A multivariable prediction model for pegvisomant dosing: monotherapy and in combination with long-acting somatostatin analogues

Background: Effective treatment of acromegaly with pegvisomant (PEGV), a growth hormone receptor antagonist, requires an appropriate dose titration. PEGV doses vary widely among individual patients, and various covariates may affect its dosing and pharmacokinetics. Objective: To identify predictors of the PEGV dose required to normalize insulin-like growth factor I (IGF-I) levels during PEGV monotherapy and in combination with long-acting somatostatin analogues (LA-SSAs). 188) were meta-analysed as a form of external replication to study the predictors of PEGV dosing in addition to LA-SSA, the LAS (n=83) was used to study the predictors of PEGV monotherapy dosing. Multivariable regression models were used to identify predictors of the PEGV dose required to normalize IGF-I levels. <0.001, p=<0.001, p=0.028 and p=0.047, respectively). Taken together, these characteristics predicted the PEGV normalization dose correctly in 63.3% of all patients within a range of +/- 60 mg/week (21.3% within a range of +/- 20 mg/week). For monotherapy, only weight was associated with the PEGV normalization dose (p=<0.001) and predicted this dosage correctly in 77.1% of all patients within a range of +/- 60 mg/week (31.3% within a range of +/- 20 mg/week). Conclusion: In this study, we show that IGF-I levels, weight, height and age can contribute to define the optimal PEGV dose in order to normalize IGF-I levels in addition to LA-SSA. For PEGV monotherapy, only the patient's weight was associated with the IGF-I normalization PEGV dosage.