Ultragenyx sets $3.95m list price for fatal rare disease therapy

Ultragenyx Pharmaceuticals has set a US list price of $3.95m for its newly approved gene therapy, making it one of the world’s most expensive drugs.

Fayuvi (rebisufligene etisparvovec-hopf) is a one-time treatment designed for children with a rare disease known as Sanfilippo syndrome Type A – an inherited condition that progressively damages the brain and nervous system.

This week, the drug became the first-ever treatment for the universally fatal disease to be granted a full FDA green light, marking the second gene therapy approval for Ultragenyx.

Gene therapy clears toxic build-up of sugars

Roughly 1 in 70,000 children is born with Sanfilippo syndrome each year globally. It is caused by a deficiency of the sulfamidase enzyme, which leads to abnormal accumulation of a complex sugar molecule called heparan sulfate in the brain and body.

Often dubbed ‘childhood Alzheimer’s’, these built-up sugar molecules cause progressive neurodegeneration, leading children to gradually lose cognitive, speech and motor skills. Most die before adulthood.

New drug Fayuvi, administered as a single intravenous infusion, works by delivering a copy of the SGSH gene into cells, enabling the body to produce sulfamidase and begin clearing the toxic build-up of sugar molecules.

According to the FDA, it showed promising results in trials. Children treated with the drug showed maintained or improved cognitive function compared with their untreated peers.

‘Historic milestone’ for Sanfilippo community

Emil D. Kakkis, chief executive officer and president, Ultragenyx, said: “This is a historic milestone for a community that has waited far too long, but has never given up hope.

“We recognize the profound urgency of making this therapy available to families, and our focus now is on supporting timely access in the U.S. as we work closely with treatment centres and payers to support families on the gene therapy treatment journey.”

Glenn O’Neill, president and co-founder of the Cure Sanfilippo Foundation, agreed, praising the first-of-its-kind treatment for a disease that “relentlessly steals a child’s abilities, independence, and future.”

“We celebrate by honouring every family who contributed and remembering the children we lost while waiting for this day. Together, we look ahead with renewed hope knowing that this treatment is now approved for children and families affected by this heartbreaking disease,” he added.

Following the approval, Ultragenyx – which specialises in developing products for the treatment of rare and ultra-rare genetic diseases – saw its share price rise by 12.6% by close on Thursday. Analysts estimate Fayuvi could reach peak worldwide sales of up to $250m.

It is expected that the drug will be available to patients in specialised treatment centres in the US within 30 to 60 days.

Featured image: MichaelVi on AdobeStock