Erstwhile rival to Sarepta, Biomarin, has suffered a major...

Erstwhile rival to Sarepta, Biomarin, has suffered a major setback after the FDA rejected its haemophilia A gene therapy, valrox, citing concerns about durability.

The FDA has demanded two years' data from an ongoing Phase 3 study to provide evidence of durability around reducing annualised bleeding rates. Four-year data presented earlier this year showed worrying declines in Factor VIII activity after 12-18 months.

To date, gene therapy has been sold as a one-off cure, which was used to justify multi-million dollar pricing. But with evidence that the efficacy of a so-called “one-off” gene therapy may wane over time, together with the uncertainty that exists as to whether a patient can even be re-dosed, investors in the gene therapy space are doubtlessly nervous.

Biomarin’s gene therapy works by using a viral vector to deliver to liver cells a working gene via a one-time IV infusion meant to enable the body to produce FVIII on its own.

https://www.evaluate.com/vantage/articles/analysis/valrox-dead
https://www.evaluate.com/vantage/articles/news/snippets/biomarin-stock-slammed-valrox-fda-snub
https://www.fiercebiotech.com/biote...iomarin-s-gene-therapy-valrox-amid-durability
https://abcnews.go.com/Health/wireS...ted-biomarin-hemophilia-gene-therapy-72469954