RF09 | PSAT70 Comparison of Prednisolone Versus Modified-release Hydrocortisone (Efmody) in the Treatment of Congenital Adrenal Hyperplasia (CAH)

Abstract

Abstract Background Prednisolone and prednisone have a longer plasma elimination half-life after oral administration than hydrocortisone: 2.1 to 3.5 vs ∼1.5hrs1,2. For this reason, prednis(ol)one has been used in Congenital Adrenal Hyperplasia (CAH) by giving a dose in the evening to try to prevent the overnight rise in adrenal androgens. Modified-release hydrocortisone (MRHC) capsules, (Efmody, Diurnal Ltd, Cardiff UK), replicate the cortisol diurnal rhythm and improve the control of CAH compared to standard glucocorticoid therapy3. This post-hoc sub-analysis examines CAH control in MRHC treated patients switched from prednis(ol)one. Methods We reviewed the data of all patients taking prednis(ol)one in the randomised study of standard treatment versus MRHC3: 39 classic CAH patients on prednis(ol)one (alone or combined with hydrocortisone) (36 prednisolone; 3 prednisone) were randomised either to continue prednis(ol)one or switched to MRHC at the same hydrocortisone dose equivalent (HDE=prednisolone dose x5). Patients were assessed after 4 weeks following which blinded dose titration according to 17OHP and A4 control was performed to bring 17OHP into the optimal range (<36 nmol/l) and A4 into the reference range. After 24 weeks, 31 patients from the prednis(ol)one prior therapy group participated in an ongoing MHRC single arm extension study with 28 patients completing 18 months follow up. Control of CAH was defined as a 0900h 17OHP <36 nmol/l. Results Median baseline dose (HDE) was 30mg (n=39), androgen control was 56%. In patients randomised to MRHC (n=18), 39% were controlled at baseline and 94% at 4 weeks without dose adjustment. At 24 weeks, after androgen-control guided titration, the HDE dose in the prednis(ol)one group was 34mg, and in the MRHC group 27.5mg, with control being 71% and 94%, respectively. Percentage inhibition of 9am 17OHP from the levels at baseline to that at 24 weeks in the prednis(ol)one group was 32% and in the MRHC group 91%. In this study period there were no adrenal crises in the MRHC group and one in the prednis(ol)one group. MRHC-treated patients in the extension study were further titrated according to clinician assessment, at interim analysis the median MRHC dose was 20mg (median reduction 10mg) and 82% of patients were controlled at 18 months (n=28). In the ongoing extension study of all patients on MRHC (221 patient years), there were 12 adrenal crises in 5 patients (5.4/100 patient years). Conclusions Control of CAH is better on MRHC than prednisolone: 94% vs 39%; and the dose of MRHC can be down titrated to an adrenal replacement dose whilst maintaining control in the majority (82%) of patients.