and a normal one
Image by Betty Pace
An investigational agent may be able to treat vaso-occlusive crises (VOC) in patients with sickle cell disease (SCD), according to research published in Blood.
The drug, rivipansel (formerly GMI-1070), is designed to prevent cells from sticking together to improve blood flow.
In a phase 2 study, SCD patients who received rivipansel used significantly less pain medication than those who received placebo.
However, rivipansel did not significantly reduce the time to resolution of VOC.
Researchers said the study’s small size, as well as the wide variability in the length of time that all patients suffered painful vascular obstruction, may explain the lack of statistical significance. A larger, international study is set to begin later this year to provide greater clarity.
“We have not had good therapies for people with [sickle cell] disease,” said study author Marilyn J. Telen, MD, of Duke University in Durham, North Carolina.
“But this approach shows more promise than anything else I’ve seen in 34 years of treating sickle cell disease.”
She and her colleagues analyzed 76 SCD patients from 17 sites in the US. The patients were randomized to receive placebo or rivipansel. All patients also received the standard treatment for pain and symptom management.
For patients who received rivipansel, the effects tended to begin within 24 hours, and their painful crises passed sooner than those receiving only treatment for pain, but the statistical difference was not significant.
The least-squares mean time to resolution of VOC was 103.64 hours in the rivipansel arm and 144.60 hours in the placebo arm (P=0.192). The median times were 69.6 hours and 132.9 hours, respectively (P=0.187).
The researchers said the improvements seen in the amount of time to resolution would likely be clinically meaningful if they were verified in a larger trial.
The team also said the findings demonstrating lower use of pain medication among patients was a critical step forward. The team assessed cumulative parenteral opioid use, and the least-squares mean dose was 9.62 mg/kg in the rivipansel arm and 55.59 mg/kg in the placebo arm (P=0.010).
“The difference in pain medication use was statistically significant, and it occurred in the first 24 hours, which implies that the therapy may be interfering with the mechanism of the vaso-occlusion,” Dr Telen said. “For these patients, having less pain is very important.”
In addition, there were no significant differences between the treatment arms with regard to adverse events.
Dr Telen said the larger study of rivipansel is set to begin later this year, with a goal of enrolling more than 300 patients.
The company developing rivipansel, GlycoMimetics, Inc., funded the current study. And Dr Telen has received consulting fees from the company.
