Atovaquone versus trimethoprim-sulfamethoxazole as Pneumocystis jirovecii pneumonia prophylaxis following renal transplantation

ISCCM Position Statement on the Management of Invasive Fungal Infections in the Intensive Care Unit

Rationale

Invasive fungal infections (IFI) in the intensive care unit (ICU) are an emerging problem owing to the use of broad-spectrum antibiotics, immunosuppressive agents, and frequency of indwelling catheters. Timely diagnosis which is imperative to improve outcomes can be challenging. This position statement is aimed at understanding risk factors, providing a rational diagnostic approach, and guiding clinicians to optimize antifungal therapy.

Objectives

To update evidence on epidemiology, risk factors, diagnostic approach, antifungal initiation strategy, therapeutic interventions including site-specific infections and role of therapeutic drug monitoring in IFI in ICU and focus on some practice points relevant to these domains.

Methodology

A committee comprising critical care specialists across the country was formed and specific aspects of fungal infections and antifungal treatment were assigned to each member. They extensively reviewed the literature including the electronic databases and the international guidelines and cross-references. The information was shared and discussed over several meetings and position statements were framed to ensure their reliability and relevance in critical practice. The draft document was prepared after obtaining inputs and consensus from all the members and was reviewed by an expert in this field.

Results

The existing evidence on the management of IFI was updated and practice points were prepared under each subheading to enable critical care practitioners to streamline diagnosis and treatment strategies for patients in the ICU with additional detail on site-specific infections therapeutic drug monitoring.

Conclusion

This position statement attempts to address the management of IFI in immunocompetent and non-neutropenic ICU patients. The practice points should guide in optimization of the management of critically ill patients with suspected or proven fungal infections.

How to cite this article

Bhattacharya PK, Chakrabarti A, Sinha S, Pande R, Gupta S, Kumar AAK, et al. ISCCM Position Statement on the Management of Invasive Fungal Infections in the Intensive Care Unit. Indian J Crit Care Med 2024;28(S2):S20-S41.

Therapeutic Myths in Solid Organ Transplantation Infectious Diseases

Infection management in solid organ transplantation poses unique challenges, with a diverse array of potential pathogens and associated antimicrobial therapies. With limited high-quality randomized clinical trials to direct optimal care, therapeutic "myths" may propagate and contribute to suboptimal or excessive antimicrobial use. We discuss 6 therapeutic myths with particular relevance to solid organ transplantation and provide recommendations for infectious diseases clinicians involved in the care of this high-risk population.

Features and global impact of invasive fungal infections caused by Pneumocystis jirovecii: A systematic review to inform the World Health Organization fungal priority pathogens list

This systematic review evaluates the current global impact of invasive infections caused by Pneumocystis jirovecii (principally pneumonia: PJP), and was carried out to inform the World Health Organization Fungal Priority Pathogens List. PubMed and Web of Science were used to find studies reporting mortality, inpatient care, complications/sequelae, antifungal susceptibility/resistance, preventability, annual incidence, global distribution, and emergence in the past 10 years, published from January 2011 to February 2021. Reported mortality is highly variable, depending on the patient population: In studies of persons with HIV, mortality was reported at 5%-30%, while in studies of persons without HIV, mortality ranged from 4% to 76%. Risk factors for disease principally include immunosuppression from HIV, but other types of immunosuppression are increasingly recognised, including solid organ and haematopoietic stem cell transplantation, autoimmune and inflammatory disease, and chemotherapy for cancer. Although prophylaxis is available and generally effective, burdensome side effects may lead to discontinuation. After a period of decline associated with improvement in access to HIV treatment, new risk groups of immunosuppressed patients with PJP are increasingly identified, including solid organ transplant patients.

Repurposing Atovaquone as a Therapeutic against Acute Myeloid Leukemia (AML): Combination with Conventional Chemotherapy Is Feasible and Well Tolerated

Survival of pediatric AML remains poor despite maximized myelosuppressive therapy. The pneumocystis jiroveci pneumonia (PJP)-treating medication atovaquone (AQ) suppresses oxidative phosphorylation (OXPHOS) and reduces AML burden in patient-derived xenograft (PDX) mouse models, making it an ideal concomitant AML therapy. Poor palatability and limited product formulations have historically limited routine use of AQ in pediatric AML patients. Patients with de novo AML were enrolled at two hospitals. Daily AQ at established PJP dosing was combined with standard AML therapy, based on the Medical Research Council backbone. AQ compliance, adverse events (AEs), ease of administration score (scale: 1 (very difficult)-5 (very easy)) and blood/marrow pharmacokinetics (PK) were collected during Induction 1. Correlative studies assessed AQ-induced apoptosis and effects on OXPHOS. PDX models were treated with AQ. A total of 26 patients enrolled (ages 7.2 months-19.7 years, median 12 years); 24 were evaluable. A total of 14 (58%) and 19 (79%) evaluable patients achieved plasma concentrations above the known anti-leukemia concentration (>10 µM) by day 11 and at the end of Induction, respectively. Seven (29%) patients achieved adequate concentrations for PJP prophylaxis (>40 µM). Mean ease of administration score was 3.8. Correlative studies with AQ in patient samples demonstrated robust apoptosis, OXPHOS suppression, and prolonged survival in PDX models. Combining AQ with chemotherapy for AML appears feasible and safe in pediatric patients during Induction 1 and shows single-agent anti-leukemic effects in PDX models. AQ appears to be an ideal concomitant AML therapeutic but may require intra-patient dose adjustment to achieve concentrations sufficient for PJP prophylaxis.

Low-Dose TMP-SMX for Pneumocystis jirovecii Pneumonia Prophylaxis in Pediatric Solid Organ Transplant Recipients

OBJECTIVE

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic infection that adversely affects solid organ transplant (SOT) recipients. Published guidelines endorse 5 to 10 mg/kg/day (trimethoprim component) trimethoprim-sulfamethoxazole (TMP-SMX) as the recommended regimen for PJP prevention, often resulting in drug-related adverse effects. We investigated the use of a low-dose TMP-SMX regimen given at 2.5 mg/kg/dose once daily every Monday, Wednesday, and Friday at a large pediatric transplantation center.

METHODS

A retrospective chart review was conducted, including patients ages 0 to 21 years who underwent SOT from January 1, 2012, to May 1, 2020, and who were subsequently started on PJP prophylaxis with low-dose TMP-SMX for a minimum of 6 months. The primary end point was the incidence of breakthrough PJP infection on the low-dose TMP-SMX regimen. Secondary end points include the prevalence of adverse effects characteristic of TMP-SMX.

RESULTS

A total of 234 patients were included in this study, and 6 of 234 patients (2.6%) were empirically transitioned to treatment dosing of TMP-SMX given a clinical concern for PJP, although none received a diagnosis of PJP. There were 7 patients (2.6%) who experienced hyperkalemia, 36 (13.3%) had neutropenia, and 22 (8.1%) had thrombocytopenia (all grade 4). Clinically significant serum creatinine elevations were seen in 43 of 271 patients (15.9%). Elevations of liver enzymes were seen in 16 of 271 patients (5.9%). Rash was documented in 4 of 271 patients (1.5%).

CONCLUSIONS

In our patient cohort, low-dose TMP-SMX preserves the efficacy of PJP prophylaxis while providing an acceptable adverse effect profile.

Effect of Prophylactic Dose of Trimethoprim-Sulfamethoxazole on Serum Creatinine in Japanese Patients With Connective Tissue Diseases

Objectives:

At normal doses of trimethoprim-sulfamethoxazole (TMP/SMX), trimethoprim inhibits tubular creatinine secretion, leading to a rapid but reversible increase in serum creatinine (SCr). Although patients with connective tissue diseases are often in the state of immunosuppression and TMP/SMX is an important prophylactic drug, clinicians often have to stop or reduce the dosage due to concerns regarding its effect on renal function. This study aimed to evaluate the effect of a prophylactic dose of TMP/SMX on SCr in Japanese patients with connective tissue diseases, the extent of SCr level elevation and the independent risk factors for creatinine elevation.

Methods:

A retrospective cohort study was undertaken. Participants included patients with connective tissue diseases who were treated with a prophylactic dose of TMP/SMX between 2004 and 2018. Using single and multiple regression analyses, the risk factors that affected SCr elevation were evaluated.

Results:

A total of 262 patients, females, n = 181; age, median (range) = 59 (19-89) years, were included. The median baseline SCr level before treatment was 0.62 (0.16-2.1) mg/dL. The median SCr elevation value was 0.07 (−0.54 to 0.84) mg/dL in 4 weeks after TMP/SMX initiation. Five (2%) participants had ⩾0.3 mg/dL SCr elevation. Multiple regression analyses, including age, baseline SCr, diuretic use, nonsteroidal anti-inflammatory drug use and diabetes mellitus, indicated that baseline SCr and advanced age were independent risk factors of SCr elevation.

Conclusions:

These results demonstrated that baseline SCr and advanced age were associated with SCr elevation by a prophylactic dose of TMP/SMX. However, a prophylactic dose of TMP/SMX rarely elevated the SCr level significantly. Therefore, other causes can be considered if patients show an SCr elevation ⩾0.3 mg/dL.

Efficacy of Low-Dose Trimethoprim/Sulfamethoxazole for the Treatment of Pneumocystis jirovecii Pneumonia in Deceased Donor Kidney Recipients

Background

Trimethoprim/sulfamethoxazole (TMP-SMX) is considered the first-choice treatment for Pneumocystis jirovecii pneumonia (PJP) in recipients of solid organ transplantation. However, this treatment is associated with various severe adverse events that might not be tolerable for some renal transplant recipients, and the optimal dose remains elusive. The present study assessed the efficacy of low-dose TMP-SMX in recipients of a deceased donor kidney.

Methods

A total of 37 adult deceased donor kidney recipients who suffered PJP between January 2015 and June 2020 were included. The survival rates of the patients and grafts, the rate of invasive ventilation, and adverse events, including gastrointestinal discomfort, hematologic side effects, hyperkalemia, and renal function impairments, were assessed.

Results

The patient and graft survival rates were both 100%. Two patients (5.4%) required invasive ventilation. Eight patients (21.6%) reported gastrointestinal discomfort, but none required dose reduction or discontinued treatment. The frequencies of hematologic side effects, hyperkalemia and impaired kidney function were 5.4% (2/37), 2.7% (1/37), and 2.7% (1/37), respectively.

Conclusion

Optimization of TMP-SMX dose may reduce the risk of adverse events without compromising efficacy for the treatment of PJP in deceased donor kidney recipients.

Comparative effectiveness of trimethoprim-sulfamethoxazole versus atovaquone for the prophylaxis of pneumocystis pneumonia in patients with connective tissue diseases receiving prolonged high-dose glucocorticoids

We compared the prophylactic effect of trimethoprim-sulfamethoxazole (TMP-SMX) with atovaquone for pneumocystis pneumonia (PCP) in patients with connective tissue diseases (CTDs) receiving high-dose glucocorticoids. Patients with CTDs aged ≥ 18 years who were treated with a prolonged course (≥ 4 weeks) of glucocorticoids (≥ 20 mg/day prednisone) in a Japanese tertiary center between 2013 and 2017 were included. The patients were categorized into two groups: TMP-SMX and atovaquone group. Adjusted cumulative incidence of PCP was compared between the two groups after propensity score weighting for differences in confounding factors. A total of 480 patients with a prolonged high-dose glucocorticoid treatment were identified. Out of 383 patients with TMP-SMX prophylaxis, 102 (26.8%) patients experienced adverse events leading to discontinuation within 4 weeks of initiation, while no patient in the atovaquone discontinued the therapy. Two hundred eighty-one patients received TMP-SMX, while 107 received atovaquone for PCP prophylaxis. During a total of 397.0 person-years, 7 PCP cases (2 in the TMP-SMX, 5 in the atovaquone) occurred with a mortality rate of 54.5%. After adjusting for differences in baseline characteristics, the adjusted cumulative incidence of PCP was similar between the two group (HR 0.97, 95% CI 0.19-5.09, p = 0.97). Prophylactic effects for PCP in CTDs patients receiving prolonged high-dose glucocorticoids were similar between TMP-SMX and atovaquone. Atovaquone was well-tolerated with no side effects.

Primary prophylaxis of bacterial infections and Pneumocystis jirovecii pneumonia in patients with hematologic malignancies and solid tumors: 2020 updated guidelines of the Infectious Diseases Working Party of the German Society of Hematology and Medical Oncology (AGIHO/DGHO)

Hematologic and oncologic patients with chemo- or immunotherapy-related immunosuppression are at substantial risk for bacterial infections and Pneumocystis jirovecii pneumonia (PcP). As bacterial resistances are increasing worldwide and new research reshapes our understanding of the interactions between the human host and bacterial commensals, administration of antibacterial prophylaxis has become a matter of discussion. This guideline constitutes an update of the 2013 published guideline of the Infectious Diseases Working Party (AGIHO) of the German Society for Hematology and Medical Oncology (DGHO). It gives an overview about current strategies for antibacterial prophylaxis in cancer patients while taking into account the impact of antibacterial prophylaxis on the human microbiome and resistance development. Current literature published from January 2012 to August 2020 was searched and evidence-based recommendations were developed by an expert panel. All recommendations were discussed and approved in a consensus conference of the AGIHO prior to publication. As a result, we present a comprehensive update and extension of our guideline for antibacterial and PcP prophylaxis in cancer patients.

Efficacy and safety of trimethoprim-sulfamethoxazole for the prevention of pneumocystis pneumonia in human immunodeficiency virus-negative immunodeficient patients: A systematic review and meta-analysis

Background

Pneumocystis pneumonia (PCP) has a significant impact on the mortality of immunocompromised patients. It is not known whether the prophylactic application of trimethoprim-sulfamethoxazole (TMP-SMZ) can reduce the incidence of PCP and mortality in the human immunodeficiency virus (HIV)-negative immunodeficient population. The safety profile is also unknown. There have been few reports on this topic. The aim of this study was to systematically evaluate the efficacy and safety of the use of TMP-SMZ for the prevention of PCP in this population of patients from the perspective of evidence-based medicine.

Methods

A comprehensive search without restrictions on publication status or other parameters was conducted. Clinical randomized controlled trials (RCTs) or case-control trials (CCSs) of TMP-SMZ used for the prevention of PCP in HIV-negative immunocompromised populations were considered eligible. A meta-analysis was performed using the Mantel-Haenszel fixed-effects model or Mantel-Haenszel random-effects model, and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated and reported.

Results

Of the 2392 records identified, 19 studies (n = 4135 patients) were included. The efficacy analysis results indicated that the PCP incidence was lower in the TMP-SMZ group than in the control group (OR = 0.27, 95% CI (0.10, 0.77), p = 0.01); however, the rate of drug discontinuation was higher in the TMP-SMZ group than in the control group (OR = 14.31, 95% CI (4.78, 42.91), p<0.00001). In addition, there was no statistically significant difference in the rate of mortality between the two groups (OR = 0.54, 95% CI (0.21, 1.37), p = 0.19). The safety analysis results showed that the rate of adverse events (AEs) was higher in the TMP-SMZ group than in the control group (OR = 1.92, 95% CI (1.06, 3.47), p = 0.03).

Conclusions

TMP-SMZ has a better effect than other drugs or the placebo with regard to preventing PCP in HIV-negative immunocompromised individuals, but it may not necessarily reduce the rate of mortality, the rate of drug discontinuation or AEs. Due to the limitations of the research methodologies used, additional large-scale clinical trials and well-designed research studies are needed to identify more effective therapies for the prevention of PCP.

A Case of Pneumocystis jirovecii Pneumonia under Belatacept and Everolimus: Benefit-Risk Balance between Renal Allograft Function and Infection

Pneumocystis jirovecii pneumonia is an opportunistic disease usually prevented by trimethoprim-sulfamethoxazole. A 49-year-old HLA-sensitized male with successful late conversion from tacrolimus-based to belatacept-based immunosuppression developed P. jirovecii pneumonia for which he presented several risks factors: low lymphocyte count with no CD4+ T cells detected since 2 years, hypogammaglobulinemia, history of acute cellular rejection 3 years before, and immunosuppressive treatment (belatacept, everolimus). Because of respiratory gravity in the acute phase, the patient was given oxygen, corticosteroids, and trimethoprim-sulfamethoxazole. Thanks to the improvement of respiratory status, and because of the renal impairment, trimethoprim-sulfamethoxazole was converted to atovaquone for 21 days. Indeed, after 1 week on intensive treatment, the benefit-risk balance favored preserving renal function according to respiratory improvement status. P. jirovecii pneumonia prophylaxis for the next 6 months was monthly aerosol of pentamidine. Long-term safety studies or early/late conversion to belatacept did not report on P. jirovecii pneumonia. Four other cases of P. jirovecii pneumonia under belatacept therapy were previously described in patients having no P. jirovecii pneumonia prophylaxis. Studies on the reintroduction of P. jiroveciipneumonia prophylaxis after conversion to belatacept would be of interest. It could be useful to continue regular evaluation within the second-year post-transplantation regarding immunosuppression: T-cell subsets and immunoglobulin G levels.

Incidence and Clinical Significance of Hyperkalemia Following Heart Transplantation

BACKGROUND

Hyperkalemia (HK) is a life-threatening complication following solid organ transplantation, and patients often need potassium-chelating agents and deviations from standard posttransplant protocols. This is the first study to report the incidence and clinical impact of hyperkalemia following heart transplantation.

METHODS

We retrospectively included patients who underwent heart transplantation at our institution between April 2014 and December 2018. Patients with multiorgan transplantation were excluded. Clinical outcomes of patients who had serum potassium >5.5 mEq/L in the first year posttransplant (HK group) were compared to patients who did not have serum potassium >5.5 mEq/L in the first year posttransplant (non-HK group).

RESULTS

A total of 143 patients were included in this study. During the first year posttransplant, cumulative incidence of serum potassium >5.0, >5.5, and >6.0 mEq/L was 96%, 63%, and 24%, respectively. Fifty-five percent of patients required treatment with potassium-chelating agents. Sulfamethoxazole-trimethoprim was discontinued because of HK in 39% of patients. Overall survival of patients in the HK group (n = 89) was comparable to that of patients in the non-HK group (n = 54, 91% vs 98% at 1 year, P = .19), whereas infection-free survival was significantly lower in the HK group (34% vs 53% at 1 year, P = .010). Multivariate analysis revealed pretransplant renal dysfunction (odds ratio = 2.62; 95% confidence interval, 1.18-5.80; P = .018) and use of mechanical circulatory support (odds ratio = 2.90; 95% confidence interval, 1.08-7.76; P = .035) as significant predictors of posttransplant hyperkalemia.

CONCLUSIONS

The incidence of HK following heart transplantation was high, with more than half of patients requiring any therapeutic interventions, and HK was related to an increase in infection events.

Alternative pneumocystis prophylaxis in solid organ transplant recipients at two large transplant centers

BACKGROUND

Trimethoprim-sulfamethoxazole (TMP-SMX) is the drug of choice for Pneumocystis jirovecii pneumonia (PJP) prophylaxis and has activity against other opportunistic infections (OIs) after solid organ transplant (SOT). We aimed to describe the incidence, reasons for and outcomes of use of alternative prophylactic agents (APAs) across SOT programs in our high volume centers.

METHODS

Solid organ transplant recipients (SOTRs) at our centers from 1/2015-12/2016 were identified. Pharmacy records identified APA (pentamidine, atovaquone, or dapsone) use within 1 year. Records were reviewed for allergies, laboratory values at APA initiation, diagnostic tests for TMP-SMX-preventable OIs, and APA side effects.

RESULTS

An APA was initiated in 105/1173 (8.9%) SOTRs. Of these, 51 (48.6%) were because of sulfonamide allergy recorded pre-SOT, mostly rash/hives (58.8%). The remaining 54 (51.4%) had TMP-SMX discontinued post-SOT, mostly for neutropenia (48%) and renal effects (34%). Differences occurred across programs, with kidney transplant never stopping TMP-SMX for renal issues. Of those changed to APAs post-transplant, 19 (35%) were later successfully re-challenged with TMP-SMX. With thresholds in mind, 67 (64%) received an APA unnecessarily, accounting for up to $100 000/y excess cost. Potential TMP-SMX-preventable OIs occurred in 7 (5 Nocardia; 2 PJP). APA side effects occurred in 14/105 (13.3%).

CONCLUSIONS

Use of APAs for PJP prophylaxis after SOT is less than previously reported but often unwarranted. Such decisions require scrutiny to avoid TMP-SMX-preventable OIs, cost and important APA side effects. Use of reasonable thresholds for cessation of TMP-SMX and data-driven approaches to re-challenge would substantially reduce APA use.

Efficacies of atovaquone, pentamidine, and trimethoprim/sulfamethoxazole for the prevention of Pneumocystis jirovecii pneumonia in patients with connective tissue diseases

BACKGROUND

Pneumocystis jirovecii pneumonia (PCP) is an opportunistic infection in patients on steroid therapy for connective tissue diseases. The standard agent for primary PCP prophylaxis is trimethoprim/sulfamethoxazole (TMP-SMX), although this agent can cause common adverse reactions, including myelosuppression and renal toxicity, that result in cessation. Aerosolized pentamidine and oral atovaquone are alternatives for PCP prophylaxis. The efficacies of atovaquone, pentamidine, and TMP-SMX to prevent PCP in patients with connective tissue diseases have never been compared.

METHODS

Hospitalized patients with connective tissue diseases who started steroid therapy and PCP prophylaxis were enrolled. PCP prophylaxis regimens were oral TMP-SMX, aerosolized pentamidine, or oral atovaquone. Information was retrospectively collected from medical records about laboratory findings, duration of PCP prophylaxis, and reasons for terminating PCP prophylaxis.

RESULTS

Ninety-six patients received PCP prophylaxis. All of them were initially treated with TMP-SMX, but this was replaced during the study period with pentamidine in 33 patients and with atovaquone in 7. Forty-one (43%) patients discontinued TMP-SMX because of adverse events, and 5 (15%) also discontinued pentamidine. None of the patients discontinued atovaquone. The most frequent causes of TMP-SMX and pentamidine cessation were cytopenia (N = 15) and asthma (N = 2). The rates of continuing treatment with TMP-SMX, pentamidine, and atovaquone at one year after starting PCP prophylaxis were 55.3%, 68.6%, and 100%, respectively (P = 0.01). None of the patients developed PCP.

CONCLUSION

Although TMP-SMX for PCP prophylaxis had to be discontinued in 43% of patients with connective tissue diseases, pentamidine and atovaquone were well tolerated.

Fungal infections in solid organ transplantation: An update on diagnosis and treatment

Invasive fungal infections constitute an important cause of morbidity and mortality in solid organ transplantation recipients. Since solid organ transplantation is an effective therapy for many patients with end-stage organ failure, prevention and treatment of fungal infections are of vital importance. Diagnosis and management of these infections, however, remain difficult due to the variety of clinical symptoms in addition to the lack of accurate diagnostic methods. The use of fungal biomarkers can lead to an increased diagnostic accuracy, resulting in improved clinical outcomes. The evidence for optimal prophylactic approaches remains inconclusive, which results in considerable variation in the administration of prophylaxis. The implementation of a standard protocol for prophylaxis remains difficult as previous treatment regimens, which can alter the distribution of different pathogens, affect the outcome of antifungal susceptibility testing. Furthermore, the increasing use of antifungals also contributes to incremental costs and the risk of development of drug resistance. This review will highlight risk factors, clinical manifestations and timing of fungal infections and will focus predominately on the current evidence for diagnosis and management of fungal infections.

Drug-Induced Hematological Cytopenia in Kidney Transplantation and the Challenges It Poses for Kidney Transplant Physicians

Drug-induced hematological cytopenia is common in kidney transplantation. Various cytopenia including leucopenia (neutropenia), thrombocytopenia, and anemia can occur in kidney transplant recipients. Persistent severe leucopenia or neutropenia can lead to opportunistic infections of various etiologies. On the contrary, reducing or stopping immunosuppressive medications in these events can provoke a rejection. Transplant clinicians are often faced with the delicate dilemma of balancing cytopenia and rejection from adjustments of immunosuppressive regimen. Differentials of drug-induced cytopenia are wide. Identification of culprit medication and subsequent modification is also challenging. In this review, we will discuss individual drug implicated in causing cytopenia and correlate it with corresponding literature evidence.

A Repurposed Drug for Brain Cancer: Enhanced Atovaquone Amorphous Solid Dispersion by Combining a Spontaneously Emulsifying Component with a Polymer Carrier

Glioblastoma multiforme (GBM) is the most common and lethal central nervous system tumor. Recently, atovaquone has shown inhibition of signal transducer and activator transcription 3, a promising target for GBM therapy. However, it is currently unable to achieve therapeutic drug concentrations in the brain with the currently reported and marketed formulations. The present study sought to explore the efficacy of atovaquone against GBM as well as develop a formulation of atovaquone that would improve oral bioavailability, resulting in higher amounts of drug delivered to the brain. Atovaquone was formulated as an amorphous solid dispersion using an optimized formulation containing a polymer and a spontaneously emulsifying component (SEC) with greatly improved wetting, disintegration, dispersibility, and dissolution properties. Atovaquone demonstrated cytotoxicity against GBM cell lines as well as provided a confirmed target for atovaquone brain concentrations in in vitro cell viability studies. This new formulation approach was then assessed in a proof-of-concept in vivo exposure study. Based on these results, the enhanced amorphous solid dispersion is promising for providing therapeutically effective brain levels of atovaquone for the treatment of GBM.

Tolerability of low-dose sulfamethoxazole/trimethoprim for Pneumocystis jirovecii pneumonia prophylaxis in kidney transplant recipients

Background- Pneumocystis jirovecii pneumonia (PCP) is an opportunistic infection seen in immunosuppressed patients, including solid-organ transplant recipients. Sulfamethoxazole/trimethoprim (SMX/TMP) has long been considered first-line therapy for PCP prophylaxis. Optimal dosing regimens in solid-organ transplant recipients have not been fully defined. Objective-To examine the tolerability of a 1-year, 3-times weekly, prophylactic regimen of a single-strength SMX/TMP tablet. Study Design-Single-center, retrospective cohort study. Setting-A tertiary-care medical center, including inpatient hospitalizations and outpatient transplant clinic visits. Patients-Adult patients who received a kidney transplant between December 1, 2010, and November 30, 2012, at Hartford Hospital. Patients receiving a concurrent extrarenal transplant were excluded. Patients' charts were reviewed for up to 1 year after transplant. Results-A total of 88 patients were included in the analysis. Sixty-seven patients finished a full year of SMX/TMP after transplant, 10 patients discontinued SMX/TMP less than 1 year after transplant, and 11 patients started taking atovaquone instead of SMX/TMP after transplant. Documented reasons for discontinuation included hyperkalemia, leukopenia, diarrhea, and simplification of medication regimen. Patients without a documented reason for discontinuation did not have any obvious anomalies in laboratory values that would account for the discontinuation. Patients who received atovaquone for PCP prophylaxis had higher rates of recurrent urinary tract infections than did patients who received SMX/TMP for prophylaxis (33% vs 7%, P = .02). A longer postoperative stay (median [interquartile range, IQR] 13 [8.25-26] days vs 7 [6-9.5] days, P = .02), higher rates of delayed graft function (50% vs 10%, P = .004), as well as higher serum creatinine levels on postoperative day 7 (6.25 [2.4-10.1] mg/dL vs 1.8 [1.2-4.2] mg/dL, P= .01), postoperative month 1 (1.9 [0.8] mg/dL vs 1.4 [0.5] mg/dL, P = .002), and postoperative month 12 (1.6 [0.5] mg/dL vs 1.3 [0.3] mg/dL, P = .04) were associated with early SMX/TMP discontinuation. Conclusion-A low-dose prophylactic SMX/TMP regimen of 1 single-strength tablet 3 times weekly is well tolerated. Discontinuation rates were lower than other rates reported for higher-dose regimens.

[Severe hypoxemic respiratory failure caused by Pneumocystis jirovecii in a late kidney transplant recipient]

Pneumonia caused by Pneumocystis jirovecii is an uncommon infection in kidney transplant patients that can have an acute and rapid progression to respiratory failure and death. The period of greatest risk occurs in the first six months after the transplant, and it relates to the high doses of immunosuppression drugs required by patients. However, it may occur late, associated with the suspension of prophylaxis with trimethoprim-sulfamethoxazole.We present two cases of renal transplant patients who had severe hypoxemic respiratory failure due to P. jirovecii six years after transplantation. In addition to steroids, they received treatment with trimethoprim-sulfamethoxazole. One patient died, while the other had clinical recovery, with preservation of the renal graft function.

Hypercalcaemia preceding diagnosis of Pneumocystis jirovecii pneumonia in renal transplant recipients

BACKGROUND

The overall incidence of Pneumocystis jirovecii pneumonia (PJP) in solid organ transplant recipients is 5-15%. A timely diagnosis of PJP is difficult and relies on imaging and detection of the organism.

METHODS

We present a case series of four patients displaying hypercalcaemia with an eventual diagnosis of PJP and document the management of the outbreak with a multidisciplinary team approach. We discuss the underlying pathophysiology and previous reports of hypercalcaemia preceding a diagnosis of PJP. We also reviewed the evidence concerning PJP diagnosis and treatment.

RESULTS

Within our renal transplant cohort, four patients presented within 7 months with hypercalcaemia followed by an eventual diagnosis of PJP. We measured their corrected calcium, parathyroid hormone (PTH), 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] and 25-hydroxycholecalciferol [25(OH)D] levels at admission and following treatment of PJP. All four patients diagnosed with PJP were 4-20 years post-transplantation. Three of the four patients demonstrated PTH-independent hypercalcaemia (corrected calcium >3.0 mmol/L). The presence of high 1,25(OH)2D3 and low 25(OH)D levels suggest negation of the negative feedback mechanism possibly due to an extrarenal source; in this case, the alveolar macrophages. All four patients had resolution of their hypercalcaemia after treatment of PJP.

CONCLUSIONS

Given the outbreak of PJP in our renal transplant cohort, and based on previous experience from other units nationally, we implemented cohort-wide prophylaxis with trimethoprim-sulphamethoxazole for 12 months in consultation with our local infectious diseases unit. Within this period there have been no further local cases of PJP.

Switch to atovaquone and subsequent re-challenge with trimethoprim-sulfamethoxazole for Pneumocystis prophylaxis in a kidney transplant population

Kidney transplant recipients who are switched to atovaquone (ATO) from trimethoprim-sulfamethoxazole (TMP/SMX) for Pneumocystis jirovecii pneumonia (PJP) prophylaxis because of adverse events or complications may miss opportunities to be re-challenged with TMP/SMX, the first-line agent. This single-site, retrospective study assessed kidney transplant recipients for documented reasons for switching from TMP/SMX to alternate PJP prophylaxis and outcomes of TMP/SMX re-challenge. Out of 166 patients, 155 initially received TMP/SMX; of these, 31 were switched to ATO for various reasons. Fourteen patients receiving ATO were re-challenged with TMP/SMX; all were successfully re-initiated on TMP/SMX therapy. Most patients switched to ATO post kidney transplant secondary to non-hypersensitivity reasons should be re-challenged with TMP/SMX because of the advantages it provides over other agents.

Cytopenia Occurrence in Kidney Transplant Recipients Within Early Post-transplant Period

Objective:

This study assessed incidence, severity, and time to occurrence of drug-induced leukopenia/thrombocytopenia within 1^st month after kidney transplantation.

Methods:

This cross-sectional study was conducted on newly kidney transplant recipients from two hospitals, Iran. Patients with thrombocytopenia due to acute antibody-mediated rejection were excluded from the study. Demographic, clinical, and laboratory data of patients within the 1^st month after transplantation were collected.

Findings:

Of 213 patients, 14.1% and 66.2% experienced leukopenia and thrombocytopenia, respectively. Cytopenia happened more commonly among patients with thymoglobulin-containing regimen (for leukopenia: 24.6% vs. 0%, P < 0.001; for thrombocytopenia 84.4% vs. 41.8%, P < 0.001). Most leukopenia patients experienced Grades 1 and 2 of leukopenia (46.6% and 40% of patients). Most thrombocytopenic patients showed Grade 1 of thrombocytopenia (78.7%). Cumulative dose of thymoglobulin did not differ between patients with and without leukopenia (5.57 ± 1.13 vs. 5.9 ± 1.96 mg/kg; P = 0.613) or with and without thrombocytopenia (5.87 ± 1.86 vs. 5.56 ± 1.38 mg/kg; P = 0.29). Cytopenia were more common among recipients from deceased compared with from living donors (91.3% vs. 8.7% for leukopenia patients, P = 0.001; 69.9% vs. 33.1% for thrombocytopenia, P = 0.02). More patients with kidney from deceased donors received thymoglobulin in their immunosuppressive regimen (82% vs. 37%; P < 0.001). The median time to leukopenia and thrombocytopenia were 3 days and 1 day, respectively.

Conclusion:

Among immunosuppressive and prophylactic antimicrobial agents, thymoglobulin is more related to cytopenia; therefore, thymoglobulin dose reduction is recommended as the first intervention to manage cytopenia without need for reduction of its cumulative dose. The higher prevalence of cytopenia among recipients from deceased donors may be related to the higher use of thymoglobulin in these patients.

Pneumocystis Pneumonia in Solid-Organ Transplant Recipients

Pneumocystis pneumonia (PCP) is well known and described in AIDS patients. Due to the increasing use of cytotoxic and immunosuppressive therapies, the incidence of this infection has dramatically increased in the last years in patients with other predisposing immunodeficiencies and remains an important cause of morbidity and mortality in solid-organ transplant (SOT) recipients. PCP in HIV-negative patients, such as SOT patients, harbors some specificity compared to AIDS patients, which could change the medical management of these patients. This article summarizes the current knowledge on the epidemiology, risk factors, clinical manifestations, diagnoses, prevention, and treatment of Pneumocystis pneumonia in solid-organ transplant recipients, with a particular focus on the changes caused by the use of post-transplantation prophylaxis.

Dapsone-induced methemoglobinemia in renal transplant recipients: more prevalent than previously thought

BACKGROUND

After an outbreak of Pneumocystis pneumonia (PCP) in our nephrology unit, dapsone was used as the second-line chemoprophylactic agent. Dapsone is the most common cause of drug-induced methemoglobinemia (MHb). Its prevalence is poorly described in the renal transplant population. Because dapsone is excreted by the kidneys, we hypothesized that the rate of MHb in these patients would be higher than previously reported. We aimed to describe the demographics, risk factors, and presenting features of MHb in these renal transplant patients.

METHODS

Twenty-six transplant recipients commenced on dapsone for chemoprophylaxis against PCP from February to September 2011. All patients had normal glucose-6-phosphate dehydrogenase levels before treatment. Characteristics of patients with MHb were compared with those of the rest of the cohort to determine potential risk factors.

RESULTS

Twelve (46%) patients developed MHb (levels 6.4 ± 4.1%). Six (50%) of the patients with MHb were asymptomatic on presentation. Cases had a mean drop in hemoglobin of 19 ± 7%. MHb led to five admissions (median length of stay 5 days, range 1-10 days). MHb level showed a strong correlation with the length of stay (correlation coefficient 0.762, P = 0.002).

CONCLUSION

This is the highest reported prevalence of MHb, to our knowledge, in patients receiving dapsone, and its use led to significant hospitalization in this population. This study raises concerns about the use of dapsone as chemoprophylaxis in renal transplant recipients.

Blood disorders after kidney transplantation

Post transplant anemia (PTA) is a common issue in kidney transplant recipients. Most importantly it is associated with an impaired allograft function. Other important factors associated with PTA are immunosuppressive drugs (MPA, AZA and SRL), iron deficiency, infections (Parvo B19), older donor age, rejection episodes, an increased inflammatory state, and erythropoietin hyporesponsiveness. As there are no adequately powered RCTs in the kidney transplant population on anemia treatment with ESA, we have to rely on what we know from the large RCTs in the CKD population. The recently published KDIGO guidelines do not recommend treatment with ESA if Hb is >10 g/dl. Repletion of iron stores is emphasized. Post transplant leukopenia (PTL) and thrombocytopenia (PTT) are frequent complications especially in the first six months after kidney transplantation. Myelosuppression caused by immunosuppressive agents (MPA, AZA, SRL, rATG), antimicrobial drugs (VGCV), and CMV infection is the predominant cause. There are no widely accepted guidelines on treatment strategies, but most often dose reduction or discontinuation of causative medication is done. Most clinicians tend to decrease MPA dose, but this is eventually associated with an increase in acute rejection episodes. VGCV dose reduction (preemptive treatment instead of CMV prophylaxis) may be a successful strategy. In severe cases G-CSF treatment is an important management option and seems to be safe.