Long-term treatment of somatostatin analog-refractory growth hormone-secreting pituitary tumors with pegvisomant alone or combined with long-acting somatostatin analogs: a retrospective analysis of clinical practice and outcomes
1 Department of Endocrinology, Catholic University, School of Medicine, Largo A. Gemelli 8, 00168, Rome, Italy
2 Endocrinology Section, San Camillo-Forlanini Hospital, Via Portuense, 332A, 00151, Rome, Italy
3 Endocrinology Section, University “La Sapienza”, Viale R. Elena, 324, 00185, Rome, Italy
4 Endocrinology Section, St. Andrea Hospital, University “La Sapienza”, 2nd Faculty, Via di Grottarossa, 1035/1039, 00189, Rome, Italy
5 Endocrinology Unit, Regina Elena Cancer Institute – IFO, Via Elio Chianesi 53, Rome, 00144, Rome, Italy
6 Endocrinology Unit, St. Eugenio and CTO Andrea Alesini Hospital, University of Tor Vergata, Via San Nemesio, 21, 00145, Rome, Italy
Journal of Experimental & Clinical Cancer Research 2013, 32:40 doi:10.1186/1756-9966-32-40Published: 21 June 2013
Pegvisomant (PEGV) is widely used, alone or with somatostatin analogs (SSA), for GH-secreting pituitary tumors poorly controlled by SSAs alone. No information is available on specific indications for or relative efficacies of PEGV?+?SSA versus PEGV monotherapy. Aim of our study was to characterize real-life clinical use of PEGV vs. PEGV?+?SSA for SSA-resistant acromegaly (patient selection, long-term outcomes, adverse event rates, doses required to achieve control).
A retrospective analysis of data collected in 2005–2010 in five hospital-based endocrinology centers in Rome was performed. Sixty-two adult acromegaly patients treated ≥6 months with PEGV (Group 1, n?=?35) or PEGV?+?SSA (Group 2, n?=?27) after unsuccessful maximal-dose SSA monotherapy (≥12 months) were enroled. Groups were compared in terms of clinical/biochemical characteristics at diagnosis and before PEGV or PEGV?+?SSA was started (baseline) and end-of-follow-up outcomes (IGF-I levels, adverse event rates, final PEGV doses).
Group 2 showed higher IGF-I and GH levels and sleep apnea rates, higher rates residual tumor tissue at baseline, more substantial responses to SSA monotherapy and worse outcomes (IGF-I normalization rates, final IGF-I levels). Tumor growth and hepatotoxicity events were rare in both groups. Final daily PEGV doses were similar and significantly increased with treatment duration in both groups.
PEGV and PEGV?+?SSA are safe, effective solutions for managing SSA-refractory acromegaly. PEGV?+?SSA tends to be used for more aggressive disease associated with detectable tumor tissue. With both regimens, ongoing monitoring of responses is important since PEGV doses needed to maintain IGF-I control are likely to increase over time.