Study Investigating STA363 Compared to Placebo in Patients With Chronic Discogenic Low Back Pain

Inclusion Criteria: 1. Signed informed consent prior to any study related procedures. 2. Male and female patients ≥18 and ≤70 years. 3. Chronic discogenic low back pain present for more than 6 months prior to the screening visit. 4. Insufficient response or lack of response to at least 6 months of non-operative treatment (analgesics and/or anti-inflammatory medications \[paracetamol, non-steroidal anti-inflammatory agents (NSAIDs), opioids\], physiotherapy, rehabilitation therapy etc.). 5. Patients who meet all the following NRS selection criteria: 1. Presence of ≥5 pain NRS assessments (entries) for 7 consecutive days. 2. NRS daily pain scores between 3-9. 3. Not more than two ratings "3". 6. One or two treatable IVDs of Pfirrmann grade 2 to 3 on MRI at L2/3 to L5/S1 as confirmed by a central reader, AND the following criteria are met: 1. Treatable IVD(s) must be IVD(s) with the highest Pfirrmann grade observed in the patient (e.g. a patient with one IVD of grade 3 and four IVDs of grade 2 is considered eligible only if IVD of grade 3 will be injected). 2. Patients with treatable IVD(s) of grade 2 must have all other lumbar discs rated as grade 1. 3. Not more than two IVDs of grade 3 at any lumbar level. 4. No IVDs of grade 4 or 5 at any lumbar level. 7. Ability to understand the written and verbal information about the study. Exclusion Criteria: 1. Treatment with any investigational product within 3 months prior to the screening visit. 2. Patients with more than two painful IVDs. 3. A painful IVD above L2/3 level. 4. Current infection or prior history of spinal infection (e.g., discitis, septic arthritis, epidural abscess) or an active systemic infection. 5. Previous lumbar spine surgery. 6. Previous disc invasive treatment procedures at the affected level(s) (e.g., intradiscal electrothermal therapy, intradiscal radiofrequency thermocoagulation). 7. Evidence of prior lumbar vertebral body fracture or trauma. 8. Need for spinal decompression assessed by the Investigator. 9. Presence of IVD extrusion or sequestration, or other radiologic findings that in the opinion of the investigator disqualify the patient from being included. 10. Spondylolisthesis or retrolisthesis Grade 2 and above or spondylolysis at the index or adjacent level(s). 11. Lumbar spondylitis or other undifferentiated spondyloarthropathy affecting the index IVD. 12. Patients previously included in the study. 13. Patients suffering from psychosomatic pain in the opinion of the Investigator. 14. Leg pain of compressive origin. 15. Patients requiring continuous treatment with warfarin or other anticoagulant therapy. 16. History of significant neurologic or psychiatric disorders including dementia or seizures. 17. Known alcohol and/or drug abuse. 18. Severe intercurrent illness (e.g. rheumatic disease or chronic pain syndrome) or concomitant treatment (e.g. immunosuppressive drugs), which, in the opinion of the Investigator, may put the patient at risk when participating in the study, or affect the patient's ability to take part in the study. 19. Pregnant or lactating females, or intention to become pregnant within the study period. 20. Known allergy to any of the components of the drug product or placebo. 21. Known allergy or intolerance to the contrast agent Omnipaque®. 22. Known opioid allergy or intolerance. 23. Any other condition that, in the opinion of the Investigator, precludes the patient from taking part in this study. 24. Any specific contraindication for MRI such as claustrophobia, intracranial clips or pacemakers.