AstraZeneca plc's MedImmune LLC unit is following a clinical development trail for lupus candidate anifrolumab first blazed by Benlysta belimumab. The company hopes that its track record of successful mid-stage trials in the indication have set it up to confirm anifrolumab's Phase II higher response rates in an ongoing Phase III.
MedImmune presented Phase II results last week showing a placebo-adjusted response rate of 22.4% at 365 days for the dose now in Phase III, outperforming the 14% placebo-adjusted response rate on Benlysta's label and the 12.3% rates GlaxoSmithKline plc reported for a subcutaneous formulation of the drug.
Anifrolumab is a human mAb that targets Type I interferon receptor 1, inhibiting the activity of all Type I IFNs. Benlysta is a human mAb against B lymphocyte stimulator protein (BLyS; BAFF). Data for anifrolumab and subcutaneous belimumab were both presented at the American College of Rheumatology meeting in San Francisco (see "Lupus Comps," page 9).
But systemic lupus erythematosus (SLE) is a notoriously difficult indication to crack, and promising Phase II results have often failed to bear out in Phase III, in part because of tremendous heterogeneity and the unpredictable course of disease.