March 5, 2010 — The US Food and Drug Administration (FDA) has approved a prefilled somatropin (rDNA origin) injection pen (Norditropin FlexPro, Novo Nordisk, Inc) for the treatment of growth hormone disorders in adult and pediatric patients. The product, an updated version of the company's NordiFlex pen introduced in 2004, is expected to be available in the second quarter of 2010.
According to a company news release, the pen was designed to facilitate use by pediatric patients. Advantages include a user-friendly design that makes it easy to learn and use, and an audible click that confirms each dose dispensed; no drug reconstitution or loading of cartridges is needed. Once started, the 5-, 10-, and 15-mg/mL pens may be left at room temperature for up to 3 weeks without spoiling.
In a usability study, 100% of patients found the device easy to master, and 99% of patients responded that they found it easy to push the dose button and administer the subcutaneous injection, respectively.
"Easy to use, growth hormone delivery devices allow patients and health care professionals alike to benefit from the convenience of these pens," noted Pinchas Cohen, MD, professor of pediatrics at the David Geffen School of Medicine at the University of California–Los Angeles and chief of endocrinology at the Mattel Children's Hospital at the University of California–Los Angeles in the news release.
Pediatric indications for recombinant somatropin (Norditropin) include the long-term treatment of growth failure resulting from growth hormone deficiency, short stature associated with Noonan and Turner syndromes, and short stature in small-for-gestational-age children with no catch-up growth by age 2 to 4 years. It also may be used to treat adults with adult- or childhood-onset growth hormone deficiency.
Somatropin therapy is contraindicated in patients with acute critical illness following open-heart surgery, abdominal surgery, or multiple accidental traumas; acute respiratory failure; active malignancy; diabetic retinopathy; hypersensitivity to any product components; and children with Prader-Willi syndrome who are severely obese, have sleep apnea, or have severe respiratory impairment.
Adverse effects most commonly reported with somatropin therapy include headaches, myalgia, joint stiffness, hyperglycemia, glucosuria, peripheral edema, injection-site reactions/rashes, and lipoatrophy.
Other potential adverse events may include impaired glucose tolerance and unmasking of diabetes mellitus; intracranial hypertension; new-onset or worsening hypothyroidism; and slipped capital femoral epiphysis and progression of existing scoliosis in children. Somatropin also increases the risk for otitis media in children with Turner syndrome.
Patients with Noonan or Turner syndrome should be closely monitored because of an increased risk for congenital heart disease.
Clinicians should be aware of patients taking glucocorticoid medication, thyroid hormones, insulin or other antidiabetic medications, oral estrogen replacement therapy, or drugs that undergo hepatic metabolism such as corticosteroids, sex steroids, anticonvulsants, and cyclosporine.
