Source: Fierce Pharma

Biogen, already battling in a patent fight over multiple sclerosis star Tecfidera, has run into another challenge–this time with fellow MS treatment Tysabri. And with IP pressure mounting, the company may need to revamp its commercial lineup to ensure that the revenue keeps on flowing.

India’s Swiss Pharma International has filed a petition for inter partes review of one of Tysabri’s patents–and another two petitions are on the way, Leerink Partners analyst Geoffrey Porges wrote in a note to clients on Monday. The move could potentially put sales of the drug, which tallied $1.89 billion in 2015, in jeopardy, he noted.

Of course, it’s far from a sure thing–and on the contrary, Porges thinks Swiss Pharma’s chances of upturning Biogen’s patents are “relatively modest.” The product is “thoroughly protected” when it comes to its IP shields, and the safety flags it carries–including the risk of rare but deadly brain disease PML–would make it tough and risky for knockoff-makers to copy. All things considered, Porges expects to see Tysabri’s sales last through 2020 in the U.S., and potentially as long as 2023 in Europe.

But unfortunately for Biogen, Tysabri isn’t its only product under attack. Pharma patent challenger Kyle Bass has been trying to bat down Tecfidera’s patents for months now, and in March he snagged an inter partes review on the drug when the U.S. Patent and Trademark Office’s Patent Trial and Appeal Board (PTAB) reversed its earlier decision not to embark on one.

With that in mind, the Tysabri threat “reinforces the vulnerability of Biogen’s core MS business to its increasingly limited regulatory and patent protection,” Porges wrote, noting that the Massachusetts company is now defending two of its top three products–and meds that accounted for 34% of its 2015 sales. Plus, he sees other “significant threats” to the company’s MS franchise, too–IP troubles notwithstanding.

So what can Biogen do? The way Porges sees it, the company needs to head to the dealmaking table. “We believe a strategic acquisition of key products in the neurological diseases field, but outside MS, could potentially mitigate the looming threat to the MS franchise that is on the horizon,” he wrote.

And Biogen could soon have some more money in its pocket to help it do just that. Last week, rumors swirled that the company may be looking to sell off its hemophilia assets, which could bring in $6 billion in a sale.