Whilst denosumab is not renally cleared, little is known about its effects and safety in patients with severe CKD. Methods: We performed a study of all patients with CKD stage IV or V administered denosumab since 1/1/2010 at Austin Health. Patients were identified by cross-referencing pharmacy administration records with patient’s renal function prior to drug administration. Data was collected and analysed retrospectively by chart review for clinical parameters, including calcium levels prior to and following administration GSK458 of denosumab. Results: 8 patients with stage V and 5 patients with stage IV CKD were identified. 6 of 8 patients with CKD V, and 2 of 5 patients with

CKD IV had significant hypocalcaemia, (corrected calcium < 2.0 mmol/L), with the lowest

corrected calcium being 1.18 mmol/L. Of these 8 patients, 3 patients had significant life-threatening complications requiring intensive monitoring. For patients who developed hypocalcaemia, the median time to serum calcium nadir was 26 days (range 10–56 days) and the median time to normalise calcium level was 86 days (range 15–140 days). Treatment of hypocalcaemia required large doses of calcium and vitamin D and increases to dialysate calcium, consistent with hungry bone syndrome. Conclusions: Patients with advanced CKD are at greatly increased risk of severe hypocalcaemia and hungry bone syndrome Akt inhibitor when administered denosumab. Denosumab is best avoided in patients with advanced CKD but if used very close monitoring is required. 174 RITUXIMAB-ASSOCIATED HYPOGAMMAGLOBULINAEMIA: INCIDENCE,

OUTCOMES AND EFFECT OF DOSE IN PATIENTS WITH MULTI-SYSTEM AUTOIMMUNE DISEASE DM ROBERTS1,2, RB JONES1, RM SMITH1, F ALBERICI1,3, DS KUMARATNE1, S BURNS1, DRW JAYNE1 1Addenbrooke’s Hospital, Cambridge, UK; 2University of Queensland, Brisbane, Australia; 3University of Parma, Italy Aim: To describe the incidence, severity and predictors of hypogammaglobulinaemia from rituximab for small vessel vasculitis and other multi-system autoimmune diseases, Erastin order and clinical outcomes following IgG replacement therapy. Background: Hypogammaglobulinaemia has occurred after rituximab treatment of lymphoma and rheumatoid arthritis but data are scarce for other autoimmune indications. Methods: Retrospective study in a tertiary referral specialist clinic. The severity of hypogammaglobulinaemia was categorised on the basis of the nadir serum IgG concentration measured during clinical care. Clinical details of patients prescribed IgG replacement therapy were reviewed. Results: 288 patients received rituximab; 243 were eligible for inclusion with median follow up of 42 months. 26% patients were IgG hypogammaglobulinaemic at the time rituximab was initiated and 56% had IgG hypogammaglobulinaemia during follow-up (5–6.9 g/L in 30%, 3–4.9 g/L in 22% and <3 g/L in 4%); IgM ≤ 0.3 g/L in 58%. The nadir IgG was non-sustained in 50% of cases with moderate or severe hypogammaglobulinaemia.