SAN FRANCISCO, Californai—A new patch that delivers parathyroid hormone (PTH) may increase bone mineral density (BMD) in the lumbar spine and hip among postmenopausal women with osteoporosis, without some of the compliance issues seen with subcutaneous daily injections of parathyroid hormone (Forteo^®, Eli Lilly and Co), according to Phase II data presented at the American College of Rheumatology (ACR) annual Scientific Meeting in San Francisco, California.¹ The new patch, hPTH (1-34) (zp-pth), is being developed by Zosano Pharma, Inc, in Fremont, California.

“The treatment of osteoporosis with an anabolic agent, rhPTH (1-34) delivered by subcutaneous daily injections is effective in reducing incident fractures, but lack of patient acceptance of daily injection might limit its use,” report the researchers, who were led by MSKreport advisory board member Nancy E. Lane, MD, director of the aging center at the University of California at Davis Medical Center in Sacramento. “Transdermal delivery of hPTH (1-34) may provide an alternative treatment option,” researchers add.

The patch outperformed placebo in increasing BMD at the lumbar spine at 24 weeks. Patients wore a 20-, 30-, or 40-mcg coated zp-pth patch or placebo for 30 minutes daily or received a 20 mcg injection of Forteo daily for 24 weeks The 40-mcg patch was similar to Forteo in producing lumbar spine BMD gains. The 40-mcg patch also increased total hip BMD (+1.33%), compared to placebo and Forteo (P <.05).

Moreover, bone turnover markers such as serum procollagen 1 N-terminal propeptide (PINP) and serum C-terminal cross-linking telopeptide of type I collagen (CTX) increased in a dose dependent manner among participants who wore the zp-pth patch and were all significantly different from placebo (P <.001), the study showed.

Overall, the treatments were well tolerated. There were few systemic serious adverse effects and no adverse effects that differed from Forteo. There was no sporadic or sustained hypercalcemia in any treatment group. Across the patch groups, patch-related topical adverse events were mild-to-moderate and transient. There were no reports of delayed type hypersensitivity or evidence of antibody formation to PTH in the patch-treated groups, the researchers report.

“Additional studies will further define the efficacy and safety of this novel transdermal delivery system,” they conclude.

Translating research into practice

“If this formulation works, it should be a great advantage, as daily shots can be an inconvenience for many patients,” said Ethel S. Siris, MD, the Madeline C. Stabile professor of clinical medicine and director of the Toni Stabile Osteoporosis Center at Columbia University Medical Center in New York City. “Anything that simplifies administration of a drug is typically a big help for patients.”

Reference

1. Lane NE, Cosman F, Bolognese M, et al. Transdermal delivery of hPTH (1-24) (zp-pth) is effective in increasing bone mineral density of the lumbar spine and hip in postmenopausal women with osteoporosis. Presented at: American College of Rheumatology 2008 Annual Scientific Meeting; October 24-29, 2008; San Francisco, Calif. Presentation L2.