* Late-stage data being presented at ASH meeting
* Novartis banking on Tasigna to replace older drug Glivec
* Drugmaker plans trials to explore treatment free remission
ZURICH, Dec 10 (Reuters) - Novartis AG's blood cancer drug Tasigna is better at treating a type of chronic myeloid leukaemia than its older drug Glivec, according to data from two late-stage trials, boosting prospects for its oncology franchise.
Novartis is hoping to convince doctors to switch patients to Tasigna to shield its sales once Glivec, one of its best-selling medicines, loses patent exclusivity in 2015.
The latest data, which are being presented at the American Society of Hematology's (ASH) annual meeting, examined the benefits of Tasigna in patients with Philadelphia chromosome-positive chronic myeloid leukaemia.
Two-year data from the ENESTcmr trial showed patients who still had evidence of residual disease after long-term treatment with Glivec achieved undetectable levels of the disease after switching to Tasigna.
More than twice as many patients treated with Tasigna continued to show undetectable levels of the disease compared with Glivec, according to the data. Novartis said the results were statistically significant.
Meanwhile, four-year data from the ENESTnd trial showed more than three times as many patients being treated with Tasigna as a frontline therapy experienced a reduction in the level of disease versus Glivec.
Novartis plans to start a clinical trial programme in early 2013 to test whether some patients may be able to stop treatment after achieving a sustained response to therapy.