Antibiotics maker faces hurdles in diversifying beyond flagship drug
As Cubist manages a substantial cut to its portfolio after a court cancelled patents on its flagship antibiotic, the drugmaker is betting on health providers' efforts to brake soaring C-diff. related hospital re-admissions and deaths to build traction for its number two product, antibiotic Dificid (fidaxomicin).
With its $8.4-billion buy of Cubist, Merck is expecting rewards from Cubist's pipeline antibiotics, notably potential blockbuster Zerbaxa, a treatment for urinary track and intra-abdominal infections for which Cubist expects FDA approval this month. The transaction is expected to close in the first quarter of next year, when Merck will take the reins on Dificid.
As Cubist's second-best-selling-product, Dificid's revenues are dwarfed by Cubicin's $1.2 billion in annual sales. The firm's flagship antibiotic treats skin and other infections. Dificid, for the infection Clostridium difficile, is showing promise as a revenue generator after Cubist re-launched the product in February.
The drug posted 10% quarter-over-quarter volume growth in the July-September period, and year-on-year revenue growth of 14% vs. Q3 of last year. Nine-month sales came in at $47.7 million.
That follows several lackluster years. Dificid net annual sales totaled $51 million in the first year after its launch in the US in July 2011 by Optimer, acquired by Cubist in 2013.
C. diff. is an infection that usually affects older patients and can cause symptoms ranging from diarrhea to potentially life-threatening inflammation of the colon.
In a third-quarter call with analysts last month, Cubist president and COO Bob Perez said the Dificid re-launch involves three initiatives: targeting Dificid for patients at the highest risk of recurrence, and those most impacted by the consequences of an extended bout of CDAD (clostridium difficile-associated diarrhea); building relationships with key opinion leaders and targeting a subset of gastroenterologists outside of hospitals that see a lot of CDAD cases; and improving patient access through the Dificid access program.
More than 700,000 CDAD cases are seen annually in the US with high recurrence rates of 20%-30%. According to the US Centers for Disease Control and Prevention, the disease is estimated to be responsible for approximately 14,000 deaths per year in the US.
Yet the drug faces an uphill climb due to a well-entrenched generic, the widely-used off-patent drug vancomycin. In one study comparing the two, Dificid compared favorably, showing superiority to vancomycin in sustained clinical response through 25 days beyond the end of treatment, and proved non-inferior to the older drug, dosed four times daily, after 10 days of treatment.
Given the availability of the much cheaper generic, Dificid's growth may depend on its ability to price the drug competitively.
Another recent study suggests the drug can also have a sizable impact on health system costs. The cost-effectiveness study, which took place in the UK where fidaxomicin is sold by Astellas under the brand name Dificlir, demonstrated that first-line use of the antibiotic was effective in reducing recurrence rates and lowering mortality.
Researchers reported that the real-world study concurred with clinical trial data in showing a 74% relative reduction in recurrence, compared with the standard of care: vancomycin and metronidazole.
“This analysis supports a growing consensus that fidaxomicin should be used first-line in all patients diagnosed with CDI to address recurrence, improve patient outcomes, and ultimately save valuable NHS resources,” stated Dr Simon Goldenberg, consultant microbiologist and infection control doctor, Guy's and St. Thomas' NHS Foundation trust.