Updated

GlaxoSmithKline expects to have pivotal clinical trial results on up to 14 medicines in the next two years, including two new products which - if they work - could change the way cancer and heart disease are treated.

Unveiling the next wave of its pipeline on Monday, Britain's biggest drugmaker said it was now developing a broader range of drugs than in the past, as it moves away from the industry's traditional focus on "blockbusters".

Some of the new medicines will be relatively small commercially but a handful have the potential to become multibillion-dollar-a-year sellers.

GSK is banking on the pipeline to revive its business after it failed to grow sales this year as hoped, due to steep pressure on drug prices in austerity-hit Europe.

Chief Executive Andrew Witty said he did not expect any significant increase in costs as a result of the roll out of new products and GSK would continue to look for ways to increase efficiency across the business.

"We feel very comfortable, particularly through 2013 and into 2014, that we can manage both with a broadly flat R&D budget and also without significant increases in our commercial organization," he said.

Key experimental drugs that will have results from final-stage Phase III clinical trials in 2013 and 2014 include the heart drug darapladib and therapeutic cancer vaccine MAGE-A3, the company said in a briefing to investors and analysts.

Both drugs are potentially high-reward but also high-risk, since they represent new medical approaches, and analysts have been reluctant to attribute substantial sales forecasts to either.

GSK acquired full rights to darapladib after buying Human Genome Sciences for $3 billion earlier this year. The jury is still out on whether the way it works, by targeting an enzyme called Lp-PLA2, actually reduces heart attacks and strokes.

MAGE-A3, meanwhile, is being tested in lung cancer and melanoma. If successful, it could provide a boost to the wider field of using vaccines to treat cancer, rather than just preventing it as happens now with cervical cancer shots.

Rare diseases

Other compounds GSK believes have considerable promise include mepolizumab for severe asthma and two drugs against rare diseases - drisapersen for Duchenne muscular dystrophy and migalastat for Fabry's disease.

Rare diseases offer small markets with high prices and are an increasing focus for large pharmaceutical companies who want to spread their bets amongst mass-market and niche therapeutic areas.

"Our strategy is to broaden the number of things coming through late-stage development by not focusing on the blockbuster model," head of drug development Patrick Vallance told Reuters.

"Within this strategy, there will be things that turn out to be very big indeed. What the world has not been good at doing is spotting which ones they are early on."

In the last two years, GSK has reported Phase III results on 12 assets, of which 10 have been broadly positive, and Vallance said the breadth of the company's pipeline was encouraging for the future - especially as many drugs were now being developed more rapidly than in the past.

"The reliability of that flow looks extremely compelling," he said.