Alexion's follow-on to Soliris succeeds in late-stage trial
- Alexion's Ultomiris met the primary endpoint of a late-stage trial in treating a rare blood clotting disorder known as aHUS. The biotech intends to submit the drug for U.S. approval in that indication during the first half of 2019 and follow with filings in Europe and Japan.
- Topline data released Monday showed more than half of the patients treated with Ultomiris for 26 weeks experienced hematologic normalization and improved kidney function.
- To hit the trial's primary goal, a participant needed to meet three criteria — normalization in platelet counts, less destruction of red blood cells and improvement in serum creatinine levels — at the same time at least once. They also had to meet each criteria for 28 straight days at some point during the length of the trial.
Alexion relies on another rare disease drug, Soliris (eculizumab), for more than 85% of its net revenue. While it remains profitable, the franchise is aging and could see biosimilar competition in Europe in a few years time.
Ultomiris (ravulizumab) is part of Alexion's mitigation strategy. It's a follow-on to Soliris that inhibits the same a part of the immune system as its predecessor. Ultomiris initially gained approval in December for the treatment of paroxysmal nocturnal hemoglobinuria (PNH) — an indication which Soliris secured back in 2007. Alexion's next target looks to be aHUS, or atypical hemolytic uremic syndrome.
Analysts had a positive view of the new data, predicting they set up Ultomiris for another approval. Investment bank Piper Jaffray estimates the drug's U.S. revenue from the aHUS indication could reach $20.3 million in 2019 and grow to $587 million in 2021.
Shareholders seemed less thrilled, as Alexion stock was down 2.5% in late morning trading Monday.
Piper's Christopher Raymond said investors were likely disappointed with Ultomiris' efficacy, which was slightly lower than what had been seen with Soliris. He noted, however, that the Soliris and Ultomis Phase 3 studies aren't apples-to-apples comparisons because the latter enrolled sicker patients.
"While we think it’s fair to wonder why [Alexion] would not have press-released top line patient baseline characteristics along with the data so that investors could more easily figure this out, we do think therein lies the opportunity as we anticipate ... shares to recover as the market figures out this important nuance," Raymond wrote.
Alexion recently said it is trying to convert 70% of PNH patients taking Soliris to Ultomiris in the first two years after launch. Investment bank Leerink expects the biotech will aim for a similar conversion rate in aHUS as well.
Both Soliris and Ultomiris are monoclonal antibodies that inhibit part of the body's immune system called complement C5. The Phase 3 Ultomiris study enrolled 56 aHUS patients who never before received a complement inhibitor, and found 53.6% of them demonstrated complete thrombotic microangiopathy after 26 weeks of treatment.
Alexion touted Ultomiris' safety profile too, highlighting in a release how there were no cases of meningococcal infection in the Phase 3 study. There were four patient deaths, but none were considered related to treatment. Those results, combined with the drug's efficacy, dosing, and much lower list price compared to Soliris, bode well for its future market prospects, according to analysts.
"Given the less frequent dosing advantage associated with Ultomiris compared to Soliris and potential for discounted pricing, we think this bodes well for conversion to Ultomiris once the drug makes it to market," wrote Raymond James analyst Laura Chico in a Jan. 28 note.
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