BioMarin up on positive gene therapy data in hemophilia A

BioMarin Pharmaceutical ($BMRN) gained almost $1 billion in market cap on positive data for its gene therapy to treat severe hemophilia A. If approved, the company expects that BMN 270 could deliver more than $1 billion in annual revenue.

The company expects that BMN 270 will be one of “four pillars of growth” that will drive BioMarin to profitability next year. The other three core opportunities are vosoritide for achondroplasia, also in the clinic, and two new candidates with regulatory filings--pegvaliase and cerliponase alfa--BioMarin Chairman and CEO Jean-Jacques Bienaimé said on a late April conference call.

Next, BioMarin plans to start a Phase IIb trial around the middle of next year for the hemophilia A gene therapy candidate, which it expects could be sufficient to support a submission for an accelerated approval by the FDA.

The latest BMN 270 data was in 9 patients. Of the 7 who received the highest dose, 6 had Factor VIII levels above 50% as a portion of their plasma with the seventh above 10%. Results seem to improve over time with the four first patients dosed having 146% of their 20-week levels of Factor VIII. The data was for follow-up ranging from 12 to 28 weeks.

Factor VIII is a blood-clotting protein encoded by the F8 gene; defects in this gene result in hemophilia A.

High-dose patients are all dosed with a steroid regimen for up to two weeks after the gene therapy dose. But the maximum ALT levels, which track liver toxicity, were roughly twice the upper limit of normal at about 12 weeks after the gene delivery and then declined over the next few weeks.

BioMarin previously noted an increase in liver enzymes in two patients who did not receive prophylactic steroids. In fact, it paused the study’s dosage for an additional three patients in the study to better understand the issue.

When it presented the latest data, the company called for a subsequent study to determine optimal dose and duration for steroid therapy.

Thus far, the gene therapy has surpassed all of BioMarin’s initial expectations.

“Our goal when we started the program was to increase the Factor VIII expression level in severe hemophilia A patients with Factor VIII expression levels below 1% at the time of enrollment to above 5% in order to move them from the severe level to mild or better,” Bienaimé noted in April.

BioMarin traded up 7% on the positive data on July 27 to reach a market cap of almost $16 billion.

- here is the release

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