FP27-1 Potential Predictors of Macroadenoma Volume Reduction After Primary Therapy With Lanreotide Autogel in a Large Treatment-Na´ve Acromegalic Population

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: FP27-Pituitary: Acromegaly and Prolactinoma
Sunday, June 16, 2013: 10:45 AM-11:15 AM
Presentation Start Time: 10:45 AM
Room 135 (Moscone Center)

Poster Board SUN-90
Philippe J Caron*1, John S Bevan2 and Pascal Maisonobe3
1CHU Larrey, Toulouse, France, 2Aberdeen Royal Infirmary, Aberdeen, Scotland, United Kingdom, 3Ipsen Pharma, Boulogne-Billancourt, France
Introduction: It would be clinically useful to be able to predict the impact of primary therapy with somatostatin analogs (SSA) on tumor volume in acromegalic patients, but present data is insufficient.

Aims: This study assessed tumor volume using a rigorous, pre-specified method for MRI evaluation after high dose lanreotide Autogel as first-line therapy over 1-yr in a large homogenous treatment-naïve acromegalic population. Here, we examine potential predictors for tumor volume reduction (TVR) using this unique data set.

Methods: In this international, multicenter, open-label, single-arm study (NCT00690898), treatment-naïve acromegalic patients with pituitary macroadenoma received primary therapy with lanreotide Autogel 120 mg every 28 d for 48 wks. Tumor volume was assessed at baseline, 12, 24, and 48 wks on MRI central assessments. The primary endpoint was % of patients with ≥20% TVR from baseline to wk 48. Gender, age, tumor volume, IGF-1, and GH level at baseline were assessed as potential explanatory variables for TVR and for ≥20% TVR using ANCOVA or Logistic regression modeling. Based on univariate analysis, those factors that initially reached the significance threshold of 0.20 were selected for multivariate analysis, which included baseline tumor volume as an explanatory variable.

Results: 90 patients received therapy (baseline mean max tumor diameter 19.0 mm [range 10.6–50.4 mm], tumor volume 2739 mm3, GH 15.0 µg/L, IGF-1 810 µg/L). The primary analysis found 56/89 patients (63% [95%CI: 52‑73%]) achieved ≥20% TVR. Only age and baseline GH reached the 20% significance threshold for further multivariate analysis as explanatory variables for TVR (p=0.051 and 0.12, respectively). In the multivariate ANCOVA model, age and baseline GH showed positive associations with TVR (p=0.027 and 0.014, respectively). Baseline GH was again selected by univariate logistic regression as explanatory variables for ≥20% TVR (p=0.12). However, this variable did not reach statistical significance in the multivariate model (p=0.074).

Conclusions: In treatment-naïve acromegalic patients with pituitary macroadenoma, primary high dose lanreotide Autogel therapy reduced pituitary macroadenoma volume. Baseline GH level was the main factor identified as a potential predictor for tumor response to primary therapy. Further evaluations are ongoing to quantify correlations between hormonal changes during treatment with TVR.

Disclosure: PJC: Consultant, Ipsen, Speaker, Ipsen, Board Member, Ipsen, Consultant, Novartis Pharmaceuticals, Speaker, Novartis Pharmaceuticals. JSB: Researcher, Ipsen, Study Investigator, Ipsen, Consultant, Ipsen, Researcher, Novartis Pharmaceuticals, Study Investigator, Novartis Pharmaceuticals. PM: Employee, Ipsen.

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: This study is funded by Ipsen.
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