Since the approval of Prosorba column apheresis therapy (PCT) for rheumatoid arthritis (RA) in 1999 there have been multiple requests for additional information on the response rate of PCT used commercially in rheumatology practice settings.
Data were collected in a noninterventional prospective fashion on patients with RA who qualified for the PCT treatment per the package insert. There were 91 patients who completed the 12 prescribed treatments. There was no washout of other drugs [i.e., disease modifying antirheumatic drugs (DMARD), biologics]. An initial baseline assessment was performed prior to first treatment and then up to 4 additional assessments were performed at Weeks 9, 16, 20, and 24. Criteria for ACR20 were noted in order to assess response rate, and commercial adverse event reporting was used to record serious/unanticipated adverse events.
There was a response rate of 53.8% (measured as ACR20 response or better) in these patients with previously refractory RA. The individual criteria showed a much greater improvement than reflected by ACR20; for example, this response included a 52% improvement in joint tenderness, 40% improvement in swelling, 42% improvement in patient's pain, 38% improvement in patient's global response, and 48% improvement in physician's global scores (76% of responders had measured ACR20 by Week 16 and 100% by Week 24). The actual measurement of an ACR response generally occurred during assessments at Week 16; however, most patients who respond will state they felt improvement some time between Weeks 8 and 12. There were no assessments between Weeks 9 and 16 so the actual week of improvement could not be identified by ACR criteria. Some patients stated that they felt improvement began closer to the 6th week. Most responders were concurrently taking biologics or DMARD, e.g., methotrexate and etanercept, despite previously inadequate RA response to those medications.
This postmarketing study of PCT used commercially in 59 rheumatology practice settings supports the safety and efficacy of this treatment regime in selected patients with RA and compares favorably with the initial sham controlled clinical trial. PCT is a relatively underutilized choice for the management of active, aggressive RA.