Drug repurposing for Castleman Disease
The drug repurposing approach has led to the discovery and clinical development of two drugs for the treatment of iMCD. CDCN’s co-founder and executive director, Dr. David Fajgenbaum, also a patient with iMCD, began testing one of these drugs on himself in 2014 and is in his longest remission ever (read more about his story here).
The drug Dr. Fajgenbaum repurposed for himself is called sirolimus and was FDA-approved for the prevention of renal allograft rejection (anti-rejection for organ transplantation patients) in 1999. It was first repurposed and FDA-approved for treatment of the rare disease lymphangioleiomyomatosis (LAM) in 2015. This repurposing made sirolimus the first drug approved to treat LAM. This brought a much needed treatment to patients who suffer from this rare progressive multisystem disorder.As a result of the work of the CDCN and Dr. Fajgenbaum, sirolimus has also been given to patients with idiopathic multicentric Castleman disease (iMCD) since 2014.
While there is an FDA-approved treatment for iMCD, siltuximab (brand name Sylvant), it is not effective for all iMCD patients. Leaving about two thirds of the iMCD patient community suffering from relapses and effects of repeated chemotherapy treatments to avoid life-threatening multi-organ dysfunction. Since discovering the promise of sirolimus, it has been a lifesaving treatment for almost 20 iMCD patients and is now undergoing a clinical trial with the FDA to be ‘approved’. The case of sirolimus also brings up an important point – that drug repurposing can be done several times and even in parallel to maximize the drug’s utilization to its full potential. For more about this approach, check out this video: