NEW YORK (AP) — Drug developer GlaxoSmithKline said Monday it extended the tender offer for shares of biotechnology company Genelabs Technologies Inc. in order to meet the deal’s 90 percent requirement. In November, U.K.-based Glaxo said it would move ahead with a $1.30 per share tender, offer, worth about $57 million. It first announced plans to buy Redwood City, Calif.-based Genelabs in October, in part to add two developing hepatitis C treatments to its product pipeline. Genelabs board of directors has already unanimously recommended that shareholders tender their shares in the offer. Glaxo has about 35.1 million Genelabs shares, or about 79 percent of the outstanding stock. Also, there are notices of guaranteed delivery for about 1.4 million shares. The tender offer is conditioned on Glaxo obtaining 90 percent of Genelabs stock. The tender offer has been extended to Dec. 29. The company eliminated the alternative for notices of guaranteed deliveries as part of the extension.