Background: Since the introduction of anti-TNF biosimilars in routine clinical practice, there has been a drive to implement the switch program for all biosimilars at the point of availability. First adalimumab biosimilar was granted marketing authorisation by the EMA in March 2017. Our Trust was aligned to NHS England strategy which required adoption of biosimilar within three months for new patients and one year for switchers. This could help deliver significant savings to the NHS whilst achieving similar clinical outcomes.

Objectives: We report our early experience of introducing adalimumab biosimilar (SB5).

Methods: A list of all patients prescribed adlimumab was extracted through our database. A ‘switch’ letter was drafted and sent to all patients including Imraldi information sheet. Patients were given the opportunity to contact nurse helpline for information or if disease control worsened/adverse effects developed. We reviewed all relevant records and collected data on any adverse events and disease outcome on either side of the switch. Patients were reviewed as originally planned by their respective clinicians.

Results: 198 patients were identified established on adalimumab. All had switched by October 2019 to Imraldi. Mean age of switchers was 48 (range 16-83 years). Gender distribution was equal (99 each). 35 (17%) were Asian, two Afro-Caribbean, four other and the remaining 157 (80%) were White Caucasian. 54 (27%) had RA, 81 (41%) PsA, 57 (29%) AS and six had JIA. Coprescribed DMARDs included methotrexate (n=53, 27%), sulfasalazine (n=15, 7.5%), hydroxychloroquine (n=14, 7%) and leflunomide in two individuals. 83 (42%) participants were prescribed adalimumab monotherapy.

Prior to switch, median DAS28 for RA group was 2.28 (0.57 – 6.29). Median BASDAI and spinal VAS for AS cohort was 3.3 (0.8 – 8.8) and 3.0 (0 – 9) respectively. Tender and swollen joint components for PsARC were median three (0-8 tender, 0-6 swollen) in PsA group. Only 30% of the patients had been reviewed face-to-face following the switch. Their respective median disease activity indices were not significantly different from pre-switch assessments. Fifteen (7.5%) patients switched back to the originator for following reasons; injection site reaction (n=7), loss of disease control (n=7) and inability to use the new device (n=1).

Conclusion: Our experience of switching adalimumab patients has been reasonably successful. All were happy to switch after receiving a letter and having the opportunity to contact if necessary. Substantial annual cost savings of over £300,000 have been projected for this financial year. At group level there were no major differences in disease outcomes and 90% reported no issues. However, just under 10% of those reviewed have decided to return to the originator within three months of switch with loss of efficacy and thereby confidence in the drug. We support the routine switching from originator to biosimilar adalimumab however close monitoring is required certainly in the first few weeks of dose administration.

Disclosure of Interests: Julie Begum: None declared, Muhammad Khurram Nisar Grant/research support from: Muhammad Nisar undertakes clinical trials and received support (including attendance at conferences, speaker fees and honoraria) from Roche, Chugai, MSD, Abbvie, Pfizer, BMS, Celgene, Novartis and UCB

, Consultant of: Muhammad Nisar undertakes clinical trials and received support (including attendance at conferences, speaker fees and honoraria) from Roche, Chugai, MSD, Abbvie, Pfizer, BMS, Celgene, Novartis and UCB

, Speakers bureau: Muhammad Nisar undertakes clinical trials and received support (including attendance at conferences, speaker fees and honoraria) from Roche, Chugai, MSD, Abbvie, Pfizer, BMS, Celgene, Novartis and UCB