Dose-exposure-IGF-I response of once-weekly somapacitan in adults with GH deficiency

Somapacitan in Children Born SGA: 52-Week Efficacy, Safety, and IGF-I Response Results From the Phase 2 REAL5 Study

CONTEXT

Somapacitan, a once-weekly reversible albumin-binding growth hormone (GH) derivative, is evaluated in short children born small for gestational age (SGA).

OBJECTIVE

Evaluate efficacy, safety, tolerability as well as total and bioactive insulin-like growth factor I (IGF-I) response of once-weekly somapacitan compared to daily GH in children born SGA.

METHODS

REAL5 is a randomized, multicenter, open-label, controlled phase 2 study comprising a 26-week main phase, a 26-week extension, and an ongoing 4-year safety extension (NCT03878446), conducted at 38 sites across 12 countries. A total of 62 GH-treatment-naïve, prepubertal short children born SGA were randomized; 61 completed 52-weeks of treatment. Patients were randomized (1:1:1:1:1) to somapacitan (0.16, 0.20, or 0.24 mg/kg/week) or daily GH (0.035 or 0.067 mg/kg/day), all administered subcutaneously.

RESULTS

Estimated mean height velocity (HV; cm/year) at week 52 was 8.5, 10.4, and 10.7 cm/year for somapacitan 0.16, 0.20, and 0.24 mg/kg/week, respectively, and 9.3 and 11.2 cm/year for daily GH 0.035 and 0.067 mg/kg/day, respectively. Dose-dependent increases in total IGF-I, as well as peak IGF-I bioactivity, were observed for both treatments and were similar between comparator groups. For somapacitan, exposure-response modeling indicated highest efficacy with 0.24 mg/kg/week after 52 weeks of treatment. Similar safety and tolerability were demonstrated across all groups.

CONCLUSION

A sustained dose-dependent growth response was demonstrated for somapacitan after 52 weeks of treatment. Overall, somapacitan 0.24 mg/kg/week provides similar efficacy, safety, and tolerability, as well as comparable bioactive and total IGF-I response, as daily GH (0.067 mg/kg/day) in children born SGA.

Utilizing Somapacitan, a Long-acting Growth Hormone Formulation, for the Treatment of Adult Growth Hormone Deficiency: A Guide for Clinicians

OBJECTIVE

Somapacitan is the first approved and currently the only long-acting growth hormone (GH) formulation in the United States for treatment of adults with growth hormone deficiency (GHD). The aim of this review was to provide a practical approach for clinicians on how to utilize somapacitan in the treatment of adults with GHD.

METHODS

Literature search was performed on PubMed using key words, including adult GHD, long-acting growth hormone, somapacitan, treatment, and management. The discussion of treatment aspects utilizing somapacitan was based on evidence from previous clinical studies and personal experience.

RESULTS

Clinical trial data demonstrated that somapacitan, a once-weekly reversible albumin-binding GH derivative, decreased truncal fat, improved visceral fat and lean body mass, increased insulin-like growth factor-I standard deviation score and exerted neutral effects on glucose metabolism. Overall, somapacitan was well-tolerated, adverse event rates were comparable with daily GH, antisomapacitan or anti-GH antibodies were not detected, and treatment satisfaction was in favor of somapacitan vs daily GH.

CONCLUSION

Somapacitan is an efficacious, safe, convenient and well-tolerated once-weekly long-acting GH formulation that reduces the treatment burden of once-daily GH injections for adults with GHD. This article provides a review of the pharmacology of somapacitan and offers practical recommendations based on previous clinical trial data on how to initiate, dose titration, monitoring and dose adjustments whilst on therapy in adults with GHD. Timing of measurement of serum insulin-like growth factor-I levels, information on administration, recommendations on missed doses, and clinical recommendations on dosing in certain sub-population of patients are also discussed.

Developments in the Management of Growth Hormone Deficiency: Clinical Utility of Somapacitan

Growth hormone (GH) replacement therapy for growth hormone deficiency (GHD) in children and adults has for over 25 years, until recently, been administered as daily injections. This daily treatment regimen often incurs a burden to patients and caregivers, leading to high rates of non-adherence and, consequently, decreased treatment efficacy outcomes. To address this shortcoming, long-acting growth hormones (LAGHs) have been developed with the aim of reducing the burden of daily injections, thereby potentially improving treatment adherence and outcomes. Somapacitan (Sogroya®) (Novo Nordisk, Bagsværd, Denmark) is a LAGH currently approved for the treatment of adult and childhood GHD (AGHD and CGHD, respectively) in several countries. Other LAGHs, such as somatrogon (Ngenla®) (Pfizer, New York, United States) and lonapegsomatropin/TransCon GH (Skytrofa®) (Ascendis Pharma, Copenhagen, Denmark), are also currently approved and available for the treatment of CGHD in several countries. In this review, we will consider the method of protraction, pharmacokinetics (PK) and pharmacodynamics (PD), efficacy, and safety results of somapacitan in adult and pediatric trials and how these characteristics differ from those of the other aforementioned LAGHs. Additionally, the administration of somapacitan and timing of measurement of serum insulin-like growth factor-I (IGF-I) levels are summarized. Information on administration, advice on missed doses, and clinical guidelines are discussed, as well as identifying which patients are suitable for somapacitan therapy, and how to monitor and adjust dosing whilst on therapy.

Comparing treatment with daily and long-acting growth hormone formulations in adults with growth hormone deficiency: Challenging issues, benefits, and risks

Daily administration of growth hormone (GH) treatment has been in clinical use for treatment for GH deficiency (GHD) in adults for more than 30 years. Numerous studies have demonstrated evidence that GH treatment improves body composition, cardiovascular risk factors and quality of life with few side effects. Less frequent GH injections are hypothesized to improve adherence and several long-acting GH (LAGH) formulations have been developed and a few have been approved and marketed. Different pharmacological modifications have been applied and the pharmacokinetics and pharmacodynamics of LAGH are different to each other and to those of daily injections and require different dosing and monitoring specific for each LAGH. Studies have shown improved adherence with LAGH, and short-term efficacy and side effects are comparable between daily GH injections and LAGHs. Long-term treatment with daily GH injections is effective and safe, while long-term studies for LAGHs are awaited. In this review challenges, benefits, and risks of treatment with daily and long-acting GH preparations will be compared.

Weekly Somapacitan in GH Deficiency: 4-Year Efficacy, Safety, and Treatment/Disease Burden Results From REAL 3

CONTEXT

Growth hormone deficiency (GHD) in children is currently treated with daily injections of GH, which can be burdensome for patients and their parents/guardians. Somapacitan is a GH derivative in development for once-weekly treatment of GHD.

OBJECTIVE

This work aimed to assess the efficacy and safety of somapacitan, and associated disease/treatment burden, after 4 years of treatment and 1 year after switching to somapacitan from daily GH.

METHODS

This long-term safety extension of a multicenter, controlled phase 2 trial (NCT02616562) took place at 29 sites in 11 countries. Patients were prepubertal, GH-naive children with GHD. Fifty patients completed 4 years of treatment. Patients in the pooled group received somapacitan (0.04, 0.08, 0.16 mg/kg/week) for 1 year, followed by the highest dose (0.16 mg/kg/week) for 3 years. Patients in the switched group received daily GH 0.034 mg/kg/day for 3 years, then somapacitan 0.16 mg/kg/week for 1 year. Main outcome measures were height velocity (HV), change from baseline in HV SD score (SDS), change from baseline in height SDS, disease burden, and treatment burden for patients and parents/guardians.

RESULTS

Changes from baseline in HV and HV SDS were similar and as expected in both groups. Observer-reported outcomes showed that patients and parents/guardians seem to have experienced a reduced treatment burden when switching from daily GH to somapacitan. Most parents/guardians (81.8%) strongly/very strongly preferred somapacitan over daily GH.

CONCLUSIONS

Somapacitan showed similar efficacy and safety in patients who continued somapacitan treatment and those who switched from daily GH to somapacitan. Once-weekly injections may lead to a reduced treatment burden relative to once-daily injections. A plain-language summary of this work is available.

Somapacitan in children born small for gestational age: a multi-centre, open-label, controlled phase 2 study

OBJECTIVE

Investigate efficacy, safety, and tolerability of 3 once-weekly somapacitan doses compared with daily growth hormone (GH) administration in short children born small for gestational age (SGA).

DESIGN

Randomised, multi-centre, open-label, controlled phase 2 study comprising a 26-week main phase and a 4-year extension (NCT03878446). The study was conducted at 38 sites across 12 countries. 26-week main phase results are presented here.Sixty-two GH treatment-naïve, prepubertal short children born SGA were randomised and exposed; 61 completed the main phase. Three somapacitan doses (0.16 [n = 12], 0.20 [n = 13], 0.24 [n = 12] mg/kg/week) and 2 daily GH doses (0.035 [n = 12], 0.067 [n = 13] mg/kg/day) were administered subcutaneously.

RESULTS

After 26 weeks of treatment, the estimated mean annualised height velocity (HV) was 8.9, 11.0, and 11.3 cm/year for somapacitan 0.16, 0.20, and 0.24 mg/kg/week, respectively, compared to 10.3 and 11.9 cm/year for daily GH 0.035 and 0.067 mg/kg/day. Changes from baseline in HV standard deviation score (SDS), height SDS, and insulin-like growth factor I (IGF-I) SDS showed similar dose-dependent responses. Exposure-response modelling indicated the greatest efficacy correlated with the highest somapacitan exposure. Similar safety and tolerability were demonstrated for all weekly somapacitan and daily GH doses.

CONCLUSIONS

Based on the totality of data on improvements in height-based parameters combined with exposure-response analyses, somapacitan 0.24 mg/kg/week appears most efficacious, providing similar efficacy, safety, and tolerability as daily GH 0.067 mg/kg/day in short children born SGA after 26 weeks of treatment.

Guidance for the treatment of adult growth hormone deficiency with somapacitan, a long-acting growth hormone preparation

Adult growth hormone deficiency (AGHD) is a rare endocrine disorder characterized by an abnormal body composition, metabolic abnormalities associated with increased cardiovascular diseases, bone loss, and impaired quality of life. Daily subcutaneous injections with recombinant growth hormone (GH) can alleviate the abnormalities associated with AGHD. Several long-acting GH (LAGH) preparations are currently in development that aim to reduce treatment burden for patients receiving daily GH injections. Somapacitan (Sogroya^®; Novo Nordisk, Denmark) is the first LAGH preparation that has been approved for treatment of AGHD in the United States, Europe, and Japan. The recent approval of somapacitan and anticipated approval of other LAGH molecules presents new questions for physicians planning to treat AGHD with LAGH in the future. Differences in the technologies used to prolong the half-life of recombinant GH are expected to result in variations in pharmacokinetic and pharmacodynamic profiles between preparations. Therefore, it is essential that physicians understand and consider such variations when treating patients with these novel GH replacement therapies. Here, we present a set of treatment recommendations that have been created to guide physicians initiating therapy with somapacitan in patients with AGHD who are eligible for GH replacement. Furthermore, we will review the published data that underlie these recommendations to explain the rationale for the treatment and monitoring advice provided.