OBJECTIVES: To assess the prescribing of biosimilar rituximab by oncologists versus rheumatologists in the EU5.

METHODS: The Ipsos Global Oncology Monitor and Rheumatoid Arthritis (RA) Therapy Monitor: multi-country, multi-centre medical chart-review studies, through which de-identified patient data are provided online by geographically representative physician panels. Specifically, 123 oncologists and 332 rheumatologists reported on 1,918 NHL patients and 3,759 RA advanced therapy patients, respectively, in UK, France, Germany, Italy and Spain from July 2017-March 2018. Participating physicians – who were screened for treatment involvement and patient caseload – provided date of diagnosis, current and historic treatment, and reasons for prescribing/discontinuing anti-cancer/RA drugs. Data on patients treated with MabThera or biosimilar rituximab were analysed using descriptive statistics.

RESULTS: In the most recent time-period (January-March 2018), 48% of oncologists reported a patient treated with biosimilar rituximab – versus just 7% of rheumatologists. In July-September 2017, these figures were at 14% and 4%, respectively, showing a sharp rise amongst oncologists versus a small increase amongst rheumatologists. In the same time-period, overall prescribing of the biosimilar version of the rituximab molecule grew from 7% to 40% in NHL and 9% to 26% in RA. In terms of prescribing of biosimilar rituximab by line in NHL/RA, 65%/24% was at first-line, 25%/29% at second-line and 10%/48% at third-line plus. Incidence of non-medical switching amongst second-line plus patients from MabThera to biosimilar rituximab was 95% in NHL versus 31% in RA. In NHL, the top 3 reasons for prescribing biosimilar rituximab were ‘approved standard of care’ (71%), ‘proven efficacy’ (50%), and ‘on formulary/hospital policy’ (32%). In RA, they were ‘mechanism of action’ (43%), ‘cost/insurance’ (38%) and ‘frequency of administration’ (29%).

CONCLUSIONS: Oncologists have adopted biosimilar rituximab significantly more quickly than rheumatologists. Further investigation into the differences in uptake between the two specialties is warranted.