Tysabri gets boost from label change, new diagnostic
Over the years, the drug has been hampered by a deadly brain infection—progressive multifocal leukoencephalopathy (PML)—in some patients. Now the FDA is allowing information on a PML risk factor to appear in the label and has cleared the first test to help detect the risk factor, known as anti-JCV antibody.
The Stratify JCV Antibody ELISA test, when used with other clinical data from the patient, can help healthcare providers determine the risk for developing PML, the FDA said. The test is sold by Quest Diagnostics.
RBC Capital Markets analyst Michael Yee predicted that the label change could boost Tysabri' s 2016 global revenue by about a billion dollars, to $2.5-$3 billion, a 50% increase from the analyst's prior forecast. The impact of the approval on Tysabri's revenue was first reported by Bloomberg. In a related research note, Yee wrote that the drug's foothold is firm, having gained 1,700 new patients in the fourth quarter, and that its popularity as a first-line treatment is growing.
The label change on Biogen Idec/Elan's injectable came as new safety signals arose on the first oral treatment for the disease—Novartis' multiple sclerosis drug Gilenya—signals which some say could limit that drug's commercial potential.
The European Medicines Agency sounded a note of caution Friday, recommending doctors enhance cardiovascular monitoring of new Gilenya patients. The drug, which received approval in the EU and US two years ago, had already been coming under FDA scrutiny following reports of the sudden, unexplained November 2011 death of a patient who died 24 hours after the first dose. The death was reported December 12.
Now, the EMA said, there have been reports of other unexpected, sudden deaths among Gilenya patients. The agency said Gilenya not been implicated as the cause of death, and that no such deaths were reported during the drug's testing.
Switzerland-based Novartis already included warnings that Gilenya decreased heart rates in the short term and could be linked to arrhythmia. More than 30,000 patients use the drug worldwide, and Novartis added Japan to its distribution area in the third quarter.
The EMA is urging doctors to use ECG monitoring for six hours after a patient receives their first dose of Gilenya and to check blood pressure and heart rate hourly. The FDA is encouraging doctors to observe patients, as opposed to the EMA's more explicit directive.
An MS drug causing harm in some patients? Sounds familiar, notes Sanford Bernstein analyst Tim Anderson, who drew comparisons to Tysabri. The shot was pulled off the market in 2005 after three clinical trial patients developed PML. It was put back on the market in 2006. According to Anderson, the infusion therapy drug continues to do well because it addresses “the unmet medical need in MS patients despite safety issues.”
Anderson expects Gilenya sales to hit $385 million and to increase to 2%, or $1.4 billion, in sales by 2015, unless Biogen Idec's BG-12, another oral MS drug in Phase III, upsets the current prescription balance and the requisite monitoring does not scare off doctors or patients.
ISI Group Biotech and Pharmaceuticals Analyst Mark Schoenebaum, MD, writes the Gilenya warning can only enhance the appeal for BG-12. Schoenebaum says BG-12's appeal is threefold: first, it lacks the known and now possibly unknown risks that accompany a Gilenya prescription, and second and third: BG-12 also lacks the stresses that accompany the Gilenya warning, which “would likely involve putting the patient in a telemetry unit in a hospital our outpatient unit . . . Note that most neurology clinics are unlikely to have telemetry capabilities.”