Positive results from PROLOR Biotech's hGH-CTP Phase II trial for growth hormone deficiency

May 7 2012

PROLOR Biotech, Inc. (NYSE Amex: PBTH) today reported top-line results from a Phase II four-month treatment extension study of hGH-CTP, its long-acting version of human growth hormone, in growth hormone deficient adults.  The data reaffirms the company's prior Phase II findings showing that a single weekly injection of hGH-CTP has the potential to replace seven consecutive daily injections of currently marketed human growth hormone (hGH), and further validates the dosing regimen for the company's planned Phase III trial.  In the Phase II clinical trial, hGH-CTP was administered to growth hormone deficient adults for a period of four weeks.

Design of the Phase II Four-Month Treatment Extension Study

The study enrolled 42 growth hormone deficient adults (34 males and 8 females) who were well titrated on daily growth hormone therapy and who had previously participated in the Phase II trial that tested a once-weekly hGH-CTP regimen or in the pilot assessment of a twice-monthly hGH-CTP regimen.  Participants received single weekly injections of hGH-CTP for a period of four months.  All patients received an initial dose containing 50% of the equivalent cumulative commercial hGH dose they would usually inject each day over the course of seven days.  Most of the patients (86%) entered the trial with insulin-like growth factor 1 (IGF-1) levels that were within the therapeutic range expected in a normal population (between -2.0 standard deviations and +2.0 standard deviations of the norm), and the remainder were outside, but close to, the normal range.  After switching the patients to single weekly injections of hGH-CTP, IGF-1 levels were monitored and dosing titration adjustments were considered once monthly.  If the patient's IGF-1 level, as measured on the 4th day of the prevailing week, was between -1.5 standard deviations and +1.5 standard deviations of the average IGF-1 level expected in a normal population stratified by age and gender (the "Narrow Normal Range"), then the patient's dose was not modified.  If the patient's IGF-1 level was below the Narrow Normal Range, the dose was increased by 33%, and if it was above the Narrow Normal Range the dose was decreased by 33%. The Narrow Normal Range is the range that treating endocrinologists typically aim to achieve during the process of optimizing dosing for their patients receiving human growth hormone therapy.

Phase II Four-Month Treatment Extension Study Top-Line Data Analysis

As shown in the table below, the study data demonstrates that the percent of patients receiving once-weekly injections of hGH-CTP who achieved IGF-1 levels within the normal range was comparable to the percent of daily-treated hGH patients who entered the study with IGF-1 levels within the normal range.  In addition, the data show that the percent of hGH-CTP patients who achieved IGF-1 levels within the Narrow Normal Range was higher than the percent of daily hGH patients who entered the study with IGF-1 levels within the Narrow Normal Range.

Preliminary analysis of the data confirmed the safety and tolerability of hGH-CTP, with no unexpected adverse events.  In addition, there was no indication that high doses of hGH-CTP can induce excessive levels of IGF-1 above the normal range.

Data from the Phase II four-month treatment extension study will be presented tomorrow at the Joint 15th International Congress of Endocrinology and 14th European Congress of Endocrinology in Florence, Italy.