Tacrolimus dose modification in patients receiving concomitant isavuconazole after hematopoietic stem cell transplantation.

INTRODUCTION: Isavuconazole is increasingly being used for antifungal prophylaxis during stem cell transplantation. Isavuconazole is a moderate inhibitor of Cytochrome P4503A4, and tacrolimus levels are anticipated to be elevated when given concomitantly with isavuconazole. We developed and validated a dose-modified tacrolimus regimen to better achieve and maintain target tacrolimus levels.Methods: Allogeneic stem cell transplantation recipients who received concomitant tacrolimus and isavuconazole from September 2017 to September 2018 were included. Tacrolimus was adjusted to achieve a target range 8-12 ng/ml. Intravenous tacrolimus was first initiated at 0.02 mg/kg/day on day 1, and transitioned to oral therapy using a 2:1 conversion ratio (n = 48). Clinical observations showed high interpatient variability. The intravenous dose was then reduced to 0.017 mg/kg/day, and oral:intravenous conversion changed to 3.1:1 (n = 24). RESULTS: Interpatient variability was high (lower in the 0.017 mg/kg/day group; P < 0.0217). Patients in the 0.017 mg/kg/day group required fewer dose changes (P < 0.023) and had fewer levels >15 ng/ml (P < 0.021). Median tacrolimus dose declined over time; 0.016, 0.012 and 0.011 on days 1, 7 and 10 for patients receiving 0.02 mg/kg/day and 0.017, 0.014 and 0.013 in the 0.017 mg/kg group. Day 10 tacrolimus accumulation factor was 1.42 Rac(Cmax) in the 0.02 mg/kg/day cohort compared to 1.23 Rac(Cmax) in the 0.017 mg/kg/day cohort (P < 0.015). When transitioned to oral therapy, a oral:intravenous conversion ratio >3.1:1 was shown to improve chances for achieving target levels (P > 0.0744). CONCLUSION: We recommend initiating intravenous tacrolimus dose at 0.017 mg/kg/day and using a 3.1:1 oral:intravenous conversion to reduce interpatient variability, drug accumulation and the number of suboptimal tacrolimus levels. Tacrolimus requires frequent drug level monitoring.

Ciprofloxacin vs levofloxacin for prophylaxis during hematopoietic stem-cell transplantation.

The objective of the current retrospective study was to compare differences in rate of breakthrough infections for ciprofloxacin vs levofloxacin prophylaxis in autologous hematopoietic stem-cell transplant (HSCT) patients treated for multiple myeloma. This was a retrospective, cohort study comparing autologous HSCT recipients treated for multiple myeloma who received ciprofloxacin prophylaxis vs levofloxacin prophylaxis. A total of 297 patients, 143 levofloxacin- and 154 ciprofloxacin-treated were included. There was a significantly higher incidence of bloodstream infections in the ciprofloxacin group (24/154) compared to the levofloxacin group (10/143), P = .03, primarily caused by a statistically higher incidence of gram-positive bloodstream infections (ciprofloxacin [21/154] vs levofloxacin [8/143]; P < .01). Clinically relevant differences exist between fluoroquinolone agents used for prophylaxis. Levofloxacin prophylaxis was more effective than ciprofloxacin prophylaxis to reduce the incidence of bloodstream infections in this study.

Frequency, risk factors, and outcomes of central nervous system relapse in lymphoma patients treated with dose-adjusted EPOCH plus rituximab.

BACKGROUND: Central nervous system (CNS) relapse in non-Hodgkin lymphoma (NHL) is a rare but serious complication that carries a poor prognosis. The use of infusional etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab (EPOCH-R) for frontline treatment of diffuse large B cell lymphoma (DLBCL) is increasing, though little is known about incidence of and risk factors for CNS relapse with this regimen PATIENTS AND METHODS: We completed a chart review of patients with NHL who received EPOCH-R as front line therapy. Data obtained included baseline and treatment characteristics including if patients received CNS directed therapy. We measured overall survival (OS), progression free survival (PFS), and progression to CNS involvement. RESULTS: We identified 223 patients who met the inclusion criteria, 72% had DLBCL. Of all the patients, 5.8% experienced CNS relapse, and 38.6% were treated with CNS prophylaxis. There was no difference in rate of CNS relapse, OS, or PFS between patients who had and had not received CNS prophylaxis. Patients whose serum lactate dehydrogenase was greater than twice the upper limit of normal at diagnosis and those with extranodal disease were significantly more likely to have CNS relapse (P = .0247 and 0.022, respectively) than their counterparts. CONCLUSIONS: The rate of CNS relapse in this patient population approaches 6%, not significantly different from reports on those receiving R-CHOP. The results of this study suggest that CNS prophylaxis might be more selectively used among patients treated with EPOCH-R with certain high-risk features.

Tumor lysis syndrome in the era of novel and targeted agents in patients with hematologic malignancies: a systematic review.

Effective new treatments are now available for patients with hematologic malignancies. However, their propensity to cause tumor lysis syndrome (TLS) has not been systematically examined. A literature search identified published Phase I-III clinical trials of monoclonal antibodies (otlertuzumab, brentuximab, obinutuzumab, ibritumomab, ofatumumab); tyrosine kinase inhibitors (alvocidib [flavopiridol], dinaciclib, ibrutinib, nilotinib, dasatinib, idelalisib, venetoclax [ABT-199]); proteasome inhibitors (oprozomib, carfilzomib); chimeric antigen receptor (CAR) T cells; and the proapoptotic agent lenalidomide. Abstracts from major congresses were also reviewed. Idelalisib and ofatumumab had no reported TLS. TLS incidence was ≤5 % with brentuximab vedotin (for anaplastic large-cell lymphoma), carfilzomib and lenalidomide (for multiple myeloma), dasatinib (for acute lymphoblastic leukemia), and oprozomib (for various hematologic malignancies). TLS incidences were 8.3 and 8.9 % in two trials of venetoclax (for chronic lymphocytic leukemia [CLL]) and 10 % in trials of CAR T cells (for B-cell malignancies) and obinutuzumab (for non-Hodgkin lymphoma). TLS rates of 15 % with dinaciclib and 42 and 53 % with alvocidib (with sequential cytarabine and mitoxantrone) were seen in trials of acute leukemias. TLS mitigation was employed routinely in clinical trials of alvocidib and lenalidomide. However, TLS mitigation strategies were not mentioned or stated only in general terms for many studies of other agents. The risk of TLS persists in the current era of novel and targeted therapy for hematologic malignancies and was seen to some extent with most agents. Our findings underscore the importance of continued awareness, risk assessment, and prevention to reduce this serious potential complication of effective anticancer therapy.

Filgrastim versus TBO-filgrastim to reduce the duration of neutropenia after autologous hematopoietic stem cell transplantation: TBO, or not TBO, that is the question.

After a hospital-wide formulary change resulted in the replacement of filgrastim with TBO-filgrastim for all on- and off-label indications, we performed a retrospective comparison of patients with myeloma receiving 200 mg/m(2) melphalan with autologous hematopoietic stem cell transplantation to see whether the type of growth factor used post-transplant made a difference. One hundred and eighty-two consecutive patients with myeloma were studied, 91 receiving filgrastim immediately prior to the change and 91 receiving TBO-filgrastim afterward. The CD34(+) cell dose was comparable, as were other characteristics. Although the overall time to neutrophil recovery was similar for both groups, early engraftment (≤ 12 d) occurred more often (p = 0.05), and late engraftment (≥ 14 d) less often (p = 0.09) in filgrastim-treated patients. The number of documented infections was significantly less in the TBO-filgrastim group. Day 100 mortality and hospital stay were similar for the two groups. These data indicate that there is no material difference between filgrastim and TBO-filgrastim in this clinical setting.

Changing epidemiology of Clostridium difficile-associated disease during stem cell transplantation.

The incidence and severity of Clostridium difficile-associated disease (CDAD) within the general population has risen dramatically over the past decade, yet little data are available from hematopoietic stem cell transplantation (HSCT) centers. In the present study, we performed a chart review of 822 consecutive autologous and allogeneic HCST recipients treated at Northwestern Memorial Hospital between 2004 and 2008 to determine the incidence of CDAD at our institution. Variables including age, sex, diagnosis, chemotherapy regimen, transplantation type, microbial colonization, coinfections, diet, antibiotic use, neutropenic fever, comorbid conditions, time to engraftment, growth factor administration, and occurrence of graft-versus-host disease were assessed as potential risk factors for the development of CDAD. Eighty-five CDAD cases (10.3%) were identified. Bivariate analysis revealed a significant association between CDAD and neutropenic fever, administration of a neutropenic diet, ciprofloxacin and aztreonam use and duration of therapy, vancomycin and aztreonam use and duration of therapy, receipt of an allogeneic transplantation, bacterial coinfection, and vancomycin-resistant Entereococcus faecium (VRE) colonization. Cox regression analysis identified the following as factors associated with the development of CDAD: age >60 years, allogeneic transplantation, and prior VRE colonization. Allogeneic recipients with CDAD experienced increased higher rates of grades II to IV gastrointestinal graft-versus-host disease and nonrelapse mortality. A risk stratification model was developed to identify HSCT recipients at different levels of risk. With an incidence >10%, CDAD is a significant infectious complication of stem cell transplantation.

Variability of cyclosporine concentrations by HPLC and TDX monoclonal assay methods, application of a correction factor, and description of a novel clinical approach to determine the practical consequences of changing assay technique.

Cyclosporine (CSA) is an immunosuppressant used for the prevention of graft rejection and graft-versus-host disease (GVHD) during hematopoietic stem cell transplantation. Therapeutic drug monitoring (TDM) is recommended to ensure efficacy and prevent toxicity. Several immunoassay assay are commercially available for measuring CSA drug concentrations. Differences in the cross-reactive metabolites measured by specific immunoassay tests contribute to the significant lack of specificity which has been reported between immunoassays and high performance liquid chromatography (HPLC) test results. Inter-assay test results can affect interpretation of CSA drug concentrations and potentially compromise patient outcomes. The current study analyzed 72 paired HPLC-monoclonal TDX (TDXm) CSA drug concentrations and calculated a clinically reliable correction factor which could be applied to HPLC-TDXm results for TDM. A unique concordance-discordance simulation model was utilized to validate the correction factor for clinical use.

Questioning the role of a neutropenic diet following hematopoetic stem cell transplantation.

The use of a neutropenic diet (ND) after hematopoietic stem cell transplantation (HSCT) was instituted more than 30 years ago as a means of preventing infection from organisms colonizing the gastrointestinal tract. Evidence supporting this practice is lacking, however, and the actual efficacy of the ND remains unknown. Institutional policy at Northwestern Memorial Hospital discontinued the use of ND in 2006. We conducted a retrospective study of 726 consecutive HSCT recipients, 363 who received an ND and 363 who received a general hospital diet, to determine the incidence of microbiologically confirmed infections during and after transplantation. Our findings indicate a higher rate of infections in the HSCT recipients who received an ND.

Evaluation of hepatotoxicity with off-label oral-treatment doses of voriconazole for invasive fungal infections.

The approved treatment dose of intravenous voriconazole is a weight-based dose of 4 mg/kg of body weight twice daily; the approved oral dosing is fixed at 200 mg twice daily. In our institution, patients frequently receive oral high-dose voriconazole at 4 mg/kg twice daily. It is unknown if higher doses are associated with increased hepatotoxicity. A retrospective cohort study of patients treated with oral voriconazole for presumed invasive fungal infection for ≥7 days was completed. Patients receiving a fixed dose (i.e., labeled dose) were frequency matched and compared to those receiving a weight-based dose (i.e., high dose). The primary endpoint of hepatotoxicity was evaluated by using NCI Common Terminology Criteria (CTC) and components of liver enzymes measuring >3× the upper limit of normal (ULN) and >5× baseline measurements. Secondary endpoints included an incidence of other adverse drug events. Twenty-five labeled-dose and 84 high-dose voriconazole patients were studied. Liver enzyme abnormalities were similar between groups, with the exception of labeled-dose patients experiencing more alkaline phosphatase (ALP) CTC >2× the baseline (P = 0.02) and ALP levels >3× the ULN (P = 0.02). Treatment with high dose was associated with the discontinuation of voriconazole for practitioner attribution of adverse drug events (P = 0.03), although reasons varied and no commonality of biomarker abnormality was identified. Multivariate analysis revealed that the duration of therapy and higher mg/kg total daily doses as interval variables were predictive of some hepatotoxicity outcomes. No difference existed in liver abnormalities for high-dose voriconazole; however, higher mg/kg doses and a longer duration of therapy may be associated with hepatotoxicity.

Revisiting Infectious Complications Following Total Parenteral Nutrition Use During Hematopoietic Stem Cell Transplantation.

BACKGROUND: Total parenteral nutrition (TPN) is frequently used to manage caloric needs during hematopoietic stem cell transplantation (HSCT). Previous studies in transplant patients who received TPN have reported widely discordant results with regard to infection and mortality, and risk factors for TPN-related infection remain unclear. METHOD: We conducted a retrospective study of all HSCT recipients treated with TPN between 2005 to 2014 at Northwestern Memorial Hospital to determine the incidence and epidemiology of infections. Electronic records were used to identify patients treated with TPN for at least 2 days who developed infection. RESULTS: Among 198 patients treated with TPN, 30% developed documented infection. Total parenteral nutrition treatment duration (13 vs. 7 days; p < .0001) and the timing of TPN initiation (> day 9 post HSCT; p < .0001) were significantly higher in patients who received TPN and developed infection. Receipt of an allogeneic transplant was associated with increased risk for infection (p < .0138), and day 60 mortality was significantly higher in TPN-treated patients with infection (p < .0001). CONCLUSION: Stem cell recipients who receive TPN, especially from an allogeneic donor, have high rates of infection and mortality. Minimizing TPN exposure may reduce the chance for infection.

Serial plasma voriconazole concentrations after allogeneic hematopoietic stem cell transplantation.

Plasma voriconazole concentrations vary considerably between patients receiving standard dosing, and trough voriconazole concentrations are known to affect efficacy and toxicity. Temporal variations in serial plasma voriconazole concentrations through the course of therapy in hematopoietic stem cell transplantation patients has not been carefully described. Paired voriconazole concentrations in 64 patients were studied to determine the predictability of the second concentration based on the first. The difference between the two values was < or = 5% in six patients. In 25 patients, the second concentration was higher by a median of 40%. In 33 patients, the subsequent concentration was lower by a median of 59%. For patients with an initial concentration of < 2 microg/ml, the correlation between the two values was poor (r = 0.24; P < 0.17). For those with an initial concentration of > or = 2 microg/ml, the correlation was good (r = 0.72; P < 0.0001). There was no relationship between the magnitude of the change and the time elapsing between the two measurements. Among the 43 patients who had an initial concentration of > or = 1 microg/ml, the two voriconazole measurements were strongly correlated (r = 0.66, P < 0.0001), but only 67% had a voriconazole serum concentration of > or = 1 microg/ml on the second measurement. No studied variables were reliable predictors in identifying concentrations above or below 1 or 2 microg/ml. Our data suggest that variations in voriconazole concentrations are unpredictable despite standard dosing, and the acceptability of a concentration on one occasion cannot be extrapolated to future concentrations in the same patient. This suggests that ongoing therapeutic drug monitoring and dose adjustment may be beneficial in patients requiring prolonged voriconazole therapy.

Aztreonam and Vancomycin for Initial Treatment of Febrile Neutropenia in Penicillin-Allergic Patients During Hematopoietic Stem Cell Transplantation.

Most patients who undergo hematopoietic stem cell transplantation develop neutropenic fever and are at high risk for developing potentially life-threatening infections. ß-lactam antibiotics remain the cornerstone for initial empiric treatment of neutropenic fever. In cancer patients with allergy or intolerance to ß-lactams, guidelines recommend using aztreonam with vancomycin (AV) for neutropenic fever treatment. To date, the efficacy of AV for the treatment of neutropenic fever during stem cell transplantation is unknown. A retrospective study was conducted to identify hematopoietic stem cell transplantation recipients who were initially treated with concomitant AV for neutropenic fever between 2007 and 2013. Febrile neutropenia was classified as neutropenia with unexplained fever, neutropenic fever with a local source of infection, or neutropenic fever with a microbiologically documented infection. Seventy-six patients were identified who received AV as initial treatment for neutropenic fever over the study period. Responses to AV for neutropenia with unexplained fever (n = 41), febrile neutropenia with local site of infection (n = 11 [pneumonia = 9, other = 2]), and neutropenic fever with microbiologically documented infection (n = 34) were 75%, 55% (45% pneumonia), and 46% respectively. Infection-related mortality was 5%. Aztreonam with vancomycin was effective in treating neutropenia with unexplained fever. For patients with neutropenic fever and local source or microbiologically documented infection, alternative antibiotic treatments should be considered.

Evaluation of serious adverse drug reactions: a proactive pharmacovigilance program (RADAR) vs safety activities conducted by the Food and Drug Administration and pharmaceutical manufacturers.

BACKGROUND: The Food and Drug Administration (FDA) and pharmaceutical manufacturers conduct most postmarketing pharmaceutical safety investigations. These efforts are frequently based on data mining of databases. In 1998, investigators initiated the Research on Adverse Drug events And Reports (RADAR) project to investigate reports of serious adverse drug reactions (ADRs) and prospectively obtain information on these cases. We compare safety efforts for evaluating serious ADRs conducted by the FDA and pharmaceutical manufacturers vs the RADAR project. METHODS: We evaluated the completeness of serious ADR descriptions in the FDA and RADAR databases and the comprehensiveness of notifications disseminated by pharmaceutical manufacturers and the RADAR investigators. A serious ADR was defined as an event that led to death or required intensive therapies to reverse. RESULTS: The RADAR investigators evaluated 16 serious ADRs. Compared with descriptions of these ADRs in FDA databases (2296 reports), reports in RADAR databases (472 reports) had a 2-fold higher rate of including information on history and physical examination (92% vs 45%; P<.001) and a 9-fold higher rate of including basic science findings (34% vs 4%; P = .08). Safety notifications were disseminated earlier by pharmaceutical suppliers (2 vs 4 years after approval, respectively), although notifications were less likely to include information on incidence (46% vs 93%; P = .02), outcomes (8% vs 100%; P<.001), treatment or prophylaxis (25% vs 93%; P<.001), or references (8% vs 80%; P<.001). CONCLUSION: Proactive safety efforts conducted by the RADAR investigators are more comprehensive than those conducted by the FDA and pharmaceutical manufacturers, but dissemination of related safety notifications is less timely.

Venous thromboembolism and mortality associated with recombinant erythropoietin and darbepoetin administration for the treatment of cancer-associated anemia.

CONTEXT: The erythropoiesis-stimulating agents (ESAs) erythropoietin and darbepoetin are licensed to treat chemotherapy-associated anemia in patients with nonmyeloid malignancies. Although systematic overviews of trials have identified venous thromboembolism (VTE) risks, none have identified mortality risks with ESAs. OBJECTIVE: To evaluate VTE and mortality rates associated with ESA administration for the treatment of anemia among patients with cancer. DATA SOURCES: A published overview from the Cochrane Collaboration (search dates: January 1, 1985-April 1, 2005) and MEDLINE and EMBASE databases (key words: clinical trial, erythropoietin, darbepoetin, and oncology), the public Web site of the US Food and Drug Administration and ESA manufacturers, and safety advisories (search dates: April 1, 2005-January 17, 2008). STUDY SELECTION: Phase 3 trials comparing ESAs with placebo or standard of care for the treatment of anemia among patients with cancer. DATA EXTRACTION: Mortality rates, VTE rates, and 95% confidence intervals (CIs) were extracted by 3 reviewers from 51 clinical trials with 13 611 patients that included survival information and 38 clinical trials with 8172 patients that included information on VTE. DATA SYNTHESIS: Patients with cancer who received ESAs had increased VTE risks (334 VTE events among 4610 patients treated with ESA vs 173 VTE events among 3562 control patients; 7.5% vs 4.9%; relative risk, 1.57; 95% CI, 1.31-1.87) and increased mortality risks (hazard ratio, 1.10; 95% CI, 1.01-1.20). CONCLUSIONS: Erythropoiesis-stimulating agent administration to patients with cancer is associated with increased risks of VTE and mortality. Our findings, in conjunction with basic science studies on erythropoietin and erythropoietin receptors in solid cancers, raise concern about the safety of ESA administration to patients with cancer.

Managing Tumor Lysis Syndrome in the Era of Novel Cancer Therapies.

Abstract Tumor lysis syndrome (TLS) is a potentially life-threatening emergency that can develop rapidly after the release of intracellular contents from lysed malignant cells. The advent of novel and targeted therapies that have improved tumor-killing efficacy has the potential to increase the risk of TLS when used as part of front-line therapy. A recent review of TLS risk in patients with hematologic malignancies treated with newer targeted agents highlighted the need to revisit TLS risk stratification and to describe the practical challenges of TLS prevention, treatment, and monitoring. Although this era of rapid development of novel cancer therapies provides new hope for patients with hematologic malignancies, it is essential to be prepared for TLS because monitoring and prophylaxis can almost always prevent severe and life-threatening consequences. Heightened awareness of the development of TLS with novel and targeted agents, accompanied by aggressive hydration and rational, risk-appropriate management, are the keys to successful outcomes.

Olanzapine Reduces Chemotherapy-induced Nausea and Vomiting Compared With Aprepitant in Myeloma Patients Receiving High-dose Melphalan Before Stem Cell Transplantation: A Retrospective Study.

INTRODUCTION: Acute and delayed chemotherapy-induced nausea and vomiting (CINV) occurs in most patients who receive high-dose melphalan and significantly affects patients' quality of life during autologous stem cell transplantation. Faced with unsatisfactory results using an aprepitant-based regimen, an olanzapine-based regimen was initiated, with the hope of improving the incidence of acute and delayed CINV. A retrospective study was conducted to compare the effectiveness of olanzapine- versus aprepitant-based regimens for CINV prevention in adult hematopoietic stem cell recipients who received high-dose melphalan. PATIENTS AND METHODS: We compared olanzapine (n = 43) to aprepitant (n = 54) and fosaprepitant (n = 20). Olanzapine was given orally at 5 mg twice daily for 5 days, aprepitant was given at 125 mg on day -1 and 80 mg on days 0 and 1, and fosaprepitant was given at 150 mg on day -1. The dose of 2 concomitant drugs (dexamethasone and 5-hydroxytryptamine type 3 receptor antagonist) was similar in the 2 groups. Nausea prevention was the primary endpoint. A complete response using a composite index of no emesis and no use of rescue medications was the secondary endpoint. RESULTS: The results showed that olanzapine significantly reduced the number of patients who experienced acute (P < .0001) or delayed (P < .004) nausea and significantly reduced the use of rescue medications for acute-onset (P < .0046) and delayed-onset (P < .0001) CINV compared with aprepitant. CONCLUSION: Compared with fosaprepitant, olanzapine reduced the number of patients with acute (P < .0318) and delayed (P < .1519) nausea and reduced the need for rescue medications for acute-onset (P < .0643) and delayed-onset (P < .0024) CINV.

The Research on Adverse Drug Events and Reports (RADAR) project.

CONTEXT: In 1998, a multidisciplinary team of investigators initiated RADAR (Research on Adverse Drug events And Reports), a clinically based postmarketing surveillance program that systematically investigates and disseminates information describing serious and previously unrecognized adverse drug and device reactions (ADRs). OBJECTIVE: To describe the structure, operations, and preliminary findings from the RADAR project and related dissemination efforts by pharmaceutical suppliers and the US Food and Drug Administration (FDA). DESIGN: After identifying a serious and unexpected clinical event suitable for further investigation, RADAR collaborators postulated clinical hypotheses and derived case series and incidence estimates from physician queries, published and unpublished clinical trials, published case reports, FDA databases, and manufacturer sales figures. RESULTS: RADAR investigators identified 16 types of serious ADRs among 1699 patients, of whom 169 (10%) died as a result of the reaction. Initial cases were identified by 7 RADAR investigators, 4 collaborating physicians, 2 attorneys, and by reviewing 3 published reports. Additional sources included queries of occupational health programs and medical directors of interventional cardiology laboratories (3 types of ADRs), published manuscripts and clinical trials (11 types of ADRs), review of medical records at a RADAR site (2 types of ADRs), unpublished clinical trial reports (3 types of ADRs), and reports from attorneys, family members, or patients (4 types of ADRs). Incidence estimates, ranging from 0.4% to 33%, were derived from 5 clinical trial reports, 2 physician queries, and 2 observational databases. Laboratory support for hypotheses included identification of 3 neutralizing antibodies and 3 histopathological findings. ADR reports were disseminated as 8 revised package inserts, 7 "dear doctor" letters, and 9 peer-reviewed articles. CONCLUSION: A new, clinically based, hypothesis-driven approach to postmarketing surveillance may supplement existing regulatory surveillance systems and improve patient safety.

Risk of anaphylaxis with repeated courses of rasburicase: a Research on Adverse Drug Events and Reports (RADAR) project.

BACKGROUND: Rasburicase, a recombinant urate oxidase, is used to rapidly metabolize uric acid in patients with hyperuricaemia. Rasburicase is an immunogenic therapeutic protein, which has been shown to elicit antibody response in 64 % of healthy volunteers within 1-6 weeks after the initial course, with persistent antibodies for over 1 year. Drug labelling indicates that anaphylaxis rarely occurs (in <1 % of patients) after a single course of therapy with rasburicase, but there are no data available on the incidence of anaphylaxis in patients receiving a subsequent rasburicase course. OBJECTIVE: The objective of this study was to determine the incidence of anaphylaxis after multiple treatment courses of rasburicase. METHODS: A retrospective chart review was performed on 97 consecutively treated patients who received repeated courses of rasburicase for hyperuricaemia. RESULTS: None of the 97 patients who were reviewed experienced anaphylaxis during the first rasburicase course; however, six patients (6.2 %) experienced anaphylaxis during a subsequent rasburicase treatment course (p = 0.03). CONCLUSION: Anaphylaxis after a second course of rasburicase appears to occur more frequently than described in the US Food and Drug Administration-approved package insert for initial treatment courses. Given the serious nature of anaphylactic events, caution is advised when administering repeated courses of rasburicase.