Pfizer's antifungal VFEND® provides significant cost advantages when used as initial therapy

05/31/05

Results demonstrate VFEND provides cost savings over amphotericin B in the treatment of invasive aspergillosis

NEW YORK, June 1, 2005 – Initial therapy with Pfizer's antifungal treatment, VFEND® (voriconazole), IV for injection, tablets, and oral suspension, has significant cost advantages over the standard therapy, amphotericin B deoxycholate, for patients with invasive aspergillosis infections, according to a study in the June issue of Pharmacotherapy. The overall antifungal drug cost per patient was found to be $961 less for patients who began treatment with VFEND compared with patients who were started on amphotericin B. Patients treated with amphotericin B required significantly more switches to other antifungal therapy due to lack of patient response or patients' inability to tolerate the drug. This is the first published study that assesses the total antifungal drug treatment costs associated with this type of life-threatening infection.

Invasive aspergillosis is a severe pulmonary infection that can occur in patients with weakened immune systems. It often results in extended hospital stays and a significant economic burden. Economic analyses show that patients with this type of infection average 17 days in the hospital with mean treatment costs of $62,426. The overall case fatality rate for invasive aspergillosis is estimated to be 58 percent, but approaches 90-100 percent in patients where the infection has spread beyond the initial site.

"The savings observed in this analysis are directly related to the efficacy, tolerability and IV and oral dosing flexibility of VFEND. These savings are especially apparent when VFEND is used as initial therapy for these infections," said James Lewis, Pharm. D., lead investigator and infectious diseases pharmacy specialist at The University of Texas Health Science Center at San Antonio.

Study Results

Lewis and other investigators analyzed data from a previously published clinical study (Herbrecht et al. NEJM Aug 2002) which compared VFEND with standard therapy with amphotericin B deoxycholate for the first-line treatment of invasive aspergillosis. VFEND and amphotericin B are the only two treatments approved for primary treatment of invasive aspergillosis by the U.S. Food and Drug Administration. In the study, patients with confirmed or probable invasive aspergillosis were started on either VFEND or amphotericin B. If during the course of the 12-week study the patient's disease progressed or the patient was unable to tolerate the initial therapy, treatment could be changed to another antifungal agent (defined in the study as other licensed antifungal therapy or OLAT).

The analysis evaluated the purchasing costs of primary therapy, the cost savings associated with patients moved from IV to oral therapy, and the types and duration of other treatments used following the initial therapy. In the VFEND study arm (N=144), only 36 percent of patients required a switch to another form of antifungal therapy, compared to 80 percent of those started on amphotericin B (N=133).

Total antifungal drug costs in the VFEND arm of the study were $67,833 less than those in the amphotericin B arm. Total antifungal drug cost per treatment success, determined by adjusting the cost per patient by positive outcomes, was $10,317 for those patients started on VFEND compared to $20,278 for those started on amphotericin B. The cost benefits observed with VFEND in this analysis are a result of the superior efficacy and improved tolerability associated with initial VFEND use, which led to fewer switches to the more expensive lipid formulations of amphotericin B.

"These results reinforce the importance of using an initial treatment that is both effective and tolerable in order to significantly reduce the need for other therapies, which drive total treatment cost," said Dr. Lewis.

About VFEND

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 also is approved as salvage therapy for fungal infections caused by 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, both on 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 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.

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Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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