Taking heart in darapladib

Investors may be losing faith that Human Genome Sciences Inc. can get more from an acquirer than the $13 per share offer on the table from partner GlaxoSmithKline plc.

HGS shares rose to $14.70 in mid-May, a month after GSK's $2.6 billion bid. By mid-June, when the biotech was wrapping up a strategic review process in which it evaluated takeover offers, the stock went as low as $13.10. Last week, HGS closed down $0.16 to $13.35...