- Alexion Pharmaceuticals could soon face a competitor to its best-selling biologic drug, after a Massachusetts biotech disclosed Tuesday results from a late-stage study which showed its drug beat out Alexion's Soliris.
- The head-to-head trial enrolled 80 adults with paroxysmal nocturnal hemoglobinuria, a rare and potentially life-threatening blood disorder, giving half Soliris and half Apellis Pharmaceuticals' pegcetacoplan. After four months of treatment, patients on Apellis' therapy experienced a 28% boost in levels of a critical oxygen-carrying protein while those on Soliris saw a 17% decline.
- As a result, fewer study participants taking pegcetacoplan required blood transfusions, which are commonly needed for treating a disorder marked by low hemoglobin levels. Fifteen percent of patients on Apellis' drug received a transfusion, compared to 85% of those in the Soliris group.
Apellis is targeting a range of rare diseases for its drug focused on the body's complement system, also the focus of Alexion's therapies.
But the two biotechs are focused on different proteins in the immune system. While Soliris targets the C5 protein, Apellis' experimental drug blocks C3, which the company believes can improve efficacy.
Monday's study result helps validate that hypothesis, and investors responded by sending shares in Apellis up more than 20%. The stock has nearly tripled in value from a year ago, as its pipeline has progressed into late-stage testing.
The primary goal of Apellis' trial was to show PNH patients on pegcetacoplan produce more hemoglobin than those on Soliris after 16 weeks of treatment.
Typically, hemoglobin levels range between 11 and 18 grams per deciliter, depending on gender and other factors. Patients enrolled in this Phase 3 study were already taking Soliris for at least three months and had hemoglobin levels below 10.5 g/dL.
All patients then went through a month-long run-in period in which they received both Soliris and pegcetacoplan before being randomized to receive only one of the two drugs.
Patients were allowed to get transfusions throughout the trial, but receiving one would trigger in a final blood level measurement prior to infusion.
Since most Soliris patients received a transfusion, this put their recorded blood values "at a nadir," Evercore ISI analyst Umer Raffat wrote in a Monday note to investors.
Those values showed the typical Soliris patient experienced a decline in hemoglobin levels of 1.5 g/dl, versus a 2.4 g/dL increase for those on Apellis' drug.
Analysts anticipated the study would show a 1.5 to 2 point difference between the two drugs, meaning the 3.8 point difference exceeded expectations. "This is excellent data and positions [Apellis] as standard of care in Soliris non-responders," wrote Raffat.
Achieving that won't be without challenges, though. Apellis' drug requires a twice-weekly injection that resulted in an injection site reaction in more than a third of patients over the 16-week study. More than one in five patients on pegcetacoplan reported diarrhea, versus none on Soliris.
Ten percent of pegcetacoplan patients and 23% of Soliris patients also suffered from hemolysis, the breakdown of red blood cells. Apellis said the three trial discontinuations were related to hemolysis and all came on the pegcetacoplan arm.
Soliris became the first approved PNH therapy in 2007. But its successful decade-plus run on market could face new competitors within the next few years. Other biotechs undergoing clinical testing for PNH drugs include Novartis, Alnylam Pharmaceuticals, Akari Therapeutics and Ra Pharmaceuticals, which was recently acquired by UCB.
Amgen is also developing a Soliris biosimilar in Phase 3 testing and has requested a court review of Soliris' patents. Alexion expects a decision by Aug. 30, 2020.
In anticipation of this competition, Alexion has prioritized its follow-on drug Ultomiris (ravulizumab), which gained approval in PNH in late 2018.
Apellis did not specify a regulatory submission timeline in its Monday release, but plans to meet with regulators in the first half of this year to discuss whether the data from the study is sufficient to demonstrate pegcetacoplan's clinical benefit.