Comparison of long-term and short-term administration of itraconazole for primary antifungal prophylaxis in recipients of allogeneic hematopoietic stem cell transplantation: a multicenter, randomized, open-label trial

Challenges in management of invasive fungal infections in stem cell transplant

Invasive fungal infections cause significant morbidity and mortality in hematopoietic stem cell transplant recipients. In order to minimize these infections, prophylaxis has become routine, although the agents used have changed over time. This presents new challenges as we consider an approach to breakthrough infections and recognize the epidemiologic shift toward isolates with higher rates of drug resistance. This review outlines the management of the most common pathogens (Candida, Aspergillus, Mucorales) as well as rarer pathogens that have higher rates of resistance (Trichosporon, Fusarium, Scedosporium, and Lomentospora). We discuss potential approaches to proven or possible breakthrough infections with yeast and pulmonary mold disease. Finally, we outline the role for combination therapy and newer antifungals, acknowledging current knowledge gaps and areas for future exploration.

Consensus guidelines for antifungal prophylaxis in haematological malignancy and haemopoietic stem cell transplantation, 2021

Antifungal prophylaxis can reduce morbidity and mortality from invasive fungal disease (IFD). However, its use needs to be optimised and appropriately targeted to patients at highest risk to derive the most benefit. In addition to established risks for IFD, considerable recent progress in the treatment of malignancies has resulted in the development of new 'at-risk' groups. The changing epidemiology of IFD and emergence of drug resistance continue to impact choice of prophylaxis, highlighting the importance of active surveillance and knowledge of local epidemiology. These guidelines aim to highlight emerging risk groups and review the evidence and limitations around new formulations of established agents and new antifungal drugs. It provides recommendations around use and choice of antifungal prophylaxis, discusses the potential impact of the changing epidemiology of IFD and emergence of drug resistance, and future directions for risk stratification to assist optimal management of highly vulnerable patients.

Clinical experience with new formulation SUBA®-itraconazole for prophylaxis in patients undergoing stem cell transplantation or treatment for haematological malignancies

Background

SUper BioAvailability-itraconazole (SUBA®-itraconazole) was introduced into Australia in April 2014 as a substitute for standard itraconazole on the basis of improved bioavailability, tolerance and interpatient variability. Shortly after its introduction, our centre converted to the novel formulation for mould prophylaxis in patients undergoing allogeneic HSCT, autologous HSCT or treatment for haematological malignancies with an intermediate/high risk of invasive fungal infection (IFI).

Methods

A single-institution, investigator-initiated retrospective cohort study was conducted between June 2016 and April 2018 to assess therapeutic drug concentrations, safety and tolerability of a standard prophylactic dose of SUBA®-itraconazole.

Results

A total of 74 patients were assessed across 98 admissions with 178 measured itraconazole trough concentrations. The median duration of prophylaxis was 15.5 (1–59) days. No significant correlation was identified between trough concentrations and patient demographics including gender and weight. Drug concentrations were reduced by gastric acid suppression and diarrhoea. Therapeutic itraconazole trough concentrations (≥0.5 mg/L) were achieved at a median of 7 (95% CI = 6–8) days, with 87% of patients achieving therapeutic concentrations at day 14 (expected steady-state). One (1%) proven/probable IFI and 5 (5%) possible breakthrough IFIs were identified. Although adverse events were experienced by 42% of the cohort, only a single event was directly attributable to SUBA®-itraconazole, resulting in change of prophylactic agent.

Conclusions

SUBA®-itraconazole achieved rapid therapeutic trough concentrations, was associated with low rates of IFI and was well tolerated in the study population. This formulation should be considered a realistic and safe first-line agent for the prevention of IFIs in those undergoing HSCT and intermediate/high-risk therapy for haematological malignancies.

Trough concentration of itraconazole and its relationship with efficacy and safety: a systematic review and meta-analysis

Objectives

The optimum trough concentration of itraconazole for clinical response and safty is controversial. The objective of this systematic review and meta-analysis was to determine the optimum trough concentration of itraconazole and evaluate its relationship with efficacy and safety.

Methods

We searched PubMed, EMBASE, Web of Science, the Cochrane Library, Clinical-Trials.gov, and three Chinese literature databases (CNKI, WanFang, and CBM). We included observational studies that compared clinical outcomes below or above the trough concentration cut-off value which we set as 0.25, 0.5, and 1.0 mg/L. The efficacy outcomes were rate of successful treatment, rate of prophylaxis failure and invasive fungal infection (IFI)-related mortality. The safety outcomes included incidents of hepatotoxicity and other adverse events.

Results

The study included a total of 29 studies involving 2,346 patients. Our meta-analysis showed that compared with itraconazole trough concentrations (C_trough) of ≥0.25 mg/L, levels of <0.25 mg/L significantly increased the incidence of IFI for prophylaxis (RR =3.279, 95% confidence interval [CI] 1.73–6.206). Moreover, the success rate of treatment decreased significantly at a cut-off level of 0.5 mg/L (RR =0.396, 95% CI 0.176–0.889). An itraconazole trough level of 1.0 mg/L was associated with hepatotoxicity and other adverse events in a review of many studies.

Conclusion

An itraconazole trough concentration of 0.25 mg/L should be considered as the lower threshold for prophylaxis, and a target concentration of 0.5 mg/L should be the lower limit for effective treatment. A trough level of 1.0 mg/L is associated with increased hepatotoxicity and other adverse events (using High Performance Liquid Chromatography [HPLC]).