UNC Health Talk

New investigational compound dramatically reduces sickle cell pain crises

Media contact: Tom Hughes, 984-974-1151,

Dec. 3, 2016

CHAPEL HILL, NC — An investigational drug reduced the rate of acute painful episodes associated with sickle cell disease by 46 percent, according to reports from doctors who conducted an international, multicenter phase 2 clinical trial.

Compared to placebo, the IV-administered compound, called SelG1, also increased the amount of time between painful episodes, called sickle-cell related pain crises (SCPC), by more than 2-fold in the group of 198 study participants. It also reduced the rate of days these patients spent in the hospital by 42 percent.

“These are very encouraging results,” said Kenneth Ataga, MBBS, principal investigator of the SUSTAIN trial and director of the Comprehensive Sickle Cell Program in the University of North Carolina School of Medicine. “SelG1 has the potential to greatly improve the lives of people with sickle cell disease.”

Results from the SUSTAIN trial were published online by the New England Journal of Medicine on Dec. 3. They will also presented Dec. 4 at the annual meeting of the American Society of Hematology in San Diego.

Sickle cell disease is an inherited, blood disorder that affects one out of every 500 African-Americans. There are approximately 80,000 people in the United States with sickle cell disease. It is also one of the most common genetic diseases, affecting millions of people worldwide. About half of the world’s sickle cell disease population lives in three countries: Nigeria, India and the Democratic Republic of Congo.

Patients with sickle cell disease suffer anemia and complications in which sickle-shaped red cells and white blood cells adhere to small vessels and block blood flow to downstream organs. This vaso-occlusive process results in intense pain and repeated hospitalizations. It also leads to progressive multi-organ dysfunction and premature death.

Sickle cell disease is considered an orphan disease with major unmet clinical needs. Currently there is only one FDA-approved drug for sickle cell disease, hydroxyurea, which received FDA approval in 1998. Although hydroxyurea is known to decrease the frequency of vaso-occlusive complications such as acute pain episodes and acute chest syndrome, and possibly prolong survival in severely affected patients, many patients continue to experience such complications with a reduced life expectancy despite treatment, highlighting the importance of developing new treatments.

SelG1 is an investigational antibody directed against P-selectin, a key member of the adhesion molecule family known as the selectins. Previous research has shown that SelG1 blocks P-selectin and therefore may help reduce or prevent vaso-occlusive crises in sickle cell patients.

In the study, 198 sickle cell patients were randomly assigned to three groups. One group received the compound in a 5.0 mg/kg dose given by IV once a month, a second group received a 2.5 mg/kg dose, and the third group received a placebo. After the course of treatment had concluded, the annual rate of sickle cell pain crises was reduced by 46 percent in the 5.0 mg/kg dose group, versus placebo, and by 33 percent in the 2.5mg/kg dose group.

In addition, the time to first sickle cell pain crisis (SCPC) in the 5.0 mg/kg dose group was increased 2.9-fold, from 1.4 months to 4.1 months, and the time to second SCPC was increased two-fold, from 5.1 months to 10.3 months. In other words, the new compound reduced the frequency of SCPC in this group of patients.

Finally, the annual rate of uncomplicated SCPC in the 5.0 mg/kg dose group was reduced by 63 percent, and the annual rate of days hospitalized was reduced by 42 percent.

Selexys Pharmaceuticals of Oklahoma City, Oklahoma, developed SelG1. The SelG1 research program at Selexys was supported by Small Business Innovation Research (SBIR) fast-track award #5R44HL093893-02 and #2R44HL093893-03 through the National Heart, Lung and Blood Institute.

Investigators in the study included researchers from UNC; the Medical College of Georgia; Medical University of South Carolina; East Carolina University; Santa Casa Medical School of São Paulo, Brazil; Hospital de Clinicas de Porto Alegre in Rio Grande do Sul, Brazil; 21st Century Oncology in Jacksonville, Florida; University of the West Indies in Kingston, Jamaica; University of Miami; University of Illinois at Chicago; University of São Paulo and University of Campinas in São Paulo, Brazil; Virginia Commonwealth University Medical Center in Richmond, Virginia; and Selexys Pharmaceuticals.