A redesigned version of the Novartis cancer med may avoid a rare heart-related side effect while more specifically targeting a type of stomach cancer, Reuters reports. And researchers, who say they tested the redesigned drug in mice, in human cancer cells in laboratory dishes and in computer models without help from Novartis, believe their work shows that extremely minor changes can be engineered to eliminate potentially dangerous side effects, while leaving them effective against disease. One can only imagine the discussion over patent possibilities.

The once-a-day pill, which is the drug maker’s second-biggest seller, with sales of $2.6 billion last year, which has been on the market since 2001 and is used to treat some forms of leukemia, cancer that arises in the white blood cells, and other cancers of the blood cells. Gleevec is also used to treat a rare type of stomach cancer called gastrointestinal stromal tumor, or GIST.

Researchers at Rice University in Houston and University of Texas M.D. Anderson Cancer Center said they re-engineered the drug to curb a life-threatening side effect in which the drug can be toxic to the heart and potentially cause heart failure, Reuters writes. The re-engineered version appears to be just as effective as Gleevec in treating GIST while posing a significantly lower risk of heart failure, they maintain. As the researchers expected, the re-engineered version does not work against leukemia, they reported in the Journal of Clinical Investigation.

“The interest of this goes way beyond this particular drug and this particular side effect. The idea is we could demonstrate for the first time that you can take a drug with side effects and re-engineer it to curb those side effects,” Ariel Fernandez, a Rice bioengineering professor, tells Reuters. “Side effects are the graveyard of most drug-discovery endeavors. So once a drug is shown to have side effects or potentially could have side effects, the drug company doesn’t want to have anything to do with it.”

The precise incidence of heart failure in patients taking Gleevec is not known but is thought to be low, the researchers said. A look at leukemia patients taking Gleevec at M.D. Anderson indicated that about 2 percent experienced symptoms that might have been linked to heart failure, they said.

The American Cancer Society said gastrointestinal stromal tumors are not common, but the precise number of people diagnosed with GIST each year is not known. It cited estimates of 4,500 to 6,000 cases each year in the United States. The tumors most often occur in the stomach, but also may occur in the small intestine and elsewhere in the gastrointestinal tract, according to ACS.