The European Society for Medical Oncology kicks off its five-day Vienna conference Friday, and Roche’s stock ticker may be expected to pulse with the conversations. That is, particularly if findings from a study – financed by the French National Institute for Cancer – are robust enough to shorten the recommended treatment time for Herceptin from 12 months to six.

Bernstein analyst Tim Anderson wrote in his September 21 research note that Roche has been unruffled by the study, which he took notice of in 2009. This in spite of an outcome that “could theoretically” remove what Anderson estimated to be about 38% of the drug’s sales by 2016 were the six-month duration to become the global treatment standard. The breast cancer study, known as PHARE, will be unveiled during the conference.  Anderson couched the impact of data supporting PHARE results by saying that a major shift – in this case, halving the time of treatment – would require “very robust” data to take hold.

Herceptin, Roche’s second biggest-selling drug according to Anderson, is usually administered for 12 months, and Anderson noted that 75% of the drug’s sales come from early-stage patients who take the therapy after having tumors removed.

PHARE is not set to be the last word on Herceptin therapy. Anderson noted that the UK and Italy are also studying therapy timelines – the UK’s Persephone study is using the six- vs. 12-month metric, and Italy’s shortHER trial is going narrower, comparing breast cancer patients with three months of therapy to those on 12. Both the UK and Italian studies are open, so results are not part of this conference.

Shorter timeframes will not be the only things on offer in Vienna. Roche announced Monday that its conference presentations will include overall survival data from yet another study in the breast cancer population — its Phase III Emilia study and the final analysis of its 5,000 patient Phase III Hera study, which looked at the impact of Herceptin treatment during cancer’s early stages.