Pegvisomant Research & Studies

Acromegaly is a rare endocrine disorder caused by excessive growth hormone secretion, leading to elevated insulin-like growth factor I (IGF-I) levels and complications. While surgery is the first-line treatment, many patients require additional therapies. Pegvisomant, a GH receptor antagonist, has emerged as an effective option, particularly for patients unresponsive to somatostatin receptor ligands. This review synthesizes studies evaluating pegvisomant’s role in managing acromegaly, focusing on its impact on comorbidities and quality-of-life (QoL). Outcomes include IGF-I normalization, cardiovascular and metabolic health, skeletal integrity, and QoL. Pegvisomant consistently shows high efficacy in IGF-I normalization, with rates of 60%–80% in real-world settings and up to 89% in clinical trials. Cardiovascular benefits include reductions in left ventricular mass, blood pressure, and improved vascular function. Metabolic improvements involve better glucose metabolism, especially in diabetic patients, as pegvisomant improves insulin sensitivity by directly blocking GH action, without suppressing insulin secretion. Skeletal outcomes include reduced vertebral fracture risk, while respiratory benefits involve reduced tongue volume and improved obstructive sleep apnea. QoL improves across multiple domains, even in patients with partial biochemical control. Limitations of pegvisomant therapy include the need for higher doses to normalize IGF-I in diabetic patients. Persistent fracture risks linked to disease activity and untreated hypogonadism remain, and slight increases in BMI and LDL cholesterol have been observed. This review underscores pegvisomant’s efficacy in IGF-I normalization and comorbidity management. However, limited studies highlight the need for further research on long-term effects, safety, and combination therapy. Individualized treatment remains key to optimizing outcomes.

Pegvisomant is a growth-hormone (GH) receptor antagonist that prevents the formation of the active heterotrimer of the dimerised GH receptor and the GH molecule necessary for downstream signal transduction. Over the past 20 years, it has become a key therapeutic option for physicians treating syndromes of GH/IGF-1 excess. Sufficient longitudinal follow-up data suggest that it can be deemed both safe and effective. It is the drug with the greatest potential for achieving an amelioration of the biochemical effects of GH excess with a corresponding normalisation of IGF-1 levels; however, insufficient dose titration has lessened real-world therapeutic outcomes. Theoretical concerns about stimulating tumour growth have been resolved as this has not been observed, while derangement of liver enzymes and local skin-related adverse reactions may occur in a minority of the patients. It may be a particularly impactful medication for the treatment of children, young people, and those with inherited disorders of GH excess, where other treatment modalities often fail. Combination therapy of pegvisomant with first- and second-generation somatostatin receptor ligands or with dopamine agonists remains an ongoing area of interest and research. High cost remains a barrier to the use of pegvisomant in many settings.

Pegvisomant, the first and currently only clinically available growth hormone receptor antagonist, is an effective therapeutic option for the medical treatment of acromegaly, a rare disorder characterized by excessive growth hormone secretion. With now over 20 years of real world experience, its safety and efficacy is well-established. However, several aspects of its clinical use are still controversially discussed. The high cost of pegvisomant has limited its use in several countries, and recent studies have reported a lower efficacy than the initial clinical trials. A reported increase in tumor volume under therapy varies between studies and has been attributed to either actual growth or re-expansion after cessation of somatostatin receptor ligand therapy. Furthermore, different combinations of pegvisomant and other therapeutic agents aiming at reduction of acromegaly disease activity have been proposed to increase or retain effectiveness while lowering side effects and cost. This review aims to assess current clinical data on the safety and efficacy of pegvisomant while also addressing controversies surrounding its use.

Despite improvements in surgical techniques, current radiotherapy options and development of long-acting somatostatin analogues, biochemical control of acromegaly is not achieved in some patients. The failure to achieve optimal serum growth hormone (RH) and insulin-like growth factor-1 (IGF-1) levels means increased morbidity and mortality of acromegaly patients. The RH receptor antagonist pegvisomant (PEG) is a genetically engineered RH analog that prevents of RH receptor dimerization, i.e. a process that is crucial for the action of RH at the cellular level. The effect of the treatment is suppression of IGF-1 production. In pilot studies, normalization of IGF-1 levels was achieved in up to 90 % of patients receiving PEG. However, PEG efficacy in clinical settings is slightly lower (65 to 97 %) than reported in the key studies. A rare side effect of treatment is elevations of liver transaminases. In addition, pituitary tumor growth progression has been reported in several cases. In this review article, we present long-term data on pegvisomant treatment and discuss its associated risks and benefits.

To review published data on pegvisomant and its therapeutic role in acromegaly.

In 2007, we published an opinion document to review the role of pegvisomant (PEG) in the treatment of acromegaly. Since then, new evidence emerged on the biochemical and clinical effects of PEG and on its long-term efficacy and safety.

Historically, medical treatment of acromegaly has mainly been used as an adjuvant therapy after surgery. In the last decades, an increased range of medical therapy options has been available. Somatostatin analogues have become the cornerstones of medical treatment in acromegaly and are even seen as a primary treatment in a selected group of acromegaly patients. The most recent medical treatment available for acromegaly patients is pegvisomant, a growth hormone receptor antagonist. To date, it is the most effective medical treatment, but it is costly. Pegvisomant is used as monotherapy and combined with somatostatin analogues. In this article, we review clinical studies and cohorts that have documented the efficacy of pegvisomant monotherapy and combined therapy and give a concise overview of associated side effects.

Clinical and biochemical remission in acromegaly can frequently be achieved with the recombinant GH receptor antagonist pegvisomant, even when other treatments fail. However, increases in tumor volume have been reported.

Pfizer (formerly Pharmacia), in collaboration with its wholly owned subsidiary Sensus, has developed and launched pegvisomant, a pegylated, genetically modified human growth hormone (hGH), for the treatment of acromegaly. Pegvisomant, in contrast to classical somatostatin analogs which lower hGH synthesis, exerts its anti-hGH action by preventing GH receptor activation. This drug is now available in the US and Europe for the treatment of acromegaly.

Pegvisomant, a polyethylene glycol (PEG) derivative of human growth hormone (GH) that acts as a highly selective GH receptor antagonist, is under development by Pharmacia (formerly Sensus) as a potential treatment for acromegaly. By February 2001, Sensus had submitted an NDA for the treatment of acromegaly, and an approvable letter indicating outstanding issues had been received by July 2001. Pegvisomant was granted Orphan Drug status by the FDA and was designated for Priority Review. Pegvisomant also received Orphan Drug designation in the EU and Japan. In March 2001, additional regulatory filings were being planned for later in 2001. In October 2001, Pharmacia was preparing an NDA in Japan for the treatment of acromegaly. By September 1998, phase 1 trials of the treatment were underway for diabetic retinopathy, and were planned for diabetic nephropathy in 1999. By September 1997, a phase II trial to test the effects of pegvisonant an insulin sensitivity and secretion in type II diabetes patients was underway. However, no development has been reported for these indications since the dates given. By 1994, Sensus had licensed technology for development of GH receptor antagonists from Genentech and Ohio University. Sensus was to pay Genentech, and Genentech was to receive equity in Sensus and royalties from the commercialization of any product resulting from the agreement. In April 2000, the company entered into a licensing agreement with Shearwater Polymers for the PEGylation of pegvisomant using Shearwater's proprietary technology, which is now used to produce the 20-kDa PEG-derivative of pegvisomant. In June 1999, Pharmacia Corp (formerly Pharmacia & Upjohn) signed an agreement to purchase 19.9% of Sensus and to potentially acquire the remainder of the company at a later date. In March 2001, Pharmacia completed its purchase of Sensus. Analysts at Merrill Lynch predicted in February 2002 that the product would be launched in 2003, with US revenues of $20 million, rising to $115 million in 2006.

Pegvisomant is the pegylated form of mutant growth hormone (B2036). B2036 has increased affinity in one binding site and lowered affinity in its second binding site, it has been shown that this molecule still enables dimerisation of the growth hormone receptor at the cell surface but does not allow the necessary conformational changes for signalling. Pegylation decreases the antagonistic activity of B2036, however the rate of clearance of the pegylated B2036 is greatly reduced compared to the unpegylated form. Even though the antagonistic activity of pegvisomant is lower than B2036, the reduced rate of clearance makes it an effective clinical drug for the treatment of conditions such as acromegaly.