In addition, 69% of those on the 10-mg/kg dose, 75% of those on the 1-mg/kg dose, and 65% of those on placebo had no new BILAG grade A or B scores. The difference between the 1-mg/kg dose and placebo was significant.
There were no significant differences between the three groups in the risk of having a flare, or in the median time to the first flare, based on the SELENA Flare Index (SFI). But the proportion of patients who had a severe SFI flare was lower in the two treatment groups (18% of those on the higher dose and 16% of those on the lower dose, compared with 24% of those on placebo), he said, noting that the difference was significant between the 1-mg/kg and placebo groups.
Other secondary end points included the mean in SF-36 Physical Component Summary (PCS) scores from baseline to week 52, which increased by a mean of 3.4, 4.4 and 2.9, in the 10-mg/kg, 1-mg/kg and placebo groups, respectively. The difference was significant only between placebo and the 1-mg/kg dose. The change in the FACIT-F (Functional Assessment of Chronic Illness Therapy–Fatigue) score from baseline at 52 weeks increased by a mean of 4.6, 5.7, and 2.9 respectively, with the difference being significant between the 1-mg/kg dose and placebo, Dr. van Vollenhoven said. “These data are important in that they reflect patient-reported aspects of the disease, namely physical function and fatigue, which are of major importance in terms of quality of life,” Dr. van Vollenhoven said in the interview. “In fact, fatigue has been identified by lupus patients in our unit as their most important symptom.”
He added, “All these instruments are blunt, however. It’s like having an old radio with a lot of background noise.”
In the study, treatment was well tolerated, with similar rates of deaths, adverse events, serious adverse events, infections, and laboratory abnormalities in the three groups. There was a modest increase in serious or severe infusion reactions among those on belimumab, compared with those on placebo, he noted. The overall infusion reaction rate was 13%-15% in the two belimumab groups, compared with 10% in the placebo group; the rate of severe infusion reactions was 1.1% in the 10-mg/kg group and 0.4% in the 1-mg/kg and placebo groups. Thus, the clinical response to the 10-mg dose appeared to be more robust. However, we need to learn more in the future about refining doses.”
There were six malignancies in the study, one in a patient on placebo, and five in the belimumab-treated patients. The infection rate was 72% in the two belimumab groups, compared with 67% in the placebo group; the serious infection rate was 7% in the 10-mg group, 6% in the 1-mg/kg group, and 5% in the placebo group, Dr. van Vollenhoven said.
Dr. van Vollenhoven was an investigator in the BLISS-76 study and is a consultant to HGS and GSK; he also served on the BLISS-52 and BLISS-76 steering committees. Some of the investigators on this trial are HGS employees.