Genentech’s subcutaneous (SC) formulation of Actemra (tocilizumab) has met the primary endpoints of the Summacta study in adult patients with moderately to severely active rheumatoid arthritis (RA).

Actemra is the first humanised IL-6 receptor-inhibiting monoclonal antibody approved for the treatment of adult patients with moderately to severely active RA who have had an inadequate response to one or more tumour necrosis factor (TNF) antagonist therapies.

Summacta is a double-blind active-controlled parallel group multicentre two-year study that randomised 1,262 patients with RA to compare the efficacy of the SC formulation of Actemra 162mg weekly, compared to Actemra 8mg/kg intravenous (IV) formulation every four weeks.

The study’s secondary endpoints include assessments at week 24 of the proportion of patients in each group with an ACR50 response, an ACR70 response, DAS 28 low disease activity and decrease of = 0.3 in the Health Assessment Questionnaire Disability Index (HAQ-DI) from baseline to week 24.

"Actemra is the first humanised antibody approved for the treatment of adult patients with RA."

The study will also evaluate long-term safety profile and efficacy, pharmacokinetics (PK) and pharmacodynamics (PD) of Actemra SC, immunogenicity of Actemra SC and the effect of switching from one formulation to another on the safety, efficacy, PK and PD of the drug candidate.

Patients in group A received Actemra 162mg SC weekly and those in group B received Actemra 8mg/kg IV. In each group, a similar proportion of RA patients achieved an ACR20 response at week 24, a measure indicating improvement in the number of tender and swollen joints, pain scale, patients and physicians’ assessment of improvement and certain laboratory markers.

The results of Brevacta, a second study investigating Actemra SC formulation administered every two weeks compared to placebo SC, are expected in late 2012.

Upon completion of the two studies, the company plans to submit Summacta and Brevacta data to health authorities in the US.