compared with control patients who only received standard therapy, in a randomized, multicenter trial with 446 evaluable patients, a finding that may help extend this treatment to a new group of lupus patients.
“The largest” treatment study of lupus nephritis reported to date showed that belimumab,by the Food and Drug Administration in 2011 for treating patients with systemic lupus erythematosus (SLE), administered at a standard dosage of 10 mg intravenously every 4 weeks, “significantly improved multiple lupus nephritis renal responses versus standard therapy alone while maintaining an acceptable safety profile,” , said at the annual European Congress of Rheumatology, held online this year due to COVID-19.
The study’s primary endpoint was a composite measure that Dr. Furie and associates called the Primary Endpoint Renal Response, which required patients to have achieved a urinary protein-to-creatinine ratio of 0.7 or less (compared with an enrollment level of 1.0 or greater), an estimated glomerular filtration rate (eGFR) of at least 60 mL/min/1.73 kg/m2 and no more than 20% below its preflare level, and continuation on the assigned treatment regimen. After 104 weeks on this treatment, which followed a 60-day induction phase that included treatment with a high-dose glucocorticoid, the percentages of patients who met the Primary Endpoint Renal Response criteria were 32% in the control arm who received standard treatment at the discretion of their treating clinicians plus placebo infusions and 43% in patients who received belimumab infusions in addition to their standard care. This calculated out to a 55% relative increase in this response with belimumab, a statistically significant result, reported Dr. Furie, professor of medicine at Hofstra University, Hempstead, N.Y., and chief of rheumatology at Northwell Health in Manhasset, N.Y.
Patients who received belimumab also had similar and statistically significant levels of improvement for several secondary endpoints, including one called Complete Renal Response, which required a protein-to-creatinine ratio of no greater than 0.5, an eGFR of at least 90 mL/min per 1.73 kg/m2 and no more than 10% below its preflare level, and maintaining the assigned treatment. The Complete Renal Response after 104 weeks was 20% among control patients and 30% among those maintained on belimumab, a 74% relative improvement that was statistically significant. The total percentage of patients with any renal-related event after 104 weeks was 28% among the control patients and 16% among those who received belimumab, a statistically significant difference.
“The fact that the primary and all key secondary endpoints were successfully attained is a major accomplishment in lupus nephritis as well as in any SLE study,” Dr. Furie said in an interview. The study’s 2-year design “provided insight into the durability of the response,” and the steady divergence of the endpoint events in the two study arms beginning after about 24 weeks into the randomized phase “provided data regarding the rapidity of onset of action.” Collectively, the endpoints “mimic our real-life treatment goals: reduce disease activity, prevent flares, preserve renal function, lower steroid treatment, and do it all safely,” he concluded.