Clinical trial results unveiled today in the New England Journal of Medicine indicate that the vast majority of patients with a difficult-to-treat form of leukaemia can benefit from therapy with Novartis’ new anti-cancer offering, Tasigna.

Data from the first ever published clinical trial of the drug showed that 92% of patients with chronic myeloid leukaemia taking Tasigna (nilotinib) in the study saw their blood cell count return to normal in less than five months.

Findings also showed that in more than a third of patients the Ph chromosome - the genetic abnormality that characterizes most cases of CML - was undetectable after Tasigna treatment, Novartis said.

Both Tasigna and Novartis’ marketed anti-cancer drug Glivec (imatinib), long considered a gold standard of CML therapy, inhibit Bcr-Abl, the cause of Ph+ CML, thereby shutting down production of the Ph chromosome. Tasigna was specifically designed to be a highly selective inhibitor of Bcr-Abl and its mutations, often the root of resistance to therapy.

“By selectively inhibiting Bcr-Abl and its common mutations, Tasigna produced dramatic positive responses in patients who have limited treatment options,” remarked Professor Charles Craddock, Professor of Haemato–oncology at the University of Birmingham. “These extremely encouraging results reinforce the validity of treating this cancer by specifically targeting the molecular basis of this disease,” he added.

Although its tolerability and safety profile has not yet been fully established, Tasigna was generally well tolerated throughout the study, with the most common side effects including myelosuppression, transient indirect hyperbilirubinemia and skin rashes, the investigators said. Moreover, the agent was usually not linked with common toxicities seen with Glivec, such as fluid retention, superficial oedema and weight gain, or rare cases of pleural and pericardial effusions, giving it a potential advantage over its predecessor.

Tasigna looks to have the potential to be a bright star in Novartis’ cancer portfolio. The drug, a next generation tyrosine kinase inhibitor, entered Phase I clinical studies just 21 months after it was first synthesized, and has been granted a fast-track review by the US Food and Drug Administration as well as orphan drug classification on both sides of the Atlantic.

As a result of its outstanding performance in the trial, Novartis is now planning to submit Tasigna for US and European regulatory approval later this year, ahead of the original schedule of submissions in 2007.