Biogen exercised a licensing option and will pay Carlsbad’s Ionis Pharmaceuticals $35 million for a drug candidate aimed at amyotrophic lateral sclerosis, or ALS.

The companies said Biogen’s decision comes on the heels of positive phase 1 data for BIIB067, intended for the rare, fatal neurodegenerative disease. Going forward, Biogen will handle worldwide drug development, and assuming regulatory green lights, manufacturing and commercialization too.

“BIIB067 is the first investigational medicine targeting the known cause of this familial form of ALS to advance towards a pivotal study,” said in a statement C. Frank Bennett, senior vice president of research and franchise leader for neurological programs at Ionis.

Final results of the phase 1 study will be presented “at a future scientific forum,” said Ionis.

Ionis could earn an additional $55 million in post-licensing payments, as well as royalties on sales if the drug wins approval.

Besides BIIB067, the companies partnered on the blockbuster drug Spinraza, six more drugs moving forward in development, and preclinical and research programs.