LONDON -(Dow Jones)- A fund with a 5.6% stake in Human Genome Sciences Inc. (HGSI), the U.S. drug company for which GlaxoSmithKline PLC (GSK.LN) has made an unsolicited $2.6 billion offer, said the approach is "unacceptable", according to the Sunday Times.

Human Genome Sciences, based in Rockville, Md., on April 20 rejected Glaxo's $13 a share offer, which it said undervalues the company.

Taube Hodson Stonex, a London-based fund, said the offer amounted to Glaxo trying to "get a steal with an offer that completely undervalues the company", the Sunday Times reports, attributing the remarks to Taube Hodson Stonex's Mark Evans.

"Towards $20 per share would still feel undervalued," Evans is quoted as saying.

THS couldn't be reached for comment Sunday.

Glaxo and Human Genome Sciences have a long working relationship, co-leveloping and sharing profits on Benlysta, a lupus medicine.

Newspaper Web site: http://www.timesonline.co.uk

-London Bureau, Dow Jones Newswires; +44 (0)20 7842 9320