Aim: To assess the efficacy and safety of pasireotide long-acting release (PAS-LAR) alone or in combination with pegvisomant by switching patients with acromegaly who were well controlled with long-acting somatostatin analogues (LA-SSAs) and pegvisomant to PAS-LAR with or without pegvisomant.
Methods: Sixty-one patients with acromegaly were enrolled in a prospective open-label study. We included patients with an insulin-like growth factor I (IGF-I) ≤1.2 × upper limit of normal (ULN) during treatment with LA-SSAs and pegvisomant. At baseline, the pegvisomant dose was reduced by 50% up to 12 weeks. When IGF-I remained ≤1.2 × ULN after 12 weeks, patients were switched to PAS-LAR 60 mg monotherapy. When IGF-I was >1.2 × ULN, patients were switched to PAS-LAR 60 mg, and they continued with the 50% reduced pegvisomant dose.
Results: At baseline, mean IGF-I was 0.97 × ULN, and the median pegvisomant dose was 80 mg/wk. At 12 weeks, mean IGF-I increased to 1.59 × ULN, and IGF-I levels ≤1.2 ULN were observed in 24.6% of participants. At 24 weeks, IGF-I levels were reduced into the reference range in 73.8% of patients. Between baseline and 24 weeks, the pegvisomant dose was reduced by 66.1%. PAS-LAR was well tolerated, but hyperglycemia was the most frequent adverse event. The frequency of diabetes increased from 32.8% at baseline to 68.9% at 24 weeks.
Conclusions: Switching to PAS-LAR, either as monotherapy or combination with pegvisomant, can control IGF-I levels in most patients. PAS-LAR demonstrated a pegvisomant-sparing effect of 66% compared with the combination with LA-SSAs. Hyperglycemia was the most important safety issue.
Trial registration: ClinicalTrials.gov NCT02668172.
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