Regeneron Pharmaceuticals Inc. REGN, +0.73% said late Friday its board has authorized a share buyback program of up to $3 billion, saying it's an opportunity to continue to invest in the business given the "strength" of its balance sheet and business. Repurchases will be made from time to time at management's discretion, the company said. Shares of Regeneron rose 1.7% in the extended session Friday after ending the regular trading day up 0.7%.