FDA approves first drug, Eiger's Zokinvy, for rare rapid-aging disease

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Eiger BioPharmaceuticals is also developing the drug, called lonafarnib, in hepatitis D. (FDA)

For a long time, children with the ultrarare genetic disease progeria, which causes rapid aging, didn’t have an FDA-approved therapy. But that's about to change. 

Friday, the FDA approved Zokinvy, or lonafarnib, to treat Hutchinson-Gilford progeria syndrome and processing-deficient progeroid laminopathies in patients ages 1 and above.

Hutchinson-Gilford and progeroid laminopathies are two distinct fatal diseases marked by premature aging, with an estimated worldwide patient population of 400 and 200, respectively. Most patients die before the age of 15 from heart diseases and strokes.

Zokinvy isn’t a cure. The drug, a farnesyltransferase inhibitor, targets the toxic buildup of progerin or progerin-like farnesylated proteins.

The FDA based the approval on data from 62 patients in two single-arm clinical trials. Compared with untreated patients from a separate history study, treatment of Zokinvy increased survival by an average 2.5 years with a maximum follow-up of 11 years.

RELATED: Eiger's progeria drug nabs speedy review

The green light gives Zokinvy developer Eiger BioPharmaceuticals a rare pediatric disease priority review voucher, which can be used to speed up FDA evaluation of a future drug. The company said it plans to sell the voucher, which, if a recent transaction from Merck is any indication, could be worth $100 million. The company will share any proceeds with the Progeria Research Foundation, which helped develop the drug.

Merck was the original developer of Zokinvy, but the company ditched its plan of spinning the drug as a cancer treatment after getting lackluster data. It has been offering the drug for free to progeroid researchers.

RELATED: Belgium biotech argenx nabs Bayer speedy review voucher for a cool $98M

Eiger is also developing lonafarnib as part of a hepatitis D regimen. In the pivotal D-Liver trial, the company is pitting a combination of lonafarnib and AbbVie’s antiretroviral Norvir (ritonavir), as well as a cocktail that contains Roche’s Pegasys (pegylated interferon alpha-2a) as a third component, against placebo. Enrollment is expected to complete next year. While that trial will assess the proportion of patients who achieve at least a 2 log decline in HDV RNA and normalization of liver enzymes, another trial will evaluate sustained virologic response.

“We believe these active antivirals have a high probability of success in the trials,” BTIG analyst Bert Hazlett wrote in a Monday note.