Prothena files for follow-on offering to build $400M R&D war chest

Prothena ($PRTA) has filed the paperwork for a follow-on offering that could net it more than $130 million (€121 million). If successful, the offering will leave the transatlantic biotech sitting pretty on a $400 million stockpile of cash as it plots the next steps in the development of its pipeline of in-house and Roche ($RHHBY)-partnered assets.

Dublin, Ireland-based Prothena plans to set aside a slice of the cash for the continued development and possible commercialization of NEOD001, a monoclonal antibody being trialled as a treatment for the hematological disorder amyloid light-chain (AL) amyloidosis. Prothena moved NEOD001 into Phase III late last year on the back of the encouraging cardiac and renal response rates seen in a small, early-stage trial.

Another tranche of the cash from the follow-on offering--which is expected to raise between $114 million and $131 million--is earmarked for development of PRX002, the Roche-partnered Parkinson's disease candidate that got investors excited last month. The reaction to the Phase I PRX002 data is a big part of why Prothena is able to price the follow-on offering at $37 a share, a figure which its stock has traded well below for most of the past 12 months.

Over that period, Prothena has raised $100 million in public offerings, around half of which came from Neil Woodford's fund. The $50 million investment marked a relatively rare foray for Woodford into the world of Nasdaq-traded biotech stocks, which as a group he has said appear to be overvalued. But with a $600 million deal with Roche and monoclonal antibody assets from Elan ($ELN) to its name, Prothena appeared an attractive option to Woodford back when it was trading for $22 a share. 

- read the release
- check out the SEC filing