Ionis Pharmaceuticals has announced the advancement of IONIS-FXIRx in clinical development under an existing exclusive license agreement with Bayer. Under this agreement, Ionis will also initiate development of IONIS-FXI-LRx, which uses Ionis' proprietary LIgand Conjugated Antisense, or LICA, technology. In conjunction with the decision to advance these programs, Ionis will receive a $75 million payment from Bayer.

"We look forward to continuing the development of IONIS-FXIRx with Bayer. IONIS-FXIRx was the first antithrombotic in development to demonstrate the potential to separate antithrombotic activity from bleeding risk. We recently completed a Phase 2 study in patients with end-stage renal disease on hemodialysis, in which IONIS-FXIRx demonstrated robust reductions in FXI activity and no treatment-related major bleeding," said B. Lynne Parshall, chief operating officer at Ionis Pharmaceuticals. "We are pleased that Bayer has decided to expand our collaboration and initiate development of a LICA antisense drug targeting Factor XI. Our LICA technology enables flexible, low and infrequent doses and dose regimens, which may be preferred for a drug targeting broad indications."

Under the agreement, Ionis plans to conduct a Phase 2b study evaluating IONIS-FXIRx in approximately 200 patients with end-stage renal disease on hemodialysis to finalize dose selection. Additionally, Ionis plans to rapidly develop IONIS-FXI-LRx through Phase 1. Following these Ionis-conducted studies and Bayer's decision to further advance these programs, Bayer will be responsible for all subsequent global clinical development activities as well as worldwide regulatory and commercialization activities for both drugs. Ionis is eligible to receive additional milestone payments as each drug advances toward the market. Ionis is also eligible to receive tiered royalties in the low to high twenty percent range on gross margins of both drugs combined.