Dificid approval promises CDAD market shake-up
This article was originally published in Scrip
On 27 May, the US Food and Drug Administration (FDA) approved San Diego-based Optimer Pharmaceuticals' Dificid (fidaxomicin), a new antibiotic for the treatment of Clostridium difficile-associated diarrhoea (CDAD).
Dificid is the first new therapy approved by the Agency for CDAD, a growing public health threat and a particular problem in hospitals and long-term care facilities, in almost 25 years. Indeed, the US Centers for Disease Control and Prevention (CDC) estimates that there are approximately 500,000 cases of CDAD in the US each year, causing around 30,000 deaths. ViroPharma's Vancocin (vancomycin) is the only FDA-approved therapy for CDAD, whilst off-label metronidazole is also commonly used.
Dificid is an orally administered, narrow-spectrum macrocyclic antibiotic. In two Phase III trials, the drug proved equally effective in clinical cure and statistically superior to Vancocin in achieving cure without recurrence, and was also shown to reduce CDAD recurrences by up to 47%. Dificid additionally has an improved safety profile compared to Vancocin and other broad-spectrum antibiotics, which are typically associated with a disruption of the normal intestinal flora.
Despite Dificid's good performance in clinical trials and some evidence that suggests a reduction in CDAD recurrence rates, members of the FDA advisory panel were split, in a 6-6 vote, on whether the extent to which Dificid prevents recurrence of infection was clinically significant. Subsequently, the Agency has decided not to include prevention of CDI recurrence as an approved indication for the drug.
Dificid is expected to go on sale in the US in July 2011, where it will be co-marketed by Optimer and Cubist Pharmaceuticals under a two-year agreement the companies announced last month (scripintelligence.com, 6 April, 2011). In February, Optimer also signed a co-marketing deal with Tokyo-based Astellas Pharma to co-market fidaxomicin in Europe and certain other countries (scripintelligence.com, 8 February, 2011).
US approval of Dificid represents a huge success for Optimer. Despite failing to gain the inclusion of prevention of CDAD recurrence in Dificid’s label, Datamonitor believes that the clinical strengths of the drug will position it strongly with both physicians and payors. Indeed, the commercial prospects for Dificid are very good. Large potential patient populations, a lack of efficacious treatment options, and clear competitive advantages over current standard-of-care Vancocin (justifying a premium price) mean that the drug is likely to gain considerable market share.
Additionally, the marketing deal inked with Cubist will strengthen Optimer’s sales and marketing capabilities and allow the company to leverage Cubist’s strong relationships with key stakeholders in the antibiotics sector, which have been a key factor in its success as the sole US marketer of its own antibiotic Cubicin (daptomycin). Datamonitor forecasts Dificid to achieve sales of up to $265m across the seven major markets (the US, Japan, France, Germany, Italy, Spain, and the UK) by 2019.
Richard Phelps is an associate analyst at Datamonitor