Tumor shrinkage with lanreotide Autogel 120 mg as primary therapy in acromegaly : results of a prospective multicenter clinical trial

Context: Methodological shortcomings often compromise investigations into the effects of primary somatostatin-analog treatment on tumor size in acromegaly. There are also limited data for the long-acting lanreotide formulation. Objective: The aim of the study was to better characterize the effects of primary lanreotide Autogel treatment on tumor size in patients with GH-secreting macroadenomas. Design: PRIMARYS was a 48-week, multicenter, open-label, single-arm study. Setting: The study was conducted at specialist endocrine centers. Patients: Treatment-naïve acromegalic patients with GH-secreting macroadenomas participated in the study. Intervention: Lanreotide Autogel 120 mg was administered sc every 28 days (without dose titration). Outcome Measures: The primary endpoint was the proportion of patients with clinically significant (≥20%) tumor volume reduction (TVR) at week 48/last post-baseline value available using central assessments from three readers. The null hypothesis (H0) for the primary endpoint was that the proportion with TVR was ≤55%. Secondary endpoints included: TVR at other time points, GH and IGF-1, acromegalic symptoms, quality of life (QoL), and safety. Results: Sixty-four of 90 (71.1%) patients completed the study. Clinically significant TVR at 48 weeks/last post-baseline value available was achieved by 62.9% (95% confidence interval, 52.0, 72.9) of 89 patients in the primary analysis (intention-to-treat population; H0 not rejected) and 71.9–75.3% in sensitivity (n = 89) and secondary analyses (n = 63) (H0 rejected). At 12 weeks, 54.1% had clinically significant TVR. Early and sustained improvements also occurred in GH and IGF-1, acromegalic symptoms, and QoL. No patients withdrew due to gastrointestinal intolerance. Conclusions: Primary treatment with lanreotide Autogel, administered at 120 mg (highest available dose) without dose titration, in patients with GH-secreting macroadenomas provides early and sustained reductions in tumor volume, GH and IGF-1, and acromegalic symptoms, and improves QoL.