Treatment with the humanized monoclonal antibody litifilimab improved scores on a validated measure of skin disease activity in an international phase 2 trial of patients with cutaneous lupus erythematosus (CLE).
Improvements in Cutaneous Lupus Erythematosus Disease Area and Severity Index–Activity (CLASI-A) scores in patients randomly assigned to receive subcutaneous litifilimab were superior to changes in patients randomly assigned to placebo over the trial period of 16 weeks. The double-blind study was published in the New England Journal of Medicine.
Dr. Victoria P. Werth
“This validated measure is working, and it’s very important to now go into phase 3 using the instrument that worked in phase 2 to measure improvement in the skin,” Victoria P. Werth, MD, professor of dermatology at the University of Pennsylvania, Philadelphia, and lead author of the study, said in an interview.
Research on lupus erythematosus has focused on systemic lupus erythematosus (SLE), with few randomized controlled trials addressing CLE, she said, and no Food and Drug Administration–approved treatments for CLE in the last 50 years.
Asked to comment on the results, Alisa Femia, MD, associate professor and director of autoimmune connective tissue disease in the department of dermatology at New York University, who was not involved in the research, said it is “exciting to have a trial that specifically investigates the effect of a drug on cutaneous lupus, as well-designed investigations into this potentially disfiguring disease are relatively sparse and novel treatment pathways are needed.”
The investigational drug targets blood dendritic cell antigen 2 (BDCA2) – a receptor expressed solely on the surface of plasmacytoid dendritic cells (pDCs) – and inhibits the production of type 1 interferon and other inflammatory cytokines and chemokines believed to play a major role in the pathogenesis of cutaneous and systemic lupus, the investigators said.
Dr. Edward Vital
Rheumatologist Edward Vital, MD, who leads a lupus research group at the University of Leeds (England), said he’s most interested in how the therapy works. The “idea [has been] that pDCs are the main source of type 1 interferon. But there’s a lot of data emerging at present that suggests there are many other sources of interferons, and the drug may work in other ways,” Dr. Vital, an associate professor at the university, said in an interview. He was not involved with the study.
“Maybe pDCs have other important roles. Or maybe other cells are targeted by the therapy, too,” he said. “Understanding this will help us understand the pathogenesis of lupus and which patients will benefit the most.”
Improvements in CLASI-A scores
Across 54 centers, the study enrolled 132 patients with primarily moderate to severe active subacute CLE or chronic CLE (including discoid lupus erythematosus), or both subacute and chronic CLE with or without systemic manifestations. Active CLE was defined as a score of at least 8 on CLASI-A, which measures erythema and scaling or hypertrophy in 13 skin regions.
Patients were randomly assigned to receive placebo or litifilimab at doses of 50 mg, 150 mg, or 450 mg subcutaneously at weeks 0, 2, 4, 8, and 12. Mean CLASI-A scores at baseline for placebo and each of the dosage groups were 16.5, 15.2, 18.4, and 16.5, respectively.
The investigators used a test of dose-response to assess response across the four groups on the basis of the percent change in CLASI-A scores from baseline to 16 weeks, the primary endpoint. The percent changes in CLASI-A score were –38.8 ± 7.5 in the 50-mg group; –47.9 ± 7.5 in the 150-mg group; –42.5 ± 5.5 in the 450-mg group; and –14.5 ± 6.4 in the placebo group. (Negative value indicates improvement from baseline.)
When compared with placebo, the change in CLASI-A scores in each of the litifilimab groups was –24.3 percentage points for the 50-mg dose (95% confidence interval, –43.7 to –4.9); –33.4 percentage points for the 150-mg dose (95% CI, –52.7 to –14.1); and –28.0 percentage points for the 450-mg dose (95% CI, –44.6 to –11.4).
“All three dosages caused a similar skin response,” said Dr. Werth. “And importantly, the placebo response is fairly low, much lower than in SLE trials, possibly because the background therapies tend to be less overall [including with slightly lower doses of prednisone]. So we can really see the broad effect of the drug.”
Just under half of participants – 42%-48% of patients receiving litifilimab and 42% of those in the placebo group – had concomitant SLE with low to moderate disease activity as measured by the Systemic Lupus Erythematosus Disease Activity Index 2000. Patients could meet SLE criteria based on previous findings, and “didn’t have to have active SLE,” Dr. Werth noted.
The trial allowed background therapy as long as treatment had begun at least 12 weeks before randomization, with a stable dose starting at least 4 weeks before randomization and maintained throughout the trial period.
Most patients had moderate to severe CLE at baseline “despite approximately 90% having received concomitant background therapy and 80% of those participants having received antimalarial drugs, either alone or with other agents,” Dr. Werth and coinvestigators wrote.
CLASI-A has been shown to correlate to patients’ quality of life, Dr. Werth emphasized in the interview.
Most of the reported side effects in the phase 2 CLE trial were mild or moderate. The treatment was associated with three cases of hypersensitivity, three cases of oral herpes infection, and one case of herpes zoster infection. One case of herpes zoster meningitis occurred 4 months after the last dose of litifilimab.
Approximately 10% of study participants who reported race and ethnicity were Black or African American.