GlaxoSmithKline PLC has tabled an offer to take over U.S. drug maker Human Genome Sciences Inc. which values the target at nearly $2.6 billion.

GlaxoSmithKline, which has profit-sharing agreements with HGS on three drugs, said Wednesday it is offering $13 per share for the company. The offer was rejected by HGS management.

GSK said its offer was 81 percent more than the HGS share price on April 18, before HGS disclosed the earlier private offer.

The tender offer, which is a direct approach to the target's shareholders, will remain open for 20 days. GSK said it hoped to complete the deal on a friendly basis.

GlaxoSmithKline share were down 0.7 percent at 1,414 pence in early trading. AP