Isis Pharmaceuticals Inc. announced that it has earned an $18 million milestone payment from GlaxoSmithKline Plc related to the advancement of the Phase 2/3 study of ISIS-TTRRx in patients with familial amyloid polyneuropathy (FAP).

"ISIS-TTRRx is the most advanced drug in our collaboration with GSK, and aside from Kynamro, it is also the furthest advanced in our late-stage clinical pipeline. We have patients who have completed fifteen months of therapy and are now receiving ISIS-TTRRx in our open-label extension study," said B. Lynne Parshall, chief operating officer at Isis. "The rapid development of ISIS-TTRRxfrom a research-stage program to a drug in a late-stage clinical trial is a testament to the efficiency and productivity of our drug discovery technology platform. As this program advances, we will continue to benefit from GSK's resources and expertise as well as earn additional milestone payments."

ISIS-TTRRx is an antisense drug in development with GSK for the treatment of transthyretin amyloidosis, a severe and rare genetic disease characterized by progressive dysfunction of peripheral nerve and/or heart tissues.

Including this $18 million milestone payment, Isis (NASDAQ: ISIS) has generated $45 million of the $70 million in upfront and milestone payments Isis is eligible to earn for advancing ISIS-TTRRx in development. In addition, if GSK elects to exercise its option to exclusively license the ISIS-TTRRx program, Isis is eligible to receive a license fee, regulatory and sales milestone payments and double-digit royalties on sales of ISIS-TTRRx.