Hotline Archive - FDA Approval of Prosorba® Immunoadsorption Column
May 1999
The Prosorba® column was approved by the FDA on March 16, 1999, for use in the treatment of moderate to severe adult rheumatoid arthritis in patients with longstanding disease who have failed or are intolerant of DMARDs.
The device had been previously approved in 1987 for treatment of idiopathic thrombocytopenia purpura. It consists of an inert silica matrix to which a component of Staphylococcus bacterium is covalently bound. This protein (protein A) has the propensity to bind immunoglobin G (IgG) and IgG bound to antigen. The standard course of treatment involves 12 weekly outpatient apheresis sessions, each of which takes approximately two hours.
The phase III clinical trial ended in January 1998 after an independent Data and Safety Monitoring Board recommended early cessation due to favorable safety and statistically significant efficacy data. The double-blinded, sham-procedure controlled multicenter trial enrolled 99 severely affected RA patients with average disease duration of approximately 15 years who had failed an average of five different DMARD regimens including methotrexate in 87% of patients. Of these patients, 52 were randomized to Prosorba treatment and 47 to the sham procedure. After a ‘wash-out’ period (one month for methotrexate, three months for other DMARDs), weekly treatments were initiated for 12 weeks. Corticosteroid and NSAID use could be continued but not adjusted during the study.
Using a 20% improvement rate to define a beneficial response (ACR 20), 29% of the Prosorba group responded as compared to 11% of the sham procedure group. The withdrawal rate in both groups was approximately 30%. Among those completing the 12 treatments, 42% of Prosorba treated patients were responders as compared with 16% of sham-treated patients. Duration of response was 37 weeks for the Prosorba group. Post-treatment flares were seen in approximately 1/3 of patients. The most frequent adverse events were hypotension and anemia. Five of nine patients who received central venous access developed significant complications including infection and thromboses.
There is no data available regarding safety or efficacy when used in combination with conventional DMARD therapies.
May 27, 1999
John J. Cush, MD
Robert F. Spiera,
MD
Co-editors, ACR Hotline
Elliot D. Rosenstein, MD
Contributor
Hotline is provided by the ACR Communications and Marketing Committee as a service to members. This Hotline reflects the views of the author(s) and does not represent a position statement of the College.
