The prevention of febrile neutropenia

Interaction between caspofungin or voriconazole and cefoperazone-sulbactam or piperacillin-tazobactam by in vitro and in vivo methods

Immunosuppressive patients are at risk of fungal and bacterial infections. Therefore, these patients receive prophylactic, preemptive, empirical or target antifungal and concomitant antibiotic therapy. To this end, caspofungin (CAS) or voriconazole (VRC) antifungals and cefoperazone-sulbactam (CPZ/SAM) or piperacillin-tazobactam (PIP/TAZ) antibiotics may be used. Here, we aimed to investigate the interaction between these antifungals and antibiotics by in vitro and in vivo methods. The interaction was tested by chequerboard analysis and fractional inhibitory concentration index (FICI). It was also tested in a neutropenic mice-invasive candidiasis model and evaluated by fungal burden in kidney tissue of infected animals from the first day to the fifth day of treatment with 24 h intervals. A synergism was detected between CAS and CPZ/SAM (FICI = 0.1) and PIP/TAZ (FICI = 0.3). Fungal burden in tissues of drug-treated mice was reduced compared with controls in a time-dependent manner. In comparison with CAS-alone treated group, there were 1.32 log10 reductions of fungal burden in CAS + CPZ/SAM (p = 0.002) and in CAS + PIP/TAZ group (p = 0.14). The same interactions were not found with VRC and antibiotics. CPZ/SAM had stronger synergistic interaction with CAS than PIP/TAZ. The mechanism of synergism is not well understood. This is most likely due to an increase in the anticandidal effect of CAS plus antibiotics.

The shape of the myelosuppression time profile is related to the probability of developing neutropenic fever in patients with docetaxel-induced grade IV neutropenia

PURPOSE

Chemotherapy-induced neutropenia is associated with the risk of developing febrile neutropenia (FN). The aim was to describe the time course of myelosuppression in breast cancer patients treated with docetaxel and to investigate how the shape of the predicted myelosuppression time course and earlier proposed risk factors influence the probability of developing FN.

METHODS

Neutrophil counts from 140 breast cancer patients with observed grade IV neutropenia during the first course of docetaxel treatment were included. Twenty-six of the patients (19%) experienced FN. The myelosuppression time course was described using a semi-mechanistic myelosuppression model in NONMEM. The individual myelosuppression model parameters [baseline neutrophil count, mean transit time (MTT) and drug effect parameter (EC(50))], myelosuppression descriptors (nadir, duration of grade IV neutropenia) and earlier suggested risk factors (age, performance status, haemoglobin and liver function) were explored to be related to FN by logistic regression.

RESULTS

The neutrophil time course following docetaxel treatment was well described by the model. EC(50) and MTT were both significantly related to the probability of developing FN where low parameter values result in a rapid decline, low nadir and an increased risk of FN. None of the evaluated risk factors or myelosuppression descriptors were significant.

CONCLUSION

The probability to develop FN in patients who experience grade IV neutropenia was dependent on the myelosuppression time profile. Patients with a rapid neutrophil decline and high drug sensitivity had a higher probability to develop FN. Model-based parameter estimates were superior predictors over descriptive values such as the nadir or duration of neutropenia.

Comparative pharmacodynamic interaction analysis between ciprofloxacin, moxifloxacin and levofloxacin and antifungal agents against Candida albicans and Aspergillus fumigatus

OBJECTIVES

Patients suffering from invasive mycoses often receive concomitant antifungal therapy and antibacterial agents. Ciprofloxacin, a carboxyfluoroquinolone, was previously observed to demonstrate the pharmacodynamic interactions with antifungal agents by altering their growth inhibitory activity against Candida albicans and Aspergillus fumigatus. However, little is known about the interaction between other extended-spectrum fluoroquinolones, such as levofloxacin and moxifloxacin, and antifungal agents against C. albicans and A. fumigatus.

METHODS

Using a microdilution chequerboard technique, we employed isobolographic analysis adapted to incorporate a non-active agent in order to analyse the potential in vitro interaction between ciprofloxacin, levofloxacin or moxifloxacin and the following representative antifungal agents: amphotericin B, fluconazole or voriconazole and caspofungin.

RESULTS

Synergistic interactions [interaction indices (Iis) 0.69-0.83, P < 0.05] were observed between amphotericin B (0.07-0.31 mg/L) and either ciprofloxacin (0.19-7.65 mg/L) or levofloxacin (0.41-32.88 mg/L) against C. albicans and A. fumigatus. Synergy (Iis 0.56-0.87, P < 0.05) also was found between voriconazole (0.09-0.14 mg/L) and ciprofloxacin (0.22-11.41 mg/L) as well as between caspofungin (8.94-22.07 mg/L) and levofloxacin (0.14-5.17 mg/L) against A. fumigatus. Some antagonistic (Iis 1.16-1.29, P < 0.05) interactions were observed between fluoroquinolones and fluconazole against C. albicans. In general, ciprofloxacin enhanced the activity of antifungal agents more than moxifloxacin and levofloxacin against both C. albicans and A. fumigatus.

CONCLUSIONS

The knowledge of the pharmacodynamic interactions between fluoroquinolones and antifungal agents may guide selection and potentially improve the outcome of immunosuppressed patients with concurrent bacterial and fungal infections.

Outpatient therapy for febrile neutropenia

PURPOSE OF REVIEW

The management of febrile neutropenia has evolved significantly with the development of risk stratification and recognition of the efficacy of oral antibiotics in low-risk patients. There remains uncertainty concerning the need for hospitalization and role of early hospital discharge. We review recent evidence in this field and identify outstanding issues for future research.

RECENT FINDINGS

Studies have confirmed the utility of the MASCC risk index. Preliminary findings suggest that early hospital discharge is feasible in low-risk patients with solid tumours and lymphomas, at least in specialist centres. Median hospital stays may be reduced to 48 h with no increase in serious medical complications. Readmission rates remain low.

SUMMARY

All patients with febrile neutropenia should undergo risk stratification on admission, and low-risk patients should be considered eligible for combination oral antibiotics from the outset. Those patients who show signs of fever resolution and subjective improvement are eligible for early discharge. More research is required with regard to patients with haematological malignancies and/or receiving prophylactic antibiotics, and in the development of factors predictive of successful early discharge. Further data are required regarding whether strategies involving early discharge can be safely implemented at centres outside those which have pioneered these approaches.