Sanofi and Regeneron Inc. announced results from a pivotal phase 3 study of sarilumab, an investigational, human antibody against the IL-6 receptor. The results of the study, SARIL-RA-TARGET, have been presented at an oral session during the American College of Rheumatology (ACR) annual meeting in San Francisco, California.

The study met both its co-primary endpoints of improvements in signs and symptoms of rheumatoid arthritis (RA) and improvements in physical function, as well as secondary efficacy endpoints.

"Rheumatoid arthritis can be a debilitating disease that has a significant impact on a patient, and despite the availability of a wide range of treatments, new agents are still needed to address unmet patient needs including failure to respond to therapy," said Dr. Roy Fleischmann, clinical professor in the department of internal medicine at the University of Texas Southwestern Medical Center and lead study author.

"These data suggest that sarilumab, if approved, may be a potential option for patients with moderate-to-severe RA."

The SARIL-RA-TARGET trial enrolled 546 RA patients who were inadequate responders or intolerant of TNF-alpha inhibitors (TNF-IR). Patients were randomized to one of three treatment groups self-administered subcutaneously (SC) every other week (Q2W): sarilumab 200 milligrams (mg), sarilumab 150 mg, or placebo, in addition to non-biologic disease modifying anti-rheumatic drugs (DMARD) therapy. Top-line results were previously announced in May 2015.

Both sarilumab groups showed clinically relevant and statistically significant improvements compared to placebo in both co-primary endpoints: improvement in physical function at week 12, as measured by mean change from baseline in the Health Assessment Questionnaire-Disability Index (HAQ-DI). The HAQ-DI measures patients' abilities to perform a standard set of daily physical activities. The change from baseline to week 12 in HAQ-DI was -0.49, -0.50, and      -0.29 in the sarilumab 200 mg (p=0.0004), sarilumab 150 mg (p=0.0007), and placebo groups, respectively.

They also show improvements in signs and symptoms of RA at week 24, as measured by the proportion of patients achieving an ACR20 response (ACR20) were 61 per cent in the sarilumab 200 mg group; 56 per cent in the sarilumab 150 mg group; and 34 per cent in the placebo group, all in combination with DMARD therapy (p less than 0.0001).

Secondary efficacy endpoints that will be presented during the ACR oral session include the following: proportion of patients achieving an ACR50 response at week 24 were 41 per cent in the sarilumab 200 mg group, 37 percent in the sarilumab 150 mg group, and 18 per cent in the placebo group (p less than 0.0001); proportion of patients achieving an ACR70 response at week 24 were 16 percent in the sarilumab 200 mg group (p=0.0056), 20 percent in the sarilumab 150 mg group (p=0.0002), and 7 percent in the placebo group; the mean change from baseline to week 24 in disease activity score in 28 joints using C-reactive protein (DAS28-CRP), which evaluates the disease activity of RA, were as follows: -2.82, -2.35 and -1.38- in the sarilumab 200 mg, sarilumab 150 mg, and placebo groups, respectively.

The proportion of patient achieving DAS28-CRP < 2.6 at week 24 were as follows: 29 percent, 25 percent, and 7 percent in the sarilumab 200 mg, sarilumab 150 mg, and placebo groups, respectively.

The change from baseline to week 24 in clinical disease activity index (CDAI), which also evaluates the disease activity of RA, were as follows: -30.43, -27.14, and -23.9 in the sarilumab 200 mg, sarilumab 150 mg, and placebo groups, respectively.

The change from baseline to week 24 in HAQ-DI were as follows: -0.58, -0.52 and -0.34 -in the sarilumab 200 mg, sarilumab 150 mg, and placebo groups, respectively.

Treatment-emergent adverse events (TEAEs) were more frequent in the sarilumab groups (65 per cent and 66 per cent in sarilumab 200 mg and 150 mg vs 50 per cent in placebo respectively). The incidence of serious adverse events (SAEs) was higher than placebo in the sarilumab 200 mg group (5 per cent vs. 3 per cent) and was similar to placebo in the 150 mg group (3 per cent). Infection was the most frequently reported adverse event (30, 22 and 27 per cent in the 200 mg, 150 mg and placebo groups respectively). Serious infections occurred in 2 patients in the sarilumab 200 mg group, 1 patient in the sarilumab 150 mg group and 2 patients on placebo. The most frequent events leading to treatment discontinuation were infection and neutropenia. Adverse events and laboratory changes were consistent with observations from the MOBILITY study and with the mechanism of action of sarilumab.

During the same oral session at ACR, data from the SARIL-RA-ASCERTAIN/1309 studies will also be presented. In total, 14 abstracts were accepted for presentation at the meeting. This includes additional abstracts detailing data from the sarilumab clinical trial programme: SARIL-RA-MOBILITY and SARIL-RA-EXTEND.

The Biologics License Application (BLA) for sarilumab was recently submitted to the FDA.

The investigational agent described above is currently under clinical development, and its safety and efficacy have not been evaluated by any regulatory authority.

Sarilumab (REGN88/SAR153191) is a human monoclonal antibody directed against the IL-6 receptor (IL-6R). Sarilumab binds with high affinity to the IL-6 receptor. It blocks the binding of IL-6 to its receptor and interrupts the resultant cytokine-mediated inflammatory signaling. Sarilumab was developed using Regeneron's VelocImmune antibody technology.