NEW YORK (AP) — GlaxoSmithKline PLC is reportedly talking this weekend with Human Genome Sciences Inc. about its $2.6 billion offer for the Maryland-based biotech company.

British drug maker GlaxoSmithKline made its first bid for the biotech company in April and extended its offer of $13 per share until July 20.

Human Genome Sciences has dismissed the GlaxoSmithKline offer as too low and said it would accept other bids until Monday.

Citing sources familiar with the situation, Reuters reported Sunday that the two sides were talking and that U.K.-based GlaxoSmithKline could sweeten its offer, but that the talks could still fall apart.

Representatives of GlaxoSmithKline and Rockville, Md.-based Humane Genome Sciences did not immediately return messages for comment.

The two companies are working together on the lupus drug Benlysta.