Nanotechnology and pulmonary delivery to overcome resistance in infectious diseases

Used since ancient times especially for the local treatment of pulmonary diseases, lungs and airways are a versatile target route for the administration of both local and systemic drugs. Despite the existence of different platforms and devices for the pulmonary administration of drugs, only a few formulations are marketed, partly due to physiological and technological limitations.

Respiratory infections represent a significant burden to health systems worldwide mainly due to intrahospital infections that more easily affect immune-compromised patients. Moreover, tuberculosis (TB) is an endemic infectious disease in many developing nations and it has resurged in the developed world associated with the human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) epidemic.

Currently, medicine faces the specter of antibiotic resistance. Besides the development of new anti-infectious drugs, the development of innovative and more efficient delivery systems for drugs that went off patent appears as a promising strategy pursued by the pharmaceutical industry to improve the therapeutic outcomes and to prolong the utilities of their intellectual property portfolio. In this context, nanotechnology-based drug delivery systems (nano-DDS) emerged as a promising approach to circumvent the limitations of conventional formulations and to treat drug resistance, opening the hypothesis for new developments in this area.

Safety and Effectiveness of Miltefosine in Post-Kala-Azar Dermal Leishmaniasis: An Observational Study

Background

Post-kala-azar dermal leishmaniasis (PKDL) is a dermal complication of visceral leishmaniasis. Oral miltefosine (MF) is the first-line treatment for PKDL patients in South Asia. This study assessed the safety and effectiveness of MF therapy after 12 months of follow-up to explore more precise data.

Methods

In this observational study, 300 confirmed PKDL patients were enrolled. MF with the usual dose was administered to all patients for 12 weeks and followed up for 1 year. Clinical evolution was recorded systematically by photographs at screening and at 12 weeks, 6 months, and 12 months after treatment onset. Definitive cure consisted of disappearance of skin lesions with a negative PCR at 12 weeks or with >70% of lesions, disappearing or fading at 12-month follow-up. Patients with reappearing clinical features and any positive diagnostics of PKDL during the follow-up were considered as nonresponsive.

Results

Among 300 patients, 286 (95.3%) completed 12 weeks of treatment. The per-protocol cure rate at 12 months was 97%, but 7 patients relapsed and 51 (17%) were lost to 12-month follow-up, resulting in a final cure rate of only 76%. Eye-related adverse events were noted in 11 (3.7%) patients and resolved in most (72.7%) within 12 months. Unfortunately, 3 patients had persistent partial vision loss. Mild to moderate gastrointestinal side effects were seen in 28% patients.

Conclusions

Moderate effectiveness of MF was observed in the present study. A significant number of patients developed ocular complications, and thus MF for treatment for PKDL should be suspended and replaced with a safer alternative regimen.

Continuously infused amphotericin B deoxycholate for primary treatment of invasive fungal disease in acute myeloid leukaemia

Continuous administration of amphotericin B deoxycholate over 24 hours (24 h-D-AmB) is better tolerated than rapid infusions. However, toxicity and outcome have not been assessed in a homogenous patient population with acute myeloid leukaemia (AML). We retrospectively analysed renal function and outcome in all adult patients with AML undergoing intensive chemotherapy between 2007 and 2012 at our institution. We compared a patient group with exposure to 24 h-D-AmB to a patient group without exposure to 24 h-D-AmB. One hundred and eighty-one consecutive patients were analysed, 133 (73.5%) received at least 1 dose of 24 h-D-AmB, and 48 (26.5%) did not. Reasons for 24 h-D-AmB initiation were invasive fungal disease (IFD) in 63.5% and empirical treatment for febrile neutropenia in 36.5% of the cases. Most patients with IFD received an oral triazole drug at hospital discharge. Baseline characteristics were well matched. Amphotericin B deoxycholate over 24 hours was given for a median 7 days (interquartile range 3-13). Peak creatinine concentration was higher in the 24 h-D-AmB-group (104.5 vs. 76 μmol/L, P < .001) but normalized within 1 month after therapy (65.5 vs. 65 μmol/L, P = .979). In neither of the 2 groups, end-stage renal disease occurred. There was no difference in 60-day survival (90% vs. 90%) and 2-year survival (58% vs. 58%). Invasive fungal disease partial response or better was observed in 68% of the patients. We conclude that antifungal therapy with continuously infused amphotericin B deoxycholate is safe in patients with AML. An antiinfective strategy based on 24 h-D-AmB in first line followed by an oral triazole compound represents an economically attractive treatment option.

Population Pharmacokinetic Model and Meta-analysis of Outcomes of Amphotericin B Deoxycholate Use in Adults with Cryptococcal Meningitis

There is a limited understanding of the population pharmacokinetics (PK) and pharmacodynamics (PD) of amphotericin B deoxycholate (DAmB) for cryptococcal meningitis. A PK study was conducted in n = 42 patients receiving DAmB (1 mg/kg of body weight every 24 h [q24h]). A 2-compartment PK model was developed. Patient weight influenced clearance and volume in the final structural model. Monte Carlo simulations estimated drug exposure associated with various DAmB dosages. A search was conducted for trials reporting outcomes of treatment of cryptococcal meningitis patients with DAmB monotherapy, and a meta-analysis was performed. The PK parameter means (standard deviations) were as follows: clearance, 0.03 (0.01) × weight + 0.67 (0.01) liters/h; volume, 0.82 (0.80) × weight + 1.76 (1.29) liters; first-order rate constant from central compartment to peripheral compartment, 5.36 (6.67) h^-1; first-order rate constant from peripheral compartment to central compartment, 9.92 (12.27) h^-1 The meta-analysis suggested that the DAmB dosage explained most of the heterogeneity in cerebrospinal fluid (CSF) sterility outcomes but not in mortality outcomes. Simulations of values corresponding to the area under concentration-time curve from h 144 to h 168 (AUC_144-168) resulted in median (interquartile range) values of 5.83 mg · h/liter (4.66 to 8.55), 10.16 mg · h/liter (8.07 to 14.55), and 14.51 mg · h/liter (11.48 to 20.42) with dosages of 0.4, 0.7, and 1.0 mg/kg q24h, respectively. DAmB PK is described adequately by a linear model that incorporates weight with clearance and volume. Interpatient PK variability is modest and unlikely to be responsible for variability in clinical outcomes. There is discordance between the impact that drug exposure has on CSF sterility and its impact on mortality outcomes, which may be due to cerebral pathology not reflected in CSF fungal burden, in addition to clinical variables.

Induction-phase treatment costs for cryptococcal meningitis in high HIV-burden African countries: New opportunities with lower costs

Introduction: Access to and the cost of induction treatment for cryptococcal meningitis (CM) is rapidly changing. The newly-announced price for flucytosine ($0.75 per 500 mg pill) and possibly lower prices for liposomal amphotericin B (AmB-L) create opportunities to reduce CM treatment costs compared to the current standard treatment in low- and middle-income countries. Methods: We developed an Excel-based cost model to estimate health system treatment costs for CM over a two-week induction phase for multiple treatment combinations, newly feasible with improved access to flucytosine and AmB-L. CM treatment costs include medications, laboratory tests and other hospital-based costs (bed-day costs and healthcare worker time). We report results from applying the model using country-specific information for South Africa, Uganda, Nigeria, and Botswana. Results: A 14-day induction-phase of seven days of inpatient AmB-D with flucytosine, followed by seven days of high-dose fluconazole as an outpatient, will cost health systems less than a 14-day hospital stay with AmB-D and fluconazole. If daily AmB-L replaces AmB-D for those with baseline renal dysfunction, with a cost of $50 or less per 50 mg vial, incremental costs would still be less than the AmB-D with fluconazole regimen. Simple oral combinations (e.g., seven days of flucytosine with fluconazole as an inpatient) are practical when AmB-D is not available, and treatment costs would remain less than the current standard treatment. Conclusions: Improved access to, and lower prices for flucytosine and AmB-L create opportunities for improving CM treatment regimens. An induction regimen of flucytosine and AmB-D for seven days is less costly than standard care in the settings studied here. As this regimen has also been shown to be more effective than current standard care, countries should prioritize scaling up flucytosine access. The cost of AmB-L based regimens is highly dependent on the price of AmB-L, which currently remains unclear.

Influence of 5% dextrose volume on amphotericin B deoxycholate preparation

OBJECTIVES

Preparation of amphotericin B deoxycholate (AmB-d) in different volumes of 5% dextrose (D5W) was studied to investigate a interesting phenomenon that AmB-d was easy to bring pipe blockage when diluted in 500 ml but not in 50 ml.

METHODS

AmB-d (25 mg/vial) in 50 ml, 250 ml or 500 ml D5W was prepared. Fluids were collected before and after infusion, then were assayed by validated high-performance liquid chromatography (HPLC) method. Light obscuration assay was used to detect the particles in transfusions.

KEY FINDINGS

pH values of different volumes of D5W were all about 3.7, which was lower than the requirement of AmB-d package insert (pH > 4.2). The number of insoluble particles >10 μm/25 μm in 25 mg/500 ml infusions exceeded China Pharmacopoeia limit. Filters in 25 mg/500 ml infusion set were full of AmB-d after dripping slowly for 6 h, and 331.3 ml solution was left in the bottles and only 11.3% of AmB-d could flow out. Whereas the AmB-d infusion consists of 25 mg/50 ml, 25 mg/250 ml and 50 mg/500 ml could meet with China Pharmacopoeia standards, and they flowed out easily and completely.

CONCLUSIONS

In practice, 25 mg/250 ml and 50 mg/500 ml would be more suitable for clinical use, rather than 25 mg/500 ml. We provided a convenient method for AmB-d preparation.

The efficacy and safety of first-line monotherapies in primary therapy of invasive aspergillosis: a systematic review

Objective

Several antifungals are available for the treatment of patients with invasive aspergillosis (IA). This study aims to evaluate the relative efficacy and safety of the first-line monotherapies in primary therapy of IA through network meta-analysis (NMA).

Methods

We systematically searched PubMed, Embase, Web of Science, Cochrane Library, China National Knowledge Infrastructure, VIP database, Wanfang database, and China Biology Medicine for randomized controlled trials (RCTs) up to July 2023 that evaluated the efficacy and safety of monotherapies. We performed NMA with a frequentist random effects model and assessed the certainty of evidence using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach. Primary outcomes were the all-cause mortality at week 12, and secondary outcomes included overall response rate, and incidence of adverse events (AEs) and severe adverse events (SAEs).

Results

A total of three RCTs involving 1,368 participants (four antifungals) were included. The NMA showed that compared to amphotericin B deoxycholate (D-AmB), the triazoles (posaconazole (POS), isavuconazole (ISA) and voriconazole (VCZ)) can improve the overall response rate in primary therapy of IA, but only VCZ and ISA can reduce the all-cause mortality at week 12 for patients with proven and probable IA (VCZ vs D-AmB: RR = 0.66, 95%CI = 0.47-0.93, moderate certainty; ISA vs D-AmB: RR = 0.52, 95%CI = 0 .31-0.86, low certainty). ISA (SUCRA = 93.50%; mean rank, 1.20) seemed to be the most effective therapy in the above population. As to proven, probable, and possible IA patients, the triazoles were superior to D-AmB in terms of reducing all-cause mortality. Furthermore, the risk of AEs and SAEs was comparable for the three triazoles, but the risk of SAEs was significantly higher for D-AmB than others.

Conclusion

The efficacy and safety of triazoles are more favorable than D-AmB in the primary therapy of IA, with ISA being the optimal choice.

Systematic Review Registration

PROSPERO CRD42023407632.

Amphotericin B Colloidal Dispersion is Efficacious and Safe for the Management of Talaromycosis in HIV-Infected Patients: Results of a Retrospective Cohort Study in China

Background

Amphotericin B deoxycholate (AmB-D) have potential toxic effects in the treatment of talaromycosis, and high-quality, non-generic liposomal AmB (L-AMB) is still inaccessible in many regions of China. As such, the efficacy and safety of alternative drugs warrant further investigation for the management of talaromycosis. This study aimed to compare the efficacy and safety of Amphotericin B Colloidal Dispersion (ABCD) and AmB-D for the treatment of talaromycosis in a retrospective cohort of HIV-infected patients.

Methods

This was a retrospective study and the data of HIV-infected patients with talaromycosis who received ABCD or AmB-D from January 2018 to December 2022, were retrospectively collected and analyzed. We compared the efficacy and safety of the two antifungal drugs.

Results

Overall, 38 patients receiving ABCD and 33 patients receiving AmB-D were included. The conversion rates to fungal negativity at one week post-treatment were 86.84% (33/38) in the ABCD group and 90.09% (30/33) in the AmB-D group, which reached 100.00% in both groups at two weeks post-treatment. A higher symptom remission rate was observed at two weeks in the ABCD group compared with the AmB-D group (94.74% vs 75.76%; p=0.003). Additionally, the serum creatinine level significantly increased from baseline in the AmB-D group, whereas it did not increase significantly in the ABCD group. Furthermore, significantly fewer patients discontinued antifungal treatment due to drug intolerance in the ABCD group, and the incidences of leukopenia and elevated creatinine levels were lower in the ABCD group compared with the AmB-D group.

Conclusion

ABCD has a clinical efficacy comparable to AmB-D, with higher symptom remission rate, lower nephrotoxicity, and lower bone marrow suppression, indicating that ABCD may be an appropriate alternative option for the clinical management of talaromycosis.

Induction-phase treatment costs for cryptococcal meningitis in high HIV-burden African countries: New opportunities with lower costs

Introduction: Access to and the cost of induction treatment for cryptococcal meningitis (CM) is rapidly changing. The newly-announced price for flucytosine ($0.75 per 500 mg pill) and possibly lower prices for liposomal amphotericin B (AmB-L) create opportunities to reduce CM treatment costs compared to the current standard treatment in low- and middle-income countries. Methods: We developed an Excel-based cost model to estimate health system treatment costs for CM over a two-week induction phase for multiple treatment combinations, newly feasible with improved access to flucytosine and AmB-L. CM treatment costs include medications, laboratory tests and other hospital-based costs (bed-day costs and healthcare worker time). We report results from applying the model using country-specific information for South Africa, Uganda, Nigeria, and Botswana. Results: A 14-day induction-phase of seven days of inpatient AmB-D with flucytosine, followed by seven days of high-dose fluconazole as an outpatient, will cost health systems less than a 14-day hospital stay with AmB-D and fluconazole. If daily AmB-L replaces AmB-D for those with baseline renal dysfunction, with a cost of $50 or less per 50 mg vial, incremental costs would still be less than the AmB-D with fluconazole regimen. Simple oral combinations (e.g., seven days of flucytosine with fluconazole as an inpatient) are practical when AmB-D is not available, and treatment costs would remain less than the current standard treatment. Conclusions: Improved access to and lower prices for flucytosine and AmB-L create opportunities for improving CM treatment regimens. An induction regimen of flucytosine and AmB-D for seven days is less costly than standard care in the settings studied here. As this regimen has also been shown to be more effective than current standard care, countries should prioritize scaling up flucytosine access. The cost of AmB-L based regimens is highly dependent on the price of AmB-L, which currently remains unclear.

Induction-phase treatment costs for cryptococcal meningitis in high HIV-burden African countries: New opportunities with lower costs

Introduction: Access to and the cost of induction treatment for cryptococcal meningitis (CM) is rapidly changing. The newly-announced price for flucytosine ($0.75 per 500 mg pill) and possibly lower prices for liposomal amphotericin B (AmB-L) create opportunities to reduce CM treatment costs compared to the current standard treatment in low- and middle-income countries. Methods: We developed an Excel-based cost model to estimate health system treatment costs for CM over a two-week induction phase for multiple treatment combinations, newly feasible with improved access to flucytosine and AmB-L. CM treatment costs include medications, laboratory tests and other hospital-based costs (bed-day costs and healthcare worker time). We report results from applying the model using country-specific information for South Africa, Uganda, Nigeria, and Botswana. Results: A 14-day induction-phase of seven days of inpatient AmB-D with flucytosine, followed by seven days of high-dose fluconazole as an outpatient, will cost health systems less than a 14-day hospital stay with AmB-D and fluconazole. If daily AmB-L replaces AmB-D for those with baseline renal dysfunction, with a cost of $50 or less per 50 mg vial, incremental costs would still be less than the AmB-D with fluconazole regimen. Simple oral combinations (e.g., seven days of flucytosine with fluconazole as an inpatient) are practical when AmB-D is not available, and treatment costs would remain less than the current standard treatment. Conclusions: Improved access to, and lower prices for flucytosine and AmB-L create opportunities for improving CM treatment regimens. An induction regimen of flucytosine and AmB-D for seven days is less costly than standard care in the settings studied here. As this regimen has also been shown to be more effective than current standard care, countries should prioritize scaling up flucytosine access. The cost of AmB-L based regimens is highly dependent on the price of AmB-L, which currently remains unclear.

Application of Physiologically Based Pharmacokinetic Model to Compare the Biodistribution of Liposomal Amphotericin B With Conventional Amphotericin B Deoxycholate in Humans

Amphotericin B (AmB) has been a cornerstone in the treatment of invasive fungal infections for over 6 decades. Compared with conventional amphotericin B deoxycholate (AmB-DOC), liposomal amphotericin B has comparable efficacy but less nephrotoxicity. The main purpose of this study was to investigate the reason why liposomal amphotericin B has similar therapeutic effects but lower toxicity and the differences of distribution in humans between liposomal amphotericin B and AmB-DOC. To compare the distribution of liposomal amphotericin B and AmB-DOC in humans, the physiologically based pharmacokinetic (PBPK) model was established by bottom-up stepwise method. A rat PBPK model was established firstly, then verified in mouse level in consideration of interspecies differences in physiological- and drug-specific parameters, and finally the PBPK model was extrapolated to humans. Based on preclinical and clinical pharmacokinetic (PK) studies, the AmB-DOC and liposomal amphotericin B PBPK model were established, respectively. The simulated results of human PBPK model showed that the liposomal formulation changed the pharmacokinetic characteristics of AmB. Compared with AmB-DOC, the plasma exposure of liposomal formulation was higher, but the renal exposure was significantly reduced.

Comparison of Early Fungicidal Activity and Mortality Between Daily Liposomal Amphotericin B and Daily Amphotericin B Deoxycholate for Cryptococcal Meningitis

BACKGROUND

Limited data exist on the antifungal activity of daily liposomal amphotericin B with flucytosine induction regimens for cryptococcal meningitis, which are recommended in high-income countries. Liposomal amphotericin B monotherapy at 3 mg/kg previously failed to meet noninferiority criteria compared to amphotericin B deoxycholate in its registrational clinical trial. We aimed to compare the quantitative antifungal activity and mortality between daily amphotericin B deoxycholate and daily liposomal amphotericin B among persons with human immunodeficiency virus (HIV)-related cryptococcal meningitis receiving adjunctive flucytosine 100 mg/kg/day.

METHODS

We analyzed data from 3 clinical studies involving participants with HIV-associated cryptococcal meningitis receiving either daily liposomal amphotericin B at 3 mg/kg/day with flucytosine (n = 94) or amphotericin B deoxycholate at 0.7-1.0 mg/kg/day with flucytosine (n = 404) as induction therapy. We compared participant baseline characteristics, cerebrospinal fluid (CSF) early fungicidal activity (EFA), and 10-week mortality.

RESULTS

We included 498 participants in this analysis, of whom 201 had available EFA data (n = 46 liposomal amphotericin B; n = 155 amphotericin B deoxycholate). Overall, there is no statistical evidence that the antifungal activity of liposomal amphotericin B (mean EFA, 0.495 [95% confidence interval {CI}, .355-.634] log10 colony-forming units [CFU]/mL/day) differ from amphotericin B deoxycholate (mean EFA, 0.402 [95% CI, .360-.445] log10 CFU/mL) (P = .13). Mortality at 10 weeks trended lower for liposomal amphotericin B (28.2%) versus amphotericin B deoxycholate (34.6%) but was not statistically different when adjusting for baseline characteristics (adjusted hazard ratio, 0.74 [95% CI, .44-1.25]; P = .26).

CONCLUSIONS

Daily liposomal amphotericin B induction demonstrated a similar rate of CSF fungal clearance and 10-week mortality as amphotericin B deoxycholate when combined with flucytosine for the treatment of HIV-associated cryptococcal meningitis.

The dose of the normal saline pre-infusion and other risk factors for amphotericin B deoxycholate-associated acute kidney injury

Background

Conventional amphotericin B deoxycholate (AmBd) is the preferred amphotericin B formulation in countries with limited resources despite its nephrotoxicity. Normal saline pre-infusion is a recommended measure to reduce the risk of nephrotoxicity in patients receiving AmBd.

Objectives

To examine the effect of different normal saline solution (NSS) pre-infusion doses, and other potential risk factors, on the development of acute kidney injury (AKI) in patients with invasive fungal infection receiving AmBd.

Methods

Adult patients with invasive fungal infections who received intravenous AmBd were included in this retrospective study. Doses of the normal saline pre-infusion were adjusted to the body weight (NSS/BW) and the daily dose of amphotericin B (NSS/AmBd). Kaplan-Meier survival analysis was used to estimate 14 d AKI-free survival rates, and the log-rank test was used to compare AKI-free survivals between groups.

Results

The present study included 60 patients; 31 patients developed AKI during the AmBd therapy. The overall 14 d AKI-free survival was 48.3%. NSS/AmBd, but not NSS/BW, was associated with AKI-free survival in patients receiving AmBd: the higher the NSS/AmBd, the higher the AKI-free survival. Gender, baseline blood urea nitrogen (BUN), and baseline plasma bicarbonate (Bicarb) also affected AKI-free survival. Female gender, higher BUN, and lower Bicarb were associated with higher AKI-free survival.

Conclusions

The present study suggests that low NSS/AmBd, male gender, low BUN, and high Bicarb are risk factors for AmBd-associated AKI. Excluding gender, these risk factors are potentially modifiable and would guide tailoring appropriate preventive measures for AmBd-associated AKI.

Clinical Improvement of Disseminated Acanthamoeba Infection in a Patient with Advanced HIV Using a Non-Miltefosine-Based Treatment Regimen in a Low-Resource Setting

Disseminated Acanthamoeba species infection is likely an underrecognized and underdiagnosed opportunistic infection in patients with advanced human immunodeficiency virus (HIV) disease in South Africa. It presents a unique clinical challenge in that the diagnosis can be difficult to establish and management options are limited in low-resource settings. To our knowledge, there is a paucity of literature to date on the successful use of combination treatment options for patients in low-resource settings without access to miltefosine. We present a case describing the clinical improvement of disseminated Acanthamoeba infection in a patient with advanced HIV using a non-miltefosine-based treatment regimen. The case serves to highlight that Acanthamoeba sp. infection should be considered as a differential diagnosis for nodular and ulcerative cutaneous lesions in patients with advanced HIV in South Africa, and that although there are alternative options for combination treatment in countries without access to miltefosine, efforts should be made to advocate for better access to miltefosine for the treatment of acanthamoebiasis in South Africa.