Testing time for Roche's breast cancer business

Roche Holding AG, the world's biggest maker of cancer drugs, faces a testing time in its breast cancer business as a near-term threat to Herceptin, its third-biggest seller, could take the shine off the long-term promise of its new medicines.

The issue is likely to be centre-stage when the Swiss group gives a research and development presentation to investors in London on Wednesday.

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).

First approved in 1998, Herceptin is a treatment for the 25-30 percent of breast cancer patients who have tumors 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 is due to publish data by year-end from the so-called HERA study 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 skeptical 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.

What are the risk factors for developing breast cancer?

- being female
- increasing age
- having a family history of breast cancer
- being older at the birth of your first child or never having a child
- not breastfeeding
- beginning menstruation before age 12 or completing menopause after age 55
- drinking alcohol (more than one drink a day)
- not getting regular exercise
- being overweight
- having a personal history of breast cancer or some non-cancerous breast diseases
- having radiation therapy to the breast/chest
- using hormone replacement therapy for a long time
- using birth control pills

However, most breast cancer cases occur in women without any risk factors, so everyone should be checked regularly.

Kepler Capital Markets analyst Fabian Wenner says the drug's adverse side effects on the heart could also mitigate against longer use.