3-Week Parathyroid Hormone-related Protein (PTHrP) Dose Escalation Study in Post-Menopausal Women
3-Week Parathyroid Hormone-related Protein (PTHrP) Dose Escalation Study in Post-Menopausal Women
The main purpose of this study is to determine the safety and effectiveness of three week
 daily subcutaneous injections of Parathyroid Hormone-related Protein (1-36). Previous studies
 indicated that PTHrP has a skeletal 'anabolic' or bone-building effect, and has shown to
 increase bone mineral density in postmenopausal women with osteoporosis. Safety of PTHrP will
 be determined by measurements of blood pressure and pulse, serum blood calcium levels and
 subjective symptoms. Effectiveness will be measured by changes in measurements of blood and
 urine markers of bone turnover.
Parathyroid Hormone-related Protein (1-36) or PTHrP is a neuroendocrine peptide which shares
 significant homology with the only currently FDA approved anabolic agent for the treatment of
 osteoporosis: parathyroid hormone(1-34) or PTH. PTH, when given alone, has shown to increase
 lumbar spine bone mass by 12-15% over a 2-3 year period.

 Previous studies indicate PTHrP may have a pure anabolic effect on bone. Postmenopausal women
 taking estrogen with osteoporosis who received daily subcutaneous PTHrP for 3 months
 exhibited a 4.7% increase in bone mineral density compared to those taking placebo. There
 were no side effects associated with PTHrP, despite the fact that the doses given were 20
 times the usual doses of PTH. In another study, young healthy volunteers received a single,
 one-time subcutaneous doses of PTHrP in amounts up to 2 mg without any dose limiting
 toxicities.

 This study will directly compare the effect of placebo and escalating doses of PTHrP given
 subcutaneously to postmenopausal women for three weeks. Each subject will have four
 outpatient visits and one inpatient 24-hour visit on the last day. 20 women in phase I will
 receive either placebo or 500 micrograms/day of PTHrP. 500 micrograms/day was selected as the
 lowest dose because it is similar to the dose used in our previous 3 month placebo controlled
 study. In Phase II, the doses of PTHrP will be increased in increments of approximately 30%
 for each successive group, i.e., 750, 1000, 1250, and 1500 micrograms. After the first group
 of 10 successfully receives 500 micrograms/day for 21 days, increased doses will be given to
 groups of three subjects until evidence of dose limiting toxicity (DLT) occurs, or a maximum
 dose of 1,500 micrograms is reached. Dose limiting toxicities are specified in the protocol
 and comprise either one major criteria: hypotension, orthostatic hypotension, tachycardia,
 hypertension, hypercalcemia or hypophosphatemia; or two minor criteria: flushing,
 nausea/vomiting, abdominal or muscle cramps, dizziness/lightheadedness, palpitations, or any
 other unpleasant subjective symptom.

 If a particular dose of PTHrP causes a dose-limiting toxicity, the immediately preceding
 lower dose will be defined as the maximum safely tolerated dose. Once the maximum safely
 tolerated dose is determined, it will be given to a total of ten healthy subjects to ensure
 that is is safe and well tolerated.

 Study methods include outpatient visits on days 1, 5, 10, 15, and an in-patient visit on day
 21 for lab collection and patient examination. Blood and urine safety labs consist of serum
 ionized calcium, total calcium, creatinine, phosphorus and albumin. Efficacy labs consist of
 urine and blood measurements of 25-hydroxy vitamin D, 1,25 vitamin D, PTH, osteocalcin, bone
 specific alkaline phosphatase, procollagen peptide-1, C-telopeptide (CTx), N-telopeptide
 (NTx), Insulin-like growth factors (IgF) and serum free deoxypyridinoline (DPD).

 Subject population includes up to 48 healthy 50-75 year old postmenopausal women who are
 Caucasian, Asian, and Hispanic. African-Americans are excluded from the study since it is
 well documented that African-Americans have clear quantitative differences in bone density
 and sensitivity to parathyroid hormone. No bone densitometry scans are done during this
 study.
Inclusion Criteria:

 -  Women

 -  Caucasian

 -  Hispanic

 -  Asian

 -  One year past onset of menopause

 -  Weigh between 50 and 90 kilograms

 Exclusion Criteria:

 -  Taking bisphosphonates in the last 2 years

 -  Estrogen replacement hormones in last year

 -  SERMS in last year

 -  One weeks worth of PTHrP, PTH or an analog of PTH in past year

 -  Recent non-traumatic bone fracture within last year

 -  Significant uncontrolled cardiac, vascular, renal, pulmonary, endocrine or
 rheumatologic disease

 -  History of malignancy

 -  Anemia

 -  Significant alcohol or drug abuse

 -  Receiving any investigational drug within past 90 days

 -  Medications that interfere with metabolism or renal clearance of study drug, oral or
 systemic glucocorticoids of > 5 mg/day prednisone (or equivalent) over the past year

 -  Thiazide-type diuretics

 -  Abnormal screening labs (calcium, vit D and PTH, CBC)