While the drug didn't make as big a difference as the doctors hoped, it was still more helpful than a placebo, the study shows. The findings are published in The New England Journal of Medicine's May 26 issue.
Sargramostim is a synthetic version of a growth factor made by the body called GM-CSF. It's usually used after chemotherapy to help bone marrow ramp up production of white blood cells. White blood cells protect the body against infection; their levels can dip during chemotherapy, weakening the body's immune defenses.
What does that have to do with Crohn's, an inflammatory bowel disease? Crohn's cause is unknown, but one theory suggests that it's the result of immune system problems. That idea was tested by the sargramostim study.
Testing Sargramostim's Impact
The study included 124 adults with moderate-to-severe Crohn's disease. They were assigned to get injections of sargramostim or a placebo for 56 days. The sargramostim dose was scaled to each person's weight.
The treatment's effectiveness and safety were checked every two weeks during treatment and 30 days after treatment. Scales for Crohn's disease activity and quality of life were used to track the patients' progress.
The results didn't match the study's goals but still showed significant improvement in disease severity and quality of life, say the researchers, who included Joshua Korzenik, MD, of Harvard Medical School and the Inflammatory Bowel Disease Center at Massachusetts General Hospital in Boston.
"The role of GM-CSF in the biology of Crohn's disease remains to be defined," write researchers.
People taking sargramostim had more bone pain and reactions at the injection site than the placebo group, the study shows.
Those side effects prompted four out of 81 patients to quit the study. However, those problems were usually temporary and diminished as treatment continued, say the researchers.
Three patients in the sargramostim group had "serious adverse events possibly or probably related to treatment," the researchers explain. Those side effects were migraines three weeks after treatment ended; anorexia, weakness, and lethargy in a 58-year-old man with poorly controlled blood pressure and heart disease; and temporary weakness on the right-hand side of the body.
One patient died during the study, but the researchers say the cause of death was not related to her treatment.
'Caution Is Warranted'
Underlying health problems may have affected some of the patients who had side effects from sargramostim, the study notes. Those underlying problems may have included high blood pressure, a history of small-bowel obstruction, atherosclerosis (hardening of the arteries), and nerve problems.
"However, given these events, caution is warranted in the use of sargramostim therapy in patients with similar underlying conditions," write Korzenik and colleagues.
The study was sponsored by Berlex, which makes a sargramostim drug called Leukine. Two of the researchers are Berlex employees, and several others have consulted for or received speaker's fees from various drug companies, including Berlex, says the journal.