Alexion to its detractors: Take a look at our Soliris switching and budding pipeline

Amid its push to switch patients from blockbuster to Soliris to follow-up drug Ultomiris, rare disease drugmaker Alexion has seen "unprecedented success" despite an activist investor's push for change. Alexion's response to the haters: We'll let our performance—and that stout conversion campaign—speak for themselves. 

Alexion is tracking ahead on its plan to convert 70% of Soliris patients over to Ultomiris in both paroxysmal nocturnal hemoglobinuria (PNH), where Ultomiris scored an FDA approval in late 2018, and atypical hemolytic uremic syndrome (aHUS), which the drug added to its label in October, executives said on a fourth-quarter earnings call with analysts Thursday. 

In the case of PNH, Ultomiris has already established itself as the leading product in Alexion's three biggest markets––the U.S., Germany and Japan––and is looking to follow suit in aHUS despite more difficult conversion conditions due to the acute nature of the disease. 

Even better, despite the push to switch patients over, Soliris sales continued to grow at a rapid clip to $3.56 billion on the year in 2019––a 10.7% increase. That growth was fueled by Soliris' expansion in neurology, including recent FDA nods in neuromyelitis optica spectrum disorder in June and myasthenia gravis back in 2017. Both indications came with blockbuster sales potential at the time. 

Alexion hopes that strong push in neurology will result in a quadrupling of treated patients in that field by 2025; a stout projection, no doubt, but one John Orloff, Alexion's chief of R&D, called feasible due to Soliris' "breadth of prescribing plus depth of prescribing" in its two approved indications. 

In all, Alexion posted $4.99 billion in sales on the year, an impressive 21% increase from the year before.

RELATED: Alexion shoots down 'proactive' sale demand from activist investor

Despite Alexion's recent run of success, executives stayed mum on ongoing discussions with infamous proxy brawler Elliott Management, which called for "proactive sale" of the company back in December.

Ludwig Hantson, Alexion's CEO, wasn't baited into a response from one analyst on those talks, choosing instead to focus on his company's recent financial performance as an indicator of its leadership's success.

"We believe we have a stock that is undervalued given our strong execution," Hantson said on the call. "The management team believes we have a strong strategy and that we need to keep executing that strategy. That's all I really have to say on that."

Alexion took a public stand against Elliott's call last month, arguing in a press release that the drugmaker's team had worked diligently to flesh out its pipeline through a series of strategic acquisitions that will help it reach a stated goal of 10 new approvals—four new launches, six new indications—by 2023.

RELATED: JPM: Alexion to take Ultomiris into tough ALS study as switching campaign exceeds expectations

Five of those hoped-for indications are expected to come from Ultomiris, including in amyotrophic lateral sclerosis (ALS), where Alexion announced it would launch a phase 3 trial for the newer drug in the first quarter.

Instead of painting a typical rosy picture of future success, Hantson admitted at the time that the indication was a long shot and not among Alexion's high-probability winners.

"We are aware that this is a high-risk, high-reward program," Hantson said at the annual J.P. Morgan Healthcare Conference in San Francisco.

Alexion is also calling its shot on four new drug launches by the end of 2023, including investigational candidates ALXN1840 in Wilson's disease, AG-10 in transthyretin amyloid-cardiomyopathy, CAEL-101 in AL amyloidosis, and danicopan in PNH and complement 3 glomerulopathy, a late-stage therapy acquired as part of Alexion's pickup of Achillion for $930 million in October.

Even without ALS, Ultomiris is expected to benefit in the coming year from an ongoing wave of Soliris conversions. As of Jan. 10, the drug had won over 59% of existing U.S. PNH patients who'd been taking its predecessor Soliris.

But with its sights set on 10 new indications in just three years, is Alexion biting off more than it can chew? Orloff said even if a few of those planned indications don't come to fruition, the drugmaker still has plenty left in reserve that could easily cover that gap.

In essence, 10 new indications is the bottom-end projection.

"We're going to continue to press the envelope in regards to business development," Orloff said. "If one or more of those (indications) fall off, we have other opportunities that we haven’t really talked about."