Efficacy and Safety Study of Talimogene Laherparepvec Compared to Granulocyte Macrophage Colony Stimulating Factor (GM-CSF) in Melanoma

Inclusion Criteria:

* Males or females age ≥ 18 years
* Stage IIIb, IIIc or stage IV disease that is not surgically resectable
* Injectable disease (i.e. suitable for direct injection or through the use of ultrasound guidance)
* At least 1 injectable cutaneous, subcutaneous or nodal melanoma lesion \>= 10 mm in longest diameter or, multiple injectable melanoma lesions which in aggregate have a longest diameter of \>= 10 mm
* Serum lactate dehydrogenase (LDH) levels less than 1.5 x upper limit of normal (ULN)
* Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
* Prolongation in International Normalized Ratio (INR), Prothrombin Time (PT), and Partial Thromboplastin Time (PTT) when the result is from therapeutic anticoagulation treatment are permitted for patients whose injectable lesions are cutaneous and/or subcutaneous such that direct pressure could be applied in the event of excessive bleeding

Exclusion Criteria:

* Clinically active cerebral or any bone metastases. Patients with up to 3 (neurological performance status of 0) cerebral metastases may be enrolled, provided that all lesions have been adequately treated with stereotactic radiation therapy, craniotomy, gammaknife therapy, with no evidence of progression, and have not required steroids, for at least two (2) months prior to randomization
* Greater than 3 visceral metastases (this does not include lung metastases or nodal metastases associated with visceral organs). For patients with \< 3 visceral metastases, no lesion \> 3 cm, and liver lesions must meet Response Evaluation Criteria In Solid Tumors (RECIST) criteria for stable disease for at least 1 month prior to randomization