The study highlights Vfend, Pfizer's antifungal treatment, as an important treatment option for candidemia in nonneutropenic patients (those who do not have low white blood cell counts). Vfend is the only treatment available in oral and IV formulations that is approved as first-line therapy against both mould and yeast infections.
"This study proves the effectiveness of Vfend for the treatment of candidemia, an often-deadly fungal infection for which we need multiple treatment options," said Dr. Jack D. Sobel, study investigator and professor and chief of the Division of Infectious Diseases at Wayne State University School of Medicine. "Because of Vfend's broad spectrum of activity against infections caused by yeasts and moulds, it is a good first-choice treatment option for immunocompromised patients who are at risk for those types of infection."
Candidemia is a systemic fungal infection in the blood that can lead to other body organ infections. Surgical patients and patients with compromised immune systems are at high risk for candidemia.
This study was the first ever to compare Vfend versus amphotericin B followed by fluconazole, both of which are approved treatments for candidemia. However, amphotericin B is commonly associated with toxic effects, including a risk of kidney failure. In addition, the prevalence of fluconazole-resistant Candida is increasing.
The study used a non-inferiority study design in which the trial objective was to evaluate the comparability of differing treatment options. Results showed that the treatment regimens were comparable in terms of effectiveness, including time required to clear Candida from the blood. Investigators concluded that Vfend is an effective alternative to this regimen and that it is among the most useful treatment options for candidemia in non-neutropenic patients due to its efficacy, tolerability and broad spectrum, and also due to the availability of IV and oral formulations.
Treatment discontinuations due to all-cause adverse events were more frequent in the Vfend group, although most discontinuations in this group were due to non-drug-related events. Patients taking Vfend experienced fewer serious adverse events, such as renal toxicity.
The study included 370 patients who had at least one positive blood culture for Candida within 96 hours of entering the study, and who did not suffer from neutropenia. Patients were randomly assigned (in a 2-to-1 ratio) to receive either Vfend or amphotericin B followed by fluconazole.
In the Vfend group, patients received IV Vfend for three days followed by oral Vfend for as long as needed, while the combination group received IV amphotericin B for three to seven days followed by oral fluconazole for as long as needed. Success was judged by improved clinical signs and symptoms and a negative blood culture for Candida 12 weeks after each patient's treatment ended.
In both treatment groups, 41 percent of patients reported a successful response when assessed at 12 weeks after the end of treatment. In the secondary analysis, which included all evaluable patients, including those whose last assessment was sooner than 12 weeks, about two-thirds of patients in both groups reported success - 65 percent of Vfend patients and 71 percent of amphotericin B/fluconazole patients, a difference that was not statistically significant.
Treatment with Vfend was able to clear Candida from the blood as quickly as amphotericin B plus fluconazole. The median time to attain a negative blood culture was two days in both groups. The adverse event rates were comparable between treatment groups. However, significantly more serious adverse events (57 percent in the amphotericin B/fluconazole group versus 46 percent in the Vfend group) and cases of renal toxicity (21 percent for the amphotericin B/fluconazole group versus 8 percent for the Vfend group) were reported in the amphotericin B/fluconazole group.
There were more reports of visual events in the Vfend arm. The mortality rate was similar at 42 percent for the amphotericin B/fluconazole group and 36 percent for the Vfend group.
Vfend was discovered by Pfizer researchers and was developed to address the unmet medical need for more effective and better-tolerated options for patients at risk for serious fungal infections. Vfend is currently approved in the United States for the treatment of invasive aspergillosis, esophageal candidiasis, candidemia in nonneutropenic patients (those without low white blood cell counts) and certain Candida infections (disseminated infections in skin and infections in abdomen, kidney, bladder wall and wounds). Vfend is also approved as salvage therapy for fungal infections caused by the pathogens Scedosporium apiospermum and Fusarium species.
Vfend is the only IV/oral antifungal specifically indicated for the first-line treatment of mould and yeast infections. The ability to switch patients from IV to oral Vfend allows patients to remain on the same medication throughout the course of treatment, on both an inpatient and outpatient basis.
Most frequently reported adverse events (all causalities) in therapeutic trials were visual disturbances, fever, rash, vomiting, nausea, diarrhea, headache, sepsis, peripheral edema, abdominal pain and respiratory disorder. Treatment-related adverse events that most often led to discontinuation in clinical trials were elevated liver function tests (LFTs), rash and visual disturbances. Vfend treatment-related visual disturbances are common. The effect of Vfend on visual function is not known if treatment continues beyond 28 days.
Vfend is contraindicated with terfenadine, astemizole, cisapride, pimozide, quinidine (since increased plasma concentrations for these drugs can lead to QT prolongation and rare occurrences of torsades de pointes), sirolimus, rifampin, rifabutin, carbamazepine, long-acting barbiturates, ergot alkaloids, efavirenz and ritonavir (400 mg q12h).
There have been uncommon cases of serious hepatic reactions during treatment with Vfend (clinical hepatitis, cholestasis and fulminant hepatic failure, including fatalities). LFTs should be evaluated at the start of and during the course of therapy. Patients have rarely developed serious cutaneous reactions, such as Stevens-Johnson syndrome, during treatment with Vfend.