Endocrine Abstracts

Background: Pegvisomant (PEG) is a second line medical treatment for active acromegalic patients. PEG efficacy is between 61.5 and 92% and even if it is administered daily its long half-life suggests a possible use with a non-daily regime.

Aim: We aim to compare acromegalic patients on daily PEG administration (DP) with patients on non-daily PEG administration (NDP).

Methods: We studied 43 acromegalic patients under PEG treatment between 2005 and 2017. Patients were divided into two groups: DP and NDP. DP were evaluated three times: at PEG start (T0), at PEG maximum dose after up-titration period (T1) and at the last follow-up visit (T3); after T1 we started the non-daily administration and only the NDP patients had an additional evaluation after 6 months (T2). At every time (T0, T1, T2, T3) we collected PAQ15 questionaries, anthropometric, clinical and endocrinological data.

Results: 14/43 patients were switched to a non-daily therapy and, before T3 only 1 patient returned to daily therapy because of increased lipohypertrophy. Both DP and NDP patients had a significantly decreased IGF-1 levels (DP: IGF-1 ULN: T0 2.30±1.06, T1 1.08±0.37, T3 1.20±0.46; P<0.000001 with mean follow-up 65±47 months vs NDP: IGF-1 ULN: T0 1.95±0.81, T1 0.74±0.25, T2 0.91±0.29, T3 0.87±0.26 P<0.000001 with mean follow-up period 81±39 months). DP patients mean PEG dose was 27±8 mg/die with 20% of the patients on combination therapy (CT) at T1 and 24±8 mg/die with 35% of the patients on CT at T3; NDP patients mean PEG dose was lower at T2 than at T1 (T2 vs T1: 12±7 −7% of patients on CT- vs 16±9 mg/die −14% of patients on CT-, P<0.01) with no difference on IGF-1 ULN levels (IGF-1 ULN: T2 0.91±0.29, T3 0.89±0.26). At T1, NDP patients presented lower IGF-1 levels, lower PEG dose, shorter mean drug titration period when compared with DP; at T3, NDP patients had lower IGF-1 levels and lower mean PEG dose when compared with DP. PAQ15 was not different in DP patients when compared to NDP patients.

Conclusions: In selected patients, non-daily PEG treatment is a good therapeutic option to control disease activity, reducing PEG dose and ameliorating compliance and patients’ quality of life.