TOCILIZUMAB for GIANT CELL ARTERITIS: BASELINE and TWELVE MONTH AUDIT DATA from the UK BRISTOL and BATH MULTIDISCIPLINARY MEETING

ABSTRACT

Background: Giant Cell Arteritis (GCA) is a systemic vasculitis involving large and medium-sized blood vessels. Treatment is with high dose glucocorticoids. Steroid-sparing agents and Tocilizumab (TCZ) are used for refractory or relapsing cases. NHS England requires all GCA patients to be discussed in a regional multidisciplinary team meeting (MDT) prior to commencing TCZ. TCZ has only been permitted for a maximum of one year;this time limitation was extended during the Covid-19 pandemic (1). The monthly virtual Bristol and Bath regional MDT started in November 2018. Objectives: We aimed to review 1) Baseline data on all patients referred to the Bristol and Bath TCZ for GCA MDT, including demographics, clinical presentation and previous steroid-sparing agents used and 2) 12 month follow up data including number of completions, adverse effects, and fares on treatment. Methods: The TCZ MDT referral proforma, adapted from the NHS England Blueteq approval form, was reviewed for all patients referred. 12 month follow up data was obtained from clinic letters. Results: Baseline data Thirty-eight cases were referred between November 2018 and September 2021. Of these, 31 were approved for TCZ usage;100% fulflled the criteria for either refractory (n=11) or relapsing (n=20) disease. Mean age was 74 years and 74.2% were female. Average disease duration was 161.5 days for the refractory and 827.3 days for the relapsing group. 77.4% had cranial GCA, 48.4% had large vessel involvement, 45.2% had visual symptoms and 25.8% had ischaemic visual loss. The positive investigations were PET-CT (48.4%), temporal artery ultrasound (41.9%) and temporal artery biopsy (32.3%). 64.5% had trialled a steroid-sparing agent at time of referral (61.3 % metho-trexate, 9.7% azathioprine, 6.5% lefunomide), 35.5% had received intravenous methylprednisolone and 58% were receiving greater than 40mg prednisolone at the time of referral. Glucocorticoid adverse effects of osteoporosis, weight gain, cataracts and hypertension were each seen in 19.4%;whilst diabetes, neuropsychiatric symptoms and sleep disturbance were each reported in 16.1%. Those with ocular involvement tended to be referred earlier than those without (478.2 days vs 648.1 days), were referred on higher doses of glucocorticoids (71.4% vs 47.1% on ≥ 40mg) and had less steroid-sparing agents prior to referral. Follow up data In December 2021, a follow-up audit revealed 14/31 patients had completed at least 12 months of tocilizumab;5 of these had had an extension under Covid-19 exceptional guidance (mean duration of 5.2 months). Of the remaining 17 3 patients had stopped early (1 death, 1 moved away, 1 due to adverse effects of headache and gastro-intestinal side effects), 4 had not started tocilizumab and 10 had not completed 12 months of treatment at that point. Adverse events in the 14 patients at 12 months included liver abnormalities (2/14;14.3%), neutropenia (2/14;14.3%), thrombocytopaenia (1/14;7.1%), soft tissue infections (3/14;21.4%), urinary tract infection (1/14;7.1%) and lipid derangement (4/14 28.6%). One case of GCA relapse occurred on TCZ (mild headache and raised infammatory markers settled on small increase in prednisolone). After 12 months, mean prednisolone dose was 3mg (range 0-15mg). Conclusion: All patients approved for Tocilizumab in the GCA MDT fulflled NHS England criteria for either relapsing or refractory disease. The majority of cases had cranial disease, but almost half had either ocular or large vessel involvement, refecting a severe spectrum of disease. Cases showed a high burden of glucocorticoid toxicity. Follow up data suggests that TCZ was effective in allowing glucocorticoid weaning and disease control, but with some adverse effects. Future work to follow up patients after stopping Tocilizumab would be informative, as the twelve month limitation on treatment is likely to be re-instated.