DRUGS company GlaxoSmith-Klineboosted its portfolio with a 453m euro (£297.5m) deal for two treatments of acute heart disease.

The group has struck a deal with Sanofi-Synthelabo to buy the rights to injectable drugs Fraxiparine and Arixtra, which have combined annual sales of £225.2m.

But the acquisition hinges on Sanofi emerging victorious from its hostile £33.1bn bid for larger rival Aventis, launched in January.

Sanofi has agreed to sell the drugs to meet regulatory concerns over the takeover, which would create one of the world's top three pharmaceutical companies.

Speculation is mounting that a bidding war for Aventis could break out, which could scupper Glaxo's acquisition of the two treatments.

Swiss drugmaker Novartis has stated that it is considering an offer for Aventis.

A spokesman for GSK said the deal would help build its position in the injectable drugs market, estimated to be worth 3.2bn euros (£2.1bn) a year.

He said: "The drugs will also give us an immediate cashflow, which is attractive to any business."

GSK has suffered a slowdown in introducing drugs to the market at a time when sales of many of its best-selling medicines are coming under pressure from generic copies.

Odiparcil, a treatment for chronic heart disease, is in advanced clinical trials, but is not due to go on sale until 2007.

Fraxiparine, which inhibits the formation of blood clots, generated sales of £209.3m last year. Annual sales of Arixtra, which prevents deep vein thrombosis in patients undergoing surgery, were smaller at £15.7m.

Glaxo will also take control of the manufacturing base for the drugs at Notre-Dame de Bonde-ville, near Rouen, France, and the 650 staff who work there.