More bad news for Novartis and its Gilenya multiple sclerosis pill? The drugmaker this morning disclosed that a patient taking the drug has been diagnosed with progressive multifocal leukoencephalopathy, or PML, a rare and often fatal brain disease. This is the first case of PML in a Gilenya patient and the disclosure comes just as the European Medicines Agency next week is set to issue a safety review, following reports of up to 11 deaths among Gilenya patients.
However, Novartis says the patient had been previously treated with another MS drug, Tysabri, which is marketed by both Biogen Idec and Elan, and which has been already associated with PML (back story). "The current assessment is that Tysabri is the drug most likely associated with this case of PML," Novartis says in a statement. "However, a contribution of Gilenya to the evolution of this case cannot be excluded."
One analyst believes the incident is connected to Tysabri. "The case of PML appears Tysabri-related," writes ISI Group analyst Mark Schoenebaum in an investor note. "Recall that the risk for PML for patients on Tysabri for >42 months is 2.58 per 1000." He adds that Gilenya has about 8 percent of the market for MS treatments. Novartis, meanwhile, notes there is currently no confirmed case of PML in Gilenya patients who had not previously taken Tysabri. So far, about 36,000 people have been treated with Gilenya.
Nonetheless, the episode adds another storm cloud over the drug. Last week, Institute for Safe Medicine Practices says the FDA should substantially restrict its use and enhance patient monitoring. The non-profit issued this recommendation after reviewing adverse events that were reported to the FDA during the second quarter of 2011, shortly after the drug was approved. "Problems of widespread toxicity that were already evident in clinical testing of (Gilenya) are now producing strong signals in the postmarket adverse event data,” the non-profit wrote in a report (read here).
[UPDATE: In an investor note, Leerink Swann analyst Seamus Fernandez writes that feedback from key opinion leaders in Europe suggests the EMA may require labeling update, but not one that is "overly onerous." However cardiovascular monitoring is likely to be strengthened, he adds. This is not seen as a "major impediment" to getting new patients started on Gilenya, but the anticipated introduction of Biogen’s forthcoming BG12 is likely to "significantly decrease the percentage of patients" who do start treatment on Gilenya.]