Alexion scores 2nd FDA nod for Soliris successor drug as switching campaign continues

With a patent challenge for blockbuster Soliris underway, Alexion is working hard to expand the reach of its successor drug Ultomiris. With one carry-over indication already in the bag, Ultomiris just added a second to keep Alexion’s switching campaign afloat.

The FDA approved Ultomiris on Friday to treat patients with atypical hemolytic uremic syndrome (aHUS).The approval gives Ultomiris its second Soliris-matching indication after the follow-up drug won its initial nod to treat adult paroxysmal nocturnal hemoglobinuria (PNH) in December.

Alexion is in the midst of switching patients off older med Soliris as patent challenges ramp up pressure on the blockbuster drug.

In late August, the U.S. Patent and Trademark Office launched a review of Soliris’ U.S. patents after Amgen requested a broad challenge. Soliris currently makes up around 88% of Alexion’s overall sales at $980.8 million in the second quarter and isn’t expected to face biosimilar challengers for several years—2022 in the EU and 2027 in the U.S.

RELATED: Is a Soliris patent review that big a threat to Alexion? Analysts are split

But Amgen's challenge could change that. SVB Leerink analyst Geoffrey Porges updated Amgen’s chances of success to 50% in a September note to investors and added an 8% to 12% “incremental erosion” to Soliris sales beyond 2022 when Amgen’s biosim challenger would likely hit the market.

Analysts still figure Alexion can weather the storm—including its stagnant share price growth—even if Amgen’s patent challenge is successful. That’s because of Alexion's faster-than-expected campaign to switch patients over to Ultomiris, which has been a rousing success so far.

RELATED: Alexion's beating forecasts with Soliris-to-Ultomiris switch. So what's up with its pesky stock price?

As of July, around 40% of PNH patients taking Soliris had switched to Ultomiris, putting Alexion well on track to hit its 70% conversion goal in that indication by mid-2020.

Even if Amgen is successful in challenging Soliris' patents, its ability to compete with the Alexion drug would be limited for several years, Evercore ISI analyst Josh Schimmer figures. In a September note, Schimmer pointed out that Soliris has orphan drug designations that would secure U.S. exclusivity in aHUS until November 2023, myasthenia gravis (MG) until October 2024 and neuromyelitis optica (NMO) until mid-2026.

Ultomiris, which is seeking approval in NMO and MG, could launch in those indications as soon as late 2022, giving Alexion an even better chance of switching patients away. For an Amgen biosim to counteract that trend, the copycat would need a compelling price point that Schimmer said would be “daunting” to achieve.