Roivant and Priovant have reported that their Phase II clinical trial of oral brepocitinib to treat adults with moderate to severe systemic lupus erythematosus (SLE) has failed to meet its primary endpoint.

According to the trial findings, oral brepocitinib did not meet the primary endpoint of the SLE Responder Index change of four (SRI-4) at week 52.

The therapy offered the highest SRI-4 responder rates ever reported in a lupus trial, with an 'encouraging' safety and tolerability profile. 

Despite this, the trial also showed a peak placebo response rate.

Based on oral brepocitinib's favourable safety and tolerability profile in the trial and data from six other Phase II trials, Priovant plans to advance the drug for other indications.

Brepocitinib is an inhibitor of TYK2/JAK1 being developed for the treatment of various autoimmune ailments.

Roivant CEO Matt Gline said: “We saw some of the highest SRI-4 responder rates ever observed in a lupus study in the active arm of this trial, along with a favorable safety and tolerability profile.

“Unfortunately, we also saw the highest placebo response rate observed in any significant SLE study, and as such it was not possible to truly assess the impact of the drug, or to establish sufficient differentiation from other therapies in lupus patients.

“While we do not plan to progress the programme in SLE, these results continue to support our view that oral brepocitinib is a highly active agent with a good safety profile, and we remain enthusiastic about brepocitinib’s ability to produce meaningful clinical benefit in non-infectious uveitis and dermatomyositis in Priovant’s ongoing trials, as well as in many other potential indications.”

Priovant will report topline data from the Phase II proof-of-concept trial of brepocitinib in non-infectious uveitis in the first quarter of next year.

Topline data from a Phase III trial of the drug to treat dermatomyositis is expected in 2025.