The purpose of this study is to evaluate the efficacy and safety of SI-6603 (condoliase) in patients with lumbar disc herniation.

Inclusion Criteria:

• Patients with lumbar disc herniation (L4-L5 or L5-S1) as assessed by MRI and clinical symptoms corresponding to position of the impaired nerve root.
• Patients assessed as positive in the SLR test.
• Patients with sciatica in either leg.
• Patients with no improvement from conservative treatment

Exclusion Criteria:

• Patients who have 2 or more lumbar disc herniations as assessed by MRI.
• Patients in whom a rupture into the posterior longitudinal ligament is identified by MRI.
• Patients who have received spinal injection, epidural injection, nerve block within 3 weeks prior to the time of informed consent.
• Patients who have undergone lumbar operation, or lumbar percutaneous nucleotomy or lumbar intradiscal therapies