Main Study was completed. LT-OLE was discontinued as sufficient safety data has been generated.

This will be a randomized, double-blind, placebo-controlled, parallel-group, multicenter study in adult subjects with GHD to assess the safety and efficacy of a long-acting, once weekly injection of modified hGH (MOD-4023).

Inclusion Criteria:

• Men and women between the age of 23 to 70 years old at screening, inclusive
• GHD subjects as defined in the Consensus guidelines for the diagnosis and treatment of adults with GH deficiency II (2007).
• No r-hGH replacement therapy or use of GH secretagogues for at least 9 months with any registered or investigational r-hGH or GH secretagogue product.
• The IGF-I level at screening ≤-1 SDS of the age and sex normal ranges according to the central laboratory measurements
• Subjects who are on a stable diet and exercise regime and do not have plans to modify their diet or exercise for at least 12 months
• Subject had a DXA screening and the results are interpretable according to the study plan.

Exclusion Criteria:

• Women who are pregnant or breast-feeding (at least 6 months delay from childbirth or lactation)
• Evidence of growth benign intracranial tumor within the last 12 months (determined by comparing a previous MRI to a new one obtained no more than 6 months prior to study entry to clarify dynamics of growth).
• History of any cancer. Exceptions to this exclusion criterion include resected in situ carcinoma of the cervix and squamous cell or basal cell carcinoma of the skin with complete local excision. Patients with GHD attributed to treatment of intracranial malignant lesions in childhood or adulthood (or, tumors) or leukemia may also be enrolled into the study provided that a recurrence-free survival period of at least 5 years is well documented in the study record.
• Signs of intracranial hypertension at screening
• Heart insufficiency, NYHA class > 2 (Appendix B)
• History of overt diabetes mellitus (including currently treated, well-controlled DM) defined according to the American Diabetes Association (ADA) Criteriaa. A history of gestational diabetes, resolved after childbirth, is not exclusionary.
• History of Acromegaly

202 subjects met the study's eligibility criteria and were randomized to either MOD-4023 or placebo. Only 198 subjects actually treated and included in the efficacy analysis.

These events were collected throughout the duration of the study and cumulative to weeks Period 1, Baseline to 26 weeks Period 2, 26 - 52 weeks Period 3, >52 weeks to end of study up to 2 years

AEs collected and reported for each period of the study. Period 1, Baseline to 26 weeks Period 2, 26 - 52 weeks Period 3, >52 weeks to end of study