* FTSEurofirst 300 jumps 2.1 percent
* Ryanair raises full-year profit forecast by 25 percent
* Mining companies top sectoral riser as China calm prevails
* GSK falls after drug disappoints in trials
By Alistair Smout
LONDON, Sept 9 (Reuters) - European shares got a boost from a rally in Ryanair shares on Wednesday, which hit an all-time high after the airline lifted its full-year profit forecast by 25 percent.
Ryanair shares surged 10 percent to hit 14.265 euros after saying its summer performance was boosted by bad weather in northern Europe and the strength of the British pound.
It led the STOXX 600 travel and leisure sector, which rose 2.4 percent.
"Overall, a solid update and we are pleased to see the increase in forecasts," Guardian Stockbrokers' director of trading, Atif Latif, said.
"Ryanair are best placed to take advantage of the rise in passenger numbers, better manage costs and more importantly continue to add more profitable routes."
Ryanair was also the top riser on the pan-European FTSEurofirst 300, which was up 2.1 percent at 1,445.15 points by 0750 GMT. The index rose for the third straight day.
The index broke out of a recent 60-point range to hit its highest level for three weeks, and is now up 10.5 percent since its lowest level of the year, hit on Aug. 24.
Markets were put under pressure in August by concerns over China's growth, and the recent rally has come after Chinese authorities increased support and regulation of stock trading.
While the moves have brought stability to prices, equities and futures are trading so thinly that they are in danger of flat lining.
Despite this, calm over China helped to support commodity prices, with mining and resource related stocks rallying 3.5 percent, making them the top sectoral gainers.
One of only two stocks in negative territory on the FTSEurofirst 300 was GlaxoSmithKline
The pharmaceutical firm fell 1.2 percent after GSK and its partner Theravance Inc said their inhaled medicine Breo failed to prolong the lives of patients with chronic respiratory disease in a high-stakes clinical trial of 16,500 people.
Goldman Sachs left its estimates for GlaxoSmithKline unchanged after the test results but said the failure was an "unexpected disappointment".
"From a purely financial perspective (especially relative to consensus) we see this as only a marginal disappointment ... (however) it raises deeper questions around GSK's overall R&D strategy and spend," Goldman analysts said in a note.
Europe bourses in 2015: link.reuters.com/pap87v
Asset performance in 2015: link.reuters.com/gap87v
Today's European research round-up (Editing by Louise Ireland)