EUSA Pharma buys rights to Janssen rare disease drug

UK-based EUSA Pharma has bought worldwide rights to Janssen’s rare diseases drug Sylvant (siltuximab) for $115 million. EUSA already markets two oncology drugs and is seeking to build its presence in the rare disease market with Sylvant, which has been approved in the US since 2014 to treat multicentric Castleman’s disease, caused by an abnormal overgrowth of cells of the lymph system. Although not classified as cancer, the disease acts very much like lymphoma and Sylvant is the only approved treatment for the condition in more than 40 countries worldwide including Europe.
The disease affects around 1,900 patients in the US and a similar number in Europe, and due to the small numbers of patients, the drug has market exclusivity under orphan drug regulations in both territories. EUSA bought worldwide rights to the drug from Janssen Sciences Ireland and says it plans to expand its availability into other countries. While the drug does not produce significant sales for the Johnson & Johnson unit, EUSA has plans to relaunch it and develop it in other indications.