Belimumab With Rituximab for Primary Membranous Nephropathy
brief summary
The primary objective of this study is to evaluate the effectiveness of belimumab and intravenous rituximab co-administration at inducing a complete or partial remission (CR or PR) compared to rituximab alone in participants with primary membranous nephropathy. Background: Primary membranous nephropathy (MN) is among the most common causes of nephrotic syndrome in adults. MN affects individuals of all ages and races. The peak incidence of MN is in the fifth decade of life. Primary MN is recognized to be an autoimmune disease, a disease where the body's own immune system causes damage to kidneys. This damage can cause the loss of too much protein in the urine. Drugs used to treat MN aim to reduce the attack by one's own immune system on the kidneys by blocking inflammation and reducing the immune system's function. These drugs can have serious side effects and often do not cure the disease. There is a need for new treatments for MN that are better at improving the disease while reducing fewer treatment associated side effects. In this study, researchers will evaluate if treatment with a combination of two different drugs, belimumab and rituximab, is effective at blocking the immune attacks on the kidney compared to rituximab alone. Rituximab works by decreasing a type of immune cell, called B cells. B cells are known to have a role in MN. Once these cells are removed, disease may become less active or even inactive. However, after stopping treatment, the body will make new B cells which may cause disease to become active again. Belimumab works by decreasing the new B cells produced by the body and, may even change the type of new B cells subsequently produced. Belimumab is approved by the US Food and Drug Administration (FDA) to treat systemic lupus erythematosus (also referred to as lupus or SLE). Rituximab is approved by the FDA to treat some types of cancer, rheumatoid arthritis, and vasculitis. Neither rituximab nor belimumab is approved by the FDA to treat MN. Treatment with a combination of belimumab and rituximab has not been studied in individuals with MN, but has been tested in other autoimmune diseases, including lupus nephritis and Sjögren's syndrome.
detailed description
This trial is a two-part study (Part A and Part B) of adults with primary membranous nephropathy (MN), ages 18-75 inclusive. The study will be conducted at multiple sites in the United States and Canada.
Part A: Open-label Phase
Part A is an open-label, PK study to compare belimumab exposure between participants who have "low" proteinuria (≥ 4 to \< 8 g/day) and "high" proteinuria (≥ 8 g/day) at Visit -1.
Initially Part A planned to enroll 20 individuals with primary MN: 10 individuals with low proteinuria and 10 individuals with high proteinuria. All Part A participants received 200 mg subcutaneous belimumab weekly, the initially approved dose of belimumab in SLE, for 52 doses (weeks 0-51). Trough serum belimumab levels would be obtained weekly following the first 4 doses of belimumab. All participants would receive rituximab 1000 mg IV at weeks 4 and 6, and are followed after the 52 week treatment period on no study medication until week 156.
Belimumab trough levels were to be analyzed after all 20 participants received the first 4 doses to compare the belimumab exposure between the low and high proteinuria groups. If the belimumab exposure was not comparable between the high and low proteinuria groups, the belimumab dose would be doubled to 400 mg/weekly for participants with high proteinuria in Part B. Dose determination for participants with high proteinuria in Part B would be made by an adjudication committee comprised of the Protocol Chair, NIAID Medical Monitor, ITN Clinical Trial Physician, and Rho Scientist, in consultation with the belimumab PK expert at GSK.
Due in part to the observed imbalance in enrollment between the high and low proteinuria groups, an ad hoc PK analysis was conducted. The serum belimumab trough levels of the first 12 participants (8 with high proteinuria and 4 with low proteinuria) who received the first 4 belimumab doses were analyzed to compare belimumab exposure between the low and high proteinuria groups.
The results of the PK analysis were reviewed by the adjudication committee, who determined that the results did not support doubling the dose of belimumab in individuals with high proteinuria nor did it identify a new proteinuria threshold that warranted an increased belimumab dose. The belimumab PK expert at GSK concurred. Thus, enrollment into Part A has been suspended, and all participants in Part B are to receive the same dose of belimumab. All participants currently enrolled in Part A continue to receive belimumab and rituximab as previously planned and are undergoing the safety assessments as presented in Appendix A.
official title
Belimumab and Rituximab Compared to Rituximab Alone for the Treatment of Primary Membranous Nephropathy (ITN080AI)