Merck to Present Positive Phase 2 Data on Atacicept, Potential SLE Therapy, at ACR 2016

Ines Martins, PhD avatar

by Ines Martins, PhD |

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Merck KGaA announced that it will present two posters showing positive clinical data for its drug candidate atacicept, a recombinant fusion protein for the treatment of systemic lupus erythematosus (SLE).

The presentations will take place at the 2016 American College of Rheumatology/Association of Rheumatology Health Professionals (ACR/ARHP) Annual Meeting in Washington, D.C., which opens on Friday and runs through Nov. 16.

“There is a significant unmet medical need in systemic lupus erythematosus, with limited treatment options currently available for this debilitating disease,” Luciano Rossetti, head of Global Research & Development for the biopharma business of Merck KGaA,  said in a press release. “The safety and efficacy data … indicate that atacicept may play an important role as a potential new therapeutic option for patients with lupus.”

The first poster, “Efficacy and Safety of Atacicept in Patients with Systematic Lupus Erythematous: Results of a 24-week Randomised Placebo-Controlled Phase IIb Study,” will be presented by Dr. Joan Merrill with the Medical Research Foundation in Oklahoma on Nov. 13.

This presentation covers data from ADDRESS II, a Phase 2b multicenter study (NCT01972568) in 306 patients with active SLE (SLEDAI-2K equal or more than 6), who were randomly assigned to receive weekly injections of atacicept (75 or 150 mg) or a placebo for 24 weeks. Its primary endpoint was the percentage of patients achieving SRI-4 response (as measured by a four-point improvement in SLEDAI-2K) at 24 weeks compared to baseline (study’s start).

Results showed that a significantly larger proportion of treated patients achieved SRI-4 response: those on atacicept 75 mg had a 55.9 percent response, those on atacicept 150 mg a 55.8 percent response, and placebo-treated patients a 41 percent response.

It concluded that atacicept was effective in treating SLE, particularly in patients with high disease activity and those with serologically active disease. Treatment reduced both disease activity and severe flares. Atacicept was also associated with a favorable safety profile.

Dr. Patricia Fraser with EMD Serono, a division of Merck, will present the second poster, “Atacicept: Integrated Safety Profile from Phase II Randomised Placebo-Controlled Studies in Autoimmune Diseases, that same day. This poster reports pooled safety data from seven double-blind, placebo-controlled, Phase 2 studies of atacicept — at 25, 75 or 150 mg doses — in people with SLE, lupus nephritis (LN), rheumatoid arthritis, multiple sclerosis, and optic neuritis. In total,  1,262 people were included in the analysis, 36 percent (455) of whom were SLE patients.

Results showed similar treatment-emergent adverse event rates (TEAEs) between atacicept and placebo-treated groups, with infections being the most commonly reported adverse event. Patients with SLE were more likely to develop infection-related and serious/severe TEAEs than other patient groups: 62.4 percent of those on  75 mg atacicept treatment, and  60.4 percent of those on 150 mg treatment developed infections or infestations, including pneumonia.

Still, the researchers concluded that the safety profile of atacicept is similar to other B cell-targeted therapies. It is being further evaluated in clinical trials of SLE patients.

Atacicept is a recombinant fusion protein designed to inhibit B-cells, and possibly autoantibody production, as a way of suppressing autoimmune disease.