Last year​, BioMarin Pharmaceutical released proof-of-concept data to support BMN 270, a gene therapy candidate using an AAV-Factor VIII vector intended to treat patients deficient in the blood clotting protein Factor VIII.

And with plans to begin a Phase IIb study later this year, the firm has said it is constructing a facility in California to manufacture clinical batches.

“Our new gene therapy manufacturing facility is expected to be completed by mid-year, enabling us to move the BMN 270 program forward, without constraints on materials needed for the Phase 2b registration enabling study in the third quarter,”​ CEO Jean-Jacques Bienaimé told investors on a call Friday.

Henry Fuchs, president of worldwide R&D, added making the investment in-house ensures has control of its supply chain for the upcoming trials, heading towards a commercial launch.

“The facility design was recently reviewed with US health authorities and the feedback was consistent with our plans for construction and operational control. The approach laid out was well received and discussed in depth with industry, academic and health authority representatives.”​

Yet while the design of the facility gave consideration to the potential for use with other gene therapies in BioMarin’s pipeline, management did not want to “get the cart before the horse,”​ and wanted to await BMN 270’s success before making any decisions, according to EVP Jeff Ajer.

The investment made in the site was not divulged, but capital expenditure for 2016 stood at $168m (€159m), though this included the buildout of a manufacturing facility in Shanbally, Ireland​, to support commercial supply of the firm’s enzyme replacement drug Vimizim (elosulfase alfa).

For the full year, the firm saw revenues of $1.12bn – up 26% on 2015 – though reported a net loss of $630m (up from $155m) attributed in part to higher operating expenses.