A first-in-man phase 1 trial for long-acting TransCon Growth Hormone

PEGylated drug delivery systems in the pharmaceutical field: past, present and future perspective

Target-site drug delivery systems are gaining interest in the pharmaceutical field due to their great advantages, such as higher drug dosing capacity and better bioavailability. However, some existing problems need to be overcome. As an example, interaction between blood proteins and drug delivery systems. A potent candidate to approach the mentioned problem is based on polyethylene glycol (PEG) surface modifications. This polymer acts as a protector towards the external possible interactions with other compounds, making targeted delivery possible. Diseases such as cancer, diabetes, haemophilia and pain treatment can benefit from these new systems.This review aims to give an overview of drug delivery systems based on PEGylation as surface modification as pharmaceutical approach. Moreover, a deeper insight of the properties of PEG and its advantages is given, as well as brief overview of present therapies based on this technology.

Spotlight on Lonapegsomatropin Once-Weekly Injection and Its Potential in the Treatment of Growth Hormone Deficiency in Pediatric Patients

Lonapegsomatropin, a long-acting GH therapy (LAGH), was approved by the United States Food and Drug Administration in August 2021 for the treatment of pediatric growth hormone deficiency (GHD). Lonapegsomatropin is a prodrug consisting of unmodified GH transiently conjugated to methoxypolyethylene glycol which enables time-release of GH with a half-life of ~25 hours allowing for once-weekly administration. Clinical trials of lonapegsomatropin have demonstrated positive efficacy results in children (phase 2 and 3) and adults (phase 2) with GHD. The phase 3 trial in children with GHD established non-inferiority and statistical superiority of height velocity with lonapegsomatropin (11.2 cm/yr) compared to daily GH (10.3 cm/yr), with no concerning side effects with lonapegsomatropin. Similar growth responses have been reported in other LAGH products in phase 2 (somapacitan) and phase 3 (somatrogon) trials. Lonapegsomatropin is distributed in temperature-stable, prefilled cartridges at 9 different doses that can be prescribed based upon specific weight brackets designed to deliver approximately 0.24 mg/kg/wk. An electronic delivery device is required to combine the powdered medication with the diluent and deliver the medication subcutaneously through a small gauge needle to the recipient. The pharmacodynamic data from the clinical trials of lonapegsomatropin has been used to develop models to estimate an average IGF-1 value drawn at any time during the weekly injection interval. This average IGF-1 value may be used to for safety monitoring and/or to guide dose adjustment. New LAGH products, including lonapegsomatropin, may potentially improve patient adherence, quality of life and clinical outcomes, particularly in patients with poor adherence to daily GH injections in the future. With the availability of new LAGH products, clinicians will need to identify the best candidates for LAGH therapy and understand how to monitor and adjust therapy. Long-term surveillance studies are needed to demonstrate adherence, efficacy, cost-effectiveness and safety of LAGH preparations.

Long-acting recombinant human growth hormone in the treatment of pediatric growth hormone deficiency, how far have we got?

The widespread availability of recombinant human growth hormone (GH) since 1985 has made it possible to extend growth hormone therapy indications for children with different etiologies of short stature. It is now accepted that GH is effective in increasing height velocity in children with GH deficiency (GHD) and well tolerated in both the short and long terms. Nevertheless, one major factor in the inter-individual variability of the growth response to GH in GHD children is adherence to daily injections. In an attempt to improve patient adherence, there has been a strong effort from industry to create a long-acting form of growth hormone to ease the burden of its use. It is theorized that by decreasing injection frequency, Long-Acting GH (LAGH) would improve adherence and therefore outcomes. These agents can be divided broadly into depot formulations, PEGylated formulations, prodrug formulations, noncovalent albumin-binding GH and GH fusion proteins. In 2021, two LAGH formulations are on the market in China and South Korea, and several promising agents are under clinical investigation at various stages of development throughout the world. A number of safety issues related to LAGH have been identified and need to be further investigated. © 2022 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.

TransCon human growth hormone for children with growth hormone deficiency: a technology evaluation

INTRODUCTION

Standard-of-care treatment for growth hormone deficiency consists of daily subcutaneous injections of recombinant human growth hormone, also known as somatropin. Although somatropin treatment is well established, the burden of daily injections can lead to poor adherence and quality of life. In this regard, a TransCon human growth hormone (lonapegsomatropin-tcgd) technology was developed to optimize the therapeutic effect of daily somatropin for the treatment of children with growth hormone deficiency.

AREAS COVERED

The authors reviewed the effects of lonapegsomatropin-tcgd in children with growth hormone deficiency.

EXPERT OPINION

Lonapegsomatropin-tcgd was found to be non-inferior to and superior to daily somatropin for annualized height velocity. In addition, the safety was comparable between them. As a result, the convenient dosing of lonapegsomatropin-tcgd has the potential to improve patient adherence, leading to increased efficacy and quality of life. Medication adherence, quality of life, long-term safety, and cost-effectiveness studies comparing lonapegsomatropin-tcgd and daily somatropin are required to confirm these possible benefits.

Lonapegsomatropin: Pediatric First Approval

Lonapegsomatropin (lonapegsomatropin-tcgd; SKYTROFA^®), a long-acting prodrug of somatropin (human growth hormone), is in development by Ascendis Pharma as a treatment for growth hormone deficiency in pediatric and adult patients. Lonapegsomatropin received its first approval in August 2021 in the USA for the treatment of pediatric patients at least 1 year of age (and weighing ≥ 11.5 kg) with growth failure due to inadequate secretion of endogenous growth hormone. Lonapegsomatropin is administered as a once-weekly subcutaneous injection; the sustained release of somatropin from lonapegsomatropin eliminates the need for daily somatropin injections. This article summarizes the milestones in the development of lonapegsomatropin leading to this first pediatric approval for the treatment of growth hormone deficiency.

Usefulness and Potential Pitfalls of Long-Acting Growth Hormone Analogs

Daily recombinant human GH (rhGH) is currently approved for use in children and adults with GH deficiency (GHD) in many countries with relatively few side-effects. Nevertheless, daily injections can be painful and distressing for some patients, often resulting in non-adherence and reduction of treatment outcomes. This has prompted the development of numerous long-acting GH (LAGH) analogs that allow for decreased injection frequency, ranging from weekly, bi-weekly to monthly. These LAGH analogs are attractive as they may theoretically offer increased patient acceptance, tolerability, and therapeutic flexibility. Conversely, there may also be pitfalls to these LAGH analogs, including an unphysiological GH profile and differing molecular structures that pose potential clinical issues in terms of dose initiation, therapeutic monitoring, incidence and duration of side-effects, and long-term safety. Furthermore, fluctuations of peak and trough serum GH and IGF-I levels and variations in therapeutic efficacy may depend on the technology used to prolong GH action. Previous studies of some LAGH analogs have demonstrated non-inferiority compared to daily rhGH in terms of increased growth velocity and improved body composition in children and adults with GHD, respectively, with no significant unanticipated adverse events. Currently, two LAGH analogs are marketed in Asia, one recently approved in the United States, another previously approved but not marketed in Europe, and several others proceeding through various stages of clinical development. Nevertheless, several practical questions still remain, including possible differences in dose initiation between naïve and switch-over patients, methodology of dose adjustment/s, timing of measuring serum IGF-I levels, safety, durability of efficacy and cost-effectiveness. Long-term surveillance of safety and efficacy of LAGH analogs are needed to answer these important questions.

Adult growth hormone deficiency: clinical advances and approaches to improve adherence

Introduction: There have been significant clinical advances in the understanding of the diagnosis and benefits of long-term recombinant human growth hormone (rhGH) replacement in adults with GH deficiency (GHD) since its approval in 1996 by the United States Food and Drug Administration.Areas covered: We searched PubMed, Medline, CINAHL, EMBASE and PsychInfo databases between January 2000 and June 2019 for published studies evaluating adults with GHD. We reviewed the data of the oral macimorelin test compared to the GHRH plus arginine and the insulin tolerance tests that led to its approval by the United States FDA and European Medicines Agency for adult diagnostic testing. We summarize the clinical advances of long-term benefits of rhGH therapy and the potential effects of GH receptor polymorphisms on individual treatment responsiveness. We identify that non-adherence and discontinuation rates are high and recommend strategies to support patients to improve adherence. We also provide an overview of several long-acting GH (LAGH) preparations currently under development and their potential role in improving treatment adherence.Expert opinion: This article summarizes recent clinical advances in rhGH replacement therapy, the biological and molecular aspects that may influence rhGH action, and offers practical strategies to enhance adherence in adults with GHD.

Perspectives on long-acting growth hormone therapy in children and adults

Growth hormone therapy with daily injections of recombinant human growth hormone has been available since 1985, and is shown to be safe and effective treatment for short stature in children and for adult growth hormone deficiency. In an effort to produce a product that would improve patient adherence, there has been a strong effort from industry to create a long acting form of growth hormone to ease the burden of use. Technologies used to increase half-life include depot formulations, PEGylated formulations, pro-drug formulations, non-covalent albumin binding growth hormone and growth hormone fusion proteins. At present, two long acting formulations are on the market in China and South Korea, and several more promising agents are under clinical investigation at various stages of development throughout the world. Arch Endocrinol Metab. 2019;63(6):601-7.

Long-Acting Growth Hormone Preparations in the Treatment of Children

Human growth hormone (hGH), which had been in use since 1958, was supplanted by recombinant human growth hormone (rhGH) in 1985 for those with growth hormone deficiency (GHD). Adherence to daily subcutaneous growth hormone is challenging for patients. Thus, several companies have pursued the creation of long acting rhGH. These agents can be divided broadly into depot formulations, PEGylated formulations, pro-drug formulations, non-covalent albumin binding GH and GH fusion proteins. Nutropin Depot is the only long acting rhGH ever approved by the U.S. Food and Drug Administration, and it was removed from the market in 2004. Of the approximately seventeen candidate drugs, only a handful remain under active clinical investigation or are commercially available.

Polymer-drug conjugate therapeutics: advances, insights and prospects

Polymer-drug conjugates have long been a mainstay of the drug delivery field, with several conjugates successfully translated into clinical practice. The conjugation of therapeutic agents to polymeric carriers, such as polyethylene glycol, offers several advantages, including improved drug solubilization, prolonged circulation, reduced immunogenicity, controlled release and enhanced safety. In this Review, we discuss the rational design, physicochemical characteristics and recent advances in the development of different classes of polymer-drug conjugates, including polymer-protein and polymer-small-molecule drug conjugates, dendrimers, polymer nanoparticles and multifunctional systems. Current obstacles hampering the clinical translation of polymer-drug conjugate therapeutics and future prospects are also presented.

The current state of long-acting growth hormone preparations for growth hormone therapy

PURPOSE OF REVIEW

To discuss the rationale of developing long-acting growth hormone (LAGH) preparations, to describe the technologies designed to prolong GH action, and to address key issues regarding efficacy, safety, and monitoring while on treatment.

REVIEW FINDINGS

Recombinant human GH is currently approved for daily use and has been shown to restore longitudinal growth, and improve body composition with relatively few side-effects in children and adults with GH deficiency, respectively. However, daily injections can be inconvenient, painful and distressing for some patients, resulting in decreased adherence and efficacy. Over a dozen pharmaceutical companies have designed LAGH preparations that are at various stages of development using a number of different methods to prolong GH action.

SUMMARY

LAGH will represent an advancement over daily recombinant human GH injections because of fewer injections that may offer increased acceptance, tolerability, and therapeutic flexibility to patients that potentially can improve treatment outcomes. However, given the unphysiological profile of LAGH preparations, long-term surveillance of efficacy and safety are needed. This review summarizes recent developments of LAGH preparations, and highlights the importance of long-term surveillance registries to assess for efficacy and safety that will be essential for understanding the impact of prolonged exposure to these compounds.