GLASGOW – Switching patients on the anti–tumor necrosis factor drug Remicade to a biosimilar infliximab product resulted in good efficacy and tolerability with substantial cost savings in two real-world studies from the United Kingdom.
A total of 52 (88%) of 59 patients who had switched to the biosimilar infliximab CT-P13 (Inflectra) for the treatment of various indications for which Remicade is approved remained on the biosimilar after 10 months of follow-up and experienced comparable adverse events and similar levels of efficacy before and after switching, Dr. Lucy Parker of University Hospital Southampton NHS Foundation Trust reported at the British Society for Rheumatology annual conference. A second smaller study reported at the conference also showed similar results with the same infliximab biosimilar, which is also marketed as Remsima in Europe.
CT-P13 had efficacy, immunogenicity, and pharmacokinetic and pharmacodynamic parameters comparable to Remicade in 1-year follow-up data from the phase III randomized PLANETRAstudy (Arthritis Res Ther. 2016;18:82. doi: 10.1186/s13075-016-0981-6), but whether these study findings hold in a routine practice setting remains to be determined, Dr. Parker noted.
In Dr. Parker and colleagues’ study of data from the Southampton Biological Therapies Review Service, every patient was initially “seen in clinic and had the opportunity to speak to their consultant rheumatologist about the potential switchover from the originator drug to the new version,” she explained. Patients were then contacted directly by letter to explain the potential switch and given an information leaflet on Inflectra. They were also given access to a dedicated helpline number that could be used to re-explain the switch and discuss any concerns after switching had occurred.
In May 2015, all 59 patients being treated with Remicade were gradually switched over to the biosimilar version. Patients were reviewed after 3 months and then at 6-month intervals.
“Every single patient agreed to switch,” Dr. Parker observed. No patient used the helpline service or asked to talk with the consultant rheumatologist. One delegate noted during discussion that it was impressive that all patients agreed to switch, but Dr. Parker suggested that it was probably important that people were invited to switch rather being told that they would be switched. “If anyone had refused, then they would have been kept on Remicade,” she observed.
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Dr. Parker noted that the patients were taking Remicade for various rheumatologic conditions, including 29 with rheumatoid arthritis (RA), 14 with ankylosing spondylitis (AS), 14 with psoriatic arthritis (PsA), and 2 with enteropathic arthritis. The mean age was 58.9 years, 51% of patients were female, mean disease duration was 18 years, and there was a mean of 5.7 years on Remicade before the switch. Patients had been diagnosed an average of 10 years before the first use of a biologic agent, 56% were also taking methotrexate, and 17% were on another disease-modifying antirheumatic drug (DMARD).
There was no significant difference in disease activity before or after switching, with respective mean 28-joint Disease Activity Scores of 3.4 and 3.3 and Bath Ankylosing Spondylitis Disease Activity Index scores of 3.7 and 3.6.
Dr. Parker noted that two 6-month periods before switching were compared to a 6-month period after switching and there were a similarly low number of cases reporting inefficacy, which was defined as any increase in symptoms or disease activity measure. Inefficacy was seen in one patient 12 months before the switch, two patients 6 months before the switch, and three patients after the switch. All three of the latter patients were switched back to Remicade, with one being then further switched to rituximab (Rituxan).
There were four adverse events in patients switched to the biosimilar versus three and four cases in the two 6-month periods before the switch. Adverse events after switching were widespread pain or myalgia and arthralgia after two infusions in two patients with PsA, multiple subjective symptoms such as dizziness and labile blood pressure and forgetfulness in another patient with PsA who also had these symptoms before the switch, and a case of chronic osteomyelitic foot infection in a patient with RA that also predated the switch. Biologic therapy was stopped in the RA patient, one of the PsA patients switched back to Remicade, and the other two were switched to ustekinumab (Stelara).
Dr. Parker reported that switching to the biosimilar has significantly cut the cost of treatment by £197,974 (about $291,000 USD) or 41.5% in their practice.
A team from St. George’s University Hospitals NHS Foundation Trust in London reported in a poster session similar findings after switching 31 patients to Remsima (Rheumatology [Oxford]. 2016;55[suppl 1]:i125-i126). Most switches occurred in RA patients (n = 18), followed by seven with AS and five with PsA. One patient did not switch following a consultant decision after the patient in question developed septic arthritis.