Swiss biotechnology company Serono SA reported a third-quarter profit increase of 20 percent Thursday on higher revenue, especially from its flagship multiple sclerosis drug Rebif.

Serono, which is being bought by German pharmaceutical and chemical company Merck KGaA, said profit for the quarter was $170.6 million, up from $142.4 million in the year-ago period.

The Geneva-based company said sales rose 9.5 percent to $699.1 million.

"We have delivered an excellent quarter with strong performance of our leading product, Rebif, and our company has again generated strong cash flow," said Chief Executive Ernesto Bertarelli.

Worldwide sales of Rebif increased by 18.7 percent to $374.8 million.

Shares in Serono rose 0.2 percent to close at 1,081 Swiss francs ($856.92) on the Zurich exchange Thursday.