ACROSTUDY: the first 5 years.

ACROSTUDY is an observational registry intended to collect safety and efficacy data on pegvisomant therapy. A total of 792 patients have been enrolled, of whom 83% had commenced pegvisomant prior to recruitment. The mean follow-up is 1.66 years with the mean duration of pegvisomant therapy 3.31 years representing 2625 patient years of treatment. About 90% of patients were on once daily pegvisomant, and 67% were on monotherapy. Disappointingly, IGF1 was normalised in <70% of patients; furthermore, in 80% of patients with an elevated IGF1, the daily dose of pegvisomant was 20 mg or less. A total of 56 serious adverse events (AEs) were reported, of which 13 were related to pegvisomant. A total of 276 AEs were reported, of which 56 were considered related to pegvisomant. The AEs most frequently attributed to pegvisomant were disturbed liver function tests and injection site reactions. Magnetic resonance imaging (MRI) was available in 684 patients. A total of 411 patients had at least one MRI on pegvisomant compared with a baseline. In 31 patients, a decrease in tumour size has been reported, of whom 20 had previously received radiotherapy. An increase in tumour size has been reported and confirmed in 22 patients. In 11 patients, there was contradictory data on tumour size, while, in six patients, central review of the films failed to confirm increase in tumour size. In conclusion, the safety data are generally reassuring, while the IGF1 normalisation rate is disappointing, which probably reflects a failure of dose titration. Further effort is needed to understand the reasons for the failure of dose titration.