Biogen’s lupus drug candidate litifilimab has improved outcomes in another phase 2 trial, adding to the momentum behind a program barreling toward pivotal data in two forms of the autoimmune disease.
Following a phase 2 win in 2019, Biogen shared data Saturday from the first part of its phase 2/3 Amethyst trial at the American Academy of Dermatology Annual Meeting. The phase 2 portion of the study compared the anti-BDCA2 antibody litifilimab to placebo in people with cutaneous lupus erythematosus (CLE).
At Week 16, 14.7% of patients who received litifilimab subcutaneously once every four weeks had clear or almost clear skin on a CLE scale, CLA-IGA-R. Fewer than 3% of patients on placebo had clear or almost clear skin, achieving the trial’s primary endpoint.
Biogen’s statistical plan stopped researchers from showing litifilimab performed significantly better than placebo on the secondary endpoints, but the numbers favor the study drug on multiple measures. The biotech reported rates of CLASI-50—which indicates a 50% or greater improvement on a CLE scale—of 19.3% for litifilimab and 5.5% for placebo at Week 4.
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Biogen sees the rate at which symptoms improve as an important consideration in CLE, Diana Gallagher, M.D., who leads the biopharma’s development efforts across Alzheimer’s disease and dementia, multiple sclerosis and immunology, said at a Piper Sandler event in February. CLE patients have inflamed skin and are losing hair, making speedy relief from symptoms a priority.
Another secondary endpoint looked at the rate of CLASI-70 at Week 24, which is the ex-U.S. primary endpoint in the ongoing pivotal part of the Amethyst trial. More participants on litifilimab, 21.7%, than placebo, 5.8%, met the CLASI-70 endpoint. William Blair analysts said in a note to investors that the data increased their confidence that the pivotal trial will meet its primary goal when it reads out in mid-2027.
Biogen is on track to publish phase 3 data on litifilimab in systemic lupus erythematosus (SLE) this year. William Blair analysts said the chances of success are higher in CLE than SLE, based on data generated to date. BMO Capital Markets analysts said in a note to investors in February that SLE is a tough indication and Biogen has reported mixed data, although they added that their hopes for the readout are rising.
The readouts will be the biggest tests of BDCA2 inhibition to date. BDCA2 is expressed on plasmacytoid dendritic cells, a rare type of immune cell implicated in lupus. Binding to BDCA2 could inhibit type I interferon, inflammatory cytokines and chemokines to improve outcomes. Dianthus Therapeutics licensed ex-U.S. rights to an inhibitor of BDCA2 and BAFF/APRIL last year.
