Novartis has presented positive Phase II data for new drug Tasigna in adults with chronic myeloid leukaemia who developed resistance to the firm’s own Gleevec treatment.

The study, data for which were presented at the American Society of Hemotology meeting in Orlando, involved 279 patients with chronic Philadelphia chromosome-positive (Ph+) CML who were resistant or intolerant to Gleevec (imatinib).

Results showed that Tasigna (nilotinib) reduced or eliminated the

presence of this defective chromosome in 51% of Gleevec-resistant patients in the chronic phase of this disease, and led to normalised white blood cell counts in 74% of these patients. The study also showed a similar magnitude of elimination or reduction of these defective cells in 55% of intolerant patients.

About 100,000 CML patients worldwide currently take Gleevec, which has sales of around $2.5 billion a year. However, Tasigna has been developed for the sizeable percentage of patients who become resistant to Gleevec within five years, becoming candidates for either a higher dose of Gleevec or an alternative therapy.

Novartis has filed applications with both the US Food and Drug Administration and the European Medicines Agency for Tasigna as a therapy for adult patients with chronic or accelerated phase

Ph+ CML with intolerance and/or resistance to Gleevec.

B-MS’ Sprycel also impresses

If approved, Tasigna will take on Bristol-Myers Squibb’s Sprycel (dasatinib), for which the US firm also presented data at the ASH. B-MS’ Phase II study of the drug showed a substantial number of patients with chronic-phase CML resistant to Gleevec responded to treatment with Sprycel by three months and maintained these responses through one year.

Data at three months and 15 months showed that the number of patients who achieved and maintained a major cytogenetic response increased from 36% to 53% with Sprycel, and from 29% to 33% with increased doses of Gleevec.

The trial could help boost sales of Sprycel, which was approved in June, but has got off to a slow start as doctors have tended to increase the dose of Gleevec in patients who become resistant to the standard 400mg dose rather than switch to the B-MS drug.