* Results for 19 clinical trials expected in next 18 months
* Swiss drugmaker plans to keep R&D budget stable
* Herceptin's fate hinges on outcome of opposing trials
* Data on opposing Herceptin trials due at ESMO meeting (Adds further comment by analysts, details from presentation)
By Caroline Copley
LONDON, Sept 5 Swiss drugmaker Roche Holding AG expects results from 19 late-stage clinical trials over the next 18 months, providing a stream of products to offset a potential near-term threat to breast cancer drug Herceptin, its third biggest seller.
The world's biggest maker of cancer medicines cited antibody drugs carrying chemotherapy and combination treatments among its most promising approaches in a presentation to investors in London on Wednesday.
With its large diagnostics division, Roche has pioneered personalised medicine, or tailoring treatment to the genetic profile of patients, and Chief Executive Severin Schwan said the group would remain market leader in the field.
"More than 60 percent of our pharmaceutical pipeline projects are coupled with the development of companion diagnostics in order to make treatments more effective," he said.
Twelve of its 19 late-stage trials involve new drugs.
Pipeline progress and Roche's pledge to keep a lid on research spending, which totalled 8.3 billion Swiss francs ($8.7 billion) in 2011, may reassure investors, ahead of uncertain times for Herceptin.
Helvea analyst Odile Rundquist said the commitment not to increase research and development (R&D) expenditure, despite a large number of late-stage projects, was important and showed Roche was adapting to tougher economic times for drug sales.
The group is targeting efficiency gains of 15 percent in drug development costs by 2015 and finance chief Alan Hippe said it aimed to gradually bring down net debt leverage to under 15 percent from 25 percent in 2011.
Roche is testing a range of new drugs, including a novel chemotherapy-carrying "armed" antibody called T-DM1 - the first of nine so-called antibody-drug conjugates (ADC) in development that it views a major advance in fighting cancer.
Another ADC called RG7593 had produced "very promising" early results in blood cancer, it said.
Shares in Roche were trading up 1.1 percent by 1250 GMT in line with the European healthcare index.
NEXT STEPS IN BREAST CANCER
T-DM1 will boost its breast cancer business, along with recently launched Perjeta, but investors are cautious about potential lost sales for Herceptin in the near term.
Results of two opposing studies examining how long patients should use Herceptin could potentially boost or cut sales of the blockbuster medicine, which had sales last year of 5.25 billion Swiss francs ($5.5 billion).
Data from both studies is now expected to be presented at the Sept. 28 to Oct. 2 European Society for Medical Oncology meeting in Vienna - earlier than many analysts had expected.
First approved in 1998, Herceptin is a treatment for around a quarter of breast cancer patients who have tumours that generate a protein called HER-2, which tends to make their disease more aggressive.
The drug is one of Roche's most lucrative and durable - with sales still growing 11 percent to 2.95 billion Swiss francs in the first half of 2012 - and the drugmaker is keen to eke out more profit before the medicine loses its patent from 2014.
Roche has conducted a study called HERA investigating the benefit of using Herceptin for two years rather than the standard one, while an opposing French study called PHARE is looking at whether patients get the same benefit from using the drug for just six months.
While analysts on the whole are sceptical that using Herceptin for longer will show additional benefit, a convincing result from PHARE could see austerity-hit European healthcare systems cutting back their use of the drug substantially.
Positive results from PHARE have the potential to wipe $1.5 billion off Herceptin's revenue in the medium term and could send the stock down some 5-10 percent, according to Kepler Capital Markets analyst Fabian Wenner.
Other analysts, however, believe the PHARE data will lack the punch to seriously damage Herceptin sales.
Thanks to its top-selling cancer medicines, most of which do not face imminent generic competition, Roche has fared better than rivals who have suffered from a wave of patent expiries sweeping the pharmaceutical industry.
But some analysts have questioned whether the company may be overspending on drug development. In June, Roche announced plans to cut its research operations after poor late-stage results from its big drug hope dalcetrapib - a medicine aimed at boosting levels of "good" HDL cholesterol.
Roche has not given up on heart disease, however.
Another drug in development called RG7652 is progressing into more advanced trials after significantly reducing levels of "bad" LDL cholesterol by targeting a protein called PCSK9 - a hot area of research for several drug companies.
Another growing area of importance for Roche is also its neuroscience franchise and it is pursuing a number of projects against Alzheimer's disease, with gantenerumab the most advanced treatment.
($1 = 0.9526 Swiss francs) (Additional reporting by Ben Hirschler; Editing by Elaine Hardcastle and David Cowell)