Apellis' Soliris rival gets a date at the FDA for a rare blood disorder, with potentially $400M worth of implications
Apellis $APLS is one step closer to catching its rival for the rare blood disorder PNH.
The Waltham, MA-based biotech announced that the FDA has begun priority review for its experimental medicine pegcetacoplan after the drug beat Alexion’s blockbuster Soliris in a head-to-head Phase III. Regulators have set a PDUFA date for May 14, 2021, and Apellis noted that no adcomm is currently expected.
Investors seemed largely indifferent at the news, with Apellis down by about 0.8% at the end of day Monday. Alexion $ALXN shares, meanwhile, were flat.
Pegcetacoplan won the review thanks to the pivotal Phase III data from January showing the candidate improving hemoglobin levels “in adjusted means” of 3.8 g/dL at week 16 compared to Soliris. Essentially, patients started at a hemoglobin baseline of 8.7 g/dL, and pegcetacoplan increased the levels by 2.4 g/dL while Soliris showed a decrease of 1.5 g/dL.
The p-value for that 80-patient study was p<0.0001. There were 41 patients randomized to the drug arm while the other 39 made up the Soliris control group.
Apellis didn’t head straight to the FDA, however, noting in an SEC filing at the time that regulators were concerned over how a rise in hemoglobin levels may not translate to clinical benefit in patients who entered the trial with high levels to begin with. Then in May, shortly after CEO Cedric Francois recovered from Covid-19, Apellis announced the FDA’s objections had been sorted out, though they didn’t specify exactly the agency’s new position.
Alexion has since pointed to an enzyme called LDH since Apellis’ trial results were published, which is released as blood cells crumble naturally — and at dangerously high levels in those with PNH. LDH in a person’s blood can measure how well a PNH drug is working, if it’s preventing the blood cells from disintegrating.
Though pegcetacoplan walloped Soliris on hemoglobin levels, Apellis’ primary endpoint, the program didn’t meet non-inferiority on LDH. However, presenting later at the European Hematological Association, Apellis released data showing 71% of patients in the drug arm saw their LDH levels fall to normal, compared with 15% of the Soliris arm.
Apellis is trying to get to the top of a market that — between Soliris and its successor Ultomiris — earned $5.5 billion last year, and Cowen analyst Phil Nadeau is expecting an approval with peak annual sales upwards of $400 million. The biotech has already attracted a licensing partner for the compound, lining up nearly $1.2 billion in a deal with the Swedish pharmaceutical company Sobi last month. That deal included $250 million upfront and $915 million in milestones to market the drug outside the US.
Soliris is a C5-targeted drug, but pegcetacoplan aims upstream for C3. The theory goes that by regulating excessive activation of the complement cascade, Apellis can prevent the onset and progression of PNH and other diseases in hematology, ophthalmology, nephrology, and neurology.