POS0550 PRE-PREGNANCY SWITCHING FROM MYCOPHENOLATE TO AZATHIOPRINE IN PATIENTS WITH LUPUS NEPHRITIS: A RETROSPECTIVE OUTCOME ANALYSIS
Authors: S. Jain, S. S. Ali, F. Alenzi, M. Al Falah, N. Jordan, S. Sangle, D. D’ Cruz
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Lupus nephritis is a major cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Following induction therapy, patients with lupus nephritis are usually maintained on either Mycophenolate Mofetil or Azathioprine. Mycophenolate is teratogenic, hence is usually switched to Azathioprine three months before trying to conceive. A previous small prospective study showed that pre-pregnancy switching from Mycophenolate to Azathioprine in patients with quiescent lupus nephritis rarely leads to renal flares. <h3>Objectives:</h3> To determine the risk of severe lupus flares (both renal and extra-renal) in lupus nephritis patients undergoing pre-pregnancy switching from from Mycophenolate to Azathioprine and to determine factors associated with flares. <h3>Methods:</h3> We retrospectively reviewed the clinical data and obstetric outcomes of patients undergoing pre-pregnancy switching from from Mycophenolate to Azathioprine in the Louise Coote lupus unit at Guy's Hospital, London. Data was collected from 1 year prior to MMF AZA switch to 1-year post-partum. Diagnosis of SLE was based on the 2019 EULAR/ACR classification criteria. Lupus nephritis was diagnosed by a biopsy and classified according to the International Society of Nephrology/Renal Pathology Society 2003 classification. Severity of flare was determined by the BILAG scoring system with a severe flare defined as 1 or more BILAG A items. Analyses included descriptive statistics [mean (standard deviation) and median (interquartile ranges) for continuous variables and frequency 9percent) for categorical variables)]. Student t-test, Chi square test and Cox regression analysis were used. <h3>Results:</h3> We reviewed 43 episodes (in 34 patients) out of which 9 patients had 2 episodes of switching each during their disease course. Majority were Caucasians (38.2%) followed by Afro-Caribbean (35.3%), Asian (23.5%) and mixed/others (3%). In 24 out of 43 (55.8%) switching episodes, patients had a severe flare of lupus (19 renal flares, 3 NPSLE flares, and 1 each cardiac and respiratory flare). Mean duration was 15.5 months (3 - 48 months) from switching. 9 patients (20.9%) had a severe flare within 6 months of switching (all renal flares). 16 flares (66.7%) occurred before pregnancy, 5 during pregnancy and 3 post-partum. Patients with positive dsDNA antibodies, low complements (either C3 or C4 or both), low serum albumin (&lt;35 g/L), creatinine &gt;65 μmol/L and urine PCR &gt;50 mg/mol at the time of switching were more likely to have severe flares Twenty-five patients progressed on to pregnancy, out of which 14 patients (56%) had a successful pregnancy and 11 (44%) had a miscarriage. Five patients developed hypertension during pregnancy and 1 each developed pre-eclampsia, pre-term labour, obstetric cholestasis and sepsis. <h3>Conclusion:</h3> Although Azathioprine is an option in patients with lupus nephritis who are planning pregnancy, our study showed significant flare rates in these patients (&gt;50%). Our study identified that patients with positive dsDNA antibodies, low complements (either C3 or C4 or both), low serum albumin (&lt;35 g/L), creatinine &gt;65 μmol/L and urine PCR &gt;50 mg/mol at the time of switching were more likely to have severe flares. <h3>REFERENCES:</h3> <b>NIL.</b> <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> Sahil Jain: None declared, Saadia Sasha Ali: None declared, Fahidah Alenzi: None declared, Maha Al Falah: None declared, Natasha Jordan: None declared, Shirish Sangle: None declared, David D' Cruz Consultant and Advisory Board member: GlaxoSmithKline, CSL Vifor.