AstraZeneca’s lupus drug anifrolumab has achieved its primary and secondary endpoints in Phase II trial, significantly reducing disease activity versus placebo across multiple endpoints.

As measured by the SLE Responder Index 4 (SRI4) at day 169, which combines criteria from three internationally validated disease activity measures, responses with a sustained reduction of oral corticosteroid use were recorded for 34.4% of patients receiving anifrolumab 300mg IV and 28.8% of those receiving anifrolumab 1,000mg IV every four weeks versus 17.6% of patients on placebo.

The trial also met both secondary efficacy endpoints measuring responses after one year of treatment, with even greater effect. More than half (51.5%) of patients taking anifrolumab 300mg and 38.5% receiving anifrolumab 1,000mg achieved SRI4 response at day 365 with sustained reduction of OCS, compared with 25.5% in the placebo arm. The trial also met its other secondary endpoint of a reduction of OCS use to _7.5 mg/day by day 365 in those patients taking _10 mg/day at baseline.

On the safety side, adverse events were similar across groups. Serious adverse events were reported in 18.8% of patients receiving placebo and 16.7% of patients in the pooled anifrolumab groups. A dosage-dependent increase in Herpes zoster (placebo: 2%; 300mg: 5.1%; 1000mg: 9.5%) cases and a greater number of (mostly unconfirmed) influenza infections (placebo: 2%; 300mg: 6.1%; 1,000mg: 7.6%) were observed for patients receiving anifrolumab.

Anifrolumab is a new monoclonal antibody against the type I interferon receptor that inhibits the activity of all type I IFNs, which play a central role in lupus. The drug is currently in Phase III development for SLE, and was recently assigned Fast Track status in the US.

“These positive results for anifrolumab represent real hope for patients with lupus, who have only seen one new treatment for their disease in almost 60 years,” noted Bing Yao, who leads R&D for Respiratory, Inflammation & Autoimmunity at AZ’ MedImmune. “We followed the science behind the potential therapeutic benefits of blocking the interferon pathway and look forward to confirming the data in our robust Phase III TULIP programme, as we seek to bring a new medicine for people with lupus.”

Findings of the trial were presented at the American College of Rheumatology 2015 Annual Scientific Meeting in San Francisco.