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.

Effective GH Replacement With Once-weekly Somapacitan vs Daily GH in Children with GHD: 3-year Results From REAL 3.

CONTEXT: Current GH therapy requires daily injections, which can be burdensome. Somapacitan is a long-acting GH derivative in development for treatment of GH deficiency (GHD). OBJECTIVE: Evaluate the efficacy, safety, and tolerability of once-weekly somapacitan after 3 years of treatment. DESIGN: A multicenter, randomized, controlled, phase 2 study comparing somapacitan and once-daily GH for 156 weeks (NCT02616562). SETTING: Twenty-nine sites in 11 countries. PATIENTS: Fifty-nine children with GHD randomized (1:1:1:1) and exposed to treatment. Fifty-three children completed the 3-year period. INTERVENTIONS: Patients received somapacitan (0.04 [n = 14], 0.08 [n = 15], or 0.16 [n = 14] mg/kg/wk) or daily GH (n = 14) (0.034 mg/kg/d, equivalent to 0.238 mg/kg/wk) subcutaneously during the first year, after which all patients on somapacitan received 0.16 mg/kg/wk. MAIN OUTCOME MEASURES: Height velocity (HV) at year 3; changes from baseline in height SD score (HSDS), HVSDS, and IGF-I SDS. RESULTS: The estimated treatment difference (95% CI) in HV for somapacitan 0.16/0.16 mg/kg/wk vs daily GH at year 3 was 0.8 cm/y (-0.4 to 2.1). Change in HVSDS from baseline to year 3 was comparable between somapacitan 0.16/0.16 mg/kg/wk, the pooled somapacitan groups, and daily GH. A gradual increase in HSDS from baseline was observed for all groups. At year 3, mean HSDS was similar for the pooled somapacitan groups and daily GH. Change from baseline to year 3 in mean IGF-I SDS was similar across treatments. CONCLUSIONS: Once-weekly somapacitan in children with GHD showed sustained efficacy over 3 years in all assessed height-based outcomes with similar safety and tolerability to daily GH. A plain language summary (1) is available for this study. CLINICAL TRIAL INFORMATION: This study has been registered at ClinicalTrials.gov, number NCT02616562 (REAL 3).

Population Pharmacokinetics and Pharmacodynamics of Once-Daily Growth Hormone Norditropin® in Children and Adults.

BACKGROUND AND OBJECTIVE: Once-daily injectable recombinant human growth hormone (GH) formulations (e.g. Norditropin®; Novo Nordisk A/S) are used to treat GH deficiency in children and adults, with much of the therapeutic effect mediated via the insulin-like growth factor-I (IGF-I) response. Despite a long history of use, there are few data on the pharmacokinetics and pharmacodynamics (serum IGF-I response) of this therapy, or of potential differences in the relationship of GH pharmacokinetic/pharmacodynamic (PK/PD) effects between children and adults. This study aimed to characterise the GH pharmacokinetics and IGF-I profile following daily subcutaneous GH in adults and children with GH deficiency. METHODS: A model was developed based on a population PK/PD modelling meta-analysis of data from three phase I clinical trials (two using Norditropin® as a comparator with somapacitan, and one as a comparator with a pegylated GH product). Sequential model building was performed, first developing a model that could describe GH pharmacokinetics. A PD model of IGF-I data was then developed using PK and PD data, and where all PK parameters were kept fixed to those estimated in the PK model. RESULTS: The model developed accurately describes and predicts GH pharmacokinetics and IGF-I response. Body weight was shown to have an important inversely correlated influence on GH exposure (and IGF-I standard deviation score), and this largely explained differences between adults and children. CONCLUSIONS: The pharmacokinetics/pharmacodynamics developed here can inform expectations about the PD effects of different doses of GH in patients with GH deficiency of different body weights, regardless of their age. CLINICAL TRIAL REGISTRATION: Pooled modelling analysis of data from ClinicalTrials.gov identifiers NCT01973244, NCT00936403 and NCT01706783. DATES OF REGISTRATION: NCT01973244: 22 October, 2013; NCT00936403: 9 July, 2009; NCT01706783: 11 October, 2012.

Effect of Kidney or Hepatic Impairment on the Pharmacokinetics and Pharmacodynamics of Somapacitan: Two Open-Label, Parallel-Group Trials.

INTRODUCTION: Somapacitan is a long-acting growth hormone (GH) derivative being developed for once-weekly dosing in patients with GH deficiency (GHD). Our objective was to evaluate the impact of kidney or hepatic impairment on somapacitan exposure in adults. METHODS: In two open-label, parallel-group, single-center, 6-week trials, eligible subjects (18-75 years of age, body mass index 18.5-34.9 kg/m2, GH-naïve, without GHD) were divided into five kidney (total n = 44) or three hepatic (n = 34) function groups. Subjects with normal kidney/hepatic function were matched to those with kidney/hepatic impairment by age, sex, and body weight. Subjects received three subcutaneous somapacitan administrations (0.08 mg/kg) on days 1, 8, and 15. Blood samples were collected before each dose, at 28 time points throughout 2 weeks after the last dose, and at follow-up (3-4 weeks after the last dose). The primary endpoint was area under the somapacitan serum concentration-time curve up to 1 week after the last dose (AUC0-168 h), while secondary endpoints included AUC0-168 h of insulin-like growth factor (IGF)-I. RESULTS: In the kidney impairment trial, somapacitan AUC0-168 h was higher in groups with severe kidney impairment and requiring hemodialysis versus the normal kidney function group (estimated ratio and 90% confidence interval 1.75 [1.00-3.06] and 1.63 [1.01-2.61], respectively). AUC0-168 h of IGF-I was increased in the moderate impairment group (1.35 [1.09-1.66]), severe impairment group (1.40 [1.10-1.78]), and requiring hemodialysis group (1.24 [1.01-1.52]), compared with the normal function group. In the hepatic impairment trial, somapacitan AUC0-168 h was significantly higher in the moderate impairment group compared with the normal hepatic function group (4.69 [2.92-7.52]). IGF-I AUC0-168 h was lower in both hepatic impairment groups (0.85 [0.67-1.08] for the mild impairment group and 0.75 [0.60-0.95] for the moderate impairment group) compared with the normal function group. No new safety or tolerability issues were observed. CONCLUSIONS: In summary, somapacitan exposure increased with level of kidney/hepatic impairment. Clinically, this will be taken into account when treating adults with GHD with somapacitan, as doses should be individually titrated. CLINICAL TRIAL REGISTRATION: NCT03186495 (kidney impairment trial, registered 12 June 2017); NCT03212131 (hepatic impairment trial, registered 30 June 2017).

Somapacitan is a long-acting growth hormone molecule for patients with growth hormone deficiency. After its administration as a subcutaneous injection, the action of somapacitan can be affected by kidney or liver disease. Thus, we conducted two trials in which the pharmacokinetic and pharmacodynamic properties of somapacitan were compared between adult subjects with different degrees of worsened kidney or liver function and their healthy counterparts. We found that subjects with severely impaired kidney function and those requiring hemodialysis had a higher somapacitan exposure in blood serum compared with subjects with normal kidney function. The concentration of insulin-like growth factor (IGF)-I, an effector molecule of growth hormone, was also increased with decreased kidney function. In subjects with moderate hepatic function impairment, somapacitan exposure was also higher than those with normal hepatic function; however, the IGF-I concentrations were lower, both at baseline and after dosing with somapacitan. Our results indicate that patients with growth hormone deficiency and kidney or liver disease may need different doses of somapacitan than people with healthy kidneys and/or liver. However, this will be taken into account because somapacitan doses will be individually titrated for each patient with growth hormone deficiency.

Psychometric Validation of the Growth Hormone Deficiency-Child Impact Measure (GHD-CIM).

OBJECTIVE: The aim of this study was to perform psychometric testing of the Growth Hormone Deficiency-Child Impact Measure (GHD-CIM): a patient-reported outcome (PRO) for children with GHD aged 9 to < 13 years and an observer-reported outcome (ObsRO) for parents/guardians of children who are unable to answer for themselves. METHODS: A non-interventional, multicenter, clinic-based study was conducted in 30 private-practice and large institutional sites in the US and the UK. Psychometric analyses were conducted following an a priori validation statistical analysis plan. RESULTS: A preliminary examination of the data determined a PRO version for children aged 9 to < 13 years was not psychometrically sound and therefore the decision was made to have only an ObsRO measure of the GHD-CIM, which would be suitable for children aged 4 to < 13 years. The GHD-CIM ObsRO validity analyses included 98 parents/guardians. Factor analyses identified three domains: Physical Functioning (PHYS), Social Well-Being (SWB), and Emotional Well-Being (EWB). Internal consistency reliability was acceptable for all domains and for the overall score (Cronbach's alpha > 0.70), as was test-retest reliability for the SWB, EWB and overall (above 0.70). At least one convergent validity hypotheses for each domain and overall was proven (r > 0.40). Known-groups validity hypotheses for the EWB and SWB domains were significant (p < 0.05). Associated effect sizes ranged from - 0.40 to - 0.58, indicating that the GHD-CIM is sensitive to change. Anchor-based patient and clinician ratings of severity of disease suggest a preliminary minimally important difference of 5 points for the overall score, and 5 for PHYS, 7 for EWB, and 5 for SWB. CONCLUSIONS: The GHD-CIM ObsRO was found to be a reliable and valid measure to assess disease-specific functioning, which will provide a more complete patient-centric picture to the growth hormone therapy experience in children. TRIAL REGISTRATION: ClinicalTrials.gov NCT02580032, first posted 20 October 2015.

Optimal Monitoring of Weekly IGF-I Levels During Growth Hormone Therapy With Once-Weekly Somapacitan.

CONTEXT: Somapacitan is a long-acting growth hormone (GH) in development for once-weekly treatment of GH deficiency (GHD). Optimal monitoring of insulin-like growth factor-I (IGF-I) levels must account for weekly IGF-I fluctuations following somapacitan administration. OBJECTIVE: To develop and assess the reliability of linear models for predicting mean and peak IGF-I levels from samples taken on different days after dosing. DESIGN: A pharmacokinetic/pharmacodynamic model was used to simulate IGF-I data in adults and children following weekly somapacitan treatment of GHD. SETTING AND PATIENTS: 39 200 IGF-I profiles were simulated with reference to data from 26 adults and 23 children with GHD. INTERVENTION(S): The simulated dose range was 0.02 to 0.12 mg/kg for adults and 0.02 to 0.16 mg/kg for children. Simulated data with >4 average standard deviation score were excluded. MAIN OUTCOME MEASURE(S): Linear models for predicting mean and peak IGF-I levels based on IGF-I samples from different days after somapacitan dose. RESULTS: Robust linear relationships were found between IGF-I sampled on any day after somapacitan dose and the weekly mean (R2 > 0.94) and peak (R2 > 0.84). Prediction uncertainties were generally low when predicting mean from samples taken on any day (residual standard deviation [RSD] ≤ 0.36) and peak from samples taken on day 1 to 4 (RSD ≤ 0.34). IGF-I monitoring on day 4 and day 2 after dose provided the most accurate estimate of IGF-I mean (RSD < 0.2) and peak (RSD < 0.1), respectively. CONCLUSIONS: Linear models provided a simple and reliable tool to aid optimal monitoring of IGF-I by predicting mean and peak IGF-I levels based on an IGF-I sample following dosing of somapacitan. A short visual summary of our work is available (1).

Similar safety and efficacy in previously treated adults with growth hormone deficiency randomized to once-weekly somapacitan or daily growth hormone.

OBJECTIVE: Somapacitan is a long-acting, reversible albumin-binding growth hormone (GH) derivative in development. This study aimed to evaluate the safety and efficacy of once-weekly somapacitan versus daily GH over 52 weeks in Japanese patients with adult growth hormone deficiency (AGHD). DESIGN: Phase 3, multicentre, randomized, parallel-group, open-label, active-controlled trial (NCT03075644). PATIENTS: Previously GH-treated Japanese patients with AGHD were randomized 3:1 to somapacitan (n = 46) or daily GH (n = 16) for 20 weeks' dose titration and 32 weeks' fixed-dose treatment. MEASUREMENTS: Primary endpoint was the incidence of adverse events (AEs). Secondary endpoints included change from baseline to week 52 in visceral, subcutaneous and total adipose tissue (VAT, SAT and TAT). RESULTS: Mean (SD) prescribed doses after titration were 1.780 (1.058) mg/week for somapacitan and 0.197 (0.083) mg/day for daily GH. Rate of AEs per 100 patient-years was similar between arms (somapacitan, 312.7; daily GH, 309.8). Four AEs in the somapacitan arm were serious; none were considered treatment-related. Mean insulin-like growth factor-I standard deviation score (IGF-I SDS) was maintained from baseline in both arms. No significant differences were observed between arms for change from baseline to week 52 in VAT, SAT or TAT (estimated difference, somapacitan - daily GH [95% CI]: -1.74 [-18.13; 14.66], -11.53 [-35.54; 12.48] and - 12.85 [-47.31; 21.62] cm2 , respectively). CONCLUSIONS: Treatment in both groups was well tolerated, with no unexpected safety findings. Impact on adipose tissue was similar to somapacitan and daily GH in patients with AGHD. A short visual summary of our work is available at https://bit.ly/3946YNF.

Once-weekly Somapacitan is Effective and Well Tolerated in Adults with GH Deficiency: A Randomized Phase 3 Trial.

CONTEXT: Growth hormone (GH) replacement requires daily GH injections, which is burdensome for some adult patients with GH deficiency (AGHD). OBJECTIVE: To demonstrate efficacy and safety of somapacitan, a once-weekly reversible albumin-binding GH derivative, versus placebo in AGHD. DESIGN: Randomized, parallel-group, placebo-controlled (double-blind) and active-controlled (open-label) phase 3 trial, REAL 1 (NCT02229851). SETTING: Clinics in 17 countries. PATIENTS: Treatment-naïve patients with AGHD (n = 301 main study period, 272 extension period); 257 patients completed the trial. INTERVENTIONS: Patients were randomized 2:2:1 to once-weekly somapacitan, daily GH, or once-weekly placebo for 34 weeks (main period). During the 52-week extension period, patients continued treatment with somapacitan or daily GH. MAIN OUTCOME MEASURES: Body composition measured using dual-energy x-ray absorptiometry (DXA). The primary endpoint was change in truncal fat percentage to week 34. Insulin-like growth factor 1 (IGF-I) standard deviation score (SDS) values were used to dose titrate. RESULTS: At 34 weeks, somapacitan significantly reduced truncal fat percentage (estimated difference: -1.53% [-2.68; -0.38]; P = 0.0090), demonstrating superiority compared with placebo, and it improved other body composition parameters (including visceral fat and lean body mass) and IGF-I SDS. At 86 weeks, improvements were maintained with both somapacitan and daily GH. Somapacitan was well tolerated, with similar adverse events (including injection-site reactions) compared with daily GH. CONCLUSIONS: In AGHD patients, somapacitan administered once weekly demonstrated superiority over placebo, and the overall treatment effects and safety of somapacitan were in accordance with known effects and safety of GH replacement for up to 86 weeks of treatment. Somapacitan may provide an effective alternative to daily GH in AGHD. A short visual summary of our work is available (1).

Once-Weekly Somapacitan vs Daily GH in Children With GH Deficiency: Results From a Randomized Phase 2 Trial.

CONTEXT: Daily growth hormone (GH) injections can be burdensome for patients and carers. Somapacitan is a long-acting, reversible albumin-binding GH derivative in development for once-weekly administration in patients with growth hormone deficiency (GHD). OBJECTIVE: The objective of this study is to evaluate the efficacy, safety, and tolerability of once-weekly somapacitan vs once-daily GH. DESIGN: REAL 3 is a multicenter, randomized, controlled, double-blind (somapacitan doses), phase 2 study with a 26-week main and 26-week extension phase (NCT02616562). SETTING: This study took place at 29 sites in 11 countries. PATIENTS: Fifty-nine GH treatment-naive prepubertal children with GHD were randomly assigned; 58 completed the trial. INTERVENTIONS: Interventions comprised 3 somapacitan doses (0.04 [n = 16], 0.08 [n = 15], or 0.16 mg/kg/wk [n = 14]) and daily GH (0.034 mg/kg/d [n = 14]), administered subcutaneously. MAIN OUTCOME MEASURES: The primary end point was height velocity (HV) at week 26. Secondary efficacy end points included HV SD score (SDS) and insulin-like growth factor-I (IGF-I) SDS. RESULTS: At week 26, mean (SD) annualized HV for the somapacitan groups was 8.0 (2.0), 10.9 (1.9), and 12.9 (3.5) cm/year, respectively, vs 11.4 (3.3) cm/year for daily GH; estimated treatment difference (somapacitan 0.16 mg/kg/week-daily GH): 1.7 [95% CI -0.2 to 3.6] cm/year. HV was sustained at week 52, and significantly greater with somapacitan 0.16 mg/kg/week vs daily GH. Mean (SD) change from baseline in HV SDS at week 52 was 4.72 (2.79), 6.14 (3.36), and 8.60 (3.15) for the somapacitan groups, respectively, vs 7.41 (4.08) for daily GH. Model-derived mean (SD) IGF-I SDS for the somapacitan groups was -1.62 (0.86), -1.09 (0.78), and 0.31 (1.06), respectively, vs -0.40 (1.50) observed for daily GH. Safety and tolerability were consistent with the profile of daily GH. CONCLUSIONS: In children with GHD, once-weekly somapacitan 0.16 mg/kg/week provided the closest efficacy match with similar safety and tolerability to daily GH after 26 and 52 weeks of treatment. A short visual summary of our work is available (1).