Nasal spray formulation of teriparatide is in the works.
Intranasal parathyroid hormone (PTH1-34) demonstrated a similar absorption profile as the approved injectable product, Forteo, in a phase I, pharmacokinetics study, Dr. Gordon Brandt and colleagues reported in a poster at the annual meeting of the American Association of Clinical Endocrinologists.
Twelve healthy men and women, ages 20-40 years, received a 20-mcg injection of teriparatide on day 1, followed by single doses of the nasal spray on 4 subsequent days. Two nasal formulations of teriparatide were evaluated: Formulation No. 1 was given at 200 mcg and 400 mcg, and No. 2 at 500 mcg and 1,000 mcg. Blood samples were taken up to 4 hours post treatment.
The times of maximal drug concentration for teriparatide nasal spray and Forteo were not statistically different, reported Dr. Brandt, executive vice president, clinical research and medical affairs, Nastech Pharmaceutical Co., Bothell, Wash., which sponsored the study.
While Forteo achieves a 50-pg/mL peak blood level after subcutaneous administration, the tested doses of nasal spray delivered up to a 400-pg/mL peak blood level, Dr. Brandt said in an interview. "In this first-in-man study, we administered higher doses than are required, so in subsequent studies we will adjust the doses," he said.
Still, while the bioavailability of Forteo was 95%, that of nasal formulation No. 1 was only 5%-8%, and 12%-15% for No. 2.
Intersubject variability for the nasal sprays was similar to or lower than Forteo, suggesting that intranasal dosing may provide consistent dosing.
There was no nasal irritation with the nasal sprays. Interestingly, two patients developed hypercalcemia after the Forteo injection, whereas there were no reports of hypercalcemia with the nasal spray.
Procter & Gamble has signed an agreement with Nastech to further develop the nasal spray formulation, Dr. Brandt said. The U.S. Food and Drug Administration has put the nasal formulation on a 505(b)(2) regulatory path, which requires only a single noninferiority study of the nasal sprays versus Forteo. The timing of this study has not been announced.
In a separate poster at the meeting, cost and side effects were identified as barriers for patients considering teriparatide.
In a retrospective study of 84 patients who had received a recommendation for teriparatide for severe osteoporosis since 2004, 28 patients (33%) refused the drug primarily because of cost, concerns about subcutaneous injections, or anxiety surrounding the incidence of osteosarcomas in rat studies, Dr. Pauline Camacho and Laurie Bachrach, of Loyola University Health System, Chicago, reported. A 28-day supply of teriparatide averaged $96.50.
Of the 56 patients who tried teriparatide, only 34 took the drug for 1 year. At 1 year, the mean change in bone mineral density of the lumbar spine was 6.9%. Of the 52 patients who responded to a survey about side effects, 26 reported one or more, mostly lower extremity cramps or fatigue, dizziness, and transient elevation of ionized calcium levels.
Seven patients were nonresponders: One showed no change, and six showed decreases in bone mineral density of the lumbar spine. Three of the patients were later found to have underlying disease processes that explained the poor response. The remaining four claimed good compliance with the drug, Ms. Bachrach, a medical student at the university, said in an interview.
BY PATRICE WENDLING
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|Publication:||Family Practice News|
|Article Type:||Drug overview|
|Date:||Jul 15, 2006|
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