A new strategic collaboration between Gilead Sciences Inc. and privately held Precision Biosciences Inc. will focus on developing therapies targeting the in vivo elimination of hepatitis B virus (HBV) with Precision's Arcus genome editing technology. Precision is eligible for milestone payments of up to $445 million under the terms of the deal and, if successful, could see tiered royalties on sales reaching the midteens. The agreement could eventually lead Gilead to a potent new offering in HBV, where generic medicines have decimated the once-formidable revenues generated by Viread (tenofovir disoproxil fumarate), and sales of its newer medicine, Vemlidy (tenofovir alafenamide), have yet to gain the same traction.