First Ocrevus patient comes down with PML—but is the Roche med really to blame?

Roche's Ocrevus bears a PML warning on its label, but no cases cropped up in clinical trials.

Roche’s new drug Ocrevus has landed in the same sentence with the three letters all makers of multiple sclerosis drugs dread: PML.

For the first time, a patient taking the Roche product has been diagnosed with the rare-yet-deadly brain disease, progressive multifocal leukoencephalopathy, Evercore ISI analyst Umer Raffat wrote to clients Wednesday. 

It’s still unclear, though, whether the Roche treatment is the drug that caused the problem. The patient in question had taken Biogen’s rival med Tysabri for three years—with the most recent infusion in February—before receiving an April dose of Ocrevus.

“[T]he case was reported as a carry-over” from Tysabri “by the treating physician,” a spokeswoman for Roche’s Genentech unit said in a statement. “Patient safety is Roche’s highest priority and we are gathering more details about the case and the patient’s history.”

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While Ocrevus’ label bears a PML warning, no cases of the malady cropped up in the MS fighter’s clinical trials. In including that warning on Ocrevus' label, the “FDA’s decision had seemed to come from an overabundance of caution, given that the instances of PML did not emerge with Biogen’s Tysabri until after the drug had launched,” Barclays analyst Geoff Meacham wrote in a note to clients.

And while one specialist recently told Mizuho analyst Salim Syed that she estimates 52% of the broader MS population has the JC virus—PML's precursor—JCV rarely becomes PML, and Roche hadn’t necessarily expected to see a case pop up so soon.

Three execs from the company—which also sells Rituxan and Gazyva, agents that bear their own PML warnings—told Bernstein analyst Tim Anderson earlier this month that there’s a baseline rate of PML in the general population as well as in those with autoimmune disorders. But considering that multiple sclerosis patients are usually “much younger” than cancer patients, and that Ocrevus is used “without immunosuppressive co-medications,” they predicted an even lower rate than they did among Ocrevus' “cousin” meds, which also deplete B-cells.

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If it turns out that Ocrevus is to blame, Meacham expects to see regulators upgrade the drug's label warning to black-box status—the FDA’s most serious, and the one already borne by Tysabri.

The good news? He doesn’t “expect this warning to blunt the positive uptake” for the med, as it’s a “later-stage option” for those with debilitating cases of relapsing-remitting MS and the only option for those with primary progressive forms of the disease. 

One MS specialist who in February spoke with Piper Jaffray analyst Joshua Schimmer is likely to agree. That doctor told Schimmer he "wouldn't be perturbed if a case of PML emerged with Ocrevus at some point as long as rates remained exceedingly low."