S. Menotti*a (Dr), S. Chiloiroa (Dr), A. Giampietroa (Dr), A. Pontecorvia (Prof), A. Bianchia (Dr), L. De Marinisa (Prof)

a Fondazione Policlinico Gemelli IRCCS, Rome, ITALY

* saramenotti@gmail.com

Introduction: The treatment of acromegaly resistant to first generation somatostatin analogues (first gen-SSA) is often difficult. The aim of this study is to investigate the role of partial response and resistance to first gen-SSA in the choice of second line treatments.

Patients and methods: A retrospective and multicenter study was conducted on 100 SSA-resistant acromegaly patients and treated with Pasireotide Lar (Pasi-Lar), Peg-V in monotherapy (m-Peg-V) or in combination with first gen-SSA (c-Peg-V).

Results: Thirty-three patients (33%) were treated with m-Peg-V, 36 (36%) with c-Peg-V and 31 with Pasi-Lar (31%). According to logistic regression, m-Peg-V was chosen in older patients (p=0.01) with not-invasive adenomas (p=0.009), c-Peg-V therapy in younger patients (p=0.001) with invasive adenomas (p=0.02), Pasi-Lar was in invasive adenomas (p=0.01) and in patients partially responsive to first-gen SSA (p=0.01). The last follow-up, 68 patients (68%) reached the acromegaly control: 22 with m-Peg-V (32.4%), 23 with c-Peg-V (33.8%) and 23 with Pasi-Lar (33.8%). Patients non-responsive to c-Peg-V had higher IGF-I levels (median 3.2 x ULN, IQR: 1.6, p<0.001) and required higher Peg-V dosage (median 30 mg/daily IQR: 10, p=0.002) as compared to responsive patients (median IGF-I x ULN: 2.1 IQR: 1.4; median Peg-V dosage 20 mg/daily IQR: 10). All patients responsive to Pasi-Lar were partially responsive to first gen-SSAs (p=0.02).

Discussion: Our data showed that c-Peg-V and Pasi-Lar are chosen for the treatment of invasive tumors. The partial response to first gen-SSA seems to be the main determinant for the choice of Pasi-Lar and positively predicts the treatment outcome.

The author has declared no conflict of interest.