Sarissa Capital Management bought a 6.22% stake in biotechnology firm Ariad Pharmaceuticals Inc. This would be the third investment that Sarissa publicly disclosed since the hedge fund was launched earlier this year. The other two investments that Sarissa made were in Vivus Inc and Astex Pharmaceuticals. Alexander Denner, a former deputy of investor Carl Icahn, had been heading Sarissa Capital. No financial details were disclosed about the new investment.

Meanwhile, shares of Ariad Pharmaceuticals had taken a beating. Share price fell after the US Food and Drug Administration placed a partial hold on the company's patient enrollment for clinical trials of its cancer drug. Shares had plunged by over 80% after the drug showed increased risks of blood clots among patients. Clinical trial for the drug was finally stopped by Ariad on October 18.

In December last year, Ariad received approval to treat chronic myeloid leukemia or CML, a type of blood cancer. Inclusig, Ariad's other drug, was also approved for the treatment of Philadelphia chromosome positive acute lymphoblastic leukemia.