Phase 1 safety, tolerability, pharmacokinetics and pharmacodynamics results of a long-acting C-type natriuretic peptide prodrug, TransCon CNP.

AIM: TransCon CNP is a novel prodrug designed to provide sustained release of C-type natriuretic peptide (CNP) for once-weekly therapy, addressing the pathology leading to aberrant skeletal development in achondroplasia. This phase 1 trial was initiated to assess the safety, tolerability, pharmacodynamics (PD) and pharmacokinetics (PK) of TransCon CNP. METHODS: This randomized, placebo-controlled, single-ascending dose phase 1 trial was performed at two sites in Australia and enrolled 45 healthy adult males. Subjects received placebo or TransCon CNP (single-ascending dose cohorts [3, 10, 25, 75 or 150 µg CNP/kg]). The primary endpoint was frequency of adverse events and other safety outcomes. Other endpoints included PK and PD measured by cyclic guanosine-monophosphate (cGMP) and amino-terminal propeptide of CNP (NTproCNP). RESULTS: TransCon CNP provided continuous systemic exposure to CNP over at least 7 days post-dose. Plasma and urine levels of cGMP were significantly increased in subjects administered TransCon CNP at 75-150 µg CNP/kg, indicating target engagement of active CNP at the natriuretic peptide receptor-B (NPR-B) for at least 1 week post-dose. TransCon CNP was well-tolerated, with no serious treatment-emergent adverse events or discontinuations. Extensive cardiac safety assessments did not reveal any clinically relevant effects on electrocardiogram parameters, including heart rate, PR, QRS and QTcF intervals. CONCLUSIONS: Safety and PD data from this phase 1 trial support that TransCon CNP is well tolerated, with a PK profile compatible with a once-weekly dosing regimen. Further studies are ongoing to evaluate the potential of TransCon CNP to positively impact abnormal endochondral ossification in children with achondroplasia.

Weekly Lonapegsomatropin in Treatment-Naïve Children With Growth Hormone Deficiency: The Phase 3 heiGHt Trial.

CONTEXT: For children with growth hormone deficiency (GHD), treatment burden with daily somatropin injections [human growth hormone (hGH)] is high, which may lead to poor adherence and suboptimal overall treatment outcomes. Lonapegsomatropin (TransCon hGH) is an investigational long-acting, once-weekly prodrug for the treatment of GHD. OBJECTIVE: The objective of this study was to evaluate the efficacy and safety of once-weekly lonapegsomatropin vs daily somatropin. DESIGN: The heiGHt trial was a randomized, open-label, active-controlled, 52-week Phase 3 trial (NCT02781727). SETTING: This trial took place at 73 sites across 15 countries. PATIENTS: This trial enrolled and dosed 161 treatment-naïve, prepubertal patients with GHD. INTERVENTIONS: Patients were randomized 2:1 to receive lonapegsomatropin 0.24 mg hGH/kg/week or an equivalent weekly dose of somatropin delivered daily. MAIN OUTCOME MEASURE: The primary end point was annualized height velocity (AHV) at week 52. Secondary efficacy end points included change from baseline in height SD scores (SDS). RESULTS: Least squares (LS) mean (SE) AHV at 52 weeks was 11.2 (0.2) cm/year for lonapegsomatropin vs 10.3 (0.3) cm/year for daily somatropin (P = 0.009), with lonapegsomatropin demonstrating both noninferiority and superiority over daily somatropin. LS mean (SE) height SDS increased from baseline to week 52 by 1.10 (0.04) vs 0.96 (0.05) in the weekly lonapegsomatropin vs daily somatropin groups (P = 0.01). Bone age/chronological age ratio, adverse events, tolerability, and immunogenicity were similar between groups. CONCLUSIONS: The trial met its primary objective of noninferiority in AHV and further showed superiority of lonapegsomatropin compared to daily somatropin, with similar safety, in treatment-naïve children with GHD.

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

TransCon growth hormone (GH) is a sustained-release inactive prodrug consisting of unmodified GH transiently bound to an inert carrier molecule designed to release fully active GH over a one-week period. This was a first-in-man phase 1 randomized trial was to evaluate the safety, tolerability, immunogenicity, pharmacokinetics (PK), and pharmacodynamics (PD) of a single dose of TransCon GH as compared to equivalent doses of daily GH (Omnitrope) or placebo in healthy adults. Forty-four healthy male adults were randomized to 4 cohorts of 11 subjects, distributed in a 7:2:2 ratio (TransCon GH: Omnitrope: placebo). A single injection of 4 possible TransCon GH doses (i.e., 0.04, 0.08, 0.16, or 0.24mg GH/kg/wk) or two different Omnitrope doses (i.e., 0.08 or 0.16mg GH/kg/wk divided into 7 equal daily doses) were administered with subjects evaluated for adverse events, immunogenicity, and GH and insulin-like growth factor-1 (IGF-1) levels. TransCon GH was well tolerated; no serious adverse events occurred, no injection site reaction differences between TransCon GH, Omnitrope, or placebo were identified, no nodules or lipoatrophy were reported, and no anti-GH binding antibodies or ECG changes were detected. Overall, the exposure of GH (Cmax) and IGF-1 (AUC0-168h) following administration of equivalent doses of TransCon GH and Omnitrope were similar. GH and IGF-1 kinetics showed a dose-proportional increase following a single SC administration of TransCon GH and indicated that the prodrug is suitable for weekly administration. These results support advancement of TransCon GH to pediatric and adult GHD trials. Clinical trial registration numbers: NCT01010425 (clinicaltrials.gov).

A phase 2 trial of long-acting TransCon growth hormone in adult GH deficiency.

TransCon growth hormone is a sustained-release human growth hormone prodrug under development in which unmodified growth hormone is transiently linked to a carrier molecule. It is intended as an alternative to daily growth hormone in the treatment of growth hormone deficiency. This was a multi-center, randomized, open-label, active-controlled trial designed to compare the safety (including tolerability and immunogenicity), pharmacokinetics and pharmacodynamics of three doses of weekly TransCon GH to daily growth hormone (Omnitrope). Thirty-seven adult males and females diagnosed with adult growth hormone deficiency and stable on growth hormone replacement therapy for at least 3 months were, following a wash-out period, randomized (regardless of their pre-study dose) to one of three TransCon GH doses (0.02, 0.04 and 0.08 mg GH/kg/week) or Omnitrope 0.04 mg GH/kg/week (divided into 7 equal daily doses) for 4 weeks. Main outcomes evaluated were adverse events, immunogenicity and growth hormone and insulin-like growth factor 1 levels. TransCon GH was well tolerated; fatigue and headache were the most frequent drug-related adverse events and reported in all groups. No lipoatrophy or nodule formation was reported. No anti-growth hormone-binding antibodies were detected. TransCon GH demonstrated a linear, dose-dependent increase in growth hormone exposure without accumulation. Growth hormone maximum serum concentration and insulin-like growth factor 1 exposure were similar after TransCon GH or Omnitrope administered at comparable doses. The results suggest that long-acting TransCon GH has a profile similar to daily growth hormone but with a more convenient dosing regimen. These findings support further TransCon GH development.