Johnson & Johnson has filed siltuximab on both sides of the Atlantic for a rare blood disorder.

Specifically, J&J's Janssen unit has filed siltuximab with the European Medicines Agency and the US Food and Drug Administration for the treatment of patients with multicentric Castleman disease who are HIV-negative and human herpes virus-8 (HHV-8)-negative.

MCD is a rare disorder in which lymphocytes are over-produced and lead to enlargement of lymph nodes. This can cause a variety of symptoms and weaken the immune system and infections in people with MCD may even be fatal. Currently, there are no approved treatments for the disorder.  

The submissions for siltuximab are based on the MCD2001 study which assessed the drug plus best supportive care (53 MCD patients) compared with placebo plus BSC (26 patients). Results of the primary study analysis have been submitted for presentation at a medical meeting later this year.

Siltuximab has been granted orphan drug status in the USA and Europe and Peter Lebowitz, head of oncology at Janssen, said that "as a rare disease with a small patient population, MCD is an area of significant unmet need”. Noting that siltuximab works by targeting interleukin-6 "which appears to be the critical driver of this disease", he added that by focusing on core biologic mechanisms, we now have the potential of helping patients with a condition that is challenging to treat".