A Phase 3 interventional study of SI-6603 and Sham injection in Lumbar Disc Herniation, sponsored by Seikagaku Corporation. Completed at 67 sites in United States. Open to participants aged 30 Years to 70 Years. Per ClinicalTrials.gov, last updated 2025-07-24.
Sponsored by Seikagaku Corporation · Phase 3, Interventional, and Treatment
This study is to evaluate the effectiveness of a single-dose intervertebral disc injection of SI-6603 in subjects with lumbar disc herniation (LDH)
474 studies on the registry are indexed under Intervertebral Disc Displacement; 100 are open to participants now.
This study's enrollment of 352 is above the median of 63 across 344 interventional studies indexed under Intervertebral Disc Displacement.
Browse Intervertebral Disc Displacement studies →Seikagaku Corporation is the lead sponsor of 13 studies on the registry; none are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Condoliase: 1.25U, intradiscal injection, one time For patients in the active treatment group, a volume of 1.0 mL was administered into the intervertebral disc in a single dose.
Drug: SI-6603
Sham injection For patients in the control group, a solution was not prepared and the needle was not placed in the intervertebral disc.
Drug: Sham injection
SI-6603 will be injected into an intervertebral disc.
The injection will be performed without needle placement into an intervertebral disc.
Change From Baseline to Week 13 in Average Worst Leg Pain Score During the Past 24 Hours Over the Previous 7 Days
The primary endpoint was the change from baseline to Week 13 in average worst leg pain score during the past 24 hours over the previous 7 days, as assessed by 100 mm Visual Analog Scale (VAS). VAS is a pain assessment tool with 0 mm representing an absence of pain, and 100 mm representing the worst pain patients have ever experienced.
Time frame: baseline and 13 weeks
Change From Baseline to Week 52 in Average Worst Leg Pain Score During the Past 24 Hours Over the Previous 7 Days
One of the key secondary endpoints was the change from baseline to Week 52 in average worst leg pain score during the past 24 hours over the previous 7 days, as assessed by 100 mm Visual Analog Scale (VAS). VAS is a pain assessment tool with 0 mm representing an absence of pain, and 100 mm representing the worst pain patients have ever experienced.
Time frame: baseline and 52 weeks
Change From Baseline to Week 13 in Herniation Volume
One of the key secondary endpoints was change from baseline to Week 13 in herniation volume. Herniation volumes were assessed with MRI by a central imaging facility.
Time frame: baseline and 13 weeks
Change From Baseline to Week 13 in Oswestry Disability Index (ODI) Score
One of the key secondary endpioints was change from baseline to Week 13 in Oswestry Disability Index (ODI) score. The ODI questionnaire is designed to provide information as to how the patient's back (or leg) pain affects their ability to manage in everyday life. A higher score on the ODI indicates a more severe disability. The final index score is calculated as a percentage, with 0% indicating no disability and 100% indicating highest disability.
Time frame: baseline and 13 weeks
Sixty sites screened at least 1 subject, and 41 of these sites enrolled at least 1 subject. The first participant was enrolled in November 2018 and the last participant was enrolled in March 2022.
| Milestone | SI-6603 | Sham |
|---|---|---|
| Started | 176 | 176 |
| Injected | 169 | 172 |
| Evaluated week 13 | 156 | 155 |
| Completed | 135 | 130 |
| Not completed | 41 | 46 |
| Withdrew: Lack of efficacy | 14 | 20 |
| Withdrew: Withdrawal by subject | 13 | 8 |
| Withdrew: Lost to follow-up | 6 | 11 |
| Withdrew: Adverse event | 2 | 2 |
| Withdrew: Physician decision | 2 | 0 |
| Withdrew: Failure to meet randomization criteria | 1 | 2 |
| Withdrew: Pregnancy | 1 | 0 |
| Withdrew: Protocol violation | 1 | 0 |
| Withdrew: Due to work | 1 | 0 |
| Withdrew: Litigation | 0 | 1 |
| Withdrew: Temperature excursion for study drug | 0 | 1 |
| Withdrew: Change of mind | 0 | 1 |
The primary endpoint was the change from baseline to Week 13 in average worst leg pain score during the past 24 hours over the previous 7 days, as assessed by 100 mm Visual Analog Scale (VAS). VAS is a pain assessment tool with 0 mm representing an absence of pain, and 100 mm representing the worst pain patients have ever experienced.
| units on a scale | SI-6603 | Sham |
|---|---|---|
| Change From Baseline to Week 13 in Average Worst Leg Pain Score During the Past 24 Hours Over the Previous 7 Days | -41.7 ± 2.38 | -34.2 ± 2.36 |
One of the key secondary endpoints was the change from baseline to Week 52 in average worst leg pain score during the past 24 hours over the previous 7 days, as assessed by 100 mm Visual Analog Scale (VAS). VAS is a pain assessment tool with 0 mm representing an absence of pain, and 100 mm representing the worst pain patients have ever experienced.
| units on a scale | SI-6603 | Sham |
|---|---|---|
| Change From Baseline to Week 52 in Average Worst Leg Pain Score During the Past 24 Hours Over the Previous 7 Days | -51.2 ± 2.40 | -44.7 ± 2.41 |
One of the key secondary endpoints was change from baseline to Week 13 in herniation volume. Herniation volumes were assessed with MRI by a central imaging facility.
| mm^3 | SI-6603 | Sham |
|---|---|---|
| Change From Baseline to Week 13 in Herniation Volume | -103.8 ± 10.74 | -78.1 ± 10.79 |
One of the key secondary endpioints was change from baseline to Week 13 in Oswestry Disability Index (ODI) score. The ODI questionnaire is designed to provide information as to how the patient's back (or leg) pain affects their ability to manage in everyday life. A higher score on the ODI indicates a more severe disability. The final index score is calculated as a percentage, with 0% indicating no disability and 100% indicating highest disability.
| percentage of disability | SI-6603 | Sham |
|---|---|---|
| Change From Baseline to Week 13 in Oswestry Disability Index (ODI) Score | -29.6 ± 1.38 | -25.4 ± 1.38 |
Collected over 52 weeks. Non-serious events are listed at a 5% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| SI-6603 | 1/167 (0.6%) | 7/167 (4.2%) | 91/167 (54.5%) |
| Sham | 0/174 (0%) | 6/174 (3.4%) | 62/174 (35.6%) |
| Event | SI-6603 | Sham |
|---|---|---|
| AppendicitisInfections and infestations | 0/167 | 2/174 |
| SciaticaNervous system disorders | 0/167 | 2/174 |
| Abdominal abscessInfections and infestations | 1/167 | 0/174 |
| COVID-19Infections and infestations | 1/167 | 0/174 |
| UrosepsisInfections and infestations | 1/167 | 0/174 |
| Diffuse large B-cell lymphomaNeoplasms benign, malignant and unspecified (incl cysts and polyps) | 1/167 | 0/174 |
| Metastases to spineNeoplasms benign, malignant and unspecified (incl cysts and polyps) | 1/167 | 0/174 |
| Intestinal obstructionGastrointestinal disorders | 1/167 | 0/174 |
| Back painMusculoskeletal and connective tissue disorders | 1/167 | 0/174 |
| Bladder perforationRenal and urinary disorders | 1/167 | 0/174 |
| Event | SI-6603 | Sham |
|---|---|---|
| Magnetic resonance imaging spinal abnormalInvestigations | 47/167 | 16/174 |
| Back painMusculoskeletal and connective tissue disorders | 32/167 | 22/174 |
| Pain in extremityMusculoskeletal and connective tissue disorders | 18/167 | 13/174 |
| COVID-19Infections and infestations | 11/167 | 17/174 |
| Spinal X-ray abnormalInvestigations | 13/167 | 3/174 |
| C-reactive protein increasedInvestigations | 10/167 | 6/174 |
| SciaticaMusculoskeletal and connective tissue disorders | 6/167 | 9/174 |
Modified intention-to-treat population
| Age, Continuous(years) | SI-6603 | Sham | Total |
|---|---|---|---|
| Mean | 46.8 ± 9.36 | 45.9 ± 9.84 | 46.3 ± 9.60 |
| Sex: Female, Male(Participants) | SI-6603 | Sham | Total |
|---|---|---|---|
| Female | 74 | 83 | 157 |
| Male | 95 | 89 | 184 |
| Ethnicity (NIH/OMB)(Participants) | SI-6603 | Sham | Total |
|---|---|---|---|
| Hispanic or Latino | 47 | 43 | 90 |
| Not Hispanic or Latino | 122 | 129 | 251 |
| Unknown or Not Reported | 0 | 0 | 0 |
| Race (NIH/OMB)(Participants) | SI-6603 | Sham | Total |
|---|---|---|---|
| American Indian or Alaska Native | 1 | 0 | 1 |
| Asian | 6 | 9 | 15 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 |
| Black or African American | 18 | 14 | 32 |
| White | 137 | 142 | 279 |
| More than one race | 1 | 2 | 3 |
| Unknown or Not Reported | 6 | 5 | 11 |
| Body Mass Index (BMI)(kilograms per square meter) | SI-6603 | Sham | Total |
|---|---|---|---|
| Mean | 29.0 ± 4.92 | 28.4 ± 4.86 | 28.7 ± 4.89 |
| Smoking History(Participants) | SI-6603 | Sham | Total |
|---|---|---|---|
| Never smoked | 106 | 103 | 209 |
| Past smoker | 34 | 36 | 70 |
| Current smoker | 29 | 33 | 62 |
| Occupation(Participants) | SI-6603 | Sham | Total |
|---|---|---|---|
| Heavy labor | 39 | 49 | 88 |
| Light labor | 130 | 123 | 253 |
| Days of Onset of Current Leg Pain(days) | SI-6603 | Sham | Total |
|---|---|---|---|
| Mean | 161.9 ± 83.57 | 172.2 ± 79.65 | 167.1 ± 81.66 |
4 further baseline measures are reported on the registry.
PDFs hosted by the registry, ClinicalTrials.gov.
This study is completed, as verified in Jul 2025. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Condoliase
Intervertebral Disc Displacement →
Seikagaku Corporation