The US Food and Drug Administration (FDA) has approved somapacitan (Sogroya, Novo Nordisk) for the replacement of endogenous growth hormone in adults with growth hormone deficiency (GHD).
Somapacitan is a human growth hormone analog. It is administered via subcutaneous injection 10 mg/1.5 mL (6.7 mg/mL) once weekly, and will be the first such product that can be administered weekly as opposed to by daily injections.
Adult GHD is a rare disorder of inadequate growth hormone secretion by the pituitary gland. It can be hereditary or acquired because of trauma, infection, radiation therapy, or brain tumor growth. GHD can also develop without a diagnosable cause.
More than 50,000 adults in the United States are estimated to have GHD, and about 6000 new patients are diagnosed each year.
The FDA approved once-weekly somapacitan for adult GHD based on a comprehensive clinical program, including the REAL 1 study, a double-blind, placebo-controlled trial involving 300 treatment-naive adults with GHD.
A total of 120 patients received once-weekly somapacitan 10 mg/1.5 mL, 60 patients received placebo, and 119 patients received daily somatropin (Norditropin FlexPro, Novo Nordisk) for 34 weeks.
Treatment with somapacitan was superior to placebo in reducing truncal fat percentage, as assessed by dual X-ray absorptiometry, after 34 weeks (–1.06% vs +0.47%).
Patients treated with daily somatropin achieved a change in truncal fat of –2.23% after 34 weeks.
Somapacitan has been shown to normalize mean insulin-like growth factor-1 (IGF-1) standard deviation score from a baseline value below –2 to within the reference range (–2 to +2) in treatment-naive adults with GHD.
Adverse reactions reported in ≥ 2% of patients treated with somapacitan were back pain, arthralgia, dyspepsia, sleep disorder, dizziness, tonsillitis, peripheral edema, vomiting, adrenal insufficiency, hypertension, blood creatine phosphokinase increase, weight increase, and anemia.
Somapacitan is contraindicated in adults with acute critical illness, active malignancy, active proliferative or severe nonproliferative diabetic retinopathy, and those with hypersensitivity to somapacitan or excipients. It is not known if somapacitan is safe and effective in children.
Full prescribing information is available online.
Novo Nordisk said it is currently finalizing plans for when somapacitan will be available.
Whether (or how) US insurance companies cover or reimburse the new weekly growth hormone might be key to its uptake, as detailed previously by Medscape Medical News.
Pfizer and OPKO Health are also developing a once-weekly human growth hormone, somatrogon, which has recently completed phase 3 trials as a treatment for growth hormone deficiency in children and adults.
And Versartis is developing a similar product, called somavaratan, which is in Phase 2 trials for adults and Phase 3 trials for children.