Better Outcome of Off-Label High-Dose Ceftazidime in Hemato-Oncological Patients with Infections Caused by Extensively Drug-Resistant Pseudomonas Aeruginosa.

Background: P. aeruginosa sepsis in immunocompromised patients is a serious complication of cancer treatment, especially in the case of an Extensively Drug Resistant (XDR) pathogen. The aim of the study is to evaluate the efficacy of high-dose ceftazidime in the treatment of XDR P. aeruginosa infection and to compare it with the conventionally treated cohort in hemato-oncological patients. Methods: We identified 27 patients with XDR P. aeruginosa infection during the 2008-2018 period, 16 patients served as a conventionally treated cohort with an antipseudomonal beta-lactam antibiotic in standard dose (cohort A), and 11 patients were treated with high-dose ceftazidime (cohort B). Most of the patients were neutropenic and under active treatment for their cancer in both cohorts. Results: Mortality and related mortality were statistically significantly better for cohort B than cohort A; it was 18.2% and 9.1% for cohort B and 68.8% and 68.8% for cohort A, respectively. More patients in cohort A needed mechanical ventilation and renal replacement therapy, 75% and 50% for cohort A and 27.3% and 9.9% for cohort B, respectively. It corresponded well with the worst sequential organ failure score (SOFA) in cohort A compared to cohort B, 16 versus 7, respectively. Reversible neurotoxicity was seen only in two patients in cohort B. Conclusion: Ceftazidime in high doses is a very potent antibiotic (ATB) for treating XDR P. aeruginosa infections in neutropenic cancer with acceptable toxicity.

Superiority of ceftazidime off-label high-dose regimen in PK/PD target attainment during treatment of extensively drug-resistant Pseudomonas aeruginosa infections in cancer patients.

AIM: The objective of this study was to evaluate off-label high-dose ceftazidime population pharmacokinetics in cancer patients with suspected or proven extensively drug-resistant (XDR) Pseudomonas aeruginosa infections and then to compare the achievement of the pharmacokinetic/pharmacodynamic (PK/PD) target after standard and off-label high-dose regimens using population model-based simulations. A further aim was to clinically observe the occurrence of adverse effects during the off-label high-dose ceftazidime treatment. METHODS: In patients treated with off-label high-dose ceftazidime (3 g every 6 h), blood samples were collected and ceftazidime serum levels measured using LC-MS/MS. A pharmacokinetic population model was developed using a nonlinear mixed-effects modelling approach and Monte Carlo simulations were then used to compare standard and high-dose regimens for PK/PD target attainment. RESULTS: A total of 14 cancer patients with serious infection suspected of XDR P. aeruginosa aetiology were eligible for PK analysis. XDR P. aeruginosa was confirmed in 10 patients as the causative pathogen. Population ceftazidime volume of distribution was 13.23 L, while clearance started at the baseline of 1.48 L/h and increased by 0.0076 L/h with each 1 mL/min/1.73 m2 of eGFR. High-dose regimen showed significantly higher probability of target attainment (i.e., 86% vs. 56% at MIC of 32 mg/L). This was translated into a very low mortality rate of 20%. Only one case of reversible neurological impairment was observed. CONCLUSION: We proved the superiority of the ceftazidime off-label high-dose regimen in PK/PD target attainment with very low occurrence of adverse effects. The off-label high-dose regimen should be used to optimize treatment of XDR P. aeruginosa infections.

Mycobacterioses Induced by Mycobacterium abscessus: Case Studies Indicating the Importance of Molecular Analysis for the Identification of Antibiotic Resistance.

Mycobacterioses are less frequently occurring but serious diseases. In recent years, at a global level, the incidence of mycobacterioses induced by the rapidly growing species Mycobacterium abscessus (M. a.), which is considered to be the most resistant to antibiotics and most difficult to treat, has been on the rise. Correct identification to the level of the subspecies (M. a. abscessus, M. a. massiliense, and M. a. bolletii) and determination of its sensitivity to macrolides, which are the basis of combination therapy, are of principal importance for the management of the disease. We describe five cases of mycobacterioses caused by M. a., where the sequencing of select genes was performed to identify the individual subspecies and antibiotic resistance. The analysis of the rpoB gene showed two isolates each of M. a. abscessus and M. a. massiliense and one isolate of M. a. bolletii. The complete (full length) erm(41) gene responsible for the development of inducible resistance to macrolides was demonstrated in both M. a. abscessus and M. a. bolletii isolates. A partially deleted and non-functional erm(41) gene was demonstrated in M. a. massiliense isolates. The subsequent sequencing of the full length erm(41) gene products showed, however, the mutation (T28→C) in both isolates of M. a. abscessus, causing a loss of the function and preserved sensitivity to macrolides. The antibiotic sensitivity testing confirmed that both the isolates of M. a. abscessus and M. a. massiliense were sensitive to clarithromycin even after prolonged 14-day incubation. The inducible resistance to clarithromycin was maintained only in M. a. bolletii. Thus, the sequence analysis of the erm(41) gene can reliably identify the preservation of sensitivity to macrolides and serve as an important tool in the establishment of therapeutic regimens in cases of infections with M. abscessus.

Targeting Pharmacokinetic Drug Resistance in Acute Myeloid Leukemia Cells with CDK4/6 Inhibitors.

Pharmacotherapy of acute myeloid leukemia (AML) remains challenging, and the disease has one of the lowest curability rates among hematological malignancies. The therapy outcomes are often compromised by the existence of a resistant AML phenotype associated with overexpression of ABCB1 and ABCG2 transporters. Because AML induction therapy frequently consists of anthracycline-like drugs, their efficiency may also be diminished by drug biotransformation via carbonyl reducing enzymes (CRE). In this study, we investigated the modulatory potential of the CDK4/6 inhibitors abemaciclib, palbociclib, and ribociclib on AML resistance using peripheral blood mononuclear cells (PBMC) isolated from patients with de novo diagnosed AML. We first confirmed inhibitory effect of the tested drugs on ABCB1 and ABCG2 in ABC transporter-expressing resistant HL-60 cells while also showing the ability to sensitize the cells to cytotoxic drugs even as no effect on AML-relevant CRE isoforms was observed. All tested CDK4/6 inhibitors elevated mitoxantrone accumulations in CD34+ PBMC and enhanced accumulation of mitoxantrone was found with abemaciclib and ribociclib in PBMC of FLT3-ITD- patients. Importantly, the accumulation rate in the presence of CDK4/6 inhibitors positively correlated with ABCB1 expression in CD34+ patients and led to enhanced apoptosis of PBMC in contrast to CD34- samples. In summary, combination therapy involving CDK4/6 inhibitors could favorably target multidrug resistance, especially when personalized based on CD34- and ABCB1-related markers.

Ciprofloxacin prophylaxis during autologous stem cell transplantation for multiple myeloma in patients with a high rate of fluoroquinolone-resistant gram-negative bacteria colonization.

BACKGROUND: Ciprofloxacin prophylaxis used to be a standard precaution during autologous stem cell transplantation. Its benefit, with a high prevalence of fluoroqinolone resistance in the population, has recently been under scrutiny. OBJECTIVE: To evaluate the impact of cessation of ciprofloxacin prophylaxis during stem cell transplantation for multiple myeloma. PATIENTS AND METHODS: Data from 104 patients with multiple myeloma transplanted during the period from January 2013 to April 2015 were retrospectively reviewed. 67 received standard ciprofloxacin prophylaxis (group A) and 37 received no antibacterial prophylaxis (group B). RESULTS: Febrile episodes during neutropenia, bloodstream infection (BSI) and mortality in these two cohorts were evaluated. Gram negative BSI was assessed for the colonization of quinolone-resistant gram-negative pathogens. Secondary Clostridium difficile enterocolitis presence was determined in both cohorts. There were 42 (63%), 7 (10%), and 0 febrile episodes, BSI and gram-negative BSI respectively in group A, and 34 (92%), 12 (32%), and 4 (11%) respectively in group B. The differences in the number of febrile episodes (P=0.0011) and deaths (P=0.0427) were statistically significance. Mortality was 0 and 3 (8%) in group A and group B, respectively. There was no significant difference in colonization with quinolone-resistant gram negative pathogens (25 (37%) versus 11 (30%)) between groups. The occurrence of Clostridium difficile colitis was the same in both groups. CONCLUSION: We resumed ciprofloxacin prophylaxis for the following reasons. There was a significant reduction in febrile episodes, and consequently a sparing effect of antibiotics used for treatment of this condition. No difference in Clostridium difficile colitis occurred and the mortality rate of 8% in group B was unacceptably high.

IDH1 and IDH2 mutations in patients with acute myeloid leukemia: Suitable targets for minimal residual disease monitoring?

OBJECTIVES: Molecular screening plays a major role in prognostic categorization and subsequent definition of treatment strategies for acute myeloid leukemia. The possibility of using IDH1/2 mutations as a marker for the monitoring of minimal residual disease (MRD) is still under investigation and remains unclear. METHODS: In this retrospective study, we evaluated 90 patients with de novo AML using Sanger sequencing (exon 4, IDH1 and IDH2). For subsequent MRD monitoring were used both methods, massive parallel sequencing and droplet digital PCR (ddPCR). RESULTS: We identified 22 patients (24%) who harboured mutations in IDH1 or IDH2 genes. Fourteen (64%) of them had other commonly used MRD markers (insertion in NPM1 and partial tandem duplication of MLL, MLL-PTD). Eight of the 22 patients had IDH1 mutations, 13 had IDH2 mutations and 1 had both IDH1 and IDH2 mutations. In our cohort, this IDH1/2 marker responded to the treatment in all of the patients and reflected the onset of the relapse very well. NPM1 mutation based MRD monitoring was more sensitive and predicted relapse earlier but IDH1/2 based monitoring was more sensitive than a method based on MLL-PTD. Both massive parallel sequencing and ddPCR were competent to monitor MRD using IDH1/2. Nevertheless, ddPCR was able to achieve a higher sensitivity in some cases and moreover this method can analyse a single sample without significant price increases. CONCLUSION: Given these data, we conclude that IDH1/2 mutations can be used as a reliable and cost-effective marker for MRD monitoring.

Detection of cytomegalovirus DNA in fecal samples in the diagnosis of enterocolitis after allogeneic stem cell transplantation.

BACKGROUND: Cytomegalovirus enterocolitis is a rare but potentially life threatening complication after allogeneic stem cell transplantation. Its early diagnosis and treatment are essential for a successful outcome. OBJECTIVE: To determine the potential benefit of fecal CMV DNA detection in the diagnosis of CMV colitis among stem cell transplant recipients. STUDY DESIGN: Biopsies from the lower gastrointestinal tract, taken during 69 episodes of diarrhea, were compared with fecal samples previously examined for CMV DNA in 45 patients after allogeneic stem cell transplantation. RESULTS: Six confirmed cases of CMV colitis were observed, with 16 out of 69 (23%) fecal samples proving positive for CMV DNA. Only one positive sample correlated with histologically confirmed CMV colitis, and 15 samples were evaluated as false positive. These results provide a 16.7% sensitivity and 76.2% specificity in the diagnosis of CMV enterocolitis. CONCLUSION: The examination of fecal samples for the presence of CMV DNA has very low potential in the diagnosis of CMV enterocolitis after allogeneic stem cell transplantation; therefore, a biopsy of the gastrointestinal mucosa is still warranted for correct diagnosis.

The first in vivo multiparametric comparison of different radiation exposure biomarkers in human blood.

The increasing risk of acute large-scale radiological/nuclear exposures of population underlines the necessity of developing new, rapid and high throughput biodosimetric tools for estimation of received dose and initial triage. We aimed to compare the induction and persistence of different radiation exposure biomarkers in human peripheral blood in vivo. Blood samples of patients with indicated radiotherapy (RT) undergoing partial body irradiation (PBI) were obtained soon before the first treatment and then after 24 h, 48 h, and 5 weeks; i.e. after 1, 2, and 25 fractionated RT procedures. We collected circulating peripheral blood from ten patients with tumor of endometrium (1.8 Gy per fraction) and eight patients with tumor of head and neck (2.0-2.121 Gy per fraction). Incidence of dicentrics and micronuclei was monitored as well as determination of apoptosis and the transcription level of selected radiation-responsive genes. Since mitochondrial DNA (mtDNA) has been reported to be a potential indicator of radiation damage in vitro, we also assessed mtDNA content and deletions by novel multiplex quantitative PCR. Cytogenetic data confirmed linear dose-dependent increase in dicentrics (p < 0.01) and micronuclei (p < 0.001) in peripheral blood mononuclear cells after PBI. Significant up-regulations of five previously identified transcriptional biomarkers of radiation exposure (PHPT1, CCNG1, CDKN1A, GADD45, and SESN1) were also found (p < 0.01). No statistical change in mtDNA deletion levels was detected; however, our data indicate that the total mtDNA content decreased with increasing number of RT fractions. Interestingly, the number of micronuclei appears to correlate with late radiation toxicity (r2 = 0.9025) in endometrial patients suggesting the possibility of predicting the severity of RT-related toxicity by monitoring this parameter. Overall, these data represent, to our best knowledge, the first study providing a multiparametric comparison of radiation biomarkers in human blood in vivo, which have potential for improving biological dosimetry.

Treatment of Multifocal Multisystem BRAF Positive Langerhans Cell Histiocytosis with Cladribine, Surgery and Allogenic Stem Cell Transplantation.

Langerhans cell histiocytosis (LCH) is a very rare disease in adults and as well a very rare cause of sellar expansion. The clinical presentation can be heterogeneous, from a single bone lesion to potentially fatal, widespread disease. We describe the difficulties with the diagnosis and treatment of LCH as well as successful treatment with cladribine chemotherapy and allogeneic stem cell transplantation.

Fifteen years of single center experience with stem cell transplantation for multiple myeloma: a retrospective analysis.

INTRODUCTION: Autologous stem cell transplantation (ASCT) became standard of care for patients with multiple myeloma (MM) under the age of 65 years. We routinely perform ASCT for newly diagnosed MM since 1996 in our department. PATIENTS AND METHODS: We retrospectively analyzed all 285 transplants in 185 patients done for MM from January 1996 till December 2010. We analyzed overall survival (OS) and progression-free survival (PFS) regarding conditioning, stage, complete or very good partial remission (CR, VGPR) achievement, renal impairment, single vs. double transplant. RESULTS: Estimated 10-years survival of the whole set of patients is 39% (median survival 95 months). Patients with renal impairment show same OS as those without (p = 0.22). Patients show similar overall survival and event free survival regardless of type of transplant. We observed better outcome in terms of overall survival in patients treated with new drugs (p = 0.0014). Reaching CR or VGPR was not translated into better OS (p = 0.30) and EFS (p = 0.10). Also stage of the disease and whether single or double transplant was used did not make any significant difference in the outcome. CONCLUSION: Stem cell transplantation greatly improved outcome of patients with MM. Poor outcome of allogeneic transplantation in our group of patients is related to high transplant related mortality (20% vs. 0%) and unexpected high relapse rate. There is a trend towards better survival, when new drugs are incorporated at any time in the course of the disease. This fact supports hypothesis that use of these drugs with ASCT should translate into better long-term outcome.

A method to identify new molecular markers for assessing minimal residual disease in acute leukemia patients.

Acute leukemias (AL) comprise a heterogeneous group of hematologic malignancies, and individual patient responses to treatment can be difficult to predict. Monitoring of minimal residual disease (MRD) is thus very important and holds great potential for improving treatment strategies. Common MRD targets include recurrent cytogenetic abnormalities and mutations in important hematological genes; unfortunately well-characterized targets are lacking in many AL patients. Here we demonstrate a technical approach for the identification and mapping of novel clone-specific chromosomal abnormalities down to the nucleotide level. We used molecular cytogenetics, chromosome microdissection, amplification of the microdissected material, and next-generation sequencing to develop PCR-based MRD assays based on unique breakpoint sequences.

Pneumocystis pneumonia during medicamentous treatment of Cushing's syndrome--a description of two cases.

Only a few cases of pneumocystis pneumonia (PCP) in Cushing's syndrome have been published in the literature so far. In the majority of these patients, the pneumonia occurred after reduction of the hypercortisolism with medicamentous treatment. We report two cases of PCP during conservative treatment of hypercortisolism. We describe clinical, imaging and laboratory findings in two patients and review published cases of pneumocystits pneumonia in Cushing's syndrome. A 60-year-old woman and 20-year-old man with Cushing's syndrome due to ectopic ACTH syndrome were treated at our department. Both developed pneumocystis pneumonia early after treatment with ketoconazole and ethomidate bromide had been introduced and the levels of cortisol rapidly decreased. PCP prophylaxis in patients with high cortisolemia should be started before treatment of hypercortisolism in current practice. Gradual lowering of plasma cortisol should also reduce the risk of infection by Pneumocystis jiroveci.