patients died within 30 days, and 91 (90%) achieved complete remission. With a median estimated potential follow-up of 4.6 years, 4-year overall survival was 84%, and 71% of the patients remained in remission at 4 years. The cumulative incidence of all relapses was 28.1%, with 15 of the 25 relapses initially identified as an isolated molecular relapse. Both FLT3 mutations (internal tandem duplications and codon 835/836 kinase domain mutations) and increased white cell count at diagnosis were associated with inferior overall survival, but in multivariate analyses only FLT3 mutations remained significant (hazard ratio 6.647, P=0.005). Maintenance therapy was significantly associated with improved remission duration (hazard ratio 0.281, P<0.001) and disease-free survival (hazard ratio 0.290, P<0.001).

CONCLUSIONS

The combination of all-trans-retinoic acid and just two cycles of idarubicin followed by triple maintenance produced durable remissions in most patients, but patients with high-risk disease, especially those with FLT3 mutations, require additional agents or alternative treatment approaches. The significant reduction in relapse seen after the addition of maintenance to the protocol supports a role for maintenance in the context of relatively low chemotherapy exposure during consolidation. (actr.org.au identifier: ACTRN12607000410459).

Response of myeloma to the proteasome inhibitor bortezomib is correlated with the unfolded protein response regulator XBP-1

BACKGROUND

Multiple myeloma, a malignancy of the antibody-secreting plasma cells, remains incurable by current therapy. However, the proteasome inhibitor bortezomib and other new drugs are revolutionizing its treatment. It remains unclear why myelomas are peculiarly sensitive to bortezomib, or what causes primary or acquired resistance. The 'unfolded protein response' is necessary for folding and assembly of immunoglobulin chains in both normal and malignant plasma cells, as well as for the disposal of incorrectly folded or unpaired chains via the ubiquitin-proteasome pathway. We tested the hypothesis that levels of transcription factor XBP-1, a major regulator of the unfolded protein response, predict response to bortezomib.

DESIGN AND METHODS

Expression of XBP-1 and other regulators of the unfolded protein response were measured in myeloma and other cancer cell lines and two cohorts of patients with refractory myeloma and correlated with sensitivity/response to bortezomib. Bortezomib-resistant myeloma cell lines were derived and the effects on expression of unfolded protein response regulators, immunoglobulin secretion, proteasome activity and cross-resistance to cytotoxic drugs and tunicamycin determined. The consequences of manipulation of XBP-1 levels for sensitivity to bortezomib were tested.

RESULTS

Low XBP-1 levels predicted poor response to bortezomib, both in vitro and in myeloma patients. Moreover, myeloma cell lines selected for resistance to bortezomib had down-regulated XBP-1 and immunoglobulin secretion. Expression of ATF6, another regulator of the unfolded protein response, also correlated with bortezomib sensitivity. Direct manipulation of XBP-1 levels had only modest effects on sensitivity to bortezomib, suggesting it is a surrogate marker of response to bortezomib rather than a target itself.

CONCLUSIONS

The unfolded protein response may be a relevant target pathway for proteasome inhibitors in the treatment of myeloma and its regulator XBP-1 is a potential response marker. (The BIR study was registered with Australian Clinical Trial Registry Number 12605000770662).

The PRKAR1A gene is fused to RARA in a new variant acute promyelocytic leukemia

We report the molecular and cytogenetic characterization of a novel variant of acute promyelocytic leukemia (APL). The bone marrow showed 88% hypergranular promyelocytes, and the karyotype was 47,XY,+22 [5]/46,XY[30]. Fluorescence in situ hybridization (FISH) indicated disruption and deletion of the 5′-end of the RARA gene. Treatment with all-trans retinoic acid, idarubicin, and arsenic trioxide induced cytogenetic complete remission without morphologic evidence of residual leukemia. The diagnostic marrow was negative for PML-RARA transcripts by reverse transcription–polymerase chain reaction (RT-PCR), but an atypical product was observed. Sequencing showed partial homology to the PRKAR1A gene, encoding the regulatory subunit type I-α of cyclic adenosine monophosphate–dependent protein kinase. RT-PCR using specific primers for PRKAR1A and RARA amplified 2 transcript splice variants of a PRKAR1A-RARA fusion gene, and PRKAR1A and RARA FISH probes confirmed the fusion. This novel PRKAR1A-RARA gene rearrangement is the fifth variant APL in which the RARA partner gene has been identified and the second known rearrangement of PRKAR1A in a malignant disease. This trial was registered at www.actr.org.au with the Australian Clinical Trials Registry as number 12605000070639.

Molecular biology of lymphoma in the microarray era

This review will focus on the molecular biology of lymphoproliferative disorders with emphasis on lymphomas. The spectrum of known recurrent gene rearrangements found in lymphomas will be outlined and their relevance to diagnosis and subclassification of disease will be discussed. Finally, a survey of the current trends in gene expression profiling of lymphomas by microarray technology will be presented with reference to implications for diagnosis, classification, prognosis and treatment.

Transformation and progression of Waldenström's macroglobulinemia following cladribine therapy in two cases: natural evolution or iatrogenic causation?

We report two cases of Waldenström's macroglobulinemia with an unusual aggressive transformation following treatment with cladribine (2-chlorodeoxyadenosine, 2-CdA), a purine analogue. The first patient developed transformation to a diffuse large-cell non-Hodgkin lymphoma, while the second developed extensive extramedullary involvement. Both patients displayed rapid progression following transformation and were refractory to chemotherapy. Both patients were pretreated with multiple courses of prednisone and chlorambucil, and transformation occurred shortly after therapy with cladribine. We propose that immune suppression from alkylating agents and purine analogues may have contributed to the unusual progression, resulting in a dismal outcome.

A rapid RT-PCR screening assay incorporating multiplexed validated control genes for CBF rearrangements at diagnosis in AML

AIMS

Our objective was to establish a multiplexed assay using the Biomed 1 primers to detect AML1-ETO transcripts and 10 different CBFB-MYH11 transcripts, using BCR and ABL transcripts as controls.

METHODS

Control genes were systematically tested for characteristics of optimal controls. The final assay was validated on 50 AML patient samples.

RESULTS

Testing confirmed that the designated control gene criteria were fulfilled. Of 50 patient samples tested, four RT-PCR results were discordant with the cytogenetic result. In three cytogenetically negative cases, RT-PCR detected cryptic CBF rearrangements (one AML1-ETO and two CBFB-MYH11). The fourth case was inv(16) positive but negative by RT-PCR; however, the control gene result revealed suboptimal RNA quality.

CONCLUSIONS

We have described a robust multiplex RT-PCR assay that incorporates experimentally validated control genes that are important for accurate interpretation. The assay is more sensitive than cytogenetics in the detection of CBF AML. Application to large patient cohorts will determine the prognostic significance of cryptic CBF rearrangements compared with their cytogenetic counterparts.

Missense C168T in the Wiskott--Aldrich Syndrome protein gene is a common mutation in X-linked thrombocytopenia

We describe a large Syrian--Lebanese family who clinically manifest X-linked thrombocytopenia (XLT). To date, five family members have undergone splenectomy with rapid and sustained normalization of their platelet numbers. Genomic analysis demonstrated that affected men in this cohort had the missense C168T (Thr45Met) mutation in exon 2 of the Wiskott-Aldrich Syndrome protein (WASp) gene. Exon 2 is the commonest site for mutations associated with XLT and mild forms of WAS, and the C168T missense mutation is the most frequent. Detection of this mutation by restriction enzyme digestion provides an efficient screening test for prompt identification and for assessment of female carrier status.

Unusual muscle pathology in McLeod syndrome

Muscle pathology in McLeod syndrome is usually mild; patchy necrotic or regenerating fibres, occasional internal nuclei, and the absence of an inflammatory cell infiltrate are the usual findings. We report on a 29 year old man presenting with chronic fatiguability and excessive sweating in whom an open quadriceps muscle biopsy demonstrated grouped necrotic fibres accompanied by striking patchy mononuclear cell infiltrates. The diagnosis of McLeod syndrome was made on the basis of red blood cell acanthocytosis, raised serum creatine kinase, and weak expression of Kell blood group antigens. The quadriceps muscle infiltrate consisted principally of histologically typical macrophages. These cells had prominent nucleoli, displayed numerous mitoses, and were strongly CD68+. A small population of typical CD3+, CD43+ lymphocytes was also present. In addition, a small population of large atypical CD3+ cells was noted. Immunoperoxidase stains for CD20, CD30, CD79a, and CD56 were negative. Immunocytochemical studies for the common muscular dystrophies were normal. The muscle biopsy findings highlight a potential for confusion of this condition with idiopathic polymyositis. The expanding range of muscle pathology reported in McLeod syndrome, to which this case adds, may reflect variable involvement of the XK gene on chromosome Xp21, or of the adjacent loci of Duchenne muscular dystrophy and chronic granulomatous disease.

Acute promyelocytic leukaemia complicating multiple myeloma: evidence of different cell lineages

The association of leukemia and multiple myeloma is well described usually as a complication of chemotherapy but also in the absence of chemotherapy or at diagnosis. Such leukemias are typically acute myeloid leukemia (AML), particularly myelomonocytic subtype, and cases of acute promyelocytic leuke (APL) are rarely reported. Controversy exists as to whether myeloma and AML originate from a single haematopoietic progenitor or arise from different cell lineages. We report a case of a 58 year old female who developed APL 10 months following diagnosis of nonsecretory light chain (kappa) myeloma which had been treated with local spinal irradiation and low dose oral melphalan and prednisone. Clonality had originally been demonstrated by light chain restriction (kappa) of her bone marrow plasma cells whilst immunoglobulin heavy chain and T cell receptor genes were germ line. At development of APL cytogenetics revealed t(15;17) and PML-RAR fusion gene was detected by RT-PCR. The patient was treated with all-trans retinoic acid (ATRA) and received 2 cycles of consolidation chemotherapy with Idarubicin. Following this therapy the t(15;17) and PML-RAR were both undetectable whilst the clonal population of kappa staining plasma cells persisted. This particular patient represents a rare case of APL complicating multiple myeloma with persistence of the myeloma clone but disappearance of PML-RAR alpha RNA following therapy. This case study appears to support the argument that the APL and myeloma originated from distinct cell lineages.

Syngeneic stem cell transplantation for HIV-related lymphoma

The treatment of human immunodeficiency virus (HIV)-related lymphoma is beset by a number of therapeutic limitations. High-dose chemotherapy followed by peripheral blood stem cell transplantation (PBSCT) for relapsed disease is one option, but may be compromised by unacceptable treatment-related morbidity and mortality. We describe an HIV-positive male with relapsed immunoblastic non-Hodgkin's lymphoma (NHL) who successfully received salvage chemotherapy followed by a syngeneic PBSCT from his HIV-negative (hepatitis C positive) brother. At 15 months post-transplant he remains in complete remission with low-level HIV viral load, an improved CD4 lymphocyte count and absent anti-hepatitis C antibodies. We believe selected patients with relapsed HIV-related NHL should be considered for high-dose therapy.

Safe mobilization of normal progenitors in advanced chronic myeloid leukemia with intensive chemotherapy and granulocyte-colony stimulating factor

Twenty-one patients with advanced chronic myeloid leukemia (late chronic phase (n = 8), accelerated phase (n = 11) and blast crisis (n = 2)) were treated with idarubicin, cytarabine, and etoposide followed by G-CSF and subsequent collection of peripheral blood progenitor cells in the early recovery phase. Treatment was reasonably well tolerated with no deaths or intensive care admissions. Despite the advanced phase of disease and heavy pretreatment with cytotoxics and interferon-alfa, 11 of 21 patients (52%) achieved a cytogenetic response. Of the nine major cytogenetic responses (complete (n = 3) and partial (n = 6)), seven achieved adequate progenitor collections for consideration for autologous transplantation. The only predictor of response was disease duration (P = 0.02). With a median follow-up of 1171 days from treatment it appears unlikely that G-CSF contributed to disease progression. Survival post-IcE was predicted by disease stage (P = 0.0001). Intensive chemotherapy followed by G-CSF allowed adequate yields of predominantly Philadelphia chromosome negative progenitor cells to be obtained from one-third of patients with advanced CML.

Experience of the Polycythemia Vera Study Group with essential thrombocythemia: a final report on diagnostic criteria, survival, and leukemic transition by treatment

This report suggests modest changes in the criteria used for the diagnosis of ET and allows tentative recommendations concerning therapy. As outlined in Table I, we believe that absent stainable marrow iron does not necessarily indicate iron deficiency in these patients and that the serum ferritin and RBC mean corpuscular volume should be incorporated in this assessment. Normal values speak strongly against iron-deficient erythropoiesis. A search for the bcr/abl gene rearrangement should be included with the marrow karyotype to exclude CML. Finally, cytogenetic data and morphologic study of the marrow should be used to be certain that a MDS should not be considered. It may be that measurements of serum thrombopoietin levels may be useful in the future. Nonetheless, in principle, ET remains a diagnosis of exclusion as we have originally suggested. For therapy, HU remains an excellent choice for the older patient at risk for thrombosis. Nonetheless, no myelosuppressive therapy remains a perfectly viable option, particularly for the young patient and the older with low thrombotic risk. The roles of anagrelide and alpha interferon in this setting have not been fully defined. Experience with both has still been relatively short. It would be ideal if prospective, randomized trials could be mounted to address these questions. We conclude with confidence that return to older approaches such as 32P and AA in patients who fail on HU is to be discouraged. The use of anagrelide or interferon alfa seems to be a much more appropriate approach. We have not investigated the role of antithrombotic agents such as aspirin in ET. In PV, the combination of aspirin, 300 mg three times daily, and dipyridamole, 75 mg three times daily, failed to reduce the rate of thrombosis and was associated with an increased rate of hemorrhage. It is rational to suggest that lower doses of aspirin (ie, < 325 mg daily) might be associated with less hemorrhage and, perhaps, a beneficial effect on thrombosis. This remains to be shown.

SSCP detection of N-ras promoter mutations in AML patients

Activation of the N-ras gene via coding region mutations has been previously documented in 25% of patients with acute myeloid leukemia (AML). Since overexpression of normal N-ras is also transforming in vitro, the N-ras promoter of AML patients was analyzed for the presence of promoter mutations that may affect expression of the N-ras gene. Single-stranded conformational polymorphism (SSCP) was used to analyze samples from 26 AML patients and 13 normal subjects. A novel polymorphism at position 390 within the N-ras promoter was observed in both AML patients and normal samples at an overall frequency of 26%. In addition, two of 26 patients had single-base substitutions within protein binding sites that altered the binding of transcription factors to the promoter. One patient had a T-->A mutation at position 520 within an AP-1 binding site; the other had an A-->G mutation at position 409 within a protein binding region adjacent to a Myb binding site. The data suggest that in addition to coding region mutations in the N-ras gene, mutations in the promoter region that could alter regulation of N-ras expression provide an alternative mechanism of involvement of N-ras in AML.

A randomised dosage study of ceftazidime with single daily tobramycin for the empirical management of febrile neutropenia in patients with hematological diseases

A single-institution, randomised trial was conducted to compare the clinical and microbiological efficacy of two different doses of ceftazidime in combination with a single daily dose of tobramycin for the empirical management of febrile neutropenic patients with hematologic disorders (absolute neutrophil count < 1 x 10(9)/l). Upon the development of fever or signs of sepsis, patients received either 2 g ceftazidime every 8 h plus a single daily dose tobramycin (5 mg/kg/day) (C2T, n = 73) or 1 g ceftazidime every 8 h plus a single daily dose of tobramycin (C1T, n = 77). In addition, flucloxacillin (1-2 g every 4 h) could be added if there was clinical suspicion of staphylococcal infection. Analysis was performed for the whole group and for the subset which did not receive flucloxacillin. When evaluated at 96 h, 70% (95% CI, +/- 11%) of patients randomised to C2T and 60% (95% CI, +/- 11%) randomised to C1T had responded (chi 2 = 1.27, P = 0.26). The response rates at 96 h for those who did not receive flucloxacillin were 77% (+/- 12%) and 74% (+/- 13%), respectively (chi 2 = 0.01, P = 0.92). Overall, 68 (93% +/- 6%) and 72 (94% +/- 6%) patients, respectively, eventually became afebrile (chi 2 = 0.06, P = 0.81). Renal function, as judged by serum creatinine, was unaffected by either antibiotic schedule. Within 10 days of antibiotic commencement there was one death in each arm and overall there were five deaths in each arm.(ABSTRACT TRUNCATED AT 250 WORDS)

Trends in bacterial infections in febrile neutropenic patients: 1986-1992

BACKGROUND

Bacterial infection is a major cause of morbidity and mortality in neutropenic patients.

AIMS

(1) To review patterns and trends in bacterial infections in three cohorts of febrile neutropenic patients managed by a single unit over a seven year period. (2) To relate any changes to the use of central venous (Hickman's) catheters and high-dose cytosine arabinoside chemotherapy.

METHODS

Retrospective review of the results of initial bacteriological work-up performed on 344 episodes of febrile neutropenia. The three cohorts were 1986-87 (n = 102), 1989-90 (n = 92) and 1991-92 (n = 150).

RESULTS

(1) The ratio of gram-negative to gram-positive bacteraemias fell from 1.36 in the first cohort to 1.05 in the second and 0.40 in the third (p = 0.03). There was a fall in both percentage and number of gram-negative isolates coupled with a rise in the frequency of gram-positive isolates. (2) Coincidentally there was a rise in the frequency of positive cultures from Hickman catheter entry wounds and an increasing frequency of simultaneous isolation of the same organism from the catheter entry site and the blood. The types of organisms isolated from catheter entry wounds showed a trend towards fewer gram-negative and more gram-positive. (3) A relationship was observed between the use of high-dose cytosine arabinoside chemotherapy and the incidence of bacteraemia (p = 0.025) but not with the change in types of organisms.

CONCLUSIONS

Over seven years we have documented a major change in the types of infections, particularly bacteraemias, seen in febrile neutropenic patients. In our institution the more widespread use of intravenous catheters and high-dose cytosine arabinoside chemotherapy have been identified as two possible contributing factors.

Single daily ceftriaxone and tobramycin in the empirical management of febrile neutropenic patients: a randomised trial

A single-institution, randomised pilot trial was conducted to compare the clinical efficacy, microbiological efficacy and possible toxicity of empirical single daily antibiotic administration in febrile neutropenic patients with haematologic disorders (absolute neutrophil count < 1 x 10(9)/l). Upon the development of signs of sepsis, patients received either single daily dose tobramycin (5 mg/kg per day) plus ceftriaxone (2 g/day) (C + T, n = 47) or tobramycin (1.5 mg/kg, every 8 h) plus azlocillin (4 g, every 6 h) (A + T, n = 45). In addition, flucloxacillin (1-2 g, every 4 h) could be added if there was clinical suspicion of staphylococcal infection (17 in each arm). Analysis was performed for the whole group and for the subset which did not receive flucloxacillin. When evaluated at 96 h, 62% of patients randomised to C + T and 67% randomised to A + T had responded (95% confidence interval (CI) for the difference in rates, -25% to +15%). Ninety-six hour response rates for those who did not receive flucloxacillin were 73% and 78%, respectively (95% CI, -17% to +27%). Overall, 42 (89%) and 41 (91%) patients, respectively, eventually became afebrile (95% CI, -14 to 10%) and there was no evidence of altered renal function or electrolyte imbalance in patients randomised to single daily antibiotic therapy compared with the conventional (multi-daily dose) arm. Within 10 days of antibiotic commencement there was 1 death in the C + T arm and 4 deaths in the A + T arm, although overall there were 4 deaths in each arm. Our results suggest that single daily empirical antibiotic therapy with tobramycin and ceftriaxone is efficacious and is not associated with an increased incidence of renal dysfunction or electrolyte imbalance compared with conventional administration schedules of azlocillin plus tobramycin. Single daily therapy has the potential to lead to savings in nursing-staff time and materials and may well contribute to an improved quality of life for febrile neutropenic patients.

c-fms point mutations in acute myeloid leukemia: fact or fiction?

Point mutations in codons 12, 13, and 61 of N-ras have consistently been reported in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) using a variety of techniques. Recently mutations in codons 301 and 969 of c-fms, preferentially involving TAT-to-TGT at codon 969, have also been identified in these disorders by allele specific oligonucleotide (ASO) hybridization. We have developed allele specific restriction analysis (ASRA) protocols for the detection of point mutations in the critical codons of these genes. ASRA involves enzymatic digestion of polymerase chain reaction (PCR)-induced restriction sites which are specific for normal but not mutant alleles. A total of 11 N-ras mutations were observed in 10 out of 46 AML patients, consistent with the reported frequency of N-ras mutations when alternative techniques of comparable sensitivity are used. In contrast, c-fms point mutations were not detected in a similar number of patients with AML, including 39 studied for mutations in both N-ras and c-fms, and this difference is statistically significant (p < 0.003). A more sensitive technique (ASRA + ASO hybridization) also failed to detect TAT-to-TGT substitutions at codon 969 in a subgroup of M4-AML patients considered to be at greatest risk of harboring c-fms mutations. This study suggests that c-fms mutations at codons 301 and 969 are not important in the pathogenesis of AML in the vast majority of patients.

Inhibitory effect of norcantharidin on K562 human myeloid leukemia cells in vitro

Mylabris, the dried body of the Chinese blister beetle, has been used as a Chinese medicinal for over 2000 years. Its active constituent, cantharidin, has antitumor properties and causes leukocytosis. Norcantharidin (NCTD), the demethylated form of cantharidin, is easier to synthesize and is less toxic. NCTD irreversibly reduced the clonogenic efficiency of parental and drug-resistant K562 sublines, with drug-resistant sublines showing greater susceptibility to NCTD than parental cells. NCTD inhibited DNA synthesis by blocking cells at the G2/M phase of the cell cycle. The data suggest that NCTD may be suitable in the treatment of drug-resistant leukemia.

A randomised trial of empirical antibiotic therapy in febrile neutropenic patients with hematological disorders: ceftazidime versus azlocillin plus amikacin

One hundred and two patients with neutropenia (less than 1 x 10(9)/L) secondary to primary hematological disorders or chemotherapy for hematological malignancies were prospectively randomised, upon the development of fever or other signs of infection, to receive empirical antibiotic treatment with either ceftazidime (+/- flucloxacillin) (n = 52) or azlocillin plus amikacin (+/- flucloxacillin) (A&A, n = 50). The two groups were equivalent with respect to clinical and laboratory parameters prior to antibiotic therapy and flucloxacillin was added to approximately 25% of the patients in each group on the clinical suspicion of Gram positive infection. When assessed at 96 hours, the complete response rates were 59.6% for the ceftazidime treated patients and 44% for A&A treated patients. Partial response rates were 17% and 20% respectively. This difference was not statistically significant. Eight patients died whilst on the trial, three of those initially randomised to ceftazidime and five initially randomised to A&A. Moderate to severe hypokalemia was encountered significantly less often in the ceftazidime treated group (p less than 0.01), whilst other parameters of toxicity were equivalent. No primary or acquired resistance to ceftazidime was encountered. Separate analysis of those patients who did not receive flucloxacillin yielded identical results. We conclude that ceftazidime (+/- flucloxacillin) is as efficacious as azlocillin plus amikacin (+/- flucloxacillin) in the empirical antibiotic management of such patients and is associated with a lower incidence of moderate to severe hypokalemia.

Myeloproliferative and lymphoproliferative disorders in the same patient

A 67-year-old man developed a Philadelphia-negative myeloproliferative disorder which initially manifested as marked thrombocytosis, followed two years later by marked leucocytosis. He subsequently developed an IgG lambda plasma cell dyscrasia together with a monoclonal proliferation of circulating lymphocytes with IgM kappa surface immunoglobulin. The lymphoid neoplasm was associated with a rapidly progressive and fatal course.