US-based Xencor has started a Phase II trial of its drug candidate XmAb5871 in patients with IgG4-related disease (IgG4-RD), as well as patients with systemic lupus erythematosus (SLE).
The Phase II pilot study in IgG4-RD is an open-label, single-arm trial being conducted at Massachusetts General Hospital by Dr John Stone.
Around 15 patients with active IgG4-RD will receive intravenous (IV) administrations of XmAb5871 every two weeks for six months.
The trial’s primary objective is to evaluate the effect of IV administration of XmAb5871 on the IgG4-RD responder index (RI) in patients with active IgG4-RD.
The secondary objectives of the trial are to determine safety and tolerability, as well as characterise pharmacokinetics, pharmacodynamics, and immunogenicity of IV administration of XmAb5871.
Xencor president and chief executive officer Bassil Dahiyat said: "We are advancing XmAb5871 in IgG4-RD and SLE because of its potent, reversible B-cell inhibition and promising treatment effect demonstrated in a Phase Ib/IIa study of patients with rheumatoid arthritis, as well as previous ex vivo results with XmAb5871 showing inhibition of SLE patient B-cell activation and humoral immunity.
"B-cell inhibition by XmAb5871 has potential in a number of autoimmune diseases, and we believe we can execute efficient clinical trials with clear outcomes in these indications and potentially address high unmet needs.
"In IgG4-RD, a newly defined disease, we have the opportunity to be at the forefront of providing a treatment for patients."
The Phase II SLE trial is designed to assess XmAb5871 after a short course of intra-muscular (IM) steroid therapy, and in the absence of immunosuppressant medication.
The trials’s design was previously tested in an observational study by Dr Joan Merrill of the Oklahoma Medical Research Foundation, who is the coordinating investigator for the XmAb5871 SLE trial.
In the trial, which is being conducted in the US at about 20 sites, around 90 SLE patients will be enrolled with a 1:1 randomisation of XmAb5871 to placebo.
The primary objective of this trial is to evaluate XmAb5871 in maintaining improvement in SLE patients achieved by steroid therapy.
Image: Low-power view of IgG4-related prostatitis. Photo: Courtesy of María T. Bourlon, Mónica Sánchez-Ávila, Fredy Chablé-Montero, Ricardo Arceo-OlaizMaría T. Bourlon, Mónica Sánchez-Ávila, Fredy Chablé-Montero, and Ricardo Arceo-Olaiz.