ViroPharma has decided to terminate the Phase II clinical evaluation of subcutaneous Cinryze (C1 Esterase Inhibitor [Human] with recombinant human hyaluronidase (rHuPH20)).
Cinryze is approved in the US as an intravenous administration for routine prophylaxis against angioedema attacks in adolescent and adult patients with hereditary angioedema (HAE).
In Europe, Cinryze is approved for routine prevention, pre-procedure prevention and acute treatment of angioedema attacks in adolescent and adult patients with HAE.
The decision, which followed a discussion with the Center for Biologics Evaluation and Research division of the FDA, is a precautionary measure related to the emergence of an unpredicted incidence and titer of non-neutralizing anti-rHuPH20 antibodies in a number of study patients.
However, antibodies with unknown clinical significance are not linked to any adverse clinical effects, according to the company.
In the fully enrolled study, around 41 patients completed at least one dosing arm of the study drug, with a total of 20 patients having completed both dosing arms.
The data from the study is expected to be informative for design of future subcutaneous administration studies.
Meanwhile, the company has developed an optimised, low-volume subcutaneous formulation of Cinryze and expects to conduct a Phase III subcutaneous registration study with the alternative formulation in the similar time frame anticipated for the combination product.