May 15, 2001 – Following research showing that an extract of parathyroid hormone (parathyroid hormone) doubles the normal rate of bone formation, pharmaceutical company Eli Lilly hopes its Forteo (trade name for teriparatide) will be available on the US market by the end of 2001. If so, it is likely to become one of the drugs of choice for women with moderate to severe osteoporosis.
Teriparatide is made up of 34 of the 84 amino acids normally found in parathyroid hormone. According to research carried out on 1,637 postmenopausal women who had already suffered at least one fracture due to osteoporosis, the drug reduced the risk of spine fractures by two-thirds (14% of new fractures in the placebo group compared with 5 and 4% in the experimental groups), and 50% the risk of other fractures (6% in the placebo group, 3% in the experimental groups). Forteo works by speeding up the formation of bone cells rather than slowing their loss like other medicines (such as Fosamax). The only difference, and it is significant, the Forteo must be injected daily, like insulin.
The drug exemplifies the potency of hormonal substances as the doses used in the study were 20 or 40 micrograms (millionths of a gram) per day. After 18 months, the women receiving the 40 microgram dose had 13% more bone material in the spine than the subjects receiving the placebo.
Normally, the parathyroid hormone secreted by the parathyroid glands regulates the presence of calcium in the body, either by speeding up or slowing the release of calcium from the bones. The fractions retained would therefore reverse the process.
The study was halted prematurely because another research, carried out in parallel on rats, showed that the animals developed bone cancer if they were given large doses of teriparide all their lives. However, the researchers concluded that the animal model did not suggest an increased risk of cancer in humans. This is because people with naturally high levels of parathyroid hormones do not have more bone cancer than others, and none of the women in this and previous studies developed cancer.
HealthPassport.net
Neer RM, Arnaud CD, Zanchetta JR, Prince R, Gaich GA, Reginster JY, Hodsman AB, Eriksen EF, Ish-Shalom S, Genant HK, Wang O. Effect of Parathyroid Hormone (1-34) on Fractures and Bone Mineral Density in Postmenopausal Women with Osteoporosis. N Engl J Med. 2001 May 10; 344 (19): 1434-1441.
