ATLANTA (CNNMoney.com) - Patients suffering from blood cancer originating in bone marrow survived nearly 90 percent of the time when taking Novartis's blockbuster cancer drug Gleevec, researchers announced Saturday, compared to a survival rate of about 50 percent with other treatments.

This data could be used by the Swiss drug giant Novartis to shore up its position against potential competition, like Bristol-Myers Squibb's Sprycel, a drug that was suggested for approval by FDA advisors on Friday.

If approved by the federal agency on June 28 - its expected review deadline - Sprycel would be used by patients of chronic myeloidal leukemia, or CML, for whom Gleevec treatment was not successful. That wouldn't necessarily affect Gleevec sales in the short term, but some analysts believe that Sprycel could eventually emerge as a direct competitor to Gleevec.

The Gleevec study was conducted over five years among patients with CML, comparing the drug with more traditional treatments like bone marrow transplants.

Gleevec is Novartis's (Research) second- biggest selling drug, with sales of $2.2 billion in 2005. The top-selling product for Novartis is blood pressure treatment Diovan, with $3.7 billion in sales. Novartis sales totaled $32 billion in 2005.

The study results were announced at the American Society of Clinical Oncology's annual conference in Atlanta.

In a separate study funded by Bristol-Myers Squibb and announced on Saturday, Sprycel completely eliminated leukemia cells in 21 percent of patients, compared to 8 percent for Gleevec. All these patients had previously been treated with Gleevec, but it didn't work for them, so this study compared Sprycel patients with those who tried Gleevec for a second time, with an increased dose.

_____________________________

• Favorable results for Glaxo's breast cancer treatment
• Bristol's Sprycel: Little drug, big ambition