Biogen announced today, few hours before Wall Street opened, that it has entered into a $1bn-worth agreement with biotech Ionis Pharmaceuticals. The agreement is aimed at developing novel therapies targeting neurological diseases, thanks to the expertise Biotech has developed in the field over the years and to Ionis’ approaches targeting mRNA . The companies have already cooperated over the past, producing Spinraza, a treatment for spinal muscular atrophy that last year generated as much as $884m. Under the agreement, Biogen will become a shareholder in Ionis by buying over 11 million shares for $54.34 per share–19% premium–for a total amount of $625m. Moreover, Biogen will pay Ionis $375m in order to finance the partnership. Biogen’s shares have declined over 1% (Nasdaq), while Ionis’ have lost 3%.