Treatment of invasive fungal infections with amphotericin B colloidal dispersion in bone marrow transplant recipients

What Drives Innovation: The Canadian Touch on Liposomal Therapeutics

Liposomes are considered one of the most successful drug delivery systems (DDS) given their established utility and success in the clinic. In the past 40–50 years, Canadian scientists have made ground-breaking discoveries, many of which were successfully translated to the clinic, leading to the formation of biotech companies, the creation of research tools, such as the Lipex Extruder and the NanoAssemblr™, as well as contributing significantly to the development of pharmaceutical products, such as Abelcet^®, MyoCet^®, Marqibo^®, Vyxeos^®, and Onpattro™, which are making positive impacts on patients’ health. This review highlights the Canadian contribution to the development of these and other important liposomal technologies that have touched patients. In this review, we try to address the question of what drives innovation: Is it the individual, the teams, the funding, and/or an entrepreneurial spirit that leads to success? From this perspective, it is possible to define how innovation will translate to meaningful commercial ventures and products with impact in the future. We begin with a brief history followed by descriptions of drug delivery technologies influenced by Canadian researchers. We will discuss recent advances in liposomal technologies, including the Metaplex technology from the author’s lab. The latter exemplifies how a nanotechnology platform can be designed based on multidisciplinary groups with expertise in coordination chemistry, nanomedicines, disease, and business to create new therapeutics that can effect better outcomes in patient populations. We conclude that the team is central to the effort; arguing if the team is entrepreneurial and well positioned, the funds needed will be found, but likely not solely in Canada.

ESCMID* guideline for the diagnosis and management of Candida diseases 2012: adults with haematological malignancies and after haematopoietic stem cell transplantation (HCT)

Fungal diseases still play a major role in morbidity and mortality in patients with haematological malignancies, including those undergoing haematopoietic stem cell transplantation. Although Aspergillus and other filamentous fungal diseases remain a major concern, Candida infections are still a major cause of mortality. This part of the ESCMID guidelines focuses on this patient population and reviews pertaining to prophylaxis, empirical/pre-emptive and targeted therapy of Candida diseases. Anti-Candida prophylaxis is only recommended for patients receiving allogeneic stem cell transplantation. The authors recognize that the recommendations would have most likely been different if the purpose would have been prevention of all fungal infections (e.g. aspergillosis). In targeted treatment of candidaemia, recommendations for treatment are available for all echinocandins, that is anidulafungin (AI), caspofungin (AI) and micafungin (AI), although a warning for resistance is expressed. Liposomal amphotericin B received a BI recommendation due to higher number of reported adverse events in the trials. Amphotericin B deoxycholate should not be used (DII); and fluconazole was rated CI because of a change in epidemiology in some areas in Europe. Removal of central venous catheters is recommended during candidaemia but if catheter retention is a clinical necessity, treatment with an echinocandin is an option (CII(t) ). In chronic disseminated candidiasis therapy, recommendations are liposomal amphotericin B for 8 weeks (AIII), fluconazole for >3 months or other azoles (BIII). Granulocyte transfusions are only an option in desperate cases of patients with Candida disease and neutropenia (CIII).

Lipid formulations of amphotericin B as first-line treatment of zygomycosis

Zygomycosis is a difficult to treat and frequently fatal infection affecting immunocompromised and, rarely, immunocompetent patients. The early diagnosis and immediate initiation of treatment with an antifungal agent in combination with surgical intervention has proved critical for the favourable outcome of the disease. Few antifungal agents are available for treatment. Amphotericin B (AmB) deoxycholate has been the drug of choice for many years and is usually given at high daily doses which can result in renal toxicity. Currently, lipid formulations of AmB (liposomal AmB (L-AmB), AmB lipid complex (ABLC), AmB colloidal dispersion (ABCD)), mainly L-AmB, rather than conventional AmB have become the standard therapy. The rationale behind the use of lipid formulations is that they decrease the nephrotoxicity associated with longterm AmB use. Although there is a developing consensus that high doses of lipid formulations of AmB should be the antifungal therapy of choice for all patients with zygomycosis, until now there have been no data available with which to define the appropriate dose. The duration of therapy remains an unresolved issue, regarding both lipid formulations of AmB as well as sequential or combination treatments consisting of lipid formulations of AmB with posaconazole, a drug which has now emerged as a new therapeutic option.

Approaches to the Management of Invasive Fungal Infections in Hematologic Malignancy and Hematopoietic Cell Transplantation

Patients with hematologic malignancy and hematopoietic cell transplant (HCT) recipients are at increased risk for invasive fungal infection (IFI) as a result of immunosuppression or organ damage stemming from their underlying disease, its treatment, or both. Such IFIs can cause significant morbidity and mortality, and the diagnosis and treatment of infected patients frequently are clinically challenging. This article discusses the epidemiology and risk factors for IFI in patients with hematologic malignancy and HCT recipients. The pros and cons of available antifungal agents are discussed, and evolving treatment strategies and recent prophylaxis guidelines from various professional organizations are reviewed. Finally, recommendations are offered for antifungal prophylaxis according to risk group.

Successful allogeneic transplantation of patients with suspected prior invasive mold infection

Prior invasive fungal infection (IFI) has historically limited the use of allogeneic stem cell transplantation for patients with hematologic malignancies. Transplantation of such patients frequently resulted in recurrent infection and high mortality rates. Several new antifungal agents have been introduced over the past 5 years with broader spectra of activity against molds such as Aspergillus and a favorable toxicity profile. In this study, we present a series of 16 consecutive patients with hematologic malignancy and prior invasive fungal infection who underwent allogeneic transplantation. Of these patients, the majority of whom were treated with voriconazole and/or caspofungin, only four experienced recurrent fungal infection and recurrent fungal infection was the primary cause of death in only one patient. The estimated 45% 2-year survival in this series is similar to that for other patients with high risk hematologic malignancy undergoing stem cell transplantation. We conclude that suspected prior invasive fungal infection should not preclude the use of allogeneic stem cell transplantation.

Adverse effects of antifungal therapies in invasive fungal infections: review and meta-analysis

Amphotericin B is the main therapeutic agent for the treatment of invasive fungal infections; however, it is associated with significant toxicities that limit its use. Other systemic antifungal agents have been developed to improve tolerability while maintaining the efficacy profile of conventional amphotericin B. Fifty-four studies involving 9,228 patients were assessed for the frequency of adverse effects of the main systemic antifungal agents. While the results suggest that liposomal amphotericin B is the least nephrotoxic of the lipid formulations (14.6%), that conventional amphotericin B is the most nephrotoxic (33.2%), and that itraconazole is the most hepatotoxic (31.5%), the lack of standard definitions of antifungal-related adverse effects limits the validity of these results. Furthermore, heterogeneous patient pools and differing protocols make it difficult to draw direct comparisons between studies. With the advent of newer classes of systemic antifungal agents, future trials should conform to definitions that are universally applicable and clinically relevant to allow for such comparisons and to enable evidence-based decision-making.

Adverse effects of antifungal therapies in invasive fungal infections: review and meta-analysis

Amphotericin B is the main therapeutic agent for the treatment of invasive fungal infections; however, it is associated with significant toxicities that limit its use. Other systemic antifungal agents have been developed to improve tolerability while maintaining the efficacy profile of conventional amphotericin B. Fifty-four studies involving 9,228 patients were assessed for the frequency of adverse effects of the main systemic antifungal agents. While the results suggest that liposomal amphotericin B (L-AmB) is the least nephrotoxic of the lipid formulations (14.6%), that conventional amphotericin B (AmB) is the most nephrotoxic (33.2%), and that itraconazole is the most hepatotoxic (31.5%), the lack of standard definitions of antifungal-related adverse effects limits the validity of these results. Furthermore, heterogeneous patient pools and differing protocols make it difficult to draw direct comparisons between studies. With the advent of newer classes of systemic antifungal agents, future trials should conform to definitions that are universally applicable and clinically relevant to allow for such comparisons and to enable evidence-based decision-making.

Guidelines for the use of antifungal agents in the treatment of invasiveCandidaand mould infections

ABSTRACT Treatment of invasive fungal infections is increasingly complex. Amphotericin B deoxycholate has long been the mainstay of treatment. However, there has been increasing recognition of both the propensity for nephro-toxicity in haematology, transplant and intensive care patients as well as its adverse impact on morbidity and mortality. This has coincided with the availabilty of newer, and in certain settings, more effective antifungal agents. Although the newer agents clearly cause less nephrotoxicity than amphotericin B, drug interactions, hepatic effects and unique side-effects need to be considered. The spectrum of the newer triazoles and echinocandins varies, highlighting the importance of accurate identification of the causative organism where possible. Consensus Australian guidelines have been developed to assist clinicians with treatment choices by reviewing the current evidence for the efficacy, the toxicity and the cost of these agents.

Stem cell transplantation post invasive fungal infection is a feasible task

Between March 1997 and January 2002, 18 consecutive patients (18-47 years) with hematological malignancies and previous proven invasive fungal infection underwent stem cell transplantation (SCT) (10 matched sibling allograft, 6 autograft, and 2 haploidentical). All patients had full myeloablative conditioning. The fungal pathogens diagnosed were Aspergillus (14), Fusarium (2), Mucor (1), Exserohilum (1), and Candida (1), involving the lungs (15), sinuses (5), and liver (1). All patients were treated pre- and during transplant with systemic antifungal therapy. Eleven out of 18 (61%) patients survived the transplant. Only 1 of 5 patients who transplanted with an active fungal infection accompanied with active leukemia survived the transplant, compared with 10/13 (84%) survivals in patients who had no clinical and radiological signs of infection or active leukemia (P < 0.025). None of the autografted patients has died, compared with 7/12 allografted patients, of whom 5 underwent transplant with active hematological/active fungal disease. In only 3 patients was the cause of death reactivation of previous fungal infection. Both active fungal infection and active leukemia place patients at a very high risk for procedure-related mortality. Pre-transplant therapy of fungal infection, aiming to achieve a clinically undetectable state of infection, followed by an antifungal treatment during transplant may allow the SCT with no fungal reactivation in selected patients.

Aspergillus infections in allogeneic stem cell transplant recipients: have we made any progress?

Invasive aspergillosis (IA) is common in allogeneic SCT recipients, with an incidence of 4-10%. The majority of these infections are diagnosed several months after SCT and they are frequently associated with GVHD. The diagnosis is difficult and often delayed. Established IA is notoriously difficult to treat with a death rate of 80-90%. This review summarises recent data on this problem to assess whether there has been any progress. Effective prophylactic measures are still lacking. Severe immunosuppression is the main obstacle to the success of therapy. Recent and ongoing developments in diagnostic measures and new antifungal agents may improve treatment results to some extent, but Aspergillus infections still remain a formidable problem in allogeneic transplantation. Further studies in this field will focus on the role of various cytokines and combinations of antifungal agents.

A double-blind, randomized, controlled trial of amphotericin B colloidal dispersion versus amphotericin B for treatment of invasive aspergillosis in immunocompromised patients

We report a randomized, double-blind, multicenter trial in which amphotericin B colloidal dispersion (ABCD [Amphotec]; 6 mg/kg/day) was compared with amphotericin B (AmB; 1.0-1.5 mg/kg/day) for the treatment of invasive aspergillosis in 174 patients. For evaluable patients in the ABCD and AmB treatment groups, respective rates of therapeutic response (52% vs. 51%; P=1.0), mortality (36% vs. 45%; P=.4), and death due to fungal infection (32% vs. 26%; P=.7) were similar. Renal toxicity was lower (25% vs. 49%; P=.002) and the median time to onset of nephrotoxicity was longer (301 vs. 22 days; P<.001) in patients treated with ABCD. Rates of drug-related toxicity in patients receiving ABCD and AmB, respectively, were 53% versus 30% (chills), 27% versus 16% (fever), 1% versus 4% (hypoxia) and 22% versus 24% (toxicity requiring study drug discontinuation). ABCD appears to have equivalent efficacy and superior renal safety, compared with AmB, in the treatment of invasive aspergillosis. However, infusion-related chills and fever occurred more frequently in patients receiving ABCD than in those receiving AmB.

The direct cost and incidence of systemic fungal infections

OBJECTIVES

In this study we determined the incidence and direct inpatient and outpatient costs of systemic fungal infections (candidiasis, aspergillosis, cryptococcosis, histoplasmosis) in 1998.

METHODS

Using primarily the National Hospital Discharge Survey (NHDS) for incidence and the Maryland Hospital Discharge Data Set (MDHDDS) for costs, we surveyed four systemic fungal infections in patients who also had HIV/AIDS, neoplasia, transplant, and all other concomitant diagnoses. Using a case-control method, we compared the cases with controls (those without fungal infections with the same underlying comorbidity) to obtain the incremental hospitalization costs. We used the Student's t-test to determine significance of incremental hospital costs. We modeled outpatient costs on the basis of discharge status to calculate the total annual cost for systemic fungal infections in 1998.

RESULTS

For 1998, the projected average incidence was 306 per million US population, with candidiasis accounting for 75% of cases. The estimated total direct cost was $2.6 billion and the average per-patient attributable cost was $31,200. The most commonly reported comorbid diagnoses with fungal infections (HIV/AIDS, neoplasms, transplants) accounted for only 45% of all infections.

CONCLUSIONS

The cost burden is high for systemic fungal infections. Additional attention should be given to the 55% with fungal disease and other comorbid diagnoses.

Infections following hematopoietic stem cell transplantation

Numerous advances have been made in the management of infection in HSCT recipients. With increasing knowledge the authors are able to prevent several serious infections from occurring, and reduce the severity of infections once they occur. Despite these advances, several previously unrecognized pathogens have emerged and pose risks to this population. Ongoing surveillance and reporting of atypical infections are warranted. Transplant and infectious disease clinicians alike must be vigilant to the shifts in infectious syndromes as a consequence of various prophylaxis and preemptive strategies, and be ready to modify empiric strategies to meet the changing microbiologic milieu. As we increase our understanding of the HSCT process, and use the immune system rather than relying on high-dose chemotherapy, the authors are likely to reduce toxicities and improve patient outcomes.

Older patients with high-risk fungal infections can be successfully allografted using non-myeloablative conditioning in combination with intensified supportive care regimens

Leukaemic patients with advanced disease and severe fungal infections as well as older patients with substantial co-morbidity are usually excluded from conventional allotransplantation because of increased morbidity and mortality. We approached allogeneic transplantation in four patients with a median age of 62 years (one chronic myeloid leukaemia in blast crisis, one high-risk acute myeloid leukaemia (AML) in first complete remission (CR1), one AML in 2nd relapse, one AML in CR2 with pre-existing fungal lung infections (two aspergillus, two mucor) and additional co-morbidity (diabetes n = 2, aortic aneurysm n = 1, arterial sclerosis n = 2) by combining non-myeloablative conditioning with an intensified supportive care regimen, including amphotericin B and 4-12 (median 9) prophylactic granulocyte transfusions from granulocyte colony-stimulating factor (G-CSF)-stimulated volunteer donors. G-CSF was also given to patients until neutrophil recovery. All four patients recovered to a neutrophil count of 0.5 x 109/l after a median of 11.5 d (range 11-13 d). Prophylactic granulocyte transfusions also reduced the need for platelet transfusions and minimized mucositis. All patients were discharged at a median of 25 d (range 18-59 d) and are alive and well after a median follow-up of > 390 d (range 336-417 d) without evidence of leukaemia. Regression of the fungal lesions was documented in three patients, with a slight progression detected by computerized tomography scan of the chest in one patient. We conclude that pulmonary fungal infections are not a contraindication for allogeneic stem cell transplantation, if non-myeloablative conditioning regimens are used in combination with granulocyte transfusions, intravenous amphotericin B and G-CSF.

Amphotericin B colloidal dispersion: an improved antifungal therapy

Amphotericin B colloidal dispersion (ABCD) is a near 1:1 discoidal complex of amphotericin B (AMB) and sodium cholesteryl sulfate (SCS) arranged as a bilayer of SCS interspersed with AMB via noncovalent interactions. The complex is stable in blood and plasma with minimal dissociation. In vitro and in vivo studies show that ABCD is as effective and four to five times safer than conventional AMB (CAB) for fungal infection. Compared with CAB treatment, ABCD demonstrates reduced peak plasma levels, prolonged residence time, and lowered AMB levels in most tissues including kidney, the major target of toxicity for CAB. In 572 patients with systemic fungal infections secondary to severe underlying disease, ABCD doses < or = 6 mg/kg/day were well tolerated, even in those who failed to tolerate or respond to CAB. Mild-to-moderate, dose-dependent, infusion-related adverse events typically seen with CAB were also observed with ABCD, with no sign of renal or hepatic toxicity. Complete or partial recovery was seen in 57.3%. Therefore, ABCD should be considered as an alternative treatment of systemic fungal infections.

Treatment and outcome of invasive Aspergillus infections in allogeneic BMT recipients

The outcome of invasive aspergillosis (IA) has been considered poor in allogeneic BMT recipients. We analyzed retrospectively the treatment and outcome of IA diagnosed during life in a recent cohort of 20 allogeneic BMT recipients. All patients were initially treated with amphotericin B (AmB) (conventional 16, liposomal 4). Due to toxicity, conventional AmB was changed to a liposomal preparation in 10 patients. Five patients also received itraconazole and three underwent surgery. Of 19 evaluable patients, two patients achieved a complete response and a partial response was observed in five patients (response rate 37%). The median survival was 37 days after the diagnosis. Only two patients (10%) were cured. The prognosis of allogeneic BMT recipients with IA has remained poor. Although treatment responses are common, immunosuppression aggravated by GVHD and its treatment, as well as the commonly disseminated presentation of IA, seem to be major obstacles to the success of therapy. Bone Marrow Transplantation (2000) 26, 759-762.

A strategy for managing fungal infections in haematopoietic stem cell transplantation

As more indications continue to be found for allogeneic haematopoietic transplantation, more patients are at risk for invasive fungal infectious diseases (IFID), particularly candidiasis and aspergillosis. Risk factors for disease are becoming better defined and diagnostic methods have improved considerably. In addition, there is now international agreement that three elements form the basis for defining IFID (host factors, clinical evidence, and mycological results), that imaging is acceptable for diagnosing disease, and that indirect tests such as antigen detection are also adequate mycological proof of cause. There are also more drugs available and still more to come, offering the potential for selective prophylaxis as well as preemptive and specific therapy, as well as for flexible administration. Hence, all the elements are in place for designing and testing an effective and economically sound strategy for dealing with IFID.

Amphotericin B colloidal dispersion (Amphocil) vs fluconazole for the prevention of fungal infections in neutropenic patients: data of a prematurely stopped clinical trial

We conducted an open label, randomised clinical trial to compare amphotericin B colloidal dispersion (ABCD, Amphocil) 2 mg/kg/day intravenously with fluconazole 200 mg/day orally, for the prevention of fungal disease in neutropenic patients with haematological malignancies. In the event of unresolved fever after 4 days of empirical antibacterial therapy, patients in both treatment groups were to receive ABCD, 4 mg/kg/day. However, the study had to be stopped in an early phase, due to severe side-effects of ABCD. A total of 24 patients were enrolled, 12 patients were randomly assigned to receive prophylactic ABCD, which was administered for a mean of 13.9 days. Fluconazole prophylaxis was given to 12 patients for a mean of 21.2 days. Therapeutic ABCD, 4 mg/kg, was initiated in four patients because of suspected fungal infection, all of whom had initially received fluconazole. A high rate of infusion-related toxicity of ABCD was observed. Chills occurred in 15/16 ABCD recipients (94%), accompanied by a temperature rise of >/=2 degrees C in 4/16 patients and of >/=1 degrees C but <2 degrees C in 10/16 patients. Other ABCD-related adverse events were hypotension (4/16), nausea with vomiting (5/16), tachycardia (7/16), headache (3/16) and dyspnoea (3/16). For premedication patients received: antihistamines (12/16), hydrocortisone (9/16) and/or morphine (6/16). ABCD was discontinued in 8/16 patients (50%) due to side-effects, which ultimately dictated early termination of the study. We conclude that ABCD is not suitable for antifungal prophylaxis in neutropenic patients due to severe infusion-related side-effects. Subject numbers were too low for conclusions on variables of antifungal efficacy.