(Reuters) - Johnson & Johnson said its experimental sirukumab treatment for rheumatoid arthritis showed mixed results against AbbVie Inc's top-selling Humira in a large trial.
By one measure, patients with moderate to severe disease who took sirukumab showed significantly greater improvement in the Phase III study than those taking Humira, J&J said on Saturday. But another comparison showed no significant benefit of one drug over the other.
In the 559-patient study, those taking sirukumab scored declines after 24 weeks of 2.58 with a low dose and 2.96 with a high dose on a widely used nine-point scale of disease activity. That compared favorably with an average decline of 2.19 for similar patients taking Humira, allowing sirukumab to achieve one of its two primary trial goals, J&J said.
But although signs and symptoms of disease decreased by at least 50 percent among many patients, according to another measure, the proportion of those who achieved that goal was not significantly different across all groups.
Serious side effects were seen in 7 percent of the low-dose sirukumab group and 3 percent of the high-dose patients, compared with 4 percent of those taking Humira.
Results of the study, pitting the injectable drugs against each other as standalone treatments, were reported on Saturday at the annual meeting of the American College of Rheumatology in Washington. The study enrolled patients who could not tolerate or who had failed to benefit from standard treatment methotrexate.
Humira, like other older medicines such as Amgen Inc's Enbrel and J&J's Remicade, works by blocking a protein called tumor necrosis factor (TNF) that is involved in inflammation.
Sirukumab is a member of an emerging new class of treatments that work instead by blocking IL-6, another protein involved in the inflammation process.
(Reporting by Ransdell Pierson; Editing by Lisa Von Ahn)