Schering-Plough: new fungicide gets US approval

The FDA has approved Schering-Plough's Noxafil (posaconazole) Oral Suspension, its new fungicidal drug. The treatment is initially indicated for the prevention of invasive fungal infections (IFIs) caused by Aspergillus (a mould) and Candida (a yeast) species in immunocompromised patients.

While healthy individuals are unlikely to develop systemic infections caused by these common fungi, patients whose immune systems have been weakened by chemotherapy, immunosuppressive therapy following an organ transplant or AIDS are at risk of contracting IFIs. Unfortunately, their fatality rate approaches 60 to 90%. IFIs are thought to affect 1.3 million hospital patients each year in the .

The safety and efficacy of Noxafil were evaluated in 1,844 patients between 13 and 82 years of age. In two randomized, controlled studies of patients who had compromised immunity and were at high risk for IFIs, those patients who received Noxafil had comparable or lower rates of invasive Aspergillus and Candida infections than those patients who received other antifungal medications.

The systemic antifungal market has undergone considerable change in the last two years. The market used to be dominated by Pfizer's Diflucan (fluconazole) until its patent expiry in July 2004. Fluconazole generics by Teva and Hospira, among others, have since taken most its market share.

Pfizer's follow-up drug, Vfend (voriconazole), launched in 2002, is showing slow growth, but the Manhattan-based drug giant has been unable to maintain its control of this market. Its acquisition of Vicuron in 2005 was partly driven by the need to expand its antifungal portfolio with Eraxis (anidulafungin), approved in February 2006. This drug belongs to a new class of antifungals known as echinocandins. Merck's Cancidas (caspofungin), the first drug in this class, was launched in 2001 and now dominates the market for systemic antifungals, achieving sales more than three times higher than Vfend.

Datamonitor believes that the strong growth seen in the systemic antifungal market has been driven by two factors: first, an increased incidence and severity of IFIs (e.g., the number of cases of sepsis caused by fungal organisms increased by 207%, from 5231 cases in 1979 to 16,042 cases in 2000) and secondly the introduction of new, improved products such as the echinocandins and second-generation triazoles.

Schering-Plough's Noxafil is well placed because it is the only antifungal agent approved for the prevention of IFIs caused by Aspergillus, an increasingly common pathogen. Noxafil's registration trials have demonstrated a superior prophylactic effect against IFIs compared to pooled fluconazole or Sporanox (itraconazole). Furthermore, growing evidence of cross resistance occurring between echinocandins may lead physicians back to azole-based antifungals.

The approval of Noxafil will be much-welcomed by both physicians treating invasive fungal infections and Schering-Plough's infectious diseases division which suffers from continued competitive pressure on its hepatitis franchise. However, things look more promising now that clinical trial setbacks for vicriviroc, its new HIV drug, appear to have been overcome; and SCH-503034, its protease inhibitor for the treatment of hepatitis C, is progressing through phase II trials.

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