The primary objective of the study is to assess the efficacy of Intravenous (IV) BG00010 (Neublastin) in improving pain in painful lumbar radiculopathy participants when administered 3 times per week for 1 week.

The secondary objectives of this study in this study population are as follows: To explore the duration of the effect of BG00010 in improving pain; To explore the dose response curve on pain reduction; To assess the safety and tolerability of BG00010; To assess the serum exposure to BG00010.

During the study, frequent assessment of allocation probability will be conducted to guide subsequent randomization of participants into dose groups.

Key Inclusion Criteria:

• Body weight ≤133 kg.
• Leg pain radiating, diagnosed as being due to painful lumbar radiculopathy or lumbosacral radiculopathy, the diagnosis of which occurred within ≥6 months and ≤5 years of the time of randomization.
• Objective, documented evidence of painful lumbar radiculopathy involvement
• Lower back pain
• Leg pain
• Male and female subjects of childbearing potential must practice effective contraception during the study and be willing and able to continue contraception for 3 months after their last dose of study treatment.

Key Exclusion Criteria:

• History of or positive test result at screening for human immunodeficiency virus, or for hepatitis C virus antibody, or current Hepatitis B infection.
• Clinically significant diseases or conditions as determined by the investigator.
• Major surgery within 30 days prior to the Screening Visit or that is scheduled to occur during the study.
• Previous participation in a study with neurotrophic factors (e.g., nerve growth factor).
• Participation in a study with another investigational drug or approved therapy for investigational use within 3 months prior to Day 1.
• Other unspecified reasons that, in the opinion of the Investigator or Biogen Idec Inc. (Biogen Idec), make the subject unsuitable for enrollment

NOTE: Other protocol-defined inclusion/exclusion criteria may apply