Endocrine Abstracts

Background: Previous studies have yielded conflicting results on biochemical control with medical therapy in patients with or without prior pituitary surgery. The LANTERN study (NCT02493517) demonstrated that lanreotide autogel (LAN ATG) was non-inferior to lanreotide prolonged release (LAN PR) in Chinese patients with active acromegaly. This post hoc analysis of the LANTERN study aimed to explore the efficacy of LAN ATG in patients with or without prior pituitary surgery.

Design: Patients with active acromegaly were randomized to LAN ATG or LAN PR 40 mg for 32 weeks. This post hoc analysis focuses on the efficacy of LAN ATG in patients with (Group I) or without (Group II) prior pituitary surgery.

Results: There were 39 patients in Group I and 18 patients in Group II at Baseline. The median time since acromegaly diagnosis prior to Baseline was longer in Group I [median (Q1,Q3) 3.37 (0.90.4.02)] than Group II [0.44 (0.12.1.30) years; P = 0.001]. Group I had higher age-adjusted mean Baseline IGF-1 standard deviation scores (SDS) than Group II (17.37 ± 5.28 vs 13.65 ± 6.11; P = 0.03). Baseline GH level was comparable between Group I and II [10.37 (5.41.24.35) vs 18.84 (8.13.29.52); P = 0.226]. Change in IGF-1 SDS from Baseline at Week 32 was –7.16 (95% CI 0.98.5.23) in Group I vs –4.96 (95% CI –7.84, –2.08) in group II (P = 0.218). The proportion of patients achieving IGF-1 normalization at Week 32 in Group I (20.5%, 8/39) was almost twice that in Group II (11.1%, 2/18) (P = 0.622). Change in GH levels from Baseline at Week 32 was comparable between Group I and II [–10.94 (95% CI –16.16, –5.71) vs –11.50 (95% CI –19.21, –3.78); P = 0.905]. 28.2% (11/39) and 27.8% (5/18) patients in Group I and II attained GH levels ≤ 2.5 µg/L, respectively (P = 0.973). Among patients with evaluable MRI both at Baseline and post-treatment, 39.4% (13/33) in Group I and 37.5% (6/16) in Group II achieved ≤ 20% reduction in tumor volume, respectively (P = 0.899). The rate of treatment-emergent adverse events (TEAEs) was 94.9% in Group I and 88. 9% in Group II. The rate of severe and moderate TEAEs was lower in Group I (43.6%) than Group II (83.3%).

Conclusion: In the LANTERN study, patients with prior surgery had longer history of acromegaly and higher Baseline IGF-1 scores than those without. LAN ATG provided comparable biochemical control and tumor volume reduction in patients with or without prior pituitary surgery. The results indicate that prior pituitary surgery does not significantly affect the treatment efficacy and safety of LAN ATG.