FDA Approves New Drug For Osteoporosis
(Rockville MD, 11/26/02): The Food and Drug Administration (FDA) has approved
teriparatide (Forteo™) for the treatment of osteoporosis in postmenopausal
women who are at high risk for having a fracture. This is the first FDA approved
medicine to treat osteoporosis by causing the body to form new, healthy bone
tissue.
Marketed by Eli Lilly, Forteo works by stimulating osteoblasts, the body's
bone-building cells, to form new bone. Active osteoblasts increase bone density
and its resistance to fractures. Osteoclasts, on the other hand, are the cells
responsible for bone resorption. Most medicines previously available to treat
osteoporosis worked by decreasing osteoclast activity.
An estimated 10 million Americans - 80 percent of them women - suffer from
osteoporosis, a progressive thinning of bones that may lead to an increased
risk of spine, wrist, and hip fractures. According to Judith Cranford, Executive
Director of the National Osteoporosis Foundation, "With an estimated 44 million
American men and women at risk for osteoporosis or low bone mass, the
need for new treatments will grow as the population ages. The fact that this
treatment actually builds bone opens new opportunities for treating this debilitating
disease." She added that - "Fortéo®. . .offers a new choice of therapy
for women and men suffering from osteoporosis and, given the large prevalence
of osteoporosis and low bone mass in the nation, NOF applauds the development
of new treatments that can help reduce the risk of fracture."
Teriparatide (Forteo) is a portion of human parathyroid hormone (PTH), which
is the primary regulator of calcium and phosphate metabolism in bones. Daily
injections of teriparatide stimulate new bone formation leading to increased
bone mineral density. Forteo is administered by injection once a day in the
thigh or abdomen. The recommended dose is 20 mcg per day.
In addition to being approved to treat osteoporosis
in women, Forteo is also approved to increase bone mass in men with primary
or hypogonadal osteoporosis who are at high risk for fracture.
Drugs approved to treat osteoporosis must be shown
to preserve or increase bone density and maintain bone quality. The effects
of teriparatide on bone mineral density and fractures were studied in 1,637
postmenopausal women with osteoporosis who were treated for a median time of
19-months and 437 men with primary or hypogonadal osteoporosis who were treated
for ten months. Patients treated with 20 mcg of teriparatide per day, along
with calcium and vitamin D supplementation, had statistically significant increases
in bone mineral density (BMD) at the spine and hip when compared to patients
taking only calcium and vitamin D supplementation. Clinical trials also demonstrated
that teriparatide reduced the risk of vertebral and non-vertebral fractures
in postmenopausal women. The effects of teriparatide on fracture risk have not
been studied in men.
In animal studies with teriparatide, there was an
increase in the number of rats developing osteosarcoma, a rare but serious cancer
of the bone. In the human studies, no osteosarcomas were reported, but the possibility
that humans treated with teriparatide may face an increased risk of developing
this cancer cannot be ruled out. This safety issue is highlighted in a black
box warning in Forteo's label for health professionals and explained in a medication
guide for patients, which will be distributed by the pharmacist each time Forteo
is dispensed. Because people with growing bones (i.e., children and adolescents)
and people with Paget's disease of the bone have a higher risk for developing
osteosarcoma, they should not be treated with teriparatide.
Persons with hypercalcemia, women who are pregnant
or nursing, or persons who have ever been diagnosed with bone cancer or other
cancers that have spread to the bones, should not use teriparatide. Because
the effects of long-term treatment with teriparatide are not known at this time,
therapy for more than 2 years is not recommended.
Most side effects reported in association with teriparatide
in clinical trials were mild and included nausea, dizziness, and leg cramps.
During the clinical trials, early discontinuation due to adverse events occurred
in 5.6% of patients assigned to placebo and 7.1% of patients taking teriparatide.
Teriparatide is manufactured by Eli Lilly and Company of Indianapolis, Ind.,
and will be marketed under the trade name Forteo.
Created: 11/26/2002 - Donnica Moore, M.D.
