Ionis Pharmaceuticals, the leader in RNA-targeted therapeutics, announced that GSK exercised its option to license Ionis' antisense medicines for people with chronic hepatitis B virus (CHB) infection following positive Phase 2 results.

CHB is a chronic viral infection of the liver that can lead to significant and potentially fatal health conditions, including cirrhosis, liver failure and liver cancer. Current treatments for patients with CHB provide low levels of hepatitis B virus S antigen seroclearance, leaving many patients without a treatment to achieve sustained disease remission. There are more than 200 million patients worldwide living with CHB.

"By targeting the root cause of CHB-related liver disease, our antisense technology can potentially deliver a transformative medicine for people who suffer from chronic hepatitis B virus infection," said Brett P. Monia, chief operating officer at Ionis. "We believe GSK's development and commercialization expertise in infectious diseases makes them the ideal partner to help address this high unmet need."

As a part of the licensing agreement, Ionis is eligible to receive license fees and milestone payments up to $262 million, including a $25 million license fee. In addition, Ionis is also eligible to receive tiered royalties in the low double digits on net sales. GSK is now responsible for all development, regulatory and commercialization activities and costs.

This transaction is subject to clearances under the Hart-Scott Rodino Antitrust Improvements Act. Review of the full data package by Ionis and GSK is ongoing and the positive results from the Phase 2 program will be presented at an upcoming medical congress.