"We were trying to find differences between the normal stem cells and the leukemia stem cells," Guzman said. She found one key difference. The cancer cells had what the researchers call a "survival factor," a mechanism for staying alive.
"The normal stem cells don't have it," she added.
Bingo. If Jordan and Guzman could figure out how to inhibit the survival factor, the cancerous cells would die and the normal cells would be left alone.
Guzman's earlier work on the molecular structure of stem cells suggested a possible course. The researchers now knew enough about stem cells to try and match the cancerous cells with a chemical that could inhibit the survival factor. When they gave the cancerous cells a dose of parthenolide, they hit pay dirt.
"It was very effective on the leukemia stem cells without harming the normal stem cells," Guzman said.
Very encouraging findings, but there was still the problem of absorption. If the drug just passed through the body without remaining in the blood, it couldn't do its work. So Jordan and Guzman turned to colleague Peter Crooks, an internationally known biochemist at the University of Kentucky. Crooks has discovered scores of drugs and holds more than 100 patents. He combined parthenolide with dimethylamino, producing a water-soluble chemical that the scientists believe will attack leukemia at its roots.
A successful outcome will set it apart from other drugs because it would eliminate the source of the cancerous cells, thus there should be no relapses. But of course what works in a laboratory frequently doesn't work in the real world.
"This is a molecule that has never been introduced in a patient before," said Jordan, painfully aware that even discussing his research could lead to heartbreak for thousands of leukemia patients and their families.
So the first step is to ensure that the treatment does no harm. The patients that are awaiting the phase one trial have already been treated with virtually every cancer drug that's available, and all of them failed. They are hanging on mostly to hope. Phase one will begin by the end of this year, and could be completed in about six months.
"But if you say six months to one of these patients they think it's an eternity," Jordan said.
The initial trial will take place in England under the direction of a British colleague of Jordan's who has already been approved to test the drug for safety. If the drug's successful there, Jordan expects numerous trials to begin almost immediately in the United States.
Because the drug is designed to attack cancerous stem cells, it's possible it will be useful in the treatment of various cancers, including breast and prostate, but at this point that's very uncertain.
But if it works on any of those, it will signal a turning point in the fight against one of the most dreaded diseases on the planet. Unfortunately, that's a very big if.
Lee Dye is a former science writer for the Los Angeles Times. He now lives in Juneau, Alaska.