Early and sustained tumour volume reduction and GH/IGF1 control in patients with GH-secreting pituitary macroadenoma primarily treated with lanreotide Autogel 120 mg for 48 weeks: the PRIMARYS study

Philippe Caron; John Bevan; Antoine Clermont; Pascal Maisonobe

doi:10.1530/endoabs.32.P840

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Endocrine Abstracts (2013) 32 P840 | DOI: 10.1530/endoabs.32.P840

ECE2013 Poster Presentations Pituitary – Clinical (<emphasis role="italic">Generously supported by IPSEN</emphasis>) (127 abstracts)

Early and sustained tumour volume reduction and GH/IGF1 control in patients with GH-secreting pituitary macroadenoma primarily treated with lanreotide Autogel 120 mg for 48 weeks: the PRIMARYS study

Philippe Caron ¹ , John Bevan ² , Antoine Clermont ³ & Pascal Maisonobe ³

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¹Department of Endocrinology and Metabolic Diseases, CHU Larrey, Toulouse, France; ²Department of Endocrinology, Aberdeen Royal Infirmary, Aberdeen, UK; ³Ipsen Pharma, Boulogne-Billancourt, France.

Introduction: First-line somatostatin analogue treatment may be an effective alternative option to surgery for some patients with GH-secreting pituitary macroadenoma. The PRIMARYS study aimed to investigate the impact of primary lanreotide Autogel 120 mg treatment on tumour volume and GH/IGF1 control in treatment-naïve acromegalic patients over a one-year time course.

Methods: PRIMARYS was an 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 (12 injections). The primary endpoint was percentage of patients with ≥20% reduction in tumour volume from baseline to week 48 based on MRI central assessments from three readers. The primary analysis used the reader with the best standardized sensitivity determined on repeatability tests. Tumour volume and hormonal status were assessed at 3, 6, and 12 months after therapy initiation. Efficacy was assessed in the intention-to-treat population.

Results: Ninety patients received treatment (baseline mean maximum adenoma diameter 19.0 mm, tumour volume 2739 mm3, GH 15.0 μg/l, IGF1 810 μg/l). The primary analysis showed 56/89 (63%) patients achieved ≥20% reduction in tumour size (95% CI: 52–73%). During the 48 weeks’ treatment, there was an early and sustained reduction in tumour volume over time (mean change: W12, −20%; W24, −25%; W48, −27%); this was mirrored by improvements in GH (W12, −62%; W24, −65%; W48, −71%) and IGF1 levels (W12, −44%; W24, −47%; W48, −57%; Figure). Overall, lanreotide Autogel 120 mg was well tolerated throughout the study period.

Conclusions: This large prospective study enrolling treatment-naïve acromegalic patients with GH-secreting pituitary macroadenoma demonstrated that primary treatment with lanreotide Autogel 120 mg every 28 days rapidly achieved tumour reduction of pituitary adenoma volume and sustained GH/IGF1 control. These data support further exploring the potential use of lanreotide as an initial therapeutic option in this patient population.