Promising targeted leukemia therapy helps patients in CTRC Phase I clinical trial
SAN ANTONIO (December 16, 2010) — Daniel Gilbert, 72, moved here from Fort Worth to be near his son after becoming very ill with acute myeloid leukemia (AML). He sought conventional chemotherapy, “the kind that makes you lose your hair and lose your mind,” he said, but the treatment did nothing for his leukemia.
On the brink of death, Gilbert came to the Cancer Therapy & Research Center (CTRC) at the UT Health Science Center San Antonio, where an experimental Phase I drug has kept his leukemia under control for over a year.
“Virtually every older patient with the type of aggressive leukemia that Dan Gilbert had will not survive beyond three months,” said Ronan Swords, M.D., an assistant professor of medicine and the principal investigator on the trial.
The new leukemia drug, MLN4924, is an example of a “targeted therapy.” Its target is a protein that helps leukemia cells to grow and divide. MLN4924 “flips a switch” to turn off the critical protein and causes the leukemia cells to die, without wreaking havoc on normal cells.
“We’re moving away from blunderbuss chemotherapy,” Dr. Swords said.
Typical chemotherapy drugs target the body’s rapidly dividing cells, which include cancer cells, but hair follicles, digestive tract cells and bone marrow cells also divide quickly. Their destruction leads to the hair loss, vomiting and infections experienced by so many patients on conventional chemotherapy drugs. Patients with AML are generally older people who suffer a great deal more from these side effects when given standard chemotherapy.
CTRC lab research on the drug MLN4924 led to the clinical trial here and at other sites, which has in turn led to new discoveries of better treatment options that will be further investigated in the laboratory, Dr. Swords said.
“We are taking what we have learned in the lab directly into the clinic and back to the lab again, so that we are continuously trying to find new drugs — and hopefully a cure for this disease,” Dr. Swords said. “MLN4924 is likely to have more than one mechanism for suppressing cancer cell activity. In the lab, it has activity in lots of different tumors.”
Dr. Swords presented a paper on the study this month at the American Society of Hematology conference in Orlando. The overall response rate in the trial has been about 20 percent so far, Dr. Swords said, compared to overall response rates of about 4% for the majority of Phase I drugs. Side effects are minimal, Swords said, making it easier for elderly patients — those most often stricken with this type of leukemia — to take.
Of all the leukemia patients to be treated with this drug, Daniel Gilbert has survived the longest. And Gilbert feels pretty good about Swords and everyone else at the CTRC.
“From the front door to the back, that’s the greatest group I’ve been around in my life,” he said. “They’re my guardian angels, they’re my family.”
The Cancer Therapy & Research Center (CTRC) at The University of Texas Health Science Center at San Antonio is one of the elite academic cancer centers in the country to be named a National Cancer Institute (NCI) Designated Cancer Center, and is one of only four in Texas. A leader in developing new drugs to treat cancer, the CTRC Institute for Drug Development (IDD) conducts one of the largest oncology Phase I clinical drug programs in the world, and participates in development of cancer drugs approved by the U.S. Food & Drug Administration. For more information, visit www.ctrc.net.