Tissue distribution and bioactivity of amphotericin B administered in liposomes to cancer patients

Amphotericin B concentration was measured by high-pressure liquid chromatography (HPLC) and by bioassay in tissues of 11 cancer patients who died from infection and/or their underlying disease after having received amphotericin B entrapped into sonicated liposomes (ampholiposomes). These concentrations were compared to those measured in 28 patients who had only received the commercially available preparation of amphotericin B-Na deoxycholate complex (Fungizone). The fungistatic and fungicidal titres of the tissue homogenates were also evaluated using two strains of Candida spp. and one strain of Cryptococcus neoformans to determine the bioactivity of amphotericin B incorporated in our liposomes. Tissue concentrations varied with the tested tissues and were correlated with the total dose of amphotericin B administered whether given as amphotericin B-Na deoxycholate or ampholiposomes. Amphotericin B concentrations measured by bioassay in tissue methanolic extracts reached 58-81% of concentrations measured by HPLC, whereas only 15-41% was recovered from the unextracted homogenates. Fungicidal titres were seldom measured in tissues, but fungistatic titres were observed and were linearly correlated with amphotericin B concentration measured by HPLC. These results were similar for the patients who received only amphotericin B-Na deoxycholate and for those who received both preparations (amphotericin B-Na deoxycholate and ampholiposomes). Our results suggest that the tissue distribution of amphotericin B is not significantly modified by the type of preparation (deoxycholate complex or liposomes) and that most of the tissue-bound amphotericin B is not bioactive. However, higher daily doses of amphotericin B can be administered safely when incorporated in liposomes and therefore high tissue concentrations may be obtained more rapidly with ampholiposomes than with amphotericin B-Na deoxycholate.

Randomized study of vancomycin versus teicoplanin for the treatment of gram-positive bacterial infections in immunocompromised hosts

Seventy-four immunocompromised patients with severe infection due to gram-positive organisms were randomized to receive either vancomycin or teicoplanin. Extensive cancer was present in 71 patients, of whom 47 died within a month. The types of infections were 46 bacteremias (39 associated with central catheters), 24 skin and soft tissue infections (3 with bacteremia), and 7 others (mainly bronchopneumonia). The most frequent pathogen was Staphylococcus epidermidis, followed by Staphylococcus aureus. Microbiological eradication was obtained in 23 of 35 evaluable patients treated with vancomycin (65.7%) and 28 of 36 patients treated with teicoplanin (77.8%) (P = 0.4). Clinical cure and improvement were obtained in 26 of 35 patients (74.3%) and 27 of 36 patients (75.0%), respectively. No significant side effects were observed with teicoplanin, in contrast to reversible increases in serum creatinine (three patients) and skin rashes (four patients) with vancomycin. Superinfection was observed in five patients treated with vancomycin and two patients treated with teicoplanin. No relation was found between peak concentration in serum (at steady state) or bactericidal titers and outcome.

Ceftazidime plus teicoplanin versus ceftazidime plus amikacin as empiric therapy for fever in cancer patients with granulocytopenia

In a prospective randomized study, 100 episodes of fever (greater than 38 degrees C) and granulocytopenia (less than 1000/microliters) in cancer patients were empirically treated with ceftazidime (2 g every 8 h) plus teicoplanin (400 mg every 8 h on day 1; 400 mg every day thereafter) or ceftazidime (2 g every 8 h) plus amikacin (500 mg every 8 h). Bacteraemia, clinically documented infection and possible infection were documented in seven, 11 and 19 patients treated with ceftazidime plus teicoplanin and in 11, four and 17 patients treated with ceftazidime plus amikacin. Overall, the response rate was similar in the two groups of patients as was the need for treatment modifications and the rate of death. For documented Gram-positive bacteraemia, the response rate was 2/5 patients treated with ceftazidime plus teicoplanin and 2/7 with ceftazidime plus amikacin; for documented Gram-negative bacteraemia, the response rate was 1/2 and 3/4 patients respectively. No breakthrough bacteraemia was observed. Tolerance was excellent, although renal toxicity (elevation of serum creatinine) was observed in three patients treated with ceftazidime plus teicoplanin and in none allocated to ceftazidime plus amikacin.

Prevention of infections in neutropenic patients with pefloxacin

Bacterial infections remain a major source of morbidity and mortality in neutropenic patients. Therefore, optimal methods of prevention seem mandatory and various means have been tested, in particular specific modalities such as chemoprophylaxis, which remains controversial. Overall, non-absorbable antibiotics have been disappointing and are less commonly used because of the poor compliance of most patients. Co-trimoxazole has been shown to be effective under certain circumstances but the emergence of resistance, and the risk of prolonging the duration of neutropenia are major drawbacks despite the advantages of co-trimoxazole being well tolerated and effective in preventing Pneumocystis carinii infections. Recently, fluoroquinolones have been developed and numerous studies of prophylaxis have been performed with norfloxacin, enoxacin, ciprofloxacin, and other agents from this class, including pefloxacin. These data show a significant reduction of bacteraemia caused by Gram-negative bacilli in neutropenic patients but a high incidence of infection caused by Gram-positive cocci, mainly streptococci. The sources of those infections are many including mucositis due to chemotherapy and/or total body irradiation, as well as changes in the patient's flora due to more effective cover against Gram-negative bacilli. Future studies should further investigate regimens to achieve optimal prophylaxis for infections caused by either Gram-negative or Gram-positive pathogens during neutropenia.

[Current progress in antifungal therapy: the value of fluconazole]

Invasive fungal infections are major problems in immunocompromised patients and optimal therapeutical modalities are still far from optimal. Recently, progresses of antifungal therapy have been achieved with the development of new antifungal agents. In particular, fluconazole seems very promising due to the availability of oral and intravenous formulations. Tolerance and compliance of patients are excellent and side effects as well as interaction with other drugs are less commonly observed than with other antifungal agents available so far. The major indications of fluconazole are candidiasis and cryptococcosis.

Fluconazole treatment of fungal infections in the immunocompromised host

Immunocompromised patients are predisposed to opportunistic fungal infections. Candidiasis is reported most frequently both as a localized infection (eg, oropharyngeal candidiasis) and as life-threatening systemic candidiasis. With relatively few antifungal agents in the clinical armamentarium, the optimal management of candidiasis remains controversial. Among the agents that are available, amphotericin B is difficult to administer, 5-fluorocytosine cannot be used alone due to the frequent emergence of resistant yeasts, and ketoconazole, which is effective for esophageal and oropharyngeal candidiasis, is not recommended for systemic candidiasis, especially in granulocytopenic patients. Recently, fluconazole, a new triazole antifungal agent, has been found to be active against Candida spp and is being studied in various clinical settings. In addition to its oral formulation, it is available for intravenous (IV) administration, which is a significant advantage in treating debilitated or noncompliant patients. In a randomized, double-blind study, we compared the efficacy of 100 mg/d oral fluconazole with that of 400 mg/d ketoconazole in cancer patients with oropharyngeal candidiasis. Although clinical and microbiological outcomes were similar for both groups, relapses occurred earlier in ketoconazole- than in fluconazole-treated patients. In another study, we administered fluconazole IV 100 to 300 mg/d to 13 patients, eight of whom had fungemia. Preliminary results are encouraging. Further studies of fluconazole as prophylaxis in granulocytopenic patients and as therapy for documented systemic candidiasis are under way. These studies are expected to define specific indications for fluconazole in immunocompromised patients.

[Antibiotherapy in the patient with granulocytopenic cancer]

Granulocytopenia is the leading alteration of the natural host defense mechanisms, whether caused by an underlying disease or associated with anticancer chemotherapy and radiation therapy. Severe granulocytopenia predisposes to septicemia which is now more often due to Gram positive than to Gram negative bacteria. The empiric therapy of febrile episodes with rapidly bactericidal antibiotics has dramatically modified the prognosis of septicemia. The optimal treatment remains controversial although the usual regimen include both a cephalosporin (or a large spectrum penicillin) with an aminoglycoside. The empiric treatment with a specific anti-Gram positive antibiotic such as vancomycin does not modify prognosis, adds significant side-effects and increases the cost. Monotherapy has been associated with the need for treatment modification in 30-80% of the episodes depending on the type of infection (fever of unknown origin, clinically or microbiologically documented infection). The patients who remain febrile despite adequate antibacterial empiric treatment beneficiate of an empiric antifungal treatment. Care should be taken about the recent emergence of vancomycin-resistant Staph. haemolyticus, Corynebacterium JK and non-JK, and non-aeruginosa pseudomonas (only susceptible to cotrimoxazole). More fungal infections are observed with a significant emergence of non-albicans Candida, dermatophytes and filamentous fungi (P. boydii, Fusarium, ...) associated with disseminated infections.

Therapy for oropharyngeal candidiasis in the immunocompromised host: a randomized double-blind study of fluconazole vs. ketoconazole

Optimal therapy for oropharyngeal candidiasis, a common infection in immunocompromised patients, has yet to be clearly defined. Topical therapy is usually poorly tolerated; ketoconazole is effective but absorption is highly variable. New antifungal agents have been developed to increase the therapeutic options. Fluconazole is active against yeasts, is available in both oral and intravenous formulations, and has a pharmacokinetic profile different from that of ketoconazole. This randomized double-blind study evaluates systemic antifungal therapy with fluconazole (100 mg daily) or ketoconazole (400-mg daily) for oropharyngeal candidiasis in patients with cancer. Clinical cure was observed in 15 of 19 and 14 of 18 patients treated with fluconazole and ketoconazole, respectively. Eradication of pathogenic yeasts ws documented for 10 patients in both groups. The rates of relapse were similar, but relapse occurred earlier in patients in the ketoconazole group. Overall, this study demonstrates the value of a dosage of 100 mg of fluconazole or of 400 mg of ketoconazole daily for the management of oropharyngeal candidiasis in patients with cancer.

In-vitro evaluation of the antifungal activity of amphotericin B entrapped into liposomes during storage for one year

The stability of the antifungal activity of amphotericin B entrapped in small sonicated liposomes (ampholiposomes) was studied in vitro over a one-year period. Preparations of ampholiposomes stored at -20 degrees C or at 4 degrees C were compared monthly with freshly-prepared ampholiposomes and a commercial preparation of amphotericin B-deoxycholate (Fungizone; Squibb) by a killing curve method with Candida albicans. The bioactivity of the four preparations, each containing 1.5 or 2 mg/l of amphotericin B, was measured as the initial rate of killing and the 'relative bioactivity'. Relative bioactivity was calculated as the percentage reduction of the area under the growth curve compared with control growth. Storage of ampholiposomes for one year did not decrease their antifungal activity. Storage of ampholiposomes containing 1.5 mg/l amphotericin B for one year at -20 degrees C, but not at 4 degrees C, gave a significant increase in relative bioactivity and killing rate in comparison with freshly-prepared ampholiposomes. This was probably due to modifications in the spatial configuration of phospholipids and amphotericin B. The persisting antifungal activity of ampholiposomes stored for one year should allow the preparation of large batches to perform comparative clinical studies.

In-vitro activity of SCH39304 in comparison with amphotericin B and fluconazole

The in-vitro activity of SCH39304, a new imidazole, was compared with that of amphotericin B using two media (Sabouraud dextrose and tissue culture (TC) medium) with or without 25% human serum. At an inoculum of 1.5 X 10(4) cfu/ml, the IC95% for amphotericin B ranged from 0.08 to 0.3 mg/l irrespective of the medium. At the same inoculum, the IC95% of the two imidazoles ranged from 0.3 to greater than 80 mg/l. The inoculum effect (from 1.5 X 10(4) to 1.5 X 10(5) cfu/ml) was less than 1 dilution for the three antifungal agents. Serum increased the inhibitory activity (IC80%) of SCH39304 and fluconazole but not of amphotericin B. The IC80%, IC95% and minimal fungicidal concentration (MFC) for amphotericin B usually ranged within two dilutions. Using kill curve methodology, the initial killing rate (0-4 h) of amphotericin B correlated with concentration (P less than 0.001), and was faster in TC medium than in Sabouraud dextrose (P less than 0.0006). SCH39304 and fluconazole did not produce any significant killing over the range of concentrations tested (0.5-20 mg/l). SCH39304 was similar to fluconazole.

[Systemic mycotic infections]

Invasive fungal infections are common in immunocompromised patients. Early diagnosis is still difficult and prophylactic modalities seems mandatory but are yet to be defined. Standard therapy of invasive fungal infections relies on the administration of intravenous amphotericin B. This agent is difficult to administer and toxic. Recently, new antifungal agents have been developed and are currently under investigation. Those new agents included itraconazole and fluconazole as well as new galenic preparations of amphotericin B such as liposomes. All these studies should provide optimal management of invasive fungal infections and improve the prognosis of those patients.

[Prevention of bacterial infections using ciprofloxacin in granulocytopenic patients with cancer]

The optimal approach to reduce bacterial infections in granulocytopenic patients is still controversial. Recently, fluoroquinolones have been developed and real progress has been achieved in the prevention of Gram negative bacilli septicemia. This study reports our experience with ciprofloxacin and shows the excellent tolerance of ciprofloxacin by our patients as well as promising data for the reduction of Gram negative bacilli infection. However, practical modalities to prevent infection caused by Gram positive cocci remain to be defined.

In-vitro effects of cilofungin (LY121019), amphotericin B and amphotericin B-deoxycholate on human polymorphonuclear leucocytes

The in-vitro influence of cilofungin (LY121019) and amphotericin B on human polymorphonuclear leucocytes (PMNs) was studied by a multifunctional approach. Cilofungin at high concentration (greater than or equal to 20 mg/l) increased adherence to plastic and ingestion of Staphylococcus aureus by PMNs in suspension and Candida albicans by adherent PMNs, and slightly decreased MTT reduction and superoxide generation. Amphotericin B and amphotericin B-deoxycholate decreased adherence to plastic (IC50: 5.1 and 8.2 mg/l respectively) and superoxide generation induced by PMA and opsonized zymosan (IC50 1.1 mg/l for amphotericin B-deoxycholate). Variable results were observed for intra-cellular killing and ingestion. The functional assessment was made with four clinical isolates of yeasts (Can. albicans, Can. tropicalis, Can. Torulopsis) (glabrata, Cryptococcus neoformans). The inoculum was preincubated with the antifungals (PRE) or they were added during (PER) or after ingestion (POST) using PMNs in suspension (PRE and PER), or adhering to plastic (PRE, PER and POST). With the scheme PRE, killing was usually increased with amphotericin B-deoxycholate and cilofungin. With Crypt. neoformans, ingestion was also increased by the antifungals and sodium-deoxycholate, probably by altering the capsule. The results of the scheme POST showed that amphotericin B-deoxycholate, but not cilofungin, increased intracellular killing of Can. albicans, Can. tropicalis and Can. glabrata.

New methods for delivery of antifungal agents

Amphotericin B remains the drug of choice for many invasive fungal infections. However, failures of therapy, relapses, and adverse effects are numerous. New modalities of antifungal therapy are extensively evaluated, including various preparations of liposomal amphotericin B and promising new agents such as itraconazole and fluconazole. Numerous studies indicate the potential benefit of liposomal amphotericin B. In particular, a dramatic decrease in the incidence of immediate adverse effects as compared with the incidence with amphotericin B complexed with deoxycholate has been documented. In addition, a prolonged in vitro antifungal activity has been observed with unilamellar liposomes. As yet there is no standardized commercially available preparation of liposomal amphotericin B. Extensive research in this field is in progress. Large comparative studies for the evaluation of the clinical efficacy of these preparations are planned. Intranasal administration of amphotericin B seems useful for the prevention of aspergillosis in predisposed patients. These various approaches should improve the management and prognosis of fungal infections.

Successful treatment with liposomal amphotericin B in two patients with persisting fungemia

Two granulocytopenic patients in whom fungemia persisted despite therapy with deoxycholate amphotericin B were subsequently successfully treated by daily intravenous administration of amphotericin B entrapped in sonicated liposomes made of egg yolk lecithin, cholesterol and stearylamine in a molar ratio of 4:3:1. High serum concentrations of amphotericin B could be maintained in both patients during therapy with liposomal amphotericin B and were associated with high in vitro antifungal activity. Liposomal amphotericin B was tolerated much better than the deoxycholate preparation. These findings suggest that the liposomal amphotericin B preparation is superior in the treatment of fungemia in granulocytopenic patients, and that randomized trials are warranted.

In-vitro activity of cilofungin (LY121019) in comparison with amphotericin B

The in-vitro activity of cilofungin, a derivative of echinocandin B, was compared with that of amphotericin B in Sabouraud dextrose and Antibiotic Medium No. 3 against 100 clinical isolates of yeasts. Cilofungin appeared to be as effective, as amphotericin B against Candida albicans and yet more effective against Can. tropicalis as far as growth inhibition was concerned. Cilofungin was less active than amphotericin B against Can. (Torulopsis) glabrata and other species of Candida. It was not active against Cryptococcus neoformans. Minimum fungicidal concentrations (MFCs) of cilofungin were highly dependent on the medium, especially with Can. albicans. Low MFCs were observed in Antibiotic Medium 3 and very high MFCs were measured in Sabouraud's medium. Using a killing curve method, the initial rate of killing of amphotericin B was proportional to concentration with Can. albicans, Can. tropicalis, and Can. glabrata. With cilofungin the rate of killing was proportional to concentration only for Can. tropicalis.

Septicemias in cancer patients during parenteral nutrition: Contributing factors and detection by weekly blood cultures

Infections constitute the main complication of parenteral nutrition, particularly in cancer patients, but prediction of catheter-related septicemias (CRS) has been little investigated. We have evaluated, in 200 consecutive episodes of parenteral nutrition (PN) in cancer patients, the factors contributing to infectious complications, and the predictive value of weekly blood cultures performed through the nutrition catheter. The median duration of PN was 22 days with a total of 5816 patient-days of PN, neutropenia (neutrophils < 1,000/microl) being present in 872 (15%). Catheters were placed either in a jugular vein (71% single-lumen silicone catheters, 18.5% double-lumen Hickman-Broviac catheters) or in a femoral vein (10.5%). We observed 62 episodes of septicemia of which 22 were CRS (11% incidence for the 200 cycles) and 40 were non-CRS (20% incidence); CRS were mostly due to Staphylococcus epidermidis (14/22). Neutropenic patients as a group did not suffer more CRS than non-neutropenic patients, but the risk of CRS was slightly increased when expressed per day of neutropenia (8 CRS/872 days vs 14 CRS/4942 days without neutropenia, P < 0.05). On the other hand, a femoral insertion site was associated with a much higher incidence of CRS (9 CRS/21 femoral catheters vs 13 CRS/179 jugular catheters, P < 0.0001). It was possible to evaluate 20 episodes of CRS for their predictability by weekly blood cultures: the sensitivity for detecting CRS due to Staphylococcus epidermidis was 67%, the specificity 92%, the negative predictive value 98% and the positive predictive value 36%. The simple and widely available procedure of routine surveillance blood cultures performed through the PN catheter should be further investigated, because it could help the clinician to determine the origin of recent fever, particularly to exclude CRS and avoid unnecessary removal of PN catheters.

Hepatic candidosis in a patient with acute leukemia

Isolated hepatic candidosis has been described more frequently in patients with leukemia and consists in a particular clinical entity which remains difficult to control. We report here the case of a patient treated for acute nonlymphoblastic who developed hepatic candidosis two months after the end of intensive consolidation therapy.

Candidiasis

Candida spp. are the most common fungal pathogens isolated in immunocompromised hosts, particularly cancer patients. Numerous clinical manifestations of candidiasis have been recognized, including localized infection such as oropharyngeal candidiasis or focal hepatic candidiasis, and disseminated infection resulting from hematogenous spread, with or without documented fungemia. Granulocytopenic patients are particularly at risk. Candida albicans is isolated in approximately 40% of cases of fungemia, other Candida spp. now also commonly being isolated. The rate of morbidity and mortality secondary to candidiasis is still significant despite numerous attempts to develop better diagnostic techniques, and more effective means of chemoprophylaxis and therapy. Currently, new antifungal agents and galenic preparations of amphotericin B are being evaluated with the aim of improving the prognosis of candidiasis in immunocompromised hosts.

Polymicrobial septicemia with Clostridium difficile in acute diverticulitis

A case is reported of a patient without previous gastrointestinal symptoms, who presented with polymicrobial septicemia caused by Escherichia coli, Enterococcus faecalis, Clostridium difficile and Bacteroides vulgatus. Septicemia occurred during acute diverticulitis. A strain of Clostridium difficile, which was of the same serogroup C as the blood culture isolate and also produced toxin, was recovered from the stools, but the pathogenic role of this organism in the gastrointestinal symptomatology was not clearly established. Other reported cases of Clostridium difficile septicemia are also reviewed.