MON-301 Long-Acting SSA Treatment Patterns in Sweden From 2005 to 2017: A Nationwide Study

Background Acromegaly is a complex disease, primarily treated with pituitary surgery or long-acting somatostatin analogues (LA-SSA). Few studies have examined real-world use of LA-SSA. This analysis evaluated LA-SSA treatment patterns in Sweden for patients with acromegaly. Methods Data were obtained from nationwide health care registers. Patients were included if they had diagnosis codes for acromegaly and neoplasm of the pituitary gland between Jul 1, 2005 and Dec 31, 2017, and at least one purchase of LA-SSA (lanreotide [LAN] 60, 90, or 120 mg, or octreotide [OCT] 10, 20, or 30 mg). Cox regression models were used for analyses of persistence and switching. Results The analysis included 176 pts treated with LA-SSA in 2005-2017. The cohort was subgrouped on year of initiation of LA-SSA (2005-2011, n=90, 51%; 2012-2017, n=86, 49%). In the first period, 36 pts (40%) initiated LAN while 54 pts (60%) initiated OCT while in the later period, 44 pts (51%) initiated LAN and 42 pts (49%) initiated OCT (p=0.17). No patients initiated pasireotide. Patient characteristics were similar between LAN and OCT initiators, but history of pituitary surgery was more common for LAN as compared to OCT (LAN 62%; OCT 46%, p<0.05). Similar results were seen for visual-field defects (LAN 20%, OCT 8%, p<0.05). Median (95%CI) follow-up was not significantly different [LAN 5.3 (3.7; 6.0) yrs.; OCT 6.4 (4.5; 7.6)]. The mean (95%CI) dose interval was not significantly different, 30.5 (28.7; 32.6) days for LAN vs 29.5 (28.5; 30.3) days for OCT. The median (95%CI) duration of 1(st)-line LA-SSA treatment was 14.4 (10.8; 21.6) months for LAN and 12.0 (7.2; 19.2) months for OCT. Fifty-one pts (64%) discontinued 1(st)-line LAN while 70 pts (73%) discontinued 1(st)-line OCT (hazard ratio (HR) LAN vs. OCT 0.80; 95% CI: 0.56-1.15). Due to the use of register data, the reason for therapy change could not be determined. Eight pts (10%) switched LAN to OCT while 29 pts (30%) switched OCT to LAN. Patients initiated on OCT were more likely to switch to LAN than the other way around (HR for switch for 1(st)-line LAN vs. OCT 0.33; 95% CI 0.15-0.72). Among patients who switched OCT to LAN, 67% of LAN dispensing was 120 mg, 21% 90 mg, and 12% 60 mg. Among patients who switch LAN to OCT, 84% of OCT dispensing was 30 mg, and 16% 20 mg. Conclusions There was no significant difference in the number of patients initiated on LAN or OCT despite the later introduction of LAN in Sweden. Patient characteristics were similar but LAN initiators were more likely to have undergone surgery and be diagnosed with visual field defects which could indicate that physicians initiate LAN in patients with more aggressive disease. Extended dose intervals with LAN (dosing every 6-8 w) do not seem to be commonly used in Sweden. In comparison to OCT, patients initiated on LAN were significantly less likely to change LA-SSA therapy.