In a week that was relatively quiet for dealmaking compared to many others this year, there were still two high-value deals in the CNS space, which continues to generate deals and funding despite recent clinical failures in the area.

In one of the largest discovery-stage deals ever, Biogen will pay Ionis Pharmaceuticals $1 billion—composed of a $375 million upfront payment and $625 million to purchase Ionis shares—to gain access to up to seven antisense drug candidates for neurological diseases. Through the deal, Biogen will have the choice to take any of the candidates through development to commercialization, and Ionis will be eligible for milestone and royalty payments. The deal expands on Biogen’s existing collaboration with Ionis, which recently provided Biogen with Spinraza (nusinersen), a pioneering antisense therapy for spinal muscular atrophy.

Also seeking to boost their pipeline, but in epilepsy specifically, UCB announced that it is to pay $150 million in cash upfront and $220 million in sales and regulatory milestones to acquire the rights to midazolam nasal spray (USL261) from Proximagen. A new drug application for USL261, which has successfully completed phase 3 trials as a rescue treatment for acute repetitive seizures, is expected to be filed in 2018. If approved, it will build on UCB’s established portfolio of marketed therapies for epilepsy.