The Wall Street Journal reported that sanofi-aventis has approached Genzyme in informal talks to pursue a possible acquisition, according to unidentified sources familiar with the matter.

According to the sources, the talks are at an early stage and issues such as price and management have yet to be discussed.

However, the people noted that Genzyme will likely pursue a takeover price that reflects the potential for a company turnaround following months of manufacturing problems.

Representatives from both companies declined to comment. Shares in the biotechnology company climbed as much as 21 percent on the news, marking the largest stock price increase for Genzyme in more than a decade. Earlier this month, sources suggested that sanofi-aventis was planning an acquisition in the US that may be worth $20 billion or more, but declined to provide further details.

At the time, analysts cited Genzyme as a potential target for a takeover, as well as Allergan and Biogen Idec.

In other news, it was announced that Novartis' Sandoz unit and partner Momenta pharmaceuticals garnered FDA approval to market the first generic version of sanofi-aventis' Lovenox. Shares in sanofi-aventis fell 5 percent.