Genzyme Corp. announced Tuesday it has boosted its hostile offer for Vancouver-based AnorMED by 58 per cent to $13.50 US a share.

The new all-cash offer tops the $12 US-a-share friendly bid from Millennium Pharmaceuticals made on Sept, 26, which handily topped Genzyme's opening bid of $8.55 US a share.

AnorMED three-month trading
AnorMED three-month trading

The new bid values AnorMED at $580 million US.

Massachusetts-based Genzyme had signalled last week that the bidding war wasn't over and said a revised offer was coming. At that time, AnorMED management said Millennium would have the right to match or better any new Genzyme bid.

AnorMED is a biopharmaceutical company that specializes in the development and commercialization of new products in the treatment of cancer and blood disorders.

Its lead product in the development pipeline is Mozobil, a stem-cell transplant drug.

Genzyme said Tuesday it boosted its offer "following the completion of additional diligence regarding Mozobil."

AnorMED shares were up 80 cents to $15.85 in early trading on the TSX. On the Nasdaq, the shares were up 75 cents to $14.05 US — 55 cents above the latest offer.

That suggests that investors think the bidding war for AnorMED still isn't over.