GlaxoSmithKline will take its $2.6bn (€2bn) bid for Human Genome Sciences direct to shareholders this week after its takeover offer was rejected last month by the US biotech group’s board.

Pharmaceutical giant GlaxoSmithKline said its $2.6bn (€1.98bn) bid for long-time partner Human Genome Sciences was “full and fair” and it was the only obvious owner for the US biotechnology firm.