AstraZeneca is making new progress with its Ultomiris expansion plan. On the heels of an FDA approval, the C5 inhibitor has returned with a clinical win in a rare autoimmune disease affecting the central nervous system.
A phase 3 clinical study testing Ultomiris in neuromyelitis optica spectrum disorder (NMOSD) has hit its goal, AZ said Thursday.
Compared with the placebo arm in a clinical trial of its predecessor Soliris, Ultomiris reduced the risk of relapse in NMOSD patients who tested positive for anti-AQP4 antibodies.
AZ described Ultomiris’ benefit as “statistically significant and clinically meaningful.” The British pharma also offered a sneak peak into how the drug performed in the open-label CHAMPION-NMOSD trial. Specifically, none of the 58 patients experienced a relapse over a median treatment duration of 73 weeks.
Soliris won its NMOSD go-ahead in 2019 based on data from the phase 3 PREVENT trial. In that study, 94 of the 96 patients (98%) who took Soliris were relapse-free at 48 weeks, compared with 30 of 47 patients (63%) in the placebo group.
Both Soliris and Ultomiris are C5 inhibitors. The difference is that Soliris requires infusions every two weeks, while Ultomiris can be given every eight weeks.
NMOSD is a rare autoimmune disease that affects the central nervous system. Patients typically experience unpredictable relapses, or attacks, of worsening of symptoms, which may lead to permanent disability.
About three-quarters of all NMOSD patients are positive for the AQP4 biomarker. In the U.S., that represents about a 4,500 target population for Ultomiris, according to a previous estimate by AZ’s Alexion.
Despite its rare nature, NMOSD has become somewhat of a crowded market. Soliris became the first FDA-approved treatment for NMOSD mid-2019. Then, in 2020, Roche won FDA approval for IL-6 receptor inhibitor Enspryng, and Horizon Therpeutics introduced CD19-directed Uplizna. Both drugs are allowed in anti-AQP4 antibody-positive disease.
Under AZ’s wings, Alexion’s focus these days has been on the conversion of Soliris takers to Ultomiris. Just last week, Ultomiris secured a go-ahead to treat generalized myasthenia gravis, for which Soliris has been marketed since 2017. Alexion has put the U.S. target patient population in that autoimmune neuromuscular disorder at 20,000, much larger than the NMOSD opportunity.
Because of less frequent dosing—and therefore lower treatment cost—for Ultomiris, AZ’s Alexion unit is experiencing some revenue pressure lately. Besides, the ongoing COVID-19 pandemic has made it difficult for patients to switch in some indications.
In the first quarter, Soliris posted sales of $990 million while Ultomiris brought in $419 million, both slightly below Wall Street expectations. Beyond switching Soliris patients, AZ expects complement-naïve patients will drive long-term growth for Ultomiris.