* ECB to re-examine monetary support measures in December
* FTSEurofirst 300 up 2.1 pct, ESTOXX 50 up 2.5 pct
* Publicis slumps after growth target cut
By Sudip Kar-Gupta
LONDON, Oct 22 (Reuters) - European stocks rallied on Thursday after the European Central Bank decided to stick with its monetary support programme and reassess in December whether further measures might be needed.
The pan-European FTSEurofirst 300 index ended up 2.1 percent, while the euro zone's blue-chip Euro STOXX 50 index climbed 2.5 percent.
The ECB kept interest rates unchanged at a record low. It also left the key parameters of its quantitative easing (QE) scheme unchanged but said it would re-examine the policy at its meeting in December.
ECB chief Mario Draghi said falling inflation expectations, driven in part by lower-than-expected demand for oil, had led it to consider a wide variety of possible measures, including a deposit rate cut, to shore up inflation.
The ECB's plans have also pushed down returns on bonds and cash, driving investors over to the better returns available from shares.
"Draghi's comments mean continuous support for equities from the ECB," said Hampstead Capital hedge fund manager Lex Van Dam.
Denmark's Novozymes, the world's largest industrial enzymes maker, was among Europe's best performers.
Its shares jumped 10.8 percent as investors expressed relief that the company's results had managed to meet market forecasts, with the stock having slumped in August after it reported disappointing second quarter results.
French spirits group Pernod Ricard rose 5.2 percent after quarterly sales rose more than expected, as a strong U.S. performance offset sluggish China sales.
Publicis slumped 7 percent, however, after the world's third-biggest advertising agency cut its annual organic growth target to 1 percent from 2.5 percent as quarterly sales slowed.
Today's European research round-up (Additional reporting by Danilo Masoni; Editing by Catherine Evans)