P161 Successful treatment of pulmonary hypertension and grade 3 lupus nephritis with triple combination treatment for pulmonary hypertension (Macitentan, Tadalafil, Selexipag) and cyclophosphamide

Background 28-year-old Goan lady presented with polyarthritis, positive ANA, RNP, dsDNA, low C4 and normal C3. She was diagnosed with SLE and received Hydroxychloroquine (HCQ), Prednisolone, and Azathioprine 150mg daily. Between 2011–2016, she had multiple flares with arthritis and serositis. She responded poorly to methotrexate, and developed a reaction to Rituximab, but improved on HCQ 400mg, mycophenolate mofetil 3 g and Prednisolone 7.5mg daily. (SLEDAI 4 in 2018). Methods She presented in 2018 with fever, urine infection, and pericarditis; ESR-92, CRP-38, low C3, C4, and dsDNA-345. Examination revealed raised JVP, loud P2, and ECG findings consistent with pulmonary hypertension (PH). CT pulmonary angiogram showed an enlarged main pulmonary artery with no PE. Renal biopsy demonstrated class 3 lupus nephritis, protein-creatinine ratio (PCR) 362. She developed autoimmune haemolysis requiring blood transfusion. Apixaban was prescribed for positive anticardiolipin antibody and lupus anticoagulant. She was treated with Cyclophosphamide (CYC) (EUROLUPUS regime) and Prednisolone. Six-Minute-walk-distance was 356m, desaturating to 85%. Borg's score was 17. Lung function test showed FVC 1.31 litres- 40% predicted, TLCO 32% predicted. Echocardiogram showed significant pulmonary hypertension, dilated RV with impaired function, TAPSE 1.9cm, dilated right atrium, RVSP-71mmHg and normal LV function. Right Heart Catheter (RHC) confirmed mPAP 52mmHg (May 2019). Results She was started on Tadalafil and Macitentan whilst receiving CYC. Within 4 months, mPAP improved to 34 mmHg. As she became more breathless in December 2020, Selexipag was added. In 2021, mPAP was 22mmHg. Echocardiogram in 2023 showed sinus rhythm, TAPSE 2.2cm, low probability of pulmonary hypertension, and no evidence of right heart strain. Conclusions PAH is a rare but severe complication of SLE. The prevalence of clinical SLE-PAH is 0.5–17%.1 Suggested pathogenic mechanisms include immune system dysregulation, inflammatory cell infiltrate deposition in pulmonary vasculature and endothelial dysfunction. Most patients are asymptomatic until the late stages. Studies suggest a better benefit with immunosuppressive therapy in SLE-PAH vs. SSC-PAH, the commonest CTD-PAH with a 3-year survival of 74% -89.4% vs. 50% respectively.1 2 Meta-analysis and RCT reported that combination therapy with immunosuppression, pulmonary vasodilators, and prostacyclin analogues yielded a favourable outcome (2) and delayed disease progression. References Bazan IS, Mensah KA, Rudkovskaia AA, Adonteng-Boateng PK, et al. Pulmonary arterial hypertension in the setting of scleroderma is different than in the setting of lupus: a review. Respiratory medicine. 2018 Jan 1;134:42–6. Parperis K, Velidakis N, Khattab E, et al. Systemic Lupus Erythematosus and Pulmonary Hypertension. International Journal of Molecular Sciences. 2023 Mar 7;24(6):5085.