Endocrine Abstracts

Introduction: Surgery is recognized first-line therapy for acromegalic patients but tumour size and GH/IGF1 control has also been observed after primary somatostatin analogue treatment. This is the first study of therapy with high-dose lanreotide Autogel over one year in a large cohort of treatment-naïve acromegalic patients.

Methods: In this international, multicentre, open-label, single-arm, phase 3b study (NCT00690898/EudraCT2007-000155-34), treatment-naïve acromegalic patients with GH-secreting pituitary macroadenoma received primary therapy with lanreotide Autogel 120 mg every 28 days for 48 weeks. The primary endpoint was percentage of patients with ≥20% tumour volume reduction (baseline, week 48) based on MRI central assessments from three readers. The primary analysis used the reader with best standardized sensitivity determined on repeatability tests.

Results: Ninety patients received treatment (baseline mean maximum adenoma diameter 19.0 mm (range 10.6–50.4 mm), tumour volume 2739 mm³, GH 15.0 μg/l, IGF1 810 μg/l). In the intention-to-treat population, the primary analysis showed 56/89 (63%) patients achieved ≥20% tumour volume reduction (95% CI: 52–73%). In the per-protocol population, the same reader found ≥20% tumour reduction in 47/63 patients (75% (62–85%)). Based on last available assessments, GH levels ≤2.5 μg/l were achieved in 58/89 (65% (54–75%)), IGF1 within age/sex-matched normal range in 34/88 (39% (28–50%)), and GH/IGF1 control in 30/88 (34% (24–45%)). Lanreotide was well-tolerated, most patients reported mild AEs (56/90 (62%)) and/or moderate AEs (36/90 (40%)), and only 5/90 discontinued due to AEs (6%). Gastrointestinal disorders were most frequent AEs (58/90 (64%)).

Conclusions: In patients with newly-diagnosed GH-secreting pituitary macroadenoma, primary therapy with lanreotide Autogel at 120 mg every 28 days achieved clinically-relevant reduction in pituitary adenoma volume and sustained GH/IGF1 control with a favourable safety profile over 48 weeks’ follow-up. These data support further exploring the potential use of lanreotide as an initial therapeutic option in this patient population.