Pharming of the Netherlands has initiated a new trial of its Europe-approved hereditary angioedema treatment Rhucin, as regulators in the USA get ready to review the drug.

Rhucin (recombinant human C1 inhibitor) was developed through Pharming's proprietary technology in the milk of transgenic rabbits. It is marketed as Ruconest in Europe and a Biologics License Application was submitted to the US Food and Drug Administration at the end of last year.  

That dossier included nine clinical studies covering 714 administrations in 190 subjects but Pharming and US partner Santarus believe it makes sense to do another trial to support the BLA. The Phase IIIb trial will enrol 50 patients and take 12-18 months.

Pharming chief financial officer Karl Keegan told Reuters that "our approach is that our studies are sufficient" but  when the deal was done with Santarus in September last year, "both teams decided it would be a prudent approach to run another trial...and that if additional data would be required before approval, we would be in a good position to address it."

Pharming is responsible for conducting and paying for the new study of Rhucin, which has been granted orphan drug status by the FDA. According to the US Hereditary Angioedema Association, cases of HAE, a genetic disorder in which the patient is deficient in a functional plasma protein C1 inhibitor, resulting in swelling of the extremities, range from one in 10,000 to one in 50,000 individuals .