Recombinant human anti-transforming growth factor beta 1 antibody therapy in systemic sclerosis - A multicenter, randomized, placebo-controlled phase I/II trial of CAT-192

Objective. To evaluate CAT-192, a recombinant human antibody that neutralizes transforming growth factor beta 1 (TGF beta 1), in the treatment of early-stage diffuse cutaneous systemic sclerosis (dcSSc). Methods. Patients with SSc duration of < 18 months were randomly assigned to the placebo group or to 1 of 3 CAT-192 treatment groups: 10 mg/kg, 5 mglkg, 0.5 mg/kg. Infusions were given on day 0 and weeks 6, 12, and 18. The primary objective of this study was to evaluate the safety, tolerability, and pharmacokinetics of CAT-192. Secondary outcomes included the modified Rodnan skin thickness score (MRSS), the Scleroderma Health Assessment Questionnaire, assessment of organ-based disease, serum levels of soluble interleukin-2 receptor, collagen propeptides (N propeptide of type I [PINP] and type III collagen), and tissue levels of messenger RNA for procollagens I and III and for TGF beta 1 and TGF beta 2. Results. Forty-five patients were enrolled. There was significant morbidity and mortality, including I death in the group receiving 0.5 mg/kg of CAT-192 and 3 deaths in the group receiving 5 mg/kg of CAT-192. There were more adverse events and more serious adverse events in patients receiving CAT-192 than in those receiving placebo, although these events were not more frequent in the high-dose treatment group. The MRSS improved in all groups during the study, but there was no evidence of a treatment effect for CAT-192. Improvement in the MRSS correlated with the disease duration (r = -0.54, P = 0.0008). Changes in the PINP level from baseline correlated with changes in the MRSS (r = 0.37, P = 0.027). Conclusion. We report the first evaluation of a systemically administered and repeatedly dosed anti-TGF beta 1 drug. In this pilot study, CAT-192, in doses up to 10 mg/kg, showed no evidence of efficacy. The utility of clinical and biochemical outcome measures and the feasibility of multicenter trials of early dcSSc were confirmed.